OSCL-LXR linux-6.0.1/​drivers/​gpio/​gpiolib.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/bitmap.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/spinlock.h>
 #include <linux/list.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/gpio.h>
 #include <linux/idr.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
 #include <linux/gpio/driver.h>
 #include <linux/gpio/machine.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/fs.h>
 #include <linux/compat.h>
 #include <linux/file.h>
 #include <uapi/linux/gpio.h>
 
 #include "gpiolib.h"
 #include "gpiolib-of.h"
 #include "gpiolib-acpi.h"
 #include "gpiolib-cdev.h"
 #include "gpiolib-sysfs.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/gpio.h>
 
 /* Implementation infrastructure for GPIO interfaces.
  *
  * The GPIO programming interface allows for inlining speed-critical
  * get/set operations for common cases, so that access to SOC-integrated
  * GPIOs can sometimes cost only an instruction or two per bit.
  */
 
 
 /* When debugging, extend minimal trust to callers and platform code.
  * Also emit diagnostic messages that may help initial bringup, when
  * board setup or driver bugs are most common.
  *
  * Otherwise, minimize overhead in what may be bitbanging codepaths.
  */
 #ifdef  DEBUG
 #define extra_checks    1
 #else
 #define extra_checks    0
 #endif
 
 /* Device and char device-related information */
 static DEFINE_IDA(gpio_ida);
 static dev_t gpio_devt;
 #define GPIO_DEV_MAX 256 /* 256 GPIO chip devices supported */
 static int gpio_bus_match(struct device *dev, struct device_driver *drv);
 static struct bus_type gpio_bus_type = {
     .name = "gpio",
     .match = gpio_bus_match,
 };
 
 /*
  * Number of GPIOs to use for the fast path in set array
  */
 #define FASTPATH_NGPIO CONFIG_GPIOLIB_FASTPATH_LIMIT
 
 /* gpio_lock prevents conflicts during gpio_desc[] table updates.
  * While any GPIO is requested, its gpio_chip is not removable;
  * each GPIO's "requested" flag serves as a lock and refcount.
  */
 DEFINE_SPINLOCK(gpio_lock);
 
 static DEFINE_MUTEX(gpio_lookup_lock);
 static LIST_HEAD(gpio_lookup_list);
 LIST_HEAD(gpio_devices);
 
 static DEFINE_MUTEX(gpio_machine_hogs_mutex);
 static LIST_HEAD(gpio_machine_hogs);
 
 static void gpiochip_free_hogs(struct gpio_chip *gc);
 static int gpiochip_add_irqchip(struct gpio_chip *gc,
                 struct lock_class_key *lock_key,
                 struct lock_class_key *request_key);
 static void gpiochip_irqchip_remove(struct gpio_chip *gc);
 static int gpiochip_irqchip_init_hw(struct gpio_chip *gc);
 static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gc);
 static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc);
 
 static bool gpiolib_initialized;
 
 static inline void desc_set_label(struct gpio_desc *d, const char *label)
 {
     d->label = label;
 }
 
 /**
  * gpio_to_desc - Convert a GPIO number to its descriptor
  * @gpio: global GPIO number
  *
  * Returns:
  * The GPIO descriptor associated with the given GPIO, or %NULL if no GPIO
  * with the given number exists in the system.
  */
 struct gpio_desc *gpio_to_desc(unsigned gpio)
 {
     struct gpio_device *gdev;
     unsigned long flags;
 
     spin_lock_irqsave(&gpio_lock, flags);
 
     list_for_each_entry(gdev, &gpio_devices, list) {
         if (gdev->base <= gpio &&
             gdev->base + gdev->ngpio > gpio) {
             spin_unlock_irqrestore(&gpio_lock, flags);
             return &gdev->descs[gpio - gdev->base];
         }
     }
 
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     if (!gpio_is_valid(gpio))
         pr_warn("invalid GPIO %d\n", gpio);
 
     return NULL;
 }
 EXPORT_SYMBOL_GPL(gpio_to_desc);
 
 /**
  * gpiochip_get_desc - get the GPIO descriptor corresponding to the given
  *                     hardware number for this chip
  * @gc: GPIO chip
  * @hwnum: hardware number of the GPIO for this chip
  *
  * Returns:
  * A pointer to the GPIO descriptor or ``ERR_PTR(-EINVAL)`` if no GPIO exists
  * in the given chip for the specified hardware number.
  */
 struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc,
                     unsigned int hwnum)
 {
     struct gpio_device *gdev = gc->gpiodev;
 
     if (hwnum >= gdev->ngpio)
         return ERR_PTR(-EINVAL);
 
     return &gdev->descs[hwnum];
 }
 EXPORT_SYMBOL_GPL(gpiochip_get_desc);
 
 /**
  * desc_to_gpio - convert a GPIO descriptor to the integer namespace
  * @desc: GPIO descriptor
  *
  * This should disappear in the future but is needed since we still
  * use GPIO numbers for error messages and sysfs nodes.
  *
  * Returns:
  * The global GPIO number for the GPIO specified by its descriptor.
  */
 int desc_to_gpio(const struct gpio_desc *desc)
 {
     return desc->gdev->base + (desc - &desc->gdev->descs[0]);
 }
 EXPORT_SYMBOL_GPL(desc_to_gpio);
 
 
 /**
  * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
  * @desc:   descriptor to return the chip of
  */
 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 {
     if (!desc || !desc->gdev)
         return NULL;
     return desc->gdev->chip;
 }
 EXPORT_SYMBOL_GPL(gpiod_to_chip);
 
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
 static int gpiochip_find_base(int ngpio)
 {
     struct gpio_device *gdev;
     int base = ARCH_NR_GPIOS - ngpio;
 
     list_for_each_entry_reverse(gdev, &gpio_devices, list) {
         /* found a free space? */
         if (gdev->base + gdev->ngpio <= base)
             break;
         /* nope, check the space right before the chip */
         base = gdev->base - ngpio;
     }
 
     if (gpio_is_valid(base)) {
         pr_debug("%s: found new base at %d\n", __func__, base);
         return base;
     } else {
         pr_err("%s: cannot find free range\n", __func__);
         return -ENOSPC;
     }
 }
 
 /**
  * gpiod_get_direction - return the current direction of a GPIO
  * @desc:   GPIO to get the direction of
  *
  * Returns 0 for output, 1 for input, or an error code in case of error.
  *
  * This function may sleep if gpiod_cansleep() is true.
  */
 int gpiod_get_direction(struct gpio_desc *desc)
 {
     struct gpio_chip *gc;
     unsigned int offset;
     int ret;
 
     gc = gpiod_to_chip(desc);
     offset = gpio_chip_hwgpio(desc);
 
     /*
      * Open drain emulation using input mode may incorrectly report
      * input here, fix that up.
      */
     if (test_bit(FLAG_OPEN_DRAIN, &desc->flags) &&
         test_bit(FLAG_IS_OUT, &desc->flags))
         return 0;
 
     if (!gc->get_direction)
         return -ENOTSUPP;
 
     ret = gc->get_direction(gc, offset);
     if (ret < 0)
         return ret;
 
     /* GPIOF_DIR_IN or other positive, otherwise GPIOF_DIR_OUT */
     if (ret > 0)
         ret = 1;
 
     assign_bit(FLAG_IS_OUT, &desc->flags, !ret);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(gpiod_get_direction);
 
 /*
  * Add a new chip to the global chips list, keeping the list of chips sorted
  * by range(means [base, base + ngpio - 1]) order.
  *
  * Return -EBUSY if the new chip overlaps with some other chip's integer
  * space.
  */
 static int gpiodev_add_to_list(struct gpio_device *gdev)
 {
     struct gpio_device *prev, *next;
 
     if (list_empty(&gpio_devices)) {
         /* initial entry in list */
         list_add_tail(&gdev->list, &gpio_devices);
         return 0;
     }
 
     next = list_first_entry(&gpio_devices, struct gpio_device, list);
     if (gdev->base + gdev->ngpio <= next->base) {
         /* add before first entry */
         list_add(&gdev->list, &gpio_devices);
         return 0;
     }
 
     prev = list_last_entry(&gpio_devices, struct gpio_device, list);
     if (prev->base + prev->ngpio <= gdev->base) {
         /* add behind last entry */
         list_add_tail(&gdev->list, &gpio_devices);
         return 0;
     }
 
     list_for_each_entry_safe(prev, next, &gpio_devices, list) {
         /* at the end of the list */
         if (&next->list == &gpio_devices)
             break;
 
         /* add between prev and next */
         if (prev->base + prev->ngpio <= gdev->base
                 && gdev->base + gdev->ngpio <= next->base) {
             list_add(&gdev->list, &prev->list);
             return 0;
         }
     }
 
     return -EBUSY;
 }
 
 /*
  * Convert a GPIO name to its descriptor
  * Note that there is no guarantee that GPIO names are globally unique!
  * Hence this function will return, if it exists, a reference to the first GPIO
  * line found that matches the given name.
  */
 static struct gpio_desc *gpio_name_to_desc(const char * const name)
 {
     struct gpio_device *gdev;
     unsigned long flags;
 
     if (!name)
         return NULL;
 
     spin_lock_irqsave(&gpio_lock, flags);
 
     list_for_each_entry(gdev, &gpio_devices, list) {
         struct gpio_desc *desc;
 
         for_each_gpio_desc(gdev->chip, desc) {
             if (desc->name && !strcmp(desc->name, name)) {
                 spin_unlock_irqrestore(&gpio_lock, flags);
                 return desc;
             }
         }
     }
 
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     return NULL;
 }
 
 /*
  * Take the names from gc->names and assign them to their GPIO descriptors.
  * Warn if a name is already used for a GPIO line on a different GPIO chip.
  *
  * Note that:
  *   1. Non-unique names are still accepted,
  *   2. Name collisions within the same GPIO chip are not reported.
  */
 static int gpiochip_set_desc_names(struct gpio_chip *gc)
 {
     struct gpio_device *gdev = gc->gpiodev;
     int i;
 
     /* First check all names if they are unique */
     for (i = 0; i != gc->ngpio; ++i) {
         struct gpio_desc *gpio;
 
         gpio = gpio_name_to_desc(gc->names[i]);
         if (gpio)
             dev_warn(&gdev->dev,
                  "Detected name collision for GPIO name '%s'\n",
                  gc->names[i]);
     }
 
     /* Then add all names to the GPIO descriptors */
     for (i = 0; i != gc->ngpio; ++i)
         gdev->descs[i].name = gc->names[i];
 
     return 0;
 }
 
 /*
  * devprop_gpiochip_set_names - Set GPIO line names using device properties
  * @chip: GPIO chip whose lines should be named, if possible
  *
  * Looks for device property "gpio-line-names" and if it exists assigns
  * GPIO line names for the chip. The memory allocated for the assigned
  * names belong to the underlying firmware node and should not be released
  * by the caller.
  */
 static int devprop_gpiochip_set_names(struct gpio_chip *chip)
 {
     struct gpio_device *gdev = chip->gpiodev;
     struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
     const char **names;
     int ret, i;
     int count;
 
     count = fwnode_property_string_array_count(fwnode, "gpio-line-names");
     if (count < 0)
         return 0;
 
     /*
      * When offset is set in the driver side we assume the driver internally
      * is using more than one gpiochip per the same device. We have to stop
      * setting friendly names if the specified ones with 'gpio-line-names'
      * are less than the offset in the device itself. This means all the
      * lines are not present for every single pin within all the internal
      * gpiochips.
      */
     if (count <= chip->offset) {
         dev_warn(&gdev->dev, "gpio-line-names too short (length %d), cannot map names for the gpiochip at offset %u\n",
              count, chip->offset);
         return 0;
     }
 
     names = kcalloc(count, sizeof(*names), GFP_KERNEL);
     if (!names)
         return -ENOMEM;
 
     ret = fwnode_property_read_string_array(fwnode, "gpio-line-names",
                         names, count);
     if (ret < 0) {
         dev_warn(&gdev->dev, "failed to read GPIO line names\n");
         kfree(names);
         return ret;
     }
 
     /*
      * When more that one gpiochip per device is used, 'count' can
      * contain at most number gpiochips x chip->ngpio. We have to
      * correctly distribute all defined lines taking into account
      * chip->offset as starting point from where we will assign
      * the names to pins from the 'names' array. Since property
      * 'gpio-line-names' cannot contains gaps, we have to be sure
      * we only assign those pins that really exists since chip->ngpio
      * can be different of the chip->offset.
      */
     count = (count > chip->offset) ? count - chip->offset : count;
     if (count > chip->ngpio)
         count = chip->ngpio;
 
     for (i = 0; i < count; i++) {
         /*
          * Allow overriding "fixed" names provided by the GPIO
          * provider. The "fixed" names are more often than not
          * generic and less informative than the names given in
          * device properties.
          */
         if (names[chip->offset + i] && names[chip->offset + i][0])
             gdev->descs[i].name = names[chip->offset + i];
     }
 
     kfree(names);
 
     return 0;
 }
 
 static unsigned long *gpiochip_allocate_mask(struct gpio_chip *gc)
 {
     unsigned long *p;
 
     p = bitmap_alloc(gc->ngpio, GFP_KERNEL);
     if (!p)
         return NULL;
 
     /* Assume by default all GPIOs are valid */
     bitmap_fill(p, gc->ngpio);
 
     return p;
 }
 
 static int gpiochip_alloc_valid_mask(struct gpio_chip *gc)
 {
     if (!(of_gpio_need_valid_mask(gc) || gc->init_valid_mask))
         return 0;
 
     gc->valid_mask = gpiochip_allocate_mask(gc);
     if (!gc->valid_mask)
         return -ENOMEM;
 
     return 0;
 }
 
 static int gpiochip_init_valid_mask(struct gpio_chip *gc)
 {
     if (gc->init_valid_mask)
         return gc->init_valid_mask(gc,
                        gc->valid_mask,
                        gc->ngpio);
 
     return 0;
 }
 
 static void gpiochip_free_valid_mask(struct gpio_chip *gc)
 {
     bitmap_free(gc->valid_mask);
     gc->valid_mask = NULL;
 }
 
 static int gpiochip_add_pin_ranges(struct gpio_chip *gc)
 {
     if (gc->add_pin_ranges)
         return gc->add_pin_ranges(gc);
 
     return 0;
 }
 
 bool gpiochip_line_is_valid(const struct gpio_chip *gc,
                 unsigned int offset)
 {
     /* No mask means all valid */
     if (likely(!gc->valid_mask))
         return true;
     return test_bit(offset, gc->valid_mask);
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
 
 static void gpiodevice_release(struct device *dev)
 {
     struct gpio_device *gdev = container_of(dev, struct gpio_device, dev);
     unsigned long flags;
 
     spin_lock_irqsave(&gpio_lock, flags);
     list_del(&gdev->list);
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     ida_free(&gpio_ida, gdev->id);
     kfree_const(gdev->label);
     kfree(gdev->descs);
     kfree(gdev);
 }
 
 #ifdef CONFIG_GPIO_CDEV
 #define gcdev_register(gdev, devt)  gpiolib_cdev_register((gdev), (devt))
 #define gcdev_unregister(gdev)      gpiolib_cdev_unregister((gdev))
 #else
 /*
  * gpiolib_cdev_register() indirectly calls device_add(), which is still
  * required even when cdev is not selected.
  */
 #define gcdev_register(gdev, devt)  device_add(&(gdev)->dev)
 #define gcdev_unregister(gdev)      device_del(&(gdev)->dev)
 #endif
 
 static int gpiochip_setup_dev(struct gpio_device *gdev)
 {
     int ret;
 
     ret = gcdev_register(gdev, gpio_devt);
     if (ret)
         return ret;
 
     ret = gpiochip_sysfs_register(gdev);
     if (ret)
         goto err_remove_device;
 
     /* From this point, the .release() function cleans up gpio_device */
     gdev->dev.release = gpiodevice_release;
     dev_dbg(&gdev->dev, "registered GPIOs %d to %d on %s\n", gdev->base,
         gdev->base + gdev->ngpio - 1, gdev->chip->label ? : "generic");
 
     return 0;
 
 err_remove_device:
     gcdev_unregister(gdev);
     return ret;
 }
 
 static void gpiochip_machine_hog(struct gpio_chip *gc, struct gpiod_hog *hog)
 {
     struct gpio_desc *desc;
     int rv;
 
     desc = gpiochip_get_desc(gc, hog->chip_hwnum);
     if (IS_ERR(desc)) {
         chip_err(gc, "%s: unable to get GPIO desc: %ld\n", __func__,
              PTR_ERR(desc));
         return;
     }
 
     if (test_bit(FLAG_IS_HOGGED, &desc->flags))
         return;
 
     rv = gpiod_hog(desc, hog->line_name, hog->lflags, hog->dflags);
     if (rv)
         gpiod_err(desc, "%s: unable to hog GPIO line (%s:%u): %d\n",
               __func__, gc->label, hog->chip_hwnum, rv);
 }
 
 static void machine_gpiochip_add(struct gpio_chip *gc)
 {
     struct gpiod_hog *hog;
 
     mutex_lock(&gpio_machine_hogs_mutex);
 
     list_for_each_entry(hog, &gpio_machine_hogs, list) {
         if (!strcmp(gc->label, hog->chip_label))
             gpiochip_machine_hog(gc, hog);
     }
 
     mutex_unlock(&gpio_machine_hogs_mutex);
 }
 
 static void gpiochip_setup_devs(void)
 {
     struct gpio_device *gdev;
     int ret;
 
     list_for_each_entry(gdev, &gpio_devices, list) {
         ret = gpiochip_setup_dev(gdev);
         if (ret)
             dev_err(&gdev->dev,
                 "Failed to initialize gpio device (%d)\n", ret);
     }
 }
 
 int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
                    struct lock_class_key *lock_key,
                    struct lock_class_key *request_key)
 {
     struct fwnode_handle *fwnode = NULL;
     struct gpio_device *gdev;
     unsigned long flags;
     int base = gc->base;
     unsigned int i;
     int ret = 0;
     u32 ngpios;
 
     if (gc->fwnode)
         fwnode = gc->fwnode;
     else if (gc->parent)
         fwnode = dev_fwnode(gc->parent);
 
     /*
      * First: allocate and populate the internal stat container, and
      * set up the struct device.
      */
     gdev = kzalloc(sizeof(*gdev), GFP_KERNEL);
     if (!gdev)
         return -ENOMEM;
     gdev->dev.bus = &gpio_bus_type;
     gdev->dev.parent = gc->parent;
     gdev->chip = gc;
     gc->gpiodev = gdev;
 
     of_gpio_dev_init(gc, gdev);
     acpi_gpio_dev_init(gc, gdev);
 
     /*
      * Assign fwnode depending on the result of the previous calls,
      * if none of them succeed, assign it to the parent's one.
      */
     gdev->dev.fwnode = dev_fwnode(&gdev->dev) ?: fwnode;
 
     gdev->id = ida_alloc(&gpio_ida, GFP_KERNEL);
     if (gdev->id < 0) {
         ret = gdev->id;
         goto err_free_gdev;
     }
 
     ret = dev_set_name(&gdev->dev, GPIOCHIP_NAME "%d", gdev->id);
     if (ret)
         goto err_free_ida;
 
     device_initialize(&gdev->dev);
     if (gc->parent && gc->parent->driver)
         gdev->owner = gc->parent->driver->owner;
     else if (gc->owner)
         /* TODO: remove chip->owner */
         gdev->owner = gc->owner;
     else
         gdev->owner = THIS_MODULE;
 
     gdev->descs = kcalloc(gc->ngpio, sizeof(gdev->descs[0]), GFP_KERNEL);
     if (!gdev->descs) {
         ret = -ENOMEM;
         goto err_free_dev_name;
     }
 
     /*
      * Try the device properties if the driver didn't supply the number
      * of GPIO lines.
      */
     if (gc->ngpio == 0) {
         ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
         if (ret == -ENODATA)
             /*
              * -ENODATA means that there is no property found and
              * we want to issue the error message to the user.
              * Besides that, we want to return different error code
              * to state that supplied value is not valid.
              */
             ngpios = 0;
         else if (ret)
             goto err_free_descs;
 
         gc->ngpio = ngpios;
     }
 
     if (gc->ngpio == 0) {
         chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
         ret = -EINVAL;
         goto err_free_descs;
     }
 
     if (gc->ngpio > FASTPATH_NGPIO)
         chip_warn(gc, "line cnt %u is greater than fast path cnt %u\n",
               gc->ngpio, FASTPATH_NGPIO);
 
     gdev->label = kstrdup_const(gc->label ?: "unknown", GFP_KERNEL);
     if (!gdev->label) {
         ret = -ENOMEM;
         goto err_free_descs;
     }
 
     gdev->ngpio = gc->ngpio;
     gdev->data = data;
 
     spin_lock_irqsave(&gpio_lock, flags);
 
     /*
      * TODO: this allocates a Linux GPIO number base in the global
      * GPIO numberspace for this chip. In the long run we want to
      * get *rid* of this numberspace and use only descriptors, but
      * it may be a pipe dream. It will not happen before we get rid
      * of the sysfs interface anyways.
      */
     if (base < 0) {
         base = gpiochip_find_base(gc->ngpio);
         if (base < 0) {
             ret = base;
             spin_unlock_irqrestore(&gpio_lock, flags);
             goto err_free_label;
         }
         /*
          * TODO: it should not be necessary to reflect the assigned
          * base outside of the GPIO subsystem. Go over drivers and
          * see if anyone makes use of this, else drop this and assign
          * a poison instead.
          */
         gc->base = base;
     }
     gdev->base = base;
 
     ret = gpiodev_add_to_list(gdev);
     if (ret) {
         spin_unlock_irqrestore(&gpio_lock, flags);
         chip_err(gc, "GPIO integer space overlap, cannot add chip\n");
         goto err_free_label;
     }
 
     for (i = 0; i < gc->ngpio; i++)
         gdev->descs[i].gdev = gdev;
 
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     BLOCKING_INIT_NOTIFIER_HEAD(&gdev->notifier);
 
 #ifdef CONFIG_PINCTRL
     INIT_LIST_HEAD(&gdev->pin_ranges);
 #endif
 
     if (gc->names) {
         ret = gpiochip_set_desc_names(gc);
         if (ret)
             goto err_remove_from_list;
     }
     ret = devprop_gpiochip_set_names(gc);
     if (ret)
         goto err_remove_from_list;
 
     ret = gpiochip_alloc_valid_mask(gc);
     if (ret)
         goto err_remove_from_list;
 
     ret = of_gpiochip_add(gc);
     if (ret)
         goto err_free_gpiochip_mask;
 
     ret = gpiochip_init_valid_mask(gc);
     if (ret)
         goto err_remove_of_chip;
 
     for (i = 0; i < gc->ngpio; i++) {
         struct gpio_desc *desc = &gdev->descs[i];
 
         if (gc->get_direction && gpiochip_line_is_valid(gc, i)) {
             assign_bit(FLAG_IS_OUT,
                    &desc->flags, !gc->get_direction(gc, i));
         } else {
             assign_bit(FLAG_IS_OUT,
                    &desc->flags, !gc->direction_input);
         }
     }
 
     ret = gpiochip_add_pin_ranges(gc);
     if (ret)
         goto err_remove_of_chip;
 
     acpi_gpiochip_add(gc);
 
     machine_gpiochip_add(gc);
 
     ret = gpiochip_irqchip_init_valid_mask(gc);
     if (ret)
         goto err_remove_acpi_chip;
 
     ret = gpiochip_irqchip_init_hw(gc);
     if (ret)
         goto err_remove_acpi_chip;
 
     ret = gpiochip_add_irqchip(gc, lock_key, request_key);
     if (ret)
         goto err_remove_irqchip_mask;
 
     /*
      * By first adding the chardev, and then adding the device,
      * we get a device node entry in sysfs under
      * /sys/bus/gpio/devices/gpiochipN/dev that can be used for
      * coldplug of device nodes and other udev business.
      * We can do this only if gpiolib has been initialized.
      * Otherwise, defer until later.
      */
     if (gpiolib_initialized) {
         ret = gpiochip_setup_dev(gdev);
         if (ret)
             goto err_remove_irqchip;
     }
     return 0;
 
 err_remove_irqchip:
     gpiochip_irqchip_remove(gc);
 err_remove_irqchip_mask:
     gpiochip_irqchip_free_valid_mask(gc);
 err_remove_acpi_chip:
     acpi_gpiochip_remove(gc);
 err_remove_of_chip:
     gpiochip_free_hogs(gc);
     of_gpiochip_remove(gc);
 err_free_gpiochip_mask:
     gpiochip_remove_pin_ranges(gc);
     gpiochip_free_valid_mask(gc);
 err_remove_from_list:
     spin_lock_irqsave(&gpio_lock, flags);
     list_del(&gdev->list);
     spin_unlock_irqrestore(&gpio_lock, flags);
 err_free_label:
     kfree_const(gdev->label);
 err_free_descs:
     kfree(gdev->descs);
 err_free_dev_name:
     kfree(dev_name(&gdev->dev));
 err_free_ida:
     ida_free(&gpio_ida, gdev->id);
 err_free_gdev:
     /* failures here can mean systems won't boot... */
     if (ret != -EPROBE_DEFER) {
         pr_err("%s: GPIOs %d..%d (%s) failed to register, %d\n", __func__,
                gdev->base, gdev->base + gdev->ngpio - 1,
                gc->label ? : "generic", ret);
     }
     kfree(gdev);
     return ret;
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_data_with_key);
 
 /**
  * gpiochip_get_data() - get per-subdriver data for the chip
  * @gc: GPIO chip
  *
  * Returns:
  * The per-subdriver data for the chip.
  */
 void *gpiochip_get_data(struct gpio_chip *gc)
 {
     return gc->gpiodev->data;
 }
 EXPORT_SYMBOL_GPL(gpiochip_get_data);
 
 /**
  * gpiochip_remove() - unregister a gpio_chip
  * @gc: the chip to unregister
  *
  * A gpio_chip with any GPIOs still requested may not be removed.
  */
 void gpiochip_remove(struct gpio_chip *gc)
 {
     struct gpio_device *gdev = gc->gpiodev;
     unsigned long   flags;
     unsigned int    i;
 
     /* FIXME: should the legacy sysfs handling be moved to gpio_device? */
     gpiochip_sysfs_unregister(gdev);
     gpiochip_free_hogs(gc);
     /* Numb the device, cancelling all outstanding operations */
     gdev->chip = NULL;
     gpiochip_irqchip_remove(gc);
     acpi_gpiochip_remove(gc);
     of_gpiochip_remove(gc);
     gpiochip_remove_pin_ranges(gc);
     gpiochip_free_valid_mask(gc);
     /*
      * We accept no more calls into the driver from this point, so
      * NULL the driver data pointer
      */
     gdev->data = NULL;
 
     spin_lock_irqsave(&gpio_lock, flags);
     for (i = 0; i < gdev->ngpio; i++) {
         if (gpiochip_is_requested(gc, i))
             break;
     }
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     if (i != gdev->ngpio)
         dev_crit(&gdev->dev,
              "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
 
     /*
      * The gpiochip side puts its use of the device to rest here:
      * if there are no userspace clients, the chardev and device will
      * be removed, else it will be dangling until the last user is
      * gone.
      */
     gcdev_unregister(gdev);
     put_device(&gdev->dev);
 }
 EXPORT_SYMBOL_GPL(gpiochip_remove);
 
 /**
  * gpiochip_find() - iterator for locating a specific gpio_chip
  * @data: data to pass to match function
  * @match: Callback function to check gpio_chip
  *
  * Similar to bus_find_device.  It returns a reference to a gpio_chip as
  * determined by a user supplied @match callback.  The callback should return
  * 0 if the device doesn't match and non-zero if it does.  If the callback is
  * non-zero, this function will return to the caller and not iterate over any
  * more gpio_chips.
  */
 struct gpio_chip *gpiochip_find(void *data,
                 int (*match)(struct gpio_chip *gc,
                          void *data))
 {
     struct gpio_device *gdev;
     struct gpio_chip *gc = NULL;
     unsigned long flags;
 
     spin_lock_irqsave(&gpio_lock, flags);
     list_for_each_entry(gdev, &gpio_devices, list)
         if (gdev->chip && match(gdev->chip, data)) {
             gc = gdev->chip;
             break;
         }
 
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     return gc;
 }
 EXPORT_SYMBOL_GPL(gpiochip_find);
 
 static int gpiochip_match_name(struct gpio_chip *gc, void *data)
 {
     const char *name = data;
 
     return !strcmp(gc->label, name);
 }
 
 static struct gpio_chip *find_chip_by_name(const char *name)
 {
     return gpiochip_find((void *)name, gpiochip_match_name);
 }
 
 #ifdef CONFIG_GPIOLIB_IRQCHIP
 
 /*
  * The following is irqchip helper code for gpiochips.
  */
 
 static int gpiochip_irqchip_init_hw(struct gpio_chip *gc)
 {
     struct gpio_irq_chip *girq = &gc->irq;
 
     if (!girq->init_hw)
         return 0;
 
     return girq->init_hw(gc);
 }
 
 static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gc)
 {
     struct gpio_irq_chip *girq = &gc->irq;
 
     if (!girq->init_valid_mask)
         return 0;
 
     girq->valid_mask = gpiochip_allocate_mask(gc);
     if (!girq->valid_mask)
         return -ENOMEM;
 
     girq->init_valid_mask(gc, girq->valid_mask, gc->ngpio);
 
     return 0;
 }
 
 static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc)
 {
     bitmap_free(gc->irq.valid_mask);
     gc->irq.valid_mask = NULL;
 }
 
 bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gc,
                 unsigned int offset)
 {
     if (!gpiochip_line_is_valid(gc, offset))
         return false;
     /* No mask means all valid */
     if (likely(!gc->irq.valid_mask))
         return true;
     return test_bit(offset, gc->irq.valid_mask);
 }
 EXPORT_SYMBOL_GPL(gpiochip_irqchip_irq_valid);
 
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
 
 /**
  * gpiochip_set_hierarchical_irqchip() - connects a hierarchical irqchip
  * to a gpiochip
  * @gc: the gpiochip to set the irqchip hierarchical handler to
  * @irqchip: the irqchip to handle this level of the hierarchy, the interrupt
  * will then percolate up to the parent
  */
 static void gpiochip_set_hierarchical_irqchip(struct gpio_chip *gc,
                           struct irq_chip *irqchip)
 {
     /* DT will deal with mapping each IRQ as we go along */
     if (is_of_node(gc->irq.fwnode))
         return;
 
     /*
      * This is for legacy and boardfile "irqchip" fwnodes: allocate
      * irqs upfront instead of dynamically since we don't have the
      * dynamic type of allocation that hardware description languages
      * provide. Once all GPIO drivers using board files are gone from
      * the kernel we can delete this code, but for a transitional period
      * it is necessary to keep this around.
      */
     if (is_fwnode_irqchip(gc->irq.fwnode)) {
         int i;
         int ret;
 
         for (i = 0; i < gc->ngpio; i++) {
             struct irq_fwspec fwspec;
             unsigned int parent_hwirq;
             unsigned int parent_type;
             struct gpio_irq_chip *girq = &gc->irq;
 
             /*
              * We call the child to parent translation function
              * only to check if the child IRQ is valid or not.
              * Just pick the rising edge type here as that is what
              * we likely need to support.
              */
             ret = girq->child_to_parent_hwirq(gc, i,
                               IRQ_TYPE_EDGE_RISING,
                               &parent_hwirq,
                               &parent_type);
             if (ret) {
                 chip_err(gc, "skip set-up on hwirq %d\n",
                      i);
                 continue;
             }
 
             fwspec.fwnode = gc->irq.fwnode;
             /* This is the hwirq for the GPIO line side of things */
             fwspec.param[0] = girq->child_offset_to_irq(gc, i);
             /* Just pick something */
             fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
             fwspec.param_count = 2;
             ret = __irq_domain_alloc_irqs(gc->irq.domain,
                               /* just pick something */
                               -1,
                               1,
                               NUMA_NO_NODE,
                               &fwspec,
                               false,
                               NULL);
             if (ret < 0) {
                 chip_err(gc,
                      "can not allocate irq for GPIO line %d parent hwirq %d in hierarchy domain: %d\n",
                      i, parent_hwirq,
                      ret);
             }
         }
     }
 
     chip_err(gc, "%s unknown fwnode type proceed anyway\n", __func__);
 
     return;
 }
 
 static int gpiochip_hierarchy_irq_domain_translate(struct irq_domain *d,
                            struct irq_fwspec *fwspec,
                            unsigned long *hwirq,
                            unsigned int *type)
 {
     /* We support standard DT translation */
     if (is_of_node(fwspec->fwnode) && fwspec->param_count == 2) {
         return irq_domain_translate_twocell(d, fwspec, hwirq, type);
     }
 
     /* This is for board files and others not using DT */
     if (is_fwnode_irqchip(fwspec->fwnode)) {
         int ret;
 
         ret = irq_domain_translate_twocell(d, fwspec, hwirq, type);
         if (ret)
             return ret;
         WARN_ON(*type == IRQ_TYPE_NONE);
         return 0;
     }
     return -EINVAL;
 }
 
 static int gpiochip_hierarchy_irq_domain_alloc(struct irq_domain *d,
                            unsigned int irq,
                            unsigned int nr_irqs,
                            void *data)
 {
     struct gpio_chip *gc = d->host_data;
     irq_hw_number_t hwirq;
     unsigned int type = IRQ_TYPE_NONE;
     struct irq_fwspec *fwspec = data;
     union gpio_irq_fwspec gpio_parent_fwspec = {};
     unsigned int parent_hwirq;
     unsigned int parent_type;
     struct gpio_irq_chip *girq = &gc->irq;
     int ret;
 
     /*
      * The nr_irqs parameter is always one except for PCI multi-MSI
      * so this should not happen.
      */
     WARN_ON(nr_irqs != 1);
 
     ret = gc->irq.child_irq_domain_ops.translate(d, fwspec, &hwirq, &type);
     if (ret)
         return ret;
 
     chip_dbg(gc, "allocate IRQ %d, hwirq %lu\n", irq,  hwirq);
 
     ret = girq->child_to_parent_hwirq(gc, hwirq, type,
                       &parent_hwirq, &parent_type);
     if (ret) {
         chip_err(gc, "can't look up hwirq %lu\n", hwirq);
         return ret;
     }
     chip_dbg(gc, "found parent hwirq %u\n", parent_hwirq);
 
     /*
      * We set handle_bad_irq because the .set_type() should
      * always be invoked and set the right type of handler.
      */
     irq_domain_set_info(d,
                 irq,
                 hwirq,
                 gc->irq.chip,
                 gc,
                 girq->handler,
                 NULL, NULL);
     irq_set_probe(irq);
 
     /* This parent only handles asserted level IRQs */
     ret = girq->populate_parent_alloc_arg(gc, &gpio_parent_fwspec,
                           parent_hwirq, parent_type);
     if (ret)
         return ret;
 
     chip_dbg(gc, "alloc_irqs_parent for %d parent hwirq %d\n",
           irq, parent_hwirq);
     irq_set_lockdep_class(irq, gc->irq.lock_key, gc->irq.request_key);
     ret = irq_domain_alloc_irqs_parent(d, irq, 1, &gpio_parent_fwspec);
     /*
      * If the parent irqdomain is msi, the interrupts have already
      * been allocated, so the EEXIST is good.
      */
     if (irq_domain_is_msi(d->parent) && (ret == -EEXIST))
         ret = 0;
     if (ret)
         chip_err(gc,
              "failed to allocate parent hwirq %d for hwirq %lu\n",
              parent_hwirq, hwirq);
 
     return ret;
 }
 
 static unsigned int gpiochip_child_offset_to_irq_noop(struct gpio_chip *gc,
                               unsigned int offset)
 {
     return offset;
 }
 
 static void gpiochip_hierarchy_setup_domain_ops(struct irq_domain_ops *ops)
 {
     ops->activate = gpiochip_irq_domain_activate;
     ops->deactivate = gpiochip_irq_domain_deactivate;
     ops->alloc = gpiochip_hierarchy_irq_domain_alloc;
 
     /*
      * We only allow overriding the translate() and free() functions for
      * hierarchical chips, and this should only be done if the user
      * really need something other than 1:1 translation for translate()
      * callback and free if user wants to free up any resources which
      * were allocated during callbacks, for example populate_parent_alloc_arg.
      */
     if (!ops->translate)
         ops->translate = gpiochip_hierarchy_irq_domain_translate;
     if (!ops->free)
         ops->free = irq_domain_free_irqs_common;
 }
 
 static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc)
 {
     if (!gc->irq.child_to_parent_hwirq ||
         !gc->irq.fwnode) {
         chip_err(gc, "missing irqdomain vital data\n");
         return -EINVAL;
     }
 
     if (!gc->irq.child_offset_to_irq)
         gc->irq.child_offset_to_irq = gpiochip_child_offset_to_irq_noop;
 
     if (!gc->irq.populate_parent_alloc_arg)
         gc->irq.populate_parent_alloc_arg =
             gpiochip_populate_parent_fwspec_twocell;
 
     gpiochip_hierarchy_setup_domain_ops(&gc->irq.child_irq_domain_ops);
 
     gc->irq.domain = irq_domain_create_hierarchy(
         gc->irq.parent_domain,
         0,
         gc->ngpio,
         gc->irq.fwnode,
         &gc->irq.child_irq_domain_ops,
         gc);
 
     if (!gc->irq.domain)
         return -ENOMEM;
 
     gpiochip_set_hierarchical_irqchip(gc, gc->irq.chip);
 
     return 0;
 }
 
 static bool gpiochip_hierarchy_is_hierarchical(struct gpio_chip *gc)
 {
     return !!gc->irq.parent_domain;
 }
 
 int gpiochip_populate_parent_fwspec_twocell(struct gpio_chip *gc,
                         union gpio_irq_fwspec *gfwspec,
                         unsigned int parent_hwirq,
                         unsigned int parent_type)
 {
     struct irq_fwspec *fwspec = &gfwspec->fwspec;
 
     fwspec->fwnode = gc->irq.parent_domain->fwnode;
     fwspec->param_count = 2;
     fwspec->param[0] = parent_hwirq;
     fwspec->param[1] = parent_type;
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_populate_parent_fwspec_twocell);
 
 int gpiochip_populate_parent_fwspec_fourcell(struct gpio_chip *gc,
                          union gpio_irq_fwspec *gfwspec,
                          unsigned int parent_hwirq,
                          unsigned int parent_type)
 {
     struct irq_fwspec *fwspec = &gfwspec->fwspec;
 
     fwspec->fwnode = gc->irq.parent_domain->fwnode;
     fwspec->param_count = 4;
     fwspec->param[0] = 0;
     fwspec->param[1] = parent_hwirq;
     fwspec->param[2] = 0;
     fwspec->param[3] = parent_type;
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_populate_parent_fwspec_fourcell);
 
 #else
 
 static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc)
 {
     return -EINVAL;
 }
 
 static bool gpiochip_hierarchy_is_hierarchical(struct gpio_chip *gc)
 {
     return false;
 }
 
 #endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */
 
 /**
  * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip
  * @d: the irqdomain used by this irqchip
  * @irq: the global irq number used by this GPIO irqchip irq
  * @hwirq: the local IRQ/GPIO line offset on this gpiochip
  *
  * This function will set up the mapping for a certain IRQ line on a
  * gpiochip by assigning the gpiochip as chip data, and using the irqchip
  * stored inside the gpiochip.
  */
 int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
              irq_hw_number_t hwirq)
 {
     struct gpio_chip *gc = d->host_data;
     int ret = 0;
 
     if (!gpiochip_irqchip_irq_valid(gc, hwirq))
         return -ENXIO;
 
     irq_set_chip_data(irq, gc);
     /*
      * This lock class tells lockdep that GPIO irqs are in a different
      * category than their parents, so it won't report false recursion.
      */
     irq_set_lockdep_class(irq, gc->irq.lock_key, gc->irq.request_key);
     irq_set_chip_and_handler(irq, gc->irq.chip, gc->irq.handler);
     /* Chips that use nested thread handlers have them marked */
     if (gc->irq.threaded)
         irq_set_nested_thread(irq, 1);
     irq_set_noprobe(irq);
 
     if (gc->irq.num_parents == 1)
         ret = irq_set_parent(irq, gc->irq.parents[0]);
     else if (gc->irq.map)
         ret = irq_set_parent(irq, gc->irq.map[hwirq]);
 
     if (ret < 0)
         return ret;
 
     /*
      * No set-up of the hardware will happen if IRQ_TYPE_NONE
      * is passed as default type.
      */
     if (gc->irq.default_type != IRQ_TYPE_NONE)
         irq_set_irq_type(irq, gc->irq.default_type);
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_irq_map);
 
 void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
 {
     struct gpio_chip *gc = d->host_data;
 
     if (gc->irq.threaded)
         irq_set_nested_thread(irq, 0);
     irq_set_chip_and_handler(irq, NULL, NULL);
     irq_set_chip_data(irq, NULL);
 }
 EXPORT_SYMBOL_GPL(gpiochip_irq_unmap);
 
 static const struct irq_domain_ops gpiochip_domain_ops = {
     .map    = gpiochip_irq_map,
     .unmap  = gpiochip_irq_unmap,
     /* Virtually all GPIO irqchips are twocell:ed */
     .xlate  = irq_domain_xlate_twocell,
 };
 
 /*
  * TODO: move these activate/deactivate in under the hierarchicial
  * irqchip implementation as static once SPMI and SSBI (all external
  * users) are phased over.
  */
 /**
  * gpiochip_irq_domain_activate() - Lock a GPIO to be used as an IRQ
  * @domain: The IRQ domain used by this IRQ chip
  * @data: Outermost irq_data associated with the IRQ
  * @reserve: If set, only reserve an interrupt vector instead of assigning one
  *
  * This function is a wrapper that calls gpiochip_lock_as_irq() and is to be
  * used as the activate function for the &struct irq_domain_ops. The host_data
  * for the IRQ domain must be the &struct gpio_chip.
  */
 int gpiochip_irq_domain_activate(struct irq_domain *domain,
                  struct irq_data *data, bool reserve)
 {
     struct gpio_chip *gc = domain->host_data;
 
     return gpiochip_lock_as_irq(gc, data->hwirq);
 }
 EXPORT_SYMBOL_GPL(gpiochip_irq_domain_activate);
 
 /**
  * gpiochip_irq_domain_deactivate() - Unlock a GPIO used as an IRQ
  * @domain: The IRQ domain used by this IRQ chip
  * @data: Outermost irq_data associated with the IRQ
  *
  * This function is a wrapper that will call gpiochip_unlock_as_irq() and is to
  * be used as the deactivate function for the &struct irq_domain_ops. The
  * host_data for the IRQ domain must be the &struct gpio_chip.
  */
 void gpiochip_irq_domain_deactivate(struct irq_domain *domain,
                     struct irq_data *data)
 {
     struct gpio_chip *gc = domain->host_data;
 
     return gpiochip_unlock_as_irq(gc, data->hwirq);
 }
 EXPORT_SYMBOL_GPL(gpiochip_irq_domain_deactivate);
 
 static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 {
     struct irq_domain *domain = gc->irq.domain;
 
 #ifdef CONFIG_GPIOLIB_IRQCHIP
     /*
      * Avoid race condition with other code, which tries to lookup
      * an IRQ before the irqchip has been properly registered,
      * i.e. while gpiochip is still being brought up.
      */
     if (!gc->irq.initialized)
         return -EPROBE_DEFER;
 #endif
 
     if (!gpiochip_irqchip_irq_valid(gc, offset))
         return -ENXIO;
 
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
     if (irq_domain_is_hierarchy(domain)) {
         struct irq_fwspec spec;
 
         spec.fwnode = domain->fwnode;
         spec.param_count = 2;
         spec.param[0] = gc->irq.child_offset_to_irq(gc, offset);
         spec.param[1] = IRQ_TYPE_NONE;
 
         return irq_create_fwspec_mapping(&spec);
     }
 #endif
 
     return irq_create_mapping(domain, offset);
 }
 
 int gpiochip_irq_reqres(struct irq_data *d)
 {
     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
     return gpiochip_reqres_irq(gc, d->hwirq);
 }
 EXPORT_SYMBOL(gpiochip_irq_reqres);
 
 void gpiochip_irq_relres(struct irq_data *d)
 {
     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
     gpiochip_relres_irq(gc, d->hwirq);
 }
 EXPORT_SYMBOL(gpiochip_irq_relres);
 
 static void gpiochip_irq_mask(struct irq_data *d)
 {
     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
     if (gc->irq.irq_mask)
         gc->irq.irq_mask(d);
     gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void gpiochip_irq_unmask(struct irq_data *d)
 {
     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
     gpiochip_enable_irq(gc, d->hwirq);
     if (gc->irq.irq_unmask)
         gc->irq.irq_unmask(d);
 }
 
 static void gpiochip_irq_enable(struct irq_data *d)
 {
     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
     gpiochip_enable_irq(gc, d->hwirq);
     gc->irq.irq_enable(d);
 }
 
 static void gpiochip_irq_disable(struct irq_data *d)
 {
     struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
 
     gc->irq.irq_disable(d);
     gpiochip_disable_irq(gc, d->hwirq);
 }
 
 static void gpiochip_set_irq_hooks(struct gpio_chip *gc)
 {
     struct irq_chip *irqchip = gc->irq.chip;
 
     if (irqchip->flags & IRQCHIP_IMMUTABLE)
         return;
 
     chip_warn(gc, "not an immutable chip, please consider fixing it!\n");
 
     if (!irqchip->irq_request_resources &&
         !irqchip->irq_release_resources) {
         irqchip->irq_request_resources = gpiochip_irq_reqres;
         irqchip->irq_release_resources = gpiochip_irq_relres;
     }
     if (WARN_ON(gc->irq.irq_enable))
         return;
     /* Check if the irqchip already has this hook... */
     if (irqchip->irq_enable == gpiochip_irq_enable ||
         irqchip->irq_mask == gpiochip_irq_mask) {
         /*
          * ...and if so, give a gentle warning that this is bad
          * practice.
          */
         chip_info(gc,
               "detected irqchip that is shared with multiple gpiochips: please fix the driver.\n");
         return;
     }
 
     if (irqchip->irq_disable) {
         gc->irq.irq_disable = irqchip->irq_disable;
         irqchip->irq_disable = gpiochip_irq_disable;
     } else {
         gc->irq.irq_mask = irqchip->irq_mask;
         irqchip->irq_mask = gpiochip_irq_mask;
     }
 
     if (irqchip->irq_enable) {
         gc->irq.irq_enable = irqchip->irq_enable;
         irqchip->irq_enable = gpiochip_irq_enable;
     } else {
         gc->irq.irq_unmask = irqchip->irq_unmask;
         irqchip->irq_unmask = gpiochip_irq_unmask;
     }
 }
 
 /**
  * gpiochip_add_irqchip() - adds an IRQ chip to a GPIO chip
  * @gc: the GPIO chip to add the IRQ chip to
  * @lock_key: lockdep class for IRQ lock
  * @request_key: lockdep class for IRQ request
  */
 static int gpiochip_add_irqchip(struct gpio_chip *gc,
                 struct lock_class_key *lock_key,
                 struct lock_class_key *request_key)
 {
     struct fwnode_handle *fwnode = dev_fwnode(&gc->gpiodev->dev);
     struct irq_chip *irqchip = gc->irq.chip;
     unsigned int type;
     unsigned int i;
 
     if (!irqchip)
         return 0;
 
     if (gc->irq.parent_handler && gc->can_sleep) {
         chip_err(gc, "you cannot have chained interrupts on a chip that may sleep\n");
         return -EINVAL;
     }
 
     type = gc->irq.default_type;
 
     /*
      * Specifying a default trigger is a terrible idea if DT or ACPI is
      * used to configure the interrupts, as you may end up with
      * conflicting triggers. Tell the user, and reset to NONE.
      */
     if (WARN(fwnode && type != IRQ_TYPE_NONE,
          "%pfw: Ignoring %u default trigger\n", fwnode, type))
         type = IRQ_TYPE_NONE;
 
     if (gc->to_irq)
         chip_warn(gc, "to_irq is redefined in %s and you shouldn't rely on it\n", __func__);
 
     gc->to_irq = gpiochip_to_irq;
     gc->irq.default_type = type;
     gc->irq.lock_key = lock_key;
     gc->irq.request_key = request_key;
 
     /* If a parent irqdomain is provided, let's build a hierarchy */
     if (gpiochip_hierarchy_is_hierarchical(gc)) {
         int ret = gpiochip_hierarchy_add_domain(gc);
         if (ret)
             return ret;
     } else {
         /* Some drivers provide custom irqdomain ops */
         gc->irq.domain = irq_domain_create_simple(fwnode,
             gc->ngpio,
             gc->irq.first,
             gc->irq.domain_ops ?: &gpiochip_domain_ops,
             gc);
         if (!gc->irq.domain)
             return -EINVAL;
     }
 
     if (gc->irq.parent_handler) {
         for (i = 0; i < gc->irq.num_parents; i++) {
             void *data;
 
             if (gc->irq.per_parent_data)
                 data = gc->irq.parent_handler_data_array[i];
             else
                 data = gc->irq.parent_handler_data ?: gc;
 
             /*
              * The parent IRQ chip is already using the chip_data
              * for this IRQ chip, so our callbacks simply use the
              * handler_data.
              */
             irq_set_chained_handler_and_data(gc->irq.parents[i],
                              gc->irq.parent_handler,
                              data);
         }
     }
 
     gpiochip_set_irq_hooks(gc);
 
     /*
      * Using barrier() here to prevent compiler from reordering
      * gc->irq.initialized before initialization of above
      * GPIO chip irq members.
      */
     barrier();
 
     gc->irq.initialized = true;
 
     acpi_gpiochip_request_interrupts(gc);
 
     return 0;
 }
 
 /**
  * gpiochip_irqchip_remove() - removes an irqchip added to a gpiochip
  * @gc: the gpiochip to remove the irqchip from
  *
  * This is called only from gpiochip_remove()
  */
 static void gpiochip_irqchip_remove(struct gpio_chip *gc)
 {
     struct irq_chip *irqchip = gc->irq.chip;
     unsigned int offset;
 
     acpi_gpiochip_free_interrupts(gc);
 
     if (irqchip && gc->irq.parent_handler) {
         struct gpio_irq_chip *irq = &gc->irq;
         unsigned int i;
 
         for (i = 0; i < irq->num_parents; i++)
             irq_set_chained_handler_and_data(irq->parents[i],
                              NULL, NULL);
     }
 
     /* Remove all IRQ mappings and delete the domain */
     if (gc->irq.domain) {
         unsigned int irq;
 
         for (offset = 0; offset < gc->ngpio; offset++) {
             if (!gpiochip_irqchip_irq_valid(gc, offset))
                 continue;
 
             irq = irq_find_mapping(gc->irq.domain, offset);
             irq_dispose_mapping(irq);
         }
 
         irq_domain_remove(gc->irq.domain);
     }
 
     if (irqchip && !(irqchip->flags & IRQCHIP_IMMUTABLE)) {
         if (irqchip->irq_request_resources == gpiochip_irq_reqres) {
             irqchip->irq_request_resources = NULL;
             irqchip->irq_release_resources = NULL;
         }
         if (irqchip->irq_enable == gpiochip_irq_enable) {
             irqchip->irq_enable = gc->irq.irq_enable;
             irqchip->irq_disable = gc->irq.irq_disable;
         }
     }
     gc->irq.irq_enable = NULL;
     gc->irq.irq_disable = NULL;
     gc->irq.chip = NULL;
 
     gpiochip_irqchip_free_valid_mask(gc);
 }
 
 /**
  * gpiochip_irqchip_add_domain() - adds an irqdomain to a gpiochip
  * @gc: the gpiochip to add the irqchip to
  * @domain: the irqdomain to add to the gpiochip
  *
  * This function adds an IRQ domain to the gpiochip.
  */
 int gpiochip_irqchip_add_domain(struct gpio_chip *gc,
                 struct irq_domain *domain)
 {
     if (!domain)
         return -EINVAL;
 
     gc->to_irq = gpiochip_to_irq;
     gc->irq.domain = domain;
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_irqchip_add_domain);
 
 #else /* CONFIG_GPIOLIB_IRQCHIP */
 
 static inline int gpiochip_add_irqchip(struct gpio_chip *gc,
                        struct lock_class_key *lock_key,
                        struct lock_class_key *request_key)
 {
     return 0;
 }
 static void gpiochip_irqchip_remove(struct gpio_chip *gc) {}
 
 static inline int gpiochip_irqchip_init_hw(struct gpio_chip *gc)
 {
     return 0;
 }
 
 static inline int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gc)
 {
     return 0;
 }
 static inline void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc)
 { }
 
 #endif /* CONFIG_GPIOLIB_IRQCHIP */
 
 /**
  * gpiochip_generic_request() - request the gpio function for a pin
  * @gc: the gpiochip owning the GPIO
  * @offset: the offset of the GPIO to request for GPIO function
  */
 int gpiochip_generic_request(struct gpio_chip *gc, unsigned int offset)
 {
 #ifdef CONFIG_PINCTRL
     if (list_empty(&gc->gpiodev->pin_ranges))
         return 0;
 #endif
 
     return pinctrl_gpio_request(gc->gpiodev->base + offset);
 }
 EXPORT_SYMBOL_GPL(gpiochip_generic_request);
 
 /**
  * gpiochip_generic_free() - free the gpio function from a pin
  * @gc: the gpiochip to request the gpio function for
  * @offset: the offset of the GPIO to free from GPIO function
  */
 void gpiochip_generic_free(struct gpio_chip *gc, unsigned int offset)
 {
 #ifdef CONFIG_PINCTRL
     if (list_empty(&gc->gpiodev->pin_ranges))
         return;
 #endif
 
     pinctrl_gpio_free(gc->gpiodev->base + offset);
 }
 EXPORT_SYMBOL_GPL(gpiochip_generic_free);
 
 /**
  * gpiochip_generic_config() - apply configuration for a pin
  * @gc: the gpiochip owning the GPIO
  * @offset: the offset of the GPIO to apply the configuration
  * @config: the configuration to be applied
  */
 int gpiochip_generic_config(struct gpio_chip *gc, unsigned int offset,
                 unsigned long config)
 {
     return pinctrl_gpio_set_config(gc->gpiodev->base + offset, config);
 }
 EXPORT_SYMBOL_GPL(gpiochip_generic_config);
 
 #ifdef CONFIG_PINCTRL
 
 /**
  * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
  * @gc: the gpiochip to add the range for
  * @pctldev: the pin controller to map to
  * @gpio_offset: the start offset in the current gpio_chip number space
  * @pin_group: name of the pin group inside the pin controller
  *
  * Calling this function directly from a DeviceTree-supported
  * pinctrl driver is DEPRECATED. Please see Section 2.1 of
  * Documentation/devicetree/bindings/gpio/gpio.txt on how to
  * bind pinctrl and gpio drivers via the "gpio-ranges" property.
  */
 int gpiochip_add_pingroup_range(struct gpio_chip *gc,
             struct pinctrl_dev *pctldev,
             unsigned int gpio_offset, const char *pin_group)
 {
     struct gpio_pin_range *pin_range;
     struct gpio_device *gdev = gc->gpiodev;
     int ret;
 
     pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
     if (!pin_range) {
         chip_err(gc, "failed to allocate pin ranges\n");
         return -ENOMEM;
     }
 
     /* Use local offset as range ID */
     pin_range->range.id = gpio_offset;
     pin_range->range.gc = gc;
     pin_range->range.name = gc->label;
     pin_range->range.base = gdev->base + gpio_offset;
     pin_range->pctldev = pctldev;
 
     ret = pinctrl_get_group_pins(pctldev, pin_group,
                     &pin_range->range.pins,
                     &pin_range->range.npins);
     if (ret < 0) {
         kfree(pin_range);
         return ret;
     }
 
     pinctrl_add_gpio_range(pctldev, &pin_range->range);
 
     chip_dbg(gc, "created GPIO range %d->%d ==> %s PINGRP %s\n",
          gpio_offset, gpio_offset + pin_range->range.npins - 1,
          pinctrl_dev_get_devname(pctldev), pin_group);
 
     list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
 
 /**
  * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
  * @gc: the gpiochip to add the range for
  * @pinctl_name: the dev_name() of the pin controller to map to
  * @gpio_offset: the start offset in the current gpio_chip number space
  * @pin_offset: the start offset in the pin controller number space
  * @npins: the number of pins from the offset of each pin space (GPIO and
  *  pin controller) to accumulate in this range
  *
  * Returns:
  * 0 on success, or a negative error-code on failure.
  *
  * Calling this function directly from a DeviceTree-supported
  * pinctrl driver is DEPRECATED. Please see Section 2.1 of
  * Documentation/devicetree/bindings/gpio/gpio.txt on how to
  * bind pinctrl and gpio drivers via the "gpio-ranges" property.
  */
 int gpiochip_add_pin_range(struct gpio_chip *gc, const char *pinctl_name,
                unsigned int gpio_offset, unsigned int pin_offset,
                unsigned int npins)
 {
     struct gpio_pin_range *pin_range;
     struct gpio_device *gdev = gc->gpiodev;
     int ret;
 
     pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
     if (!pin_range) {
         chip_err(gc, "failed to allocate pin ranges\n");
         return -ENOMEM;
     }
 
     /* Use local offset as range ID */
     pin_range->range.id = gpio_offset;
     pin_range->range.gc = gc;
     pin_range->range.name = gc->label;
     pin_range->range.base = gdev->base + gpio_offset;
     pin_range->range.pin_base = pin_offset;
     pin_range->range.npins = npins;
     pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
             &pin_range->range);
     if (IS_ERR(pin_range->pctldev)) {
         ret = PTR_ERR(pin_range->pctldev);
         chip_err(gc, "could not create pin range\n");
         kfree(pin_range);
         return ret;
     }
     chip_dbg(gc, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
          gpio_offset, gpio_offset + npins - 1,
          pinctl_name,
          pin_offset, pin_offset + npins - 1);
 
     list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
 
 /**
  * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
  * @gc: the chip to remove all the mappings for
  */
 void gpiochip_remove_pin_ranges(struct gpio_chip *gc)
 {
     struct gpio_pin_range *pin_range, *tmp;
     struct gpio_device *gdev = gc->gpiodev;
 
     list_for_each_entry_safe(pin_range, tmp, &gdev->pin_ranges, node) {
         list_del(&pin_range->node);
         pinctrl_remove_gpio_range(pin_range->pctldev,
                 &pin_range->range);
         kfree(pin_range);
     }
 }
 EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
 
 #endif /* CONFIG_PINCTRL */
 
 /* These "optional" allocation calls help prevent drivers from stomping
  * on each other, and help provide better diagnostics in debugfs.
  * They're called even less than the "set direction" calls.
  */
 static int gpiod_request_commit(struct gpio_desc *desc, const char *label)
 {
     struct gpio_chip    *gc = desc->gdev->chip;
     int         ret;
     unsigned long       flags;
     unsigned        offset;
 
     if (label) {
         label = kstrdup_const(label, GFP_KERNEL);
         if (!label)
             return -ENOMEM;
     }
 
     spin_lock_irqsave(&gpio_lock, flags);
 
     /* NOTE:  gpio_request() can be called in early boot,
      * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
      */
 
     if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
         desc_set_label(desc, label ? : "?");
     } else {
         ret = -EBUSY;
         goto out_free_unlock;
     }
 
     if (gc->request) {
         /* gc->request may sleep */
         spin_unlock_irqrestore(&gpio_lock, flags);
         offset = gpio_chip_hwgpio(desc);
         if (gpiochip_line_is_valid(gc, offset))
             ret = gc->request(gc, offset);
         else
             ret = -EINVAL;
         spin_lock_irqsave(&gpio_lock, flags);
 
         if (ret) {
             desc_set_label(desc, NULL);
             clear_bit(FLAG_REQUESTED, &desc->flags);
             goto out_free_unlock;
         }
     }
     if (gc->get_direction) {
         /* gc->get_direction may sleep */
         spin_unlock_irqrestore(&gpio_lock, flags);
         gpiod_get_direction(desc);
         spin_lock_irqsave(&gpio_lock, flags);
     }
     spin_unlock_irqrestore(&gpio_lock, flags);
     return 0;
 
 out_free_unlock:
     spin_unlock_irqrestore(&gpio_lock, flags);
     kfree_const(label);
     return ret;
 }
 
 /*
  * This descriptor validation needs to be inserted verbatim into each
  * function taking a descriptor, so we need to use a preprocessor
  * macro to avoid endless duplication. If the desc is NULL it is an
  * optional GPIO and calls should just bail out.
  */
 static int validate_desc(const struct gpio_desc *desc, const char *func)
 {
     if (!desc)
         return 0;
     if (IS_ERR(desc)) {
         pr_warn("%s: invalid GPIO (errorpointer)\n", func);
         return PTR_ERR(desc);
     }
     if (!desc->gdev) {
         pr_warn("%s: invalid GPIO (no device)\n", func);
         return -EINVAL;
     }
     if (!desc->gdev->chip) {
         dev_warn(&desc->gdev->dev,
              "%s: backing chip is gone\n", func);
         return 0;
     }
     return 1;
 }
 
 #define VALIDATE_DESC(desc) do { \
     int __valid = validate_desc(desc, __func__); \
     if (__valid <= 0) \
         return __valid; \
     } while (0)
 
 #define VALIDATE_DESC_VOID(desc) do { \
     int __valid = validate_desc(desc, __func__); \
     if (__valid <= 0) \
         return; \
     } while (0)
 
 int gpiod_request(struct gpio_desc *desc, const char *label)
 {
     int ret = -EPROBE_DEFER;
     struct gpio_device *gdev;
 
     VALIDATE_DESC(desc);
     gdev = desc->gdev;
 
     if (try_module_get(gdev->owner)) {
         ret = gpiod_request_commit(desc, label);
         if (ret)
             module_put(gdev->owner);
         else
             get_device(&gdev->dev);
     }
 
     if (ret)
         gpiod_dbg(desc, "%s: status %d\n", __func__, ret);
 
     return ret;
 }
 
 static bool gpiod_free_commit(struct gpio_desc *desc)
 {
     bool            ret = false;
     unsigned long       flags;
     struct gpio_chip    *gc;
 
     might_sleep();
 
     gpiod_unexport(desc);
 
     spin_lock_irqsave(&gpio_lock, flags);
 
     gc = desc->gdev->chip;
     if (gc && test_bit(FLAG_REQUESTED, &desc->flags)) {
         if (gc->free) {
             spin_unlock_irqrestore(&gpio_lock, flags);
             might_sleep_if(gc->can_sleep);
             gc->free(gc, gpio_chip_hwgpio(desc));
             spin_lock_irqsave(&gpio_lock, flags);
         }
         kfree_const(desc->label);
         desc_set_label(desc, NULL);
         clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
         clear_bit(FLAG_REQUESTED, &desc->flags);
         clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
         clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
         clear_bit(FLAG_PULL_UP, &desc->flags);
         clear_bit(FLAG_PULL_DOWN, &desc->flags);
         clear_bit(FLAG_BIAS_DISABLE, &desc->flags);
         clear_bit(FLAG_EDGE_RISING, &desc->flags);
         clear_bit(FLAG_EDGE_FALLING, &desc->flags);
         clear_bit(FLAG_IS_HOGGED, &desc->flags);
 #ifdef CONFIG_OF_DYNAMIC
         desc->hog = NULL;
 #endif
 #ifdef CONFIG_GPIO_CDEV
         WRITE_ONCE(desc->debounce_period_us, 0);
 #endif
         ret = true;
     }
 
     spin_unlock_irqrestore(&gpio_lock, flags);
     blocking_notifier_call_chain(&desc->gdev->notifier,
                      GPIOLINE_CHANGED_RELEASED, desc);
 
     return ret;
 }
 
 void gpiod_free(struct gpio_desc *desc)
 {
     if (desc && desc->gdev && gpiod_free_commit(desc)) {
         module_put(desc->gdev->owner);
         put_device(&desc->gdev->dev);
     } else {
         WARN_ON(extra_checks);
     }
 }
 
 /**
  * gpiochip_is_requested - return string iff signal was requested
  * @gc: controller managing the signal
  * @offset: of signal within controller's 0..(ngpio - 1) range
  *
  * Returns NULL if the GPIO is not currently requested, else a string.
  * The string returned is the label passed to gpio_request(); if none has been
  * passed it is a meaningless, non-NULL constant.
  *
  * This function is for use by GPIO controller drivers.  The label can
  * help with diagnostics, and knowing that the signal is used as a GPIO
  * can help avoid accidentally multiplexing it to another controller.
  */
 const char *gpiochip_is_requested(struct gpio_chip *gc, unsigned int offset)
 {
     struct gpio_desc *desc;
 
     desc = gpiochip_get_desc(gc, offset);
     if (IS_ERR(desc))
         return NULL;
 
     if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
         return NULL;
     return desc->label;
 }
 EXPORT_SYMBOL_GPL(gpiochip_is_requested);
 
 /**
  * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
  * @gc: GPIO chip
  * @hwnum: hardware number of the GPIO for which to request the descriptor
  * @label: label for the GPIO
  * @lflags: lookup flags for this GPIO or 0 if default, this can be used to
  * specify things like line inversion semantics with the machine flags
  * such as GPIO_OUT_LOW
  * @dflags: descriptor request flags for this GPIO or 0 if default, this
  * can be used to specify consumer semantics such as open drain
  *
  * Function allows GPIO chip drivers to request and use their own GPIO
  * descriptors via gpiolib API. Difference to gpiod_request() is that this
  * function will not increase reference count of the GPIO chip module. This
  * allows the GPIO chip module to be unloaded as needed (we assume that the
  * GPIO chip driver handles freeing the GPIOs it has requested).
  *
  * Returns:
  * A pointer to the GPIO descriptor, or an ERR_PTR()-encoded negative error
  * code on failure.
  */
 struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *gc,
                         unsigned int hwnum,
                         const char *label,
                         enum gpio_lookup_flags lflags,
                         enum gpiod_flags dflags)
 {
     struct gpio_desc *desc = gpiochip_get_desc(gc, hwnum);
     int ret;
 
     if (IS_ERR(desc)) {
         chip_err(gc, "failed to get GPIO descriptor\n");
         return desc;
     }
 
     ret = gpiod_request_commit(desc, label);
     if (ret < 0)
         return ERR_PTR(ret);
 
     ret = gpiod_configure_flags(desc, label, lflags, dflags);
     if (ret) {
         chip_err(gc, "setup of own GPIO %s failed\n", label);
         gpiod_free_commit(desc);
         return ERR_PTR(ret);
     }
 
     return desc;
 }
 EXPORT_SYMBOL_GPL(gpiochip_request_own_desc);
 
 /**
  * gpiochip_free_own_desc - Free GPIO requested by the chip driver
  * @desc: GPIO descriptor to free
  *
  * Function frees the given GPIO requested previously with
  * gpiochip_request_own_desc().
  */
 void gpiochip_free_own_desc(struct gpio_desc *desc)
 {
     if (desc)
         gpiod_free_commit(desc);
 }
 EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
 
 /*
  * Drivers MUST set GPIO direction before making get/set calls.  In
  * some cases this is done in early boot, before IRQs are enabled.
  *
  * As a rule these aren't called more than once (except for drivers
  * using the open-drain emulation idiom) so these are natural places
  * to accumulate extra debugging checks.  Note that we can't (yet)
  * rely on gpio_request() having been called beforehand.
  */
 
 static int gpio_do_set_config(struct gpio_chip *gc, unsigned int offset,
                   unsigned long config)
 {
     if (!gc->set_config)
         return -ENOTSUPP;
 
     return gc->set_config(gc, offset, config);
 }
 
 static int gpio_set_config_with_argument(struct gpio_desc *desc,
                      enum pin_config_param mode,
                      u32 argument)
 {
     struct gpio_chip *gc = desc->gdev->chip;
     unsigned long config;
 
     config = pinconf_to_config_packed(mode, argument);
     return gpio_do_set_config(gc, gpio_chip_hwgpio(desc), config);
 }
 
 static int gpio_set_config_with_argument_optional(struct gpio_desc *desc,
                           enum pin_config_param mode,
                           u32 argument)
 {
     struct device *dev = &desc->gdev->dev;
     int gpio = gpio_chip_hwgpio(desc);
     int ret;
 
     ret = gpio_set_config_with_argument(desc, mode, argument);
     if (ret != -ENOTSUPP)
         return ret;
 
     switch (mode) {
     case PIN_CONFIG_PERSIST_STATE:
         dev_dbg(dev, "Persistence not supported for GPIO %d\n", gpio);
         break;
     default:
         break;
     }
 
     return 0;
 }
 
 static int gpio_set_config(struct gpio_desc *desc, enum pin_config_param mode)
 {
     return gpio_set_config_with_argument(desc, mode, 0);
 }
 
 static int gpio_set_bias(struct gpio_desc *desc)
 {
     enum pin_config_param bias;
     unsigned int arg;
 
     if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
         bias = PIN_CONFIG_BIAS_DISABLE;
     else if (test_bit(FLAG_PULL_UP, &desc->flags))
         bias = PIN_CONFIG_BIAS_PULL_UP;
     else if (test_bit(FLAG_PULL_DOWN, &desc->flags))
         bias = PIN_CONFIG_BIAS_PULL_DOWN;
     else
         return 0;
 
     switch (bias) {
     case PIN_CONFIG_BIAS_PULL_DOWN:
     case PIN_CONFIG_BIAS_PULL_UP:
         arg = 1;
         break;
 
     default:
         arg = 0;
         break;
     }
 
     return gpio_set_config_with_argument_optional(desc, bias, arg);
 }
 
 /**
  * gpio_set_debounce_timeout() - Set debounce timeout
  * @desc:   GPIO descriptor to set the debounce timeout
  * @debounce:   Debounce timeout in microseconds
  *
  * The function calls the certain GPIO driver to set debounce timeout
  * in the hardware.
  *
  * Returns 0 on success, or negative error code otherwise.
  */
 int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce)
 {
     return gpio_set_config_with_argument_optional(desc,
                               PIN_CONFIG_INPUT_DEBOUNCE,
                               debounce);
 }
 
 /**
  * gpiod_direction_input - set the GPIO direction to input
  * @desc:   GPIO to set to input
  *
  * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
  * be called safely on it.
  *
  * Return 0 in case of success, else an error code.
  */
 int gpiod_direction_input(struct gpio_desc *desc)
 {
     struct gpio_chip    *gc;
     int         ret = 0;
 
     VALIDATE_DESC(desc);
     gc = desc->gdev->chip;
 
     /*
      * It is legal to have no .get() and .direction_input() specified if
      * the chip is output-only, but you can't specify .direction_input()
      * and not support the .get() operation, that doesn't make sense.
      */
     if (!gc->get && gc->direction_input) {
         gpiod_warn(desc,
                "%s: missing get() but have direction_input()\n",
                __func__);
         return -EIO;
     }
 
     /*
      * If we have a .direction_input() callback, things are simple,
      * just call it. Else we are some input-only chip so try to check the
      * direction (if .get_direction() is supported) else we silently
      * assume we are in input mode after this.
      */
     if (gc->direction_input) {
         ret = gc->direction_input(gc, gpio_chip_hwgpio(desc));
     } else if (gc->get_direction &&
           (gc->get_direction(gc, gpio_chip_hwgpio(desc)) != 1)) {
         gpiod_warn(desc,
                "%s: missing direction_input() operation and line is output\n",
                __func__);
         return -EIO;
     }
     if (ret == 0) {
         clear_bit(FLAG_IS_OUT, &desc->flags);
         ret = gpio_set_bias(desc);
     }
 
     trace_gpio_direction(desc_to_gpio(desc), 1, ret);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(gpiod_direction_input);
 
 static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value)
 {
     struct gpio_chip *gc = desc->gdev->chip;
     int val = !!value;
     int ret = 0;
 
     /*
      * It's OK not to specify .direction_output() if the gpiochip is
      * output-only, but if there is then not even a .set() operation it
      * is pretty tricky to drive the output line.
      */
     if (!gc->set && !gc->direction_output) {
         gpiod_warn(desc,
                "%s: missing set() and direction_output() operations\n",
                __func__);
         return -EIO;
     }
 
     if (gc->direction_output) {
         ret = gc->direction_output(gc, gpio_chip_hwgpio(desc), val);
     } else {
         /* Check that we are in output mode if we can */
         if (gc->get_direction &&
             gc->get_direction(gc, gpio_chip_hwgpio(desc))) {
             gpiod_warn(desc,
                 "%s: missing direction_output() operation\n",
                 __func__);
             return -EIO;
         }
         /*
          * If we can't actively set the direction, we are some
          * output-only chip, so just drive the output as desired.
          */
         gc->set(gc, gpio_chip_hwgpio(desc), val);
     }
 
     if (!ret)
         set_bit(FLAG_IS_OUT, &desc->flags);
     trace_gpio_value(desc_to_gpio(desc), 0, val);
     trace_gpio_direction(desc_to_gpio(desc), 0, ret);
     return ret;
 }
 
 /**
  * gpiod_direction_output_raw - set the GPIO direction to output
  * @desc:   GPIO to set to output
  * @value:  initial output value of the GPIO
  *
  * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
  * be called safely on it. The initial value of the output must be specified
  * as raw value on the physical line without regard for the ACTIVE_LOW status.
  *
  * Return 0 in case of success, else an error code.
  */
 int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 {
     VALIDATE_DESC(desc);
     return gpiod_direction_output_raw_commit(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
 
 /**
  * gpiod_direction_output - set the GPIO direction to output
  * @desc:   GPIO to set to output
  * @value:  initial output value of the GPIO
  *
  * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
  * be called safely on it. The initial value of the output must be specified
  * as the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
  * account.
  *
  * Return 0 in case of success, else an error code.
  */
 int gpiod_direction_output(struct gpio_desc *desc, int value)
 {
     int ret;
 
     VALIDATE_DESC(desc);
     if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
         value = !value;
     else
         value = !!value;
 
     /* GPIOs used for enabled IRQs shall not be set as output */
     if (test_bit(FLAG_USED_AS_IRQ, &desc->flags) &&
         test_bit(FLAG_IRQ_IS_ENABLED, &desc->flags)) {
         gpiod_err(desc,
               "%s: tried to set a GPIO tied to an IRQ as output\n",
               __func__);
         return -EIO;
     }
 
     if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
         /* First see if we can enable open drain in hardware */
         ret = gpio_set_config(desc, PIN_CONFIG_DRIVE_OPEN_DRAIN);
         if (!ret)
             goto set_output_value;
         /* Emulate open drain by not actively driving the line high */
         if (value) {
             ret = gpiod_direction_input(desc);
             goto set_output_flag;
         }
     } else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
         ret = gpio_set_config(desc, PIN_CONFIG_DRIVE_OPEN_SOURCE);
         if (!ret)
             goto set_output_value;
         /* Emulate open source by not actively driving the line low */
         if (!value) {
             ret = gpiod_direction_input(desc);
             goto set_output_flag;
         }
     } else {
         gpio_set_config(desc, PIN_CONFIG_DRIVE_PUSH_PULL);
     }
 
 set_output_value:
     ret = gpio_set_bias(desc);
     if (ret)
         return ret;
     return gpiod_direction_output_raw_commit(desc, value);
 
 set_output_flag:
     /*
      * When emulating open-source or open-drain functionalities by not
      * actively driving the line (setting mode to input) we still need to
      * set the IS_OUT flag or otherwise we won't be able to set the line
      * value anymore.
      */
     if (ret == 0)
         set_bit(FLAG_IS_OUT, &desc->flags);
     return ret;
 }
 EXPORT_SYMBOL_GPL(gpiod_direction_output);
 
 /**
  * gpiod_enable_hw_timestamp_ns - Enable hardware timestamp in nanoseconds.
  *
  * @desc: GPIO to enable.
  * @flags: Flags related to GPIO edge.
  *
  * Return 0 in case of success, else negative error code.
  */
 int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags)
 {
     int ret = 0;
     struct gpio_chip *gc;
 
     VALIDATE_DESC(desc);
 
     gc = desc->gdev->chip;
     if (!gc->en_hw_timestamp) {
         gpiod_warn(desc, "%s: hw ts not supported\n", __func__);
         return -ENOTSUPP;
     }
 
     ret = gc->en_hw_timestamp(gc, gpio_chip_hwgpio(desc), flags);
     if (ret)
         gpiod_warn(desc, "%s: hw ts request failed\n", __func__);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(gpiod_enable_hw_timestamp_ns);
 
 /**
  * gpiod_disable_hw_timestamp_ns - Disable hardware timestamp.
  *
  * @desc: GPIO to disable.
  * @flags: Flags related to GPIO edge, same value as used during enable call.
  *
  * Return 0 in case of success, else negative error code.
  */
 int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags)
 {
     int ret = 0;
     struct gpio_chip *gc;
 
     VALIDATE_DESC(desc);
 
     gc = desc->gdev->chip;
     if (!gc->dis_hw_timestamp) {
         gpiod_warn(desc, "%s: hw ts not supported\n", __func__);
         return -ENOTSUPP;
     }
 
     ret = gc->dis_hw_timestamp(gc, gpio_chip_hwgpio(desc), flags);
     if (ret)
         gpiod_warn(desc, "%s: hw ts release failed\n", __func__);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(gpiod_disable_hw_timestamp_ns);
 
 /**
  * gpiod_set_config - sets @config for a GPIO
  * @desc: descriptor of the GPIO for which to set the configuration
  * @config: Same packed config format as generic pinconf
  *
  * Returns:
  * 0 on success, %-ENOTSUPP if the controller doesn't support setting the
  * configuration.
  */
 int gpiod_set_config(struct gpio_desc *desc, unsigned long config)
 {
     struct gpio_chip *gc;
 
     VALIDATE_DESC(desc);
     gc = desc->gdev->chip;
 
     return gpio_do_set_config(gc, gpio_chip_hwgpio(desc), config);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_config);
 
 /**
  * gpiod_set_debounce - sets @debounce time for a GPIO
  * @desc: descriptor of the GPIO for which to set debounce time
  * @debounce: debounce time in microseconds
  *
  * Returns:
  * 0 on success, %-ENOTSUPP if the controller doesn't support setting the
  * debounce time.
  */
 int gpiod_set_debounce(struct gpio_desc *desc, unsigned int debounce)
 {
     unsigned long config;
 
     config = pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, debounce);
     return gpiod_set_config(desc, config);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_debounce);
 
 /**
  * gpiod_set_transitory - Lose or retain GPIO state on suspend or reset
  * @desc: descriptor of the GPIO for which to configure persistence
  * @transitory: True to lose state on suspend or reset, false for persistence
  *
  * Returns:
  * 0 on success, otherwise a negative error code.
  */
 int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
 {
     VALIDATE_DESC(desc);
     /*
      * Handle FLAG_TRANSITORY first, enabling queries to gpiolib for
      * persistence state.
      */
     assign_bit(FLAG_TRANSITORY, &desc->flags, transitory);
 
     /* If the driver supports it, set the persistence state now */
     return gpio_set_config_with_argument_optional(desc,
                               PIN_CONFIG_PERSIST_STATE,
                               !transitory);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_transitory);
 
 /**
  * gpiod_is_active_low - test whether a GPIO is active-low or not
  * @desc: the gpio descriptor to test
  *
  * Returns 1 if the GPIO is active-low, 0 otherwise.
  */
 int gpiod_is_active_low(const struct gpio_desc *desc)
 {
     VALIDATE_DESC(desc);
     return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
 }
 EXPORT_SYMBOL_GPL(gpiod_is_active_low);
 
 /**
  * gpiod_toggle_active_low - toggle whether a GPIO is active-low or not
  * @desc: the gpio descriptor to change
  */
 void gpiod_toggle_active_low(struct gpio_desc *desc)
 {
     VALIDATE_DESC_VOID(desc);
     change_bit(FLAG_ACTIVE_LOW, &desc->flags);
 }
 EXPORT_SYMBOL_GPL(gpiod_toggle_active_low);
 
 static int gpio_chip_get_value(struct gpio_chip *gc, const struct gpio_desc *desc)
 {
     return gc->get ? gc->get(gc, gpio_chip_hwgpio(desc)) : -EIO;
 }
 
 /* I/O calls are only valid after configuration completed; the relevant
  * "is this a valid GPIO" error checks should already have been done.
  *
  * "Get" operations are often inlinable as reading a pin value register,
  * and masking the relevant bit in that register.
  *
  * When "set" operations are inlinable, they involve writing that mask to
  * one register to set a low value, or a different register to set it high.
  * Otherwise locking is needed, so there may be little value to inlining.
  *
  *------------------------------------------------------------------------
  *
  * IMPORTANT!!!  The hot paths -- get/set value -- assume that callers
  * have requested the GPIO.  That can include implicit requesting by
  * a direction setting call.  Marking a gpio as requested locks its chip
  * in memory, guaranteeing that these table lookups need no more locking
  * and that gpiochip_remove() will fail.
  *
  * REVISIT when debugging, consider adding some instrumentation to ensure
  * that the GPIO was actually requested.
  */
 
 static int gpiod_get_raw_value_commit(const struct gpio_desc *desc)
 {
     struct gpio_chip    *gc;
     int value;
 
     gc = desc->gdev->chip;
     value = gpio_chip_get_value(gc, desc);
     value = value < 0 ? value : !!value;
     trace_gpio_value(desc_to_gpio(desc), 1, value);
     return value;
 }
 
 static int gpio_chip_get_multiple(struct gpio_chip *gc,
                   unsigned long *mask, unsigned long *bits)
 {
     if (gc->get_multiple)
         return gc->get_multiple(gc, mask, bits);
     if (gc->get) {
         int i, value;
 
         for_each_set_bit(i, mask, gc->ngpio) {
             value = gc->get(gc, i);
             if (value < 0)
                 return value;
             __assign_bit(i, bits, value);
         }
         return 0;
     }
     return -EIO;
 }
 
 int gpiod_get_array_value_complex(bool raw, bool can_sleep,
                   unsigned int array_size,
                   struct gpio_desc **desc_array,
                   struct gpio_array *array_info,
                   unsigned long *value_bitmap)
 {
     int ret, i = 0;
 
     /*
      * Validate array_info against desc_array and its size.
      * It should immediately follow desc_array if both
      * have been obtained from the same gpiod_get_array() call.
      */
     if (array_info && array_info->desc == desc_array &&
         array_size <= array_info->size &&
         (void *)array_info == desc_array + array_info->size) {
         if (!can_sleep)
             WARN_ON(array_info->chip->can_sleep);
 
         ret = gpio_chip_get_multiple(array_info->chip,
                          array_info->get_mask,
                          value_bitmap);
         if (ret)
             return ret;
 
         if (!raw && !bitmap_empty(array_info->invert_mask, array_size))
             bitmap_xor(value_bitmap, value_bitmap,
                    array_info->invert_mask, array_size);
 
         i = find_first_zero_bit(array_info->get_mask, array_size);
         if (i == array_size)
             return 0;
     } else {
         array_info = NULL;
     }
 
     while (i < array_size) {
         struct gpio_chip *gc = desc_array[i]->gdev->chip;
         DECLARE_BITMAP(fastpath_mask, FASTPATH_NGPIO);
         DECLARE_BITMAP(fastpath_bits, FASTPATH_NGPIO);
         unsigned long *mask, *bits;
         int first, j;
 
         if (likely(gc->ngpio <= FASTPATH_NGPIO)) {
             mask = fastpath_mask;
             bits = fastpath_bits;
         } else {
             gfp_t flags = can_sleep ? GFP_KERNEL : GFP_ATOMIC;
 
             mask = bitmap_alloc(gc->ngpio, flags);
             if (!mask)
                 return -ENOMEM;
 
             bits = bitmap_alloc(gc->ngpio, flags);
             if (!bits) {
                 bitmap_free(mask);
                 return -ENOMEM;
             }
         }
 
         bitmap_zero(mask, gc->ngpio);
 
         if (!can_sleep)
             WARN_ON(gc->can_sleep);
 
         /* collect all inputs belonging to the same chip */
         first = i;
         do {
             const struct gpio_desc *desc = desc_array[i];
             int hwgpio = gpio_chip_hwgpio(desc);
 
             __set_bit(hwgpio, mask);
             i++;
 
             if (array_info)
                 i = find_next_zero_bit(array_info->get_mask,
                                array_size, i);
         } while ((i < array_size) &&
              (desc_array[i]->gdev->chip == gc));
 
         ret = gpio_chip_get_multiple(gc, mask, bits);
         if (ret) {
             if (mask != fastpath_mask)
                 bitmap_free(mask);
             if (bits != fastpath_bits)
                 bitmap_free(bits);
             return ret;
         }
 
         for (j = first; j < i; ) {
             const struct gpio_desc *desc = desc_array[j];
             int hwgpio = gpio_chip_hwgpio(desc);
             int value = test_bit(hwgpio, bits);
 
             if (!raw && test_bit(FLAG_ACTIVE_LOW, &desc->flags))
                 value = !value;
             __assign_bit(j, value_bitmap, value);
             trace_gpio_value(desc_to_gpio(desc), 1, value);
             j++;
 
             if (array_info)
                 j = find_next_zero_bit(array_info->get_mask, i,
                                j);
         }
 
         if (mask != fastpath_mask)
             bitmap_free(mask);
         if (bits != fastpath_bits)
             bitmap_free(bits);
     }
     return 0;
 }
 
 /**
  * gpiod_get_raw_value() - return a gpio's raw value
  * @desc: gpio whose value will be returned
  *
  * Return the GPIO's raw value, i.e. the value of the physical line disregarding
  * its ACTIVE_LOW status, or negative errno on failure.
  *
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
 int gpiod_get_raw_value(const struct gpio_desc *desc)
 {
     VALIDATE_DESC(desc);
     /* Should be using gpiod_get_raw_value_cansleep() */
     WARN_ON(desc->gdev->chip->can_sleep);
     return gpiod_get_raw_value_commit(desc);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
 
 /**
  * gpiod_get_value() - return a gpio's value
  * @desc: gpio whose value will be returned
  *
  * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
  * account, or negative errno on failure.
  *
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
 int gpiod_get_value(const struct gpio_desc *desc)
 {
     int value;
 
     VALIDATE_DESC(desc);
     /* Should be using gpiod_get_value_cansleep() */
     WARN_ON(desc->gdev->chip->can_sleep);
 
     value = gpiod_get_raw_value_commit(desc);
     if (value < 0)
         return value;
 
     if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
         value = !value;
 
     return value;
 }
 EXPORT_SYMBOL_GPL(gpiod_get_value);
 
 /**
  * gpiod_get_raw_array_value() - read raw values from an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be read
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap to store the read values
  *
  * Read the raw values of the GPIOs, i.e. the values of the physical lines
  * without regard for their ACTIVE_LOW status.  Return 0 in case of success,
  * else an error code.
  *
  * This function can be called from contexts where we cannot sleep,
  * and it will complain if the GPIO chip functions potentially sleep.
  */
 int gpiod_get_raw_array_value(unsigned int array_size,
                   struct gpio_desc **desc_array,
                   struct gpio_array *array_info,
                   unsigned long *value_bitmap)
 {
     if (!desc_array)
         return -EINVAL;
     return gpiod_get_array_value_complex(true, false, array_size,
                          desc_array, array_info,
                          value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_raw_array_value);
 
 /**
  * gpiod_get_array_value() - read values from an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be read
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap to store the read values
  *
  * Read the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
  * into account.  Return 0 in case of success, else an error code.
  *
  * This function can be called from contexts where we cannot sleep,
  * and it will complain if the GPIO chip functions potentially sleep.
  */
 int gpiod_get_array_value(unsigned int array_size,
               struct gpio_desc **desc_array,
               struct gpio_array *array_info,
               unsigned long *value_bitmap)
 {
     if (!desc_array)
         return -EINVAL;
     return gpiod_get_array_value_complex(false, false, array_size,
                          desc_array, array_info,
                          value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_array_value);
 
 /*
  *  gpio_set_open_drain_value_commit() - Set the open drain gpio's value.
  * @desc: gpio descriptor whose state need to be set.
  * @value: Non-zero for setting it HIGH otherwise it will set to LOW.
  */
 static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
 {
     int ret = 0;
     struct gpio_chip *gc = desc->gdev->chip;
     int offset = gpio_chip_hwgpio(desc);
 
     if (value) {
         ret = gc->direction_input(gc, offset);
     } else {
         ret = gc->direction_output(gc, offset, 0);
         if (!ret)
             set_bit(FLAG_IS_OUT, &desc->flags);
     }
     trace_gpio_direction(desc_to_gpio(desc), value, ret);
     if (ret < 0)
         gpiod_err(desc,
               "%s: Error in set_value for open drain err %d\n",
               __func__, ret);
 }
 
 /*
  *  _gpio_set_open_source_value() - Set the open source gpio's value.
  * @desc: gpio descriptor whose state need to be set.
  * @value: Non-zero for setting it HIGH otherwise it will set to LOW.
  */
 static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value)
 {
     int ret = 0;
     struct gpio_chip *gc = desc->gdev->chip;
     int offset = gpio_chip_hwgpio(desc);
 
     if (value) {
         ret = gc->direction_output(gc, offset, 1);
         if (!ret)
             set_bit(FLAG_IS_OUT, &desc->flags);
     } else {
         ret = gc->direction_input(gc, offset);
     }
     trace_gpio_direction(desc_to_gpio(desc), !value, ret);
     if (ret < 0)
         gpiod_err(desc,
               "%s: Error in set_value for open source err %d\n",
               __func__, ret);
 }
 
 static void gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value)
 {
     struct gpio_chip    *gc;
 
     gc = desc->gdev->chip;
     trace_gpio_value(desc_to_gpio(desc), 0, value);
     gc->set(gc, gpio_chip_hwgpio(desc), value);
 }
 
 /*
  * set multiple outputs on the same chip;
  * use the chip's set_multiple function if available;
  * otherwise set the outputs sequentially;
  * @chip: the GPIO chip we operate on
  * @mask: bit mask array; one bit per output; BITS_PER_LONG bits per word
  *        defines which outputs are to be changed
  * @bits: bit value array; one bit per output; BITS_PER_LONG bits per word
  *        defines the values the outputs specified by mask are to be set to
  */
 static void gpio_chip_set_multiple(struct gpio_chip *gc,
                    unsigned long *mask, unsigned long *bits)
 {
     if (gc->set_multiple) {
         gc->set_multiple(gc, mask, bits);
     } else {
         unsigned int i;
 
         /* set outputs if the corresponding mask bit is set */
         for_each_set_bit(i, mask, gc->ngpio)
             gc->set(gc, i, test_bit(i, bits));
     }
 }
 
 int gpiod_set_array_value_complex(bool raw, bool can_sleep,
                   unsigned int array_size,
                   struct gpio_desc **desc_array,
                   struct gpio_array *array_info,
                   unsigned long *value_bitmap)
 {
     int i = 0;
 
     /*
      * Validate array_info against desc_array and its size.
      * It should immediately follow desc_array if both
      * have been obtained from the same gpiod_get_array() call.
      */
     if (array_info && array_info->desc == desc_array &&
         array_size <= array_info->size &&
         (void *)array_info == desc_array + array_info->size) {
         if (!can_sleep)
             WARN_ON(array_info->chip->can_sleep);
 
         if (!raw && !bitmap_empty(array_info->invert_mask, array_size))
             bitmap_xor(value_bitmap, value_bitmap,
                    array_info->invert_mask, array_size);
 
         gpio_chip_set_multiple(array_info->chip, array_info->set_mask,
                        value_bitmap);
 
         i = find_first_zero_bit(array_info->set_mask, array_size);
         if (i == array_size)
             return 0;
     } else {
         array_info = NULL;
     }
 
     while (i < array_size) {
         struct gpio_chip *gc = desc_array[i]->gdev->chip;
         DECLARE_BITMAP(fastpath_mask, FASTPATH_NGPIO);
         DECLARE_BITMAP(fastpath_bits, FASTPATH_NGPIO);
         unsigned long *mask, *bits;
         int count = 0;
 
         if (likely(gc->ngpio <= FASTPATH_NGPIO)) {
             mask = fastpath_mask;
             bits = fastpath_bits;
         } else {
             gfp_t flags = can_sleep ? GFP_KERNEL : GFP_ATOMIC;
 
             mask = bitmap_alloc(gc->ngpio, flags);
             if (!mask)
                 return -ENOMEM;
 
             bits = bitmap_alloc(gc->ngpio, flags);
             if (!bits) {
                 bitmap_free(mask);
                 return -ENOMEM;
             }
         }
 
         bitmap_zero(mask, gc->ngpio);
 
         if (!can_sleep)
             WARN_ON(gc->can_sleep);
 
         do {
             struct gpio_desc *desc = desc_array[i];
             int hwgpio = gpio_chip_hwgpio(desc);
             int value = test_bit(i, value_bitmap);
 
             /*
              * Pins applicable for fast input but not for
              * fast output processing may have been already
              * inverted inside the fast path, skip them.
              */
             if (!raw && !(array_info &&
                 test_bit(i, array_info->invert_mask)) &&
                 test_bit(FLAG_ACTIVE_LOW, &desc->flags))
                 value = !value;
             trace_gpio_value(desc_to_gpio(desc), 0, value);
             /*
              * collect all normal outputs belonging to the same chip
              * open drain and open source outputs are set individually
              */
             if (test_bit(FLAG_OPEN_DRAIN, &desc->flags) && !raw) {
                 gpio_set_open_drain_value_commit(desc, value);
             } else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags) && !raw) {
                 gpio_set_open_source_value_commit(desc, value);
             } else {
                 __set_bit(hwgpio, mask);
                 __assign_bit(hwgpio, bits, value);
                 count++;
             }
             i++;
 
             if (array_info)
                 i = find_next_zero_bit(array_info->set_mask,
                                array_size, i);
         } while ((i < array_size) &&
              (desc_array[i]->gdev->chip == gc));
         /* push collected bits to outputs */
         if (count != 0)
             gpio_chip_set_multiple(gc, mask, bits);
 
         if (mask != fastpath_mask)
             bitmap_free(mask);
         if (bits != fastpath_bits)
             bitmap_free(bits);
     }
     return 0;
 }
 
 /**
  * gpiod_set_raw_value() - assign a gpio's raw value
  * @desc: gpio whose value will be assigned
  * @value: value to assign
  *
  * Set the raw value of the GPIO, i.e. the value of its physical line without
  * regard for its ACTIVE_LOW status.
  *
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
 void gpiod_set_raw_value(struct gpio_desc *desc, int value)
 {
     VALIDATE_DESC_VOID(desc);
     /* Should be using gpiod_set_raw_value_cansleep() */
     WARN_ON(desc->gdev->chip->can_sleep);
     gpiod_set_raw_value_commit(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
 
 /**
  * gpiod_set_value_nocheck() - set a GPIO line value without checking
  * @desc: the descriptor to set the value on
  * @value: value to set
  *
  * This sets the value of a GPIO line backing a descriptor, applying
  * different semantic quirks like active low and open drain/source
  * handling.
  */
 static void gpiod_set_value_nocheck(struct gpio_desc *desc, int value)
 {
     if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
         value = !value;
     if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
         gpio_set_open_drain_value_commit(desc, value);
     else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
         gpio_set_open_source_value_commit(desc, value);
     else
         gpiod_set_raw_value_commit(desc, value);
 }
 
 /**
  * gpiod_set_value() - assign a gpio's value
  * @desc: gpio whose value will be assigned
  * @value: value to assign
  *
  * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW,
  * OPEN_DRAIN and OPEN_SOURCE flags into account.
  *
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
 void gpiod_set_value(struct gpio_desc *desc, int value)
 {
     VALIDATE_DESC_VOID(desc);
     /* Should be using gpiod_set_value_cansleep() */
     WARN_ON(desc->gdev->chip->can_sleep);
     gpiod_set_value_nocheck(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_value);
 
 /**
  * gpiod_set_raw_array_value() - assign values to an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be assigned
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap of values to assign
  *
  * Set the raw values of the GPIOs, i.e. the values of the physical lines
  * without regard for their ACTIVE_LOW status.
  *
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
 int gpiod_set_raw_array_value(unsigned int array_size,
                   struct gpio_desc **desc_array,
                   struct gpio_array *array_info,
                   unsigned long *value_bitmap)
 {
     if (!desc_array)
         return -EINVAL;
     return gpiod_set_array_value_complex(true, false, array_size,
                     desc_array, array_info, value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_array_value);
 
 /**
  * gpiod_set_array_value() - assign values to an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be assigned
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap of values to assign
  *
  * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
  * into account.
  *
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
 int gpiod_set_array_value(unsigned int array_size,
               struct gpio_desc **desc_array,
               struct gpio_array *array_info,
               unsigned long *value_bitmap)
 {
     if (!desc_array)
         return -EINVAL;
     return gpiod_set_array_value_complex(false, false, array_size,
                          desc_array, array_info,
                          value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_array_value);
 
 /**
  * gpiod_cansleep() - report whether gpio value access may sleep
  * @desc: gpio to check
  *
  */
 int gpiod_cansleep(const struct gpio_desc *desc)
 {
     VALIDATE_DESC(desc);
     return desc->gdev->chip->can_sleep;
 }
 EXPORT_SYMBOL_GPL(gpiod_cansleep);
 
 /**
  * gpiod_set_consumer_name() - set the consumer name for the descriptor
  * @desc: gpio to set the consumer name on
  * @name: the new consumer name
  */
 int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name)
 {
     VALIDATE_DESC(desc);
     if (name) {
         name = kstrdup_const(name, GFP_KERNEL);
         if (!name)
             return -ENOMEM;
     }
 
     kfree_const(desc->label);
     desc_set_label(desc, name);
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiod_set_consumer_name);
 
 /**
  * gpiod_to_irq() - return the IRQ corresponding to a GPIO
  * @desc: gpio whose IRQ will be returned (already requested)
  *
  * Return the IRQ corresponding to the passed GPIO, or an error code in case of
  * error.
  */
 int gpiod_to_irq(const struct gpio_desc *desc)
 {
     struct gpio_chip *gc;
     int offset;
 
     /*
      * Cannot VALIDATE_DESC() here as gpiod_to_irq() consumer semantics
      * requires this function to not return zero on an invalid descriptor
      * but rather a negative error number.
      */
     if (!desc || IS_ERR(desc) || !desc->gdev || !desc->gdev->chip)
         return -EINVAL;
 
     gc = desc->gdev->chip;
     offset = gpio_chip_hwgpio(desc);
     if (gc->to_irq) {
         int retirq = gc->to_irq(gc, offset);
 
         /* Zero means NO_IRQ */
         if (!retirq)
             return -ENXIO;
 
         return retirq;
     }
 #ifdef CONFIG_GPIOLIB_IRQCHIP
     if (gc->irq.chip) {
         /*
          * Avoid race condition with other code, which tries to lookup
          * an IRQ before the irqchip has been properly registered,
          * i.e. while gpiochip is still being brought up.
          */
         return -EPROBE_DEFER;
     }
 #endif
     return -ENXIO;
 }
 EXPORT_SYMBOL_GPL(gpiod_to_irq);
 
 /**
  * gpiochip_lock_as_irq() - lock a GPIO to be used as IRQ
  * @gc: the chip the GPIO to lock belongs to
  * @offset: the offset of the GPIO to lock as IRQ
  *
  * This is used directly by GPIO drivers that want to lock down
  * a certain GPIO line to be used for IRQs.
  */
 int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset)
 {
     struct gpio_desc *desc;
 
     desc = gpiochip_get_desc(gc, offset);
     if (IS_ERR(desc))
         return PTR_ERR(desc);
 
     /*
      * If it's fast: flush the direction setting if something changed
      * behind our back
      */
     if (!gc->can_sleep && gc->get_direction) {
         int dir = gpiod_get_direction(desc);
 
         if (dir < 0) {
             chip_err(gc, "%s: cannot get GPIO direction\n",
                  __func__);
             return dir;
         }
     }
 
     /* To be valid for IRQ the line needs to be input or open drain */
     if (test_bit(FLAG_IS_OUT, &desc->flags) &&
         !test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
         chip_err(gc,
              "%s: tried to flag a GPIO set as output for IRQ\n",
              __func__);
         return -EIO;
     }
 
     set_bit(FLAG_USED_AS_IRQ, &desc->flags);
     set_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
 
     /*
      * If the consumer has not set up a label (such as when the
      * IRQ is referenced from .to_irq()) we set up a label here
      * so it is clear this is used as an interrupt.
      */
     if (!desc->label)
         desc_set_label(desc, "interrupt");
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);
 
 /**
  * gpiochip_unlock_as_irq() - unlock a GPIO used as IRQ
  * @gc: the chip the GPIO to lock belongs to
  * @offset: the offset of the GPIO to lock as IRQ
  *
  * This is used directly by GPIO drivers that want to indicate
  * that a certain GPIO is no longer used exclusively for IRQ.
  */
 void gpiochip_unlock_as_irq(struct gpio_chip *gc, unsigned int offset)
 {
     struct gpio_desc *desc;
 
     desc = gpiochip_get_desc(gc, offset);
     if (IS_ERR(desc))
         return;
 
     clear_bit(FLAG_USED_AS_IRQ, &desc->flags);
     clear_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
 
     /* If we only had this marking, erase it */
     if (desc->label && !strcmp(desc->label, "interrupt"))
         desc_set_label(desc, NULL);
 }
 EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
 
 void gpiochip_disable_irq(struct gpio_chip *gc, unsigned int offset)
 {
     struct gpio_desc *desc = gpiochip_get_desc(gc, offset);
 
     if (!IS_ERR(desc) &&
         !WARN_ON(!test_bit(FLAG_USED_AS_IRQ, &desc->flags)))
         clear_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
 }
 EXPORT_SYMBOL_GPL(gpiochip_disable_irq);
 
 void gpiochip_enable_irq(struct gpio_chip *gc, unsigned int offset)
 {
     struct gpio_desc *desc = gpiochip_get_desc(gc, offset);
 
     if (!IS_ERR(desc) &&
         !WARN_ON(!test_bit(FLAG_USED_AS_IRQ, &desc->flags))) {
         /*
          * We must not be output when using IRQ UNLESS we are
          * open drain.
          */
         WARN_ON(test_bit(FLAG_IS_OUT, &desc->flags) &&
             !test_bit(FLAG_OPEN_DRAIN, &desc->flags));
         set_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
     }
 }
 EXPORT_SYMBOL_GPL(gpiochip_enable_irq);
 
 bool gpiochip_line_is_irq(struct gpio_chip *gc, unsigned int offset)
 {
     if (offset >= gc->ngpio)
         return false;
 
     return test_bit(FLAG_USED_AS_IRQ, &gc->gpiodev->descs[offset].flags);
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_irq);
 
 int gpiochip_reqres_irq(struct gpio_chip *gc, unsigned int offset)
 {
     int ret;
 
     if (!try_module_get(gc->gpiodev->owner))
         return -ENODEV;
 
     ret = gpiochip_lock_as_irq(gc, offset);
     if (ret) {
         chip_err(gc, "unable to lock HW IRQ %u for IRQ\n", offset);
         module_put(gc->gpiodev->owner);
         return ret;
     }
     return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_reqres_irq);
 
 void gpiochip_relres_irq(struct gpio_chip *gc, unsigned int offset)
 {
     gpiochip_unlock_as_irq(gc, offset);
     module_put(gc->gpiodev->owner);
 }
 EXPORT_SYMBOL_GPL(gpiochip_relres_irq);
 
 bool gpiochip_line_is_open_drain(struct gpio_chip *gc, unsigned int offset)
 {
     if (offset >= gc->ngpio)
         return false;
 
     return test_bit(FLAG_OPEN_DRAIN, &gc->gpiodev->descs[offset].flags);
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_open_drain);
 
 bool gpiochip_line_is_open_source(struct gpio_chip *gc, unsigned int offset)
 {
     if (offset >= gc->ngpio)
         return false;
 
     return test_bit(FLAG_OPEN_SOURCE, &gc->gpiodev->descs[offset].flags);
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_open_source);
 
 bool gpiochip_line_is_persistent(struct gpio_chip *gc, unsigned int offset)
 {
     if (offset >= gc->ngpio)
         return false;
 
     return !test_bit(FLAG_TRANSITORY, &gc->gpiodev->descs[offset].flags);
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_persistent);
 
 /**
  * gpiod_get_raw_value_cansleep() - return a gpio's raw value
  * @desc: gpio whose value will be returned
  *
  * Return the GPIO's raw value, i.e. the value of the physical line disregarding
  * its ACTIVE_LOW status, or negative errno on failure.
  *
  * This function is to be called from contexts that can sleep.
  */
 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
 {
     might_sleep_if(extra_checks);
     VALIDATE_DESC(desc);
     return gpiod_get_raw_value_commit(desc);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
 
 /**
  * gpiod_get_value_cansleep() - return a gpio's value
  * @desc: gpio whose value will be returned
  *
  * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
  * account, or negative errno on failure.
  *
  * This function is to be called from contexts that can sleep.
  */
 int gpiod_get_value_cansleep(const struct gpio_desc *desc)
 {
     int value;
 
     might_sleep_if(extra_checks);
     VALIDATE_DESC(desc);
     value = gpiod_get_raw_value_commit(desc);
     if (value < 0)
         return value;
 
     if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
         value = !value;
 
     return value;
 }
 EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
 
 /**
  * gpiod_get_raw_array_value_cansleep() - read raw values from an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be read
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap to store the read values
  *
  * Read the raw values of the GPIOs, i.e. the values of the physical lines
  * without regard for their ACTIVE_LOW status.  Return 0 in case of success,
  * else an error code.
  *
  * This function is to be called from contexts that can sleep.
  */
 int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
                        struct gpio_desc **desc_array,
                        struct gpio_array *array_info,
                        unsigned long *value_bitmap)
 {
     might_sleep_if(extra_checks);
     if (!desc_array)
         return -EINVAL;
     return gpiod_get_array_value_complex(true, true, array_size,
                          desc_array, array_info,
                          value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_raw_array_value_cansleep);
 
 /**
  * gpiod_get_array_value_cansleep() - read values from an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be read
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap to store the read values
  *
  * Read the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
  * into account.  Return 0 in case of success, else an error code.
  *
  * This function is to be called from contexts that can sleep.
  */
 int gpiod_get_array_value_cansleep(unsigned int array_size,
                    struct gpio_desc **desc_array,
                    struct gpio_array *array_info,
                    unsigned long *value_bitmap)
 {
     might_sleep_if(extra_checks);
     if (!desc_array)
         return -EINVAL;
     return gpiod_get_array_value_complex(false, true, array_size,
                          desc_array, array_info,
                          value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_array_value_cansleep);
 
 /**
  * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
  * @desc: gpio whose value will be assigned
  * @value: value to assign
  *
  * Set the raw value of the GPIO, i.e. the value of its physical line without
  * regard for its ACTIVE_LOW status.
  *
  * This function is to be called from contexts that can sleep.
  */
 void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
 {
     might_sleep_if(extra_checks);
     VALIDATE_DESC_VOID(desc);
     gpiod_set_raw_value_commit(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
 
 /**
  * gpiod_set_value_cansleep() - assign a gpio's value
  * @desc: gpio whose value will be assigned
  * @value: value to assign
  *
  * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
  * account
  *
  * This function is to be called from contexts that can sleep.
  */
 void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
 {
     might_sleep_if(extra_checks);
     VALIDATE_DESC_VOID(desc);
     gpiod_set_value_nocheck(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
 
 /**
  * gpiod_set_raw_array_value_cansleep() - assign values to an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be assigned
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap of values to assign
  *
  * Set the raw values of the GPIOs, i.e. the values of the physical lines
  * without regard for their ACTIVE_LOW status.
  *
  * This function is to be called from contexts that can sleep.
  */
 int gpiod_set_raw_array_value_cansleep(unsigned int array_size,
                        struct gpio_desc **desc_array,
                        struct gpio_array *array_info,
                        unsigned long *value_bitmap)
 {
     might_sleep_if(extra_checks);
     if (!desc_array)
         return -EINVAL;
     return gpiod_set_array_value_complex(true, true, array_size, desc_array,
                       array_info, value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_array_value_cansleep);
 
 /**
  * gpiod_add_lookup_tables() - register GPIO device consumers
  * @tables: list of tables of consumers to register
  * @n: number of tables in the list
  */
 void gpiod_add_lookup_tables(struct gpiod_lookup_table **tables, size_t n)
 {
     unsigned int i;
 
     mutex_lock(&gpio_lookup_lock);
 
     for (i = 0; i < n; i++)
         list_add_tail(&tables[i]->list, &gpio_lookup_list);
 
     mutex_unlock(&gpio_lookup_lock);
 }
 
 /**
  * gpiod_set_array_value_cansleep() - assign values to an array of GPIOs
  * @array_size: number of elements in the descriptor array / value bitmap
  * @desc_array: array of GPIO descriptors whose values will be assigned
  * @array_info: information on applicability of fast bitmap processing path
  * @value_bitmap: bitmap of values to assign
  *
  * Set the logical values of the GPIOs, i.e. taking their ACTIVE_LOW status
  * into account.
  *
  * This function is to be called from contexts that can sleep.
  */
 int gpiod_set_array_value_cansleep(unsigned int array_size,
                    struct gpio_desc **desc_array,
                    struct gpio_array *array_info,
                    unsigned long *value_bitmap)
 {
     might_sleep_if(extra_checks);
     if (!desc_array)
         return -EINVAL;
     return gpiod_set_array_value_complex(false, true, array_size,
                          desc_array, array_info,
                          value_bitmap);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_array_value_cansleep);
 
 /**
  * gpiod_add_lookup_table() - register GPIO device consumers
  * @table: table of consumers to register
  */
 void gpiod_add_lookup_table(struct gpiod_lookup_table *table)
 {
     gpiod_add_lookup_tables(&table, 1);
 }
 EXPORT_SYMBOL_GPL(gpiod_add_lookup_table);
 
 /**
  * gpiod_remove_lookup_table() - unregister GPIO device consumers
  * @table: table of consumers to unregister
  */
 void gpiod_remove_lookup_table(struct gpiod_lookup_table *table)
 {
     /* Nothing to remove */
     if (!table)
         return;
 
     mutex_lock(&gpio_lookup_lock);
 
     list_del(&table->list);
 
     mutex_unlock(&gpio_lookup_lock);
 }
 EXPORT_SYMBOL_GPL(gpiod_remove_lookup_table);
 
 /**
  * gpiod_add_hogs() - register a set of GPIO hogs from machine code
  * @hogs: table of gpio hog entries with a zeroed sentinel at the end
  */
 void gpiod_add_hogs(struct gpiod_hog *hogs)
 {
     struct gpio_chip *gc;
     struct gpiod_hog *hog;
 
     mutex_lock(&gpio_machine_hogs_mutex);
 
     for (hog = &hogs[0]; hog->chip_label; hog++) {
         list_add_tail(&hog->list, &gpio_machine_hogs);
 
         /*
          * The chip may have been registered earlier, so check if it
          * exists and, if so, try to hog the line now.
          */
         gc = find_chip_by_name(hog->chip_label);
         if (gc)
             gpiochip_machine_hog(gc, hog);
     }
 
     mutex_unlock(&gpio_machine_hogs_mutex);
 }
 EXPORT_SYMBOL_GPL(gpiod_add_hogs);
 
 void gpiod_remove_hogs(struct gpiod_hog *hogs)
 {
     struct gpiod_hog *hog;
 
     mutex_lock(&gpio_machine_hogs_mutex);
     for (hog = &hogs[0]; hog->chip_label; hog++)
         list_del(&hog->list);
     mutex_unlock(&gpio_machine_hogs_mutex);
 }
 EXPORT_SYMBOL_GPL(gpiod_remove_hogs);
 
 static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
 {
     const char *dev_id = dev ? dev_name(dev) : NULL;
     struct gpiod_lookup_table *table;
 
     mutex_lock(&gpio_lookup_lock);
 
     list_for_each_entry(table, &gpio_lookup_list, list) {
         if (table->dev_id && dev_id) {
             /*
              * Valid strings on both ends, must be identical to have
              * a match
              */
             if (!strcmp(table->dev_id, dev_id))
                 goto found;
         } else {
             /*
              * One of the pointers is NULL, so both must be to have
              * a match
              */
             if (dev_id == table->dev_id)
                 goto found;
         }
     }
     table = NULL;
 
 found:
     mutex_unlock(&gpio_lookup_lock);
     return table;
 }
 
 static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
                     unsigned int idx, unsigned long *flags)
 {
     struct gpio_desc *desc = ERR_PTR(-ENOENT);
     struct gpiod_lookup_table *table;
     struct gpiod_lookup *p;
 
     table = gpiod_find_lookup_table(dev);
     if (!table)
         return desc;
 
     for (p = &table->table[0]; p->key; p++) {
         struct gpio_chip *gc;
 
         /* idx must always match exactly */
         if (p->idx != idx)
             continue;
 
         /* If the lookup entry has a con_id, require exact match */
         if (p->con_id && (!con_id || strcmp(p->con_id, con_id)))
             continue;
 
         if (p->chip_hwnum == U16_MAX) {
             desc = gpio_name_to_desc(p->key);
             if (desc) {
                 *flags = p->flags;
                 return desc;
             }
 
             dev_warn(dev, "cannot find GPIO line %s, deferring\n",
                  p->key);
             return ERR_PTR(-EPROBE_DEFER);
         }
 
         gc = find_chip_by_name(p->key);
 
         if (!gc) {
             /*
              * As the lookup table indicates a chip with
              * p->key should exist, assume it may
              * still appear later and let the interested
              * consumer be probed again or let the Deferred
              * Probe infrastructure handle the error.
              */
             dev_warn(dev, "cannot find GPIO chip %s, deferring\n",
                  p->key);
             return ERR_PTR(-EPROBE_DEFER);
         }
 
         if (gc->ngpio <= p->chip_hwnum) {
             dev_err(dev,
                 "requested GPIO %u (%u) is out of range [0..%u] for chip %s\n",
                 idx, p->chip_hwnum, gc->ngpio - 1,
                 gc->label);
             return ERR_PTR(-EINVAL);
         }
 
         desc = gpiochip_get_desc(gc, p->chip_hwnum);
         *flags = p->flags;
 
         return desc;
     }
 
     return desc;
 }
 
 static int platform_gpio_count(struct device *dev, const char *con_id)
 {
     struct gpiod_lookup_table *table;
     struct gpiod_lookup *p;
     unsigned int count = 0;
 
     table = gpiod_find_lookup_table(dev);
     if (!table)
         return -ENOENT;
 
     for (p = &table->table[0]; p->key; p++) {
         if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) ||
             (!con_id && !p->con_id))
             count++;
     }
     if (!count)
         return -ENOENT;
 
     return count;
 }
 
 /**
  * fwnode_gpiod_get_index - obtain a GPIO from firmware node
  * @fwnode: handle of the firmware node
  * @con_id: function within the GPIO consumer
  * @index:  index of the GPIO to obtain for the consumer
  * @flags:  GPIO initialization flags
  * @label:  label to attach to the requested GPIO
  *
  * This function can be used for drivers that get their configuration
  * from opaque firmware.
  *
  * The function properly finds the corresponding GPIO using whatever is the
  * underlying firmware interface and then makes sure that the GPIO
  * descriptor is requested before it is returned to the caller.
  *
  * Returns:
  * On successful request the GPIO pin is configured in accordance with
  * provided @flags.
  *
  * In case of error an ERR_PTR() is returned.
  */
 struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
                      const char *con_id, int index,
                      enum gpiod_flags flags,
                      const char *label)
 {
     struct gpio_desc *desc;
     char prop_name[32]; /* 32 is max size of property name */
     unsigned int i;
 
     for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
         if (con_id)
             snprintf(prop_name, sizeof(prop_name), "%s-%s",
                         con_id, gpio_suffixes[i]);
         else
             snprintf(prop_name, sizeof(prop_name), "%s",
                         gpio_suffixes[i]);
 
         desc = fwnode_get_named_gpiod(fwnode, prop_name, index, flags,
                           label);
         if (!gpiod_not_found(desc))
             break;
     }
 
     return desc;
 }
 EXPORT_SYMBOL_GPL(fwnode_gpiod_get_index);
 
 /**
  * gpiod_count - return the number of GPIOs associated with a device / function
  *      or -ENOENT if no GPIO has been assigned to the requested function
  * @dev:    GPIO consumer, can be NULL for system-global GPIOs
  * @con_id: function within the GPIO consumer
  */
 int gpiod_count(struct device *dev, const char *con_id)
 {
     const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
     int count = -ENOENT;
 
     if (is_of_node(fwnode))
         count = of_gpio_get_count(dev, con_id);
     else if (is_acpi_node(fwnode))
         count = acpi_gpio_count(dev, con_id);
 
     if (count < 0)
         count = platform_gpio_count(dev, con_id);
 
     return count;
 }
 EXPORT_SYMBOL_GPL(gpiod_count);
 
 /**
  * gpiod_get - obtain a GPIO for a given GPIO function
  * @dev:    GPIO consumer, can be NULL for system-global GPIOs
  * @con_id: function within the GPIO consumer
  * @flags:  optional GPIO initialization flags
  *
  * Return the GPIO descriptor corresponding to the function con_id of device
  * dev, -ENOENT if no GPIO has been assigned to the requested function, or
  * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
  */
 struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id,
                      enum gpiod_flags flags)
 {
     return gpiod_get_index(dev, con_id, 0, flags);
 }
 EXPORT_SYMBOL_GPL(gpiod_get);
 
 /**
  * gpiod_get_optional - obtain an optional GPIO for a given GPIO function
  * @dev: GPIO consumer, can be NULL for system-global GPIOs
  * @con_id: function within the GPIO consumer
  * @flags: optional GPIO initialization flags
  *
  * This is equivalent to gpiod_get(), except that when no GPIO was assigned to
  * the requested function it will return NULL. This is convenient for drivers
  * that need to handle optional GPIOs.
  */
 struct gpio_desc *__must_check gpiod_get_optional(struct device *dev,
                           const char *con_id,
                           enum gpiod_flags flags)
 {
     return gpiod_get_index_optional(dev, con_id, 0, flags);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_optional);
 
 
 /**
  * gpiod_configure_flags - helper function to configure a given GPIO
  * @desc:   gpio whose value will be assigned
  * @con_id: function within the GPIO consumer
  * @lflags: bitmask of gpio_lookup_flags GPIO_* values - returned from
  *      of_find_gpio() or of_get_gpio_hog()
  * @dflags: gpiod_flags - optional GPIO initialization flags
  *
  * Return 0 on success, -ENOENT if no GPIO has been assigned to the
  * requested function and/or index, or another IS_ERR() code if an error
  * occurred while trying to acquire the GPIO.
  */
 int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
         unsigned long lflags, enum gpiod_flags dflags)
 {
     int ret;
 
     if (lflags & GPIO_ACTIVE_LOW)
         set_bit(FLAG_ACTIVE_LOW, &desc->flags);
 
     if (lflags & GPIO_OPEN_DRAIN)
         set_bit(FLAG_OPEN_DRAIN, &desc->flags);
     else if (dflags & GPIOD_FLAGS_BIT_OPEN_DRAIN) {
         /*
          * This enforces open drain mode from the consumer side.
          * This is necessary for some busses like I2C, but the lookup
          * should *REALLY* have specified them as open drain in the
          * first place, so print a little warning here.
          */
         set_bit(FLAG_OPEN_DRAIN, &desc->flags);
         gpiod_warn(desc,
                "enforced open drain please flag it properly in DT/ACPI DSDT/board file\n");
     }
 
     if (lflags & GPIO_OPEN_SOURCE)
         set_bit(FLAG_OPEN_SOURCE, &desc->flags);
 
     if (((lflags & GPIO_PULL_UP) && (lflags & GPIO_PULL_DOWN)) ||
         ((lflags & GPIO_PULL_UP) && (lflags & GPIO_PULL_DISABLE)) ||
         ((lflags & GPIO_PULL_DOWN) && (lflags & GPIO_PULL_DISABLE))) {
         gpiod_err(desc,
               "multiple pull-up, pull-down or pull-disable enabled, invalid configuration\n");
         return -EINVAL;
     }
 
     if (lflags & GPIO_PULL_UP)
         set_bit(FLAG_PULL_UP, &desc->flags);
     else if (lflags & GPIO_PULL_DOWN)
         set_bit(FLAG_PULL_DOWN, &desc->flags);
     else if (lflags & GPIO_PULL_DISABLE)
         set_bit(FLAG_BIAS_DISABLE, &desc->flags);
 
     ret = gpiod_set_transitory(desc, (lflags & GPIO_TRANSITORY));
     if (ret < 0)
         return ret;
 
     /* No particular flag request, return here... */
     if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {
         gpiod_dbg(desc, "no flags found for %s\n", con_id);
         return 0;
     }
 
     /* Process flags */
     if (dflags & GPIOD_FLAGS_BIT_DIR_OUT)
         ret = gpiod_direction_output(desc,
                 !!(dflags & GPIOD_FLAGS_BIT_DIR_VAL));
     else
         ret = gpiod_direction_input(desc);
 
     return ret;
 }
 
 /**
  * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
  * @dev:    GPIO consumer, can be NULL for system-global GPIOs
  * @con_id: function within the GPIO consumer
  * @idx:    index of the GPIO to obtain in the consumer
  * @flags:  optional GPIO initialization flags
  *
  * This variant of gpiod_get() allows to access GPIOs other than the first
  * defined one for functions that define several GPIOs.
  *
  * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the
  * requested function and/or index, or another IS_ERR() code if an error
  * occurred while trying to acquire the GPIO.
  */
 struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
                            const char *con_id,
                            unsigned int idx,
                            enum gpiod_flags flags)
 {
     unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
     struct gpio_desc *desc = NULL;
     int ret;
     /* Maybe we have a device name, maybe not */
     const char *devname = dev ? dev_name(dev) : "?";
     const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
 
     dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
 
     /* Using device tree? */
     if (is_of_node(fwnode)) {
         dev_dbg(dev, "using device tree for GPIO lookup\n");
         desc = of_find_gpio(dev, con_id, idx, &lookupflags);
     } else if (is_acpi_node(fwnode)) {
         dev_dbg(dev, "using ACPI for GPIO lookup\n");
         desc = acpi_find_gpio(dev, con_id, idx, &flags, &lookupflags);
     }
 
     /*
      * Either we are not using DT or ACPI, or their lookup did not return
      * a result. In that case, use platform lookup as a fallback.
      */
     if (!desc || gpiod_not_found(desc)) {
         dev_dbg(dev, "using lookup tables for GPIO lookup\n");
         desc = gpiod_find(dev, con_id, idx, &lookupflags);
     }
 
     if (IS_ERR(desc)) {
         dev_dbg(dev, "No GPIO consumer %s found\n", con_id);
         return desc;
     }
 
     /*
      * If a connection label was passed use that, else attempt to use
      * the device name as label
      */
     ret = gpiod_request(desc, con_id ?: devname);
     if (ret) {
         if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
             return ERR_PTR(ret);
 
         /*
          * This happens when there are several consumers for
          * the same GPIO line: we just return here without
          * further initialization. It is a bit of a hack.
          * This is necessary to support fixed regulators.
          *
          * FIXME: Make this more sane and safe.
          */
         dev_info(dev, "nonexclusive access to GPIO for %s\n", con_id ?: devname);
         return desc;
     }
 
     ret = gpiod_configure_flags(desc, con_id, lookupflags, flags);
     if (ret < 0) {
         dev_dbg(dev, "setup of GPIO %s failed\n", con_id);
         gpiod_put(desc);
         return ERR_PTR(ret);
     }
 
     blocking_notifier_call_chain(&desc->gdev->notifier,
                      GPIOLINE_CHANGED_REQUESTED, desc);
 
     return desc;
 }
 EXPORT_SYMBOL_GPL(gpiod_get_index);
 
 /**
  * fwnode_get_named_gpiod - obtain a GPIO from firmware node
  * @fwnode: handle of the firmware node
  * @propname:   name of the firmware property representing the GPIO
  * @index:  index of the GPIO to obtain for the consumer
  * @dflags: GPIO initialization flags
  * @label:  label to attach to the requested GPIO
  *
  * This function can be used for drivers that get their configuration
  * from opaque firmware.
  *
  * The function properly finds the corresponding GPIO using whatever is the
  * underlying firmware interface and then makes sure that the GPIO
  * descriptor is requested before it is returned to the caller.
  *
  * Returns:
  * On successful request the GPIO pin is configured in accordance with
  * provided @dflags.
  *
  * In case of error an ERR_PTR() is returned.
  */
 struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
                      const char *propname, int index,
                      enum gpiod_flags dflags,
                      const char *label)
 {
     unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
     struct gpio_desc *desc = ERR_PTR(-ENODEV);
     int ret;
 
     if (is_of_node(fwnode)) {
         desc = gpiod_get_from_of_node(to_of_node(fwnode),
                           propname, index,
                           dflags,
                           label);
         return desc;
     } else if (is_acpi_node(fwnode)) {
         struct acpi_gpio_info info;
 
         desc = acpi_node_get_gpiod(fwnode, propname, index, &info);
         if (IS_ERR(desc))
             return desc;
 
         acpi_gpio_update_gpiod_flags(&dflags, &info);
         acpi_gpio_update_gpiod_lookup_flags(&lflags, &info);
     } else
         return ERR_PTR(-EINVAL);
 
     /* Currently only ACPI takes this path */
     ret = gpiod_request(desc, label);
     if (ret)
         return ERR_PTR(ret);
 
     ret = gpiod_configure_flags(desc, propname, lflags, dflags);
     if (ret < 0) {
         gpiod_put(desc);
         return ERR_PTR(ret);
     }
 
     blocking_notifier_call_chain(&desc->gdev->notifier,
                      GPIOLINE_CHANGED_REQUESTED, desc);
 
     return desc;
 }
 EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod);
 
 /**
  * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO
  *                            function
  * @dev: GPIO consumer, can be NULL for system-global GPIOs
  * @con_id: function within the GPIO consumer
  * @index: index of the GPIO to obtain in the consumer
  * @flags: optional GPIO initialization flags
  *
  * This is equivalent to gpiod_get_index(), except that when no GPIO with the
  * specified index was assigned to the requested function it will return NULL.
  * This is convenient for drivers that need to handle optional GPIOs.
  */
 struct gpio_desc *__must_check gpiod_get_index_optional(struct device *dev,
                             const char *con_id,
                             unsigned int index,
                             enum gpiod_flags flags)
 {
     struct gpio_desc *desc;
 
     desc = gpiod_get_index(dev, con_id, index, flags);
     if (gpiod_not_found(desc))
         return NULL;
 
     return desc;
 }
 EXPORT_SYMBOL_GPL(gpiod_get_index_optional);
 
 /**
  * gpiod_hog - Hog the specified GPIO desc given the provided flags
  * @desc:   gpio whose value will be assigned
  * @name:   gpio line name
  * @lflags: bitmask of gpio_lookup_flags GPIO_* values - returned from
  *      of_find_gpio() or of_get_gpio_hog()
  * @dflags: gpiod_flags - optional GPIO initialization flags
  */
 int gpiod_hog(struct gpio_desc *desc, const char *name,
           unsigned long lflags, enum gpiod_flags dflags)
 {
     struct gpio_chip *gc;
     struct gpio_desc *local_desc;
     int hwnum;
     int ret;
 
     gc = gpiod_to_chip(desc);
     hwnum = gpio_chip_hwgpio(desc);
 
     local_desc = gpiochip_request_own_desc(gc, hwnum, name,
                            lflags, dflags);
     if (IS_ERR(local_desc)) {
         ret = PTR_ERR(local_desc);
         pr_err("requesting hog GPIO %s (chip %s, offset %d) failed, %d\n",
                name, gc->label, hwnum, ret);
         return ret;
     }
 
     /* Mark GPIO as hogged so it can be identified and removed later */
     set_bit(FLAG_IS_HOGGED, &desc->flags);
 
     gpiod_info(desc, "hogged as %s%s\n",
         (dflags & GPIOD_FLAGS_BIT_DIR_OUT) ? "output" : "input",
         (dflags & GPIOD_FLAGS_BIT_DIR_OUT) ?
           (dflags & GPIOD_FLAGS_BIT_DIR_VAL) ? "/high" : "/low" : "");
 
     return 0;
 }
 
 /**
  * gpiochip_free_hogs - Scan gpio-controller chip and release GPIO hog
  * @gc: gpio chip to act on
  */
 static void gpiochip_free_hogs(struct gpio_chip *gc)
 {
     struct gpio_desc *desc;
 
     for_each_gpio_desc_with_flag(gc, desc, FLAG_IS_HOGGED)
         gpiochip_free_own_desc(desc);
 }
 
 /**
  * gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO function
  * @dev:    GPIO consumer, can be NULL for system-global GPIOs
  * @con_id: function within the GPIO consumer
  * @flags:  optional GPIO initialization flags
  *
  * This function acquires all the GPIOs defined under a given function.
  *
  * Return a struct gpio_descs containing an array of descriptors, -ENOENT if
  * no GPIO has been assigned to the requested function, or another IS_ERR()
  * code if an error occurred while trying to acquire the GPIOs.
  */
 struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
                         const char *con_id,
                         enum gpiod_flags flags)
 {
     struct gpio_desc *desc;
     struct gpio_descs *descs;
     struct gpio_array *array_info = NULL;
     struct gpio_chip *gc;
     int count, bitmap_size;
 
     count = gpiod_count(dev, con_id);
     if (count < 0)
         return ERR_PTR(count);
 
     descs = kzalloc(struct_size(descs, desc, count), GFP_KERNEL);
     if (!descs)
         return ERR_PTR(-ENOMEM);
 
     for (descs->ndescs = 0; descs->ndescs < count; ) {
         desc = gpiod_get_index(dev, con_id, descs->ndescs, flags);
         if (IS_ERR(desc)) {
             gpiod_put_array(descs);
             return ERR_CAST(desc);
         }
 
         descs->desc[descs->ndescs] = desc;
 
         gc = gpiod_to_chip(desc);
         /*
          * If pin hardware number of array member 0 is also 0, select
          * its chip as a candidate for fast bitmap processing path.
          */
         if (descs->ndescs == 0 && gpio_chip_hwgpio(desc) == 0) {
             struct gpio_descs *array;
 
             bitmap_size = BITS_TO_LONGS(gc->ngpio > count ?
                             gc->ngpio : count);
 
             array = kzalloc(struct_size(descs, desc, count) +
                     struct_size(array_info, invert_mask,
                     3 * bitmap_size), GFP_KERNEL);
             if (!array) {
                 gpiod_put_array(descs);
                 return ERR_PTR(-ENOMEM);
             }
 
             memcpy(array, descs,
                    struct_size(descs, desc, descs->ndescs + 1));
             kfree(descs);
 
             descs = array;
             array_info = (void *)(descs->desc + count);
             array_info->get_mask = array_info->invert_mask +
                           bitmap_size;
             array_info->set_mask = array_info->get_mask +
                           bitmap_size;
 
             array_info->desc = descs->desc;
             array_info->size = count;
             array_info->chip = gc;
             bitmap_set(array_info->get_mask, descs->ndescs,
                    count - descs->ndescs);
             bitmap_set(array_info->set_mask, descs->ndescs,
                    count - descs->ndescs);
             descs->info = array_info;
         }
         /* Unmark array members which don't belong to the 'fast' chip */
         if (array_info && array_info->chip != gc) {
             __clear_bit(descs->ndescs, array_info->get_mask);
             __clear_bit(descs->ndescs, array_info->set_mask);
         }
         /*
          * Detect array members which belong to the 'fast' chip
          * but their pins are not in hardware order.
          */
         else if (array_info &&
                gpio_chip_hwgpio(desc) != descs->ndescs) {
             /*
              * Don't use fast path if all array members processed so
              * far belong to the same chip as this one but its pin
              * hardware number is different from its array index.
              */
             if (bitmap_full(array_info->get_mask, descs->ndescs)) {
                 array_info = NULL;
             } else {
                 __clear_bit(descs->ndescs,
                         array_info->get_mask);
                 __clear_bit(descs->ndescs,
                         array_info->set_mask);
             }
         } else if (array_info) {
             /* Exclude open drain or open source from fast output */
             if (gpiochip_line_is_open_drain(gc, descs->ndescs) ||
                 gpiochip_line_is_open_source(gc, descs->ndescs))
                 __clear_bit(descs->ndescs,
                         array_info->set_mask);
             /* Identify 'fast' pins which require invertion */
             if (gpiod_is_active_low(desc))
                 __set_bit(descs->ndescs,
                       array_info->invert_mask);
         }
 
         descs->ndescs++;
     }
     if (array_info)
         dev_dbg(dev,
             "GPIO array info: chip=%s, size=%d, get_mask=%lx, set_mask=%lx, invert_mask=%lx\n",
             array_info->chip->label, array_info->size,
             *array_info->get_mask, *array_info->set_mask,
             *array_info->invert_mask);
     return descs;
 }
 EXPORT_SYMBOL_GPL(gpiod_get_array);
 
 /**
  * gpiod_get_array_optional - obtain multiple GPIOs from a multi-index GPIO
  *                            function
  * @dev:    GPIO consumer, can be NULL for system-global GPIOs
  * @con_id: function within the GPIO consumer
  * @flags:  optional GPIO initialization flags
  *
  * This is equivalent to gpiod_get_array(), except that when no GPIO was
  * assigned to the requested function it will return NULL.
  */
 struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
                             const char *con_id,
                             enum gpiod_flags flags)
 {
     struct gpio_descs *descs;
 
     descs = gpiod_get_array(dev, con_id, flags);
     if (gpiod_not_found(descs))
         return NULL;
 
     return descs;
 }
 EXPORT_SYMBOL_GPL(gpiod_get_array_optional);
 
 /**
  * gpiod_put - dispose of a GPIO descriptor
  * @desc:   GPIO descriptor to dispose of
  *
  * No descriptor can be used after gpiod_put() has been called on it.
  */
 void gpiod_put(struct gpio_desc *desc)
 {
     if (desc)
         gpiod_free(desc);
 }
 EXPORT_SYMBOL_GPL(gpiod_put);
 
 /**
  * gpiod_put_array - dispose of multiple GPIO descriptors
  * @descs:  struct gpio_descs containing an array of descriptors
  */
 void gpiod_put_array(struct gpio_descs *descs)
 {
     unsigned int i;
 
     for (i = 0; i < descs->ndescs; i++)
         gpiod_put(descs->desc[i]);
 
     kfree(descs);
 }
 EXPORT_SYMBOL_GPL(gpiod_put_array);
 
 
 static int gpio_bus_match(struct device *dev, struct device_driver *drv)
 {
     struct fwnode_handle *fwnode = dev_fwnode(dev);
 
     /*
      * Only match if the fwnode doesn't already have a proper struct device
      * created for it.
      */
     if (fwnode && fwnode->dev != dev)
         return 0;
     return 1;
 }
 
 static int gpio_stub_drv_probe(struct device *dev)
 {
     /*
      * The DT node of some GPIO chips have a "compatible" property, but
      * never have a struct device added and probed by a driver to register
      * the GPIO chip with gpiolib. In such cases, fw_devlink=on will cause
      * the consumers of the GPIO chip to get probe deferred forever because
      * they will be waiting for a device associated with the GPIO chip
      * firmware node to get added and bound to a driver.
      *
      * To allow these consumers to probe, we associate the struct
      * gpio_device of the GPIO chip with the firmware node and then simply
      * bind it to this stub driver.
      */
     return 0;
 }
 
 static struct device_driver gpio_stub_drv = {
     .name = "gpio_stub_drv",
     .bus = &gpio_bus_type,
     .probe = gpio_stub_drv_probe,
 };
 
 static int __init gpiolib_dev_init(void)
 {
     int ret;
 
     /* Register GPIO sysfs bus */
     ret = bus_register(&gpio_bus_type);
     if (ret < 0) {
         pr_err("gpiolib: could not register GPIO bus type\n");
         return ret;
     }
 
     ret = driver_register(&gpio_stub_drv);
     if (ret < 0) {
         pr_err("gpiolib: could not register GPIO stub driver\n");
         bus_unregister(&gpio_bus_type);
         return ret;
     }
 
     ret = alloc_chrdev_region(&gpio_devt, 0, GPIO_DEV_MAX, GPIOCHIP_NAME);
     if (ret < 0) {
         pr_err("gpiolib: failed to allocate char dev region\n");
         driver_unregister(&gpio_stub_drv);
         bus_unregister(&gpio_bus_type);
         return ret;
     }
 
     gpiolib_initialized = true;
     gpiochip_setup_devs();
 
 #if IS_ENABLED(CONFIG_OF_DYNAMIC) && IS_ENABLED(CONFIG_OF_GPIO)
     WARN_ON(of_reconfig_notifier_register(&gpio_of_notifier));
 #endif /* CONFIG_OF_DYNAMIC && CONFIG_OF_GPIO */
 
     return ret;
 }
 core_initcall(gpiolib_dev_init);
 
 #ifdef CONFIG_DEBUG_FS
 
 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 {
     struct gpio_chip    *gc = gdev->chip;
     struct gpio_desc    *desc;
     unsigned        gpio = gdev->base;
     int         value;
     bool            is_out;
     bool            is_irq;
     bool            active_low;
 
     for_each_gpio_desc(gc, desc) {
         if (test_bit(FLAG_REQUESTED, &desc->flags)) {
             gpiod_get_direction(desc);
             is_out = test_bit(FLAG_IS_OUT, &desc->flags);
             value = gpio_chip_get_value(gc, desc);
             is_irq = test_bit(FLAG_USED_AS_IRQ, &desc->flags);
             active_low = test_bit(FLAG_ACTIVE_LOW, &desc->flags);
             seq_printf(s, " gpio-%-3d (%-20.20s|%-20.20s) %s %s %s%s\n",
                    gpio, desc->name ?: "", desc->label,
                    is_out ? "out" : "in ",
                    value >= 0 ? (value ? "hi" : "lo") : "?  ",
                    is_irq ? "IRQ " : "",
                    active_low ? "ACTIVE LOW" : "");
         } else if (desc->name) {
             seq_printf(s, " gpio-%-3d (%-20.20s)\n", gpio, desc->name);
         }
 
         gpio++;
     }
 }
 
 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
 {
     unsigned long flags;
     struct gpio_device *gdev = NULL;
     loff_t index = *pos;
 
     s->private = "";
 
     spin_lock_irqsave(&gpio_lock, flags);
     list_for_each_entry(gdev, &gpio_devices, list)
         if (index-- == 0) {
             spin_unlock_irqrestore(&gpio_lock, flags);
             return gdev;
         }
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     return NULL;
 }
 
 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
     unsigned long flags;
     struct gpio_device *gdev = v;
     void *ret = NULL;
 
     spin_lock_irqsave(&gpio_lock, flags);
     if (list_is_last(&gdev->list, &gpio_devices))
         ret = NULL;
     else
         ret = list_first_entry(&gdev->list, struct gpio_device, list);
     spin_unlock_irqrestore(&gpio_lock, flags);
 
     s->private = "\n";
     ++*pos;
 
     return ret;
 }
 
 static void gpiolib_seq_stop(struct seq_file *s, void *v)
 {
 }
 
 static int gpiolib_seq_show(struct seq_file *s, void *v)
 {
     struct gpio_device *gdev = v;
     struct gpio_chip *gc = gdev->chip;
     struct device *parent;
 
     if (!gc) {
         seq_printf(s, "%s%s: (dangling chip)", (char *)s->private,
                dev_name(&gdev->dev));
         return 0;
     }
 
     seq_printf(s, "%s%s: GPIOs %d-%d", (char *)s->private,
            dev_name(&gdev->dev),
            gdev->base, gdev->base + gdev->ngpio - 1);
     parent = gc->parent;
     if (parent)
         seq_printf(s, ", parent: %s/%s",
                parent->bus ? parent->bus->name : "no-bus",
                dev_name(parent));
     if (gc->label)
         seq_printf(s, ", %s", gc->label);
     if (gc->can_sleep)
         seq_printf(s, ", can sleep");
     seq_printf(s, ":\n");
 
     if (gc->dbg_show)
         gc->dbg_show(s, gc);
     else
         gpiolib_dbg_show(s, gdev);
 
     return 0;
 }
 
 static const struct seq_operations gpiolib_sops = {
     .start = gpiolib_seq_start,
     .next = gpiolib_seq_next,
     .stop = gpiolib_seq_stop,
     .show = gpiolib_seq_show,
 };
 DEFINE_SEQ_ATTRIBUTE(gpiolib);
 
 static int __init gpiolib_debugfs_init(void)
 {
     /* /sys/kernel/debug/gpio */
     debugfs_create_file("gpio", 0444, NULL, NULL, &gpiolib_fops);
     return 0;
 }
 subsys_initcall(gpiolib_debugfs_init);
 
 #endif  /* DEBUG_FS */