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	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-only
 /*
  * The input core
  *
  * Copyright (c) 1999-2002 Vojtech Pavlik
  */
 
 
 #define pr_fmt(fmt) KBUILD_BASENAME ": " fmt
 
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/idr.h>
 #include <linux/input/mt.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/random.h>
 #include <linux/major.h>
 #include <linux/proc_fs.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/poll.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
 #include <linux/rcupdate.h>
 #include "input-compat.h"
 #include "input-core-private.h"
 #include "input-poller.h"
 
 MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
 MODULE_DESCRIPTION("Input core");
 MODULE_LICENSE("GPL");
 
 #define INPUT_MAX_CHAR_DEVICES      1024
 #define INPUT_FIRST_DYNAMIC_DEV     256
 static DEFINE_IDA(input_ida);
 
 static LIST_HEAD(input_dev_list);
 static LIST_HEAD(input_handler_list);
 
 /*
  * input_mutex protects access to both input_dev_list and input_handler_list.
  * This also causes input_[un]register_device and input_[un]register_handler
  * be mutually exclusive which simplifies locking in drivers implementing
  * input handlers.
  */
 static DEFINE_MUTEX(input_mutex);
 
 static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };
 
 static const unsigned int input_max_code[EV_CNT] = {
     [EV_KEY] = KEY_MAX,
     [EV_REL] = REL_MAX,
     [EV_ABS] = ABS_MAX,
     [EV_MSC] = MSC_MAX,
     [EV_SW] = SW_MAX,
     [EV_LED] = LED_MAX,
     [EV_SND] = SND_MAX,
     [EV_FF] = FF_MAX,
 };
 
 static inline int is_event_supported(unsigned int code,
                      unsigned long *bm, unsigned int max)
 {
     return code <= max && test_bit(code, bm);
 }
 
 static int input_defuzz_abs_event(int value, int old_val, int fuzz)
 {
     if (fuzz) {
         if (value > old_val - fuzz / 2 && value < old_val + fuzz / 2)
             return old_val;
 
         if (value > old_val - fuzz && value < old_val + fuzz)
             return (old_val * 3 + value) / 4;
 
         if (value > old_val - fuzz * 2 && value < old_val + fuzz * 2)
             return (old_val + value) / 2;
     }
 
     return value;
 }
 
 static void input_start_autorepeat(struct input_dev *dev, int code)
 {
     if (test_bit(EV_REP, dev->evbit) &&
         dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
         dev->timer.function) {
         dev->repeat_key = code;
         mod_timer(&dev->timer,
               jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
     }
 }
 
 static void input_stop_autorepeat(struct input_dev *dev)
 {
     del_timer(&dev->timer);
 }
 
 /*
  * Pass event first through all filters and then, if event has not been
  * filtered out, through all open handles. This function is called with
  * dev->event_lock held and interrupts disabled.
  */
 static unsigned int input_to_handler(struct input_handle *handle,
             struct input_value *vals, unsigned int count)
 {
     struct input_handler *handler = handle->handler;
     struct input_value *end = vals;
     struct input_value *v;
 
     if (handler->filter) {
         for (v = vals; v != vals + count; v++) {
             if (handler->filter(handle, v->type, v->code, v->value))
                 continue;
             if (end != v)
                 *end = *v;
             end++;
         }
         count = end - vals;
     }
 
     if (!count)
         return 0;
 
     if (handler->events)
         handler->events(handle, vals, count);
     else if (handler->event)
         for (v = vals; v != vals + count; v++)
             handler->event(handle, v->type, v->code, v->value);
 
     return count;
 }
 
 /*
  * Pass values first through all filters and then, if event has not been
  * filtered out, through all open handles. This function is called with
  * dev->event_lock held and interrupts disabled.
  */
 static void input_pass_values(struct input_dev *dev,
                   struct input_value *vals, unsigned int count)
 {
     struct input_handle *handle;
     struct input_value *v;
 
     lockdep_assert_held(&dev->event_lock);
 
     if (!count)
         return;
 
     rcu_read_lock();
 
     handle = rcu_dereference(dev->grab);
     if (handle) {
         count = input_to_handler(handle, vals, count);
     } else {
         list_for_each_entry_rcu(handle, &dev->h_list, d_node)
             if (handle->open) {
                 count = input_to_handler(handle, vals, count);
                 if (!count)
                     break;
             }
     }
 
     rcu_read_unlock();
 
     /* trigger auto repeat for key events */
     if (test_bit(EV_REP, dev->evbit) && test_bit(EV_KEY, dev->evbit)) {
         for (v = vals; v != vals + count; v++) {
             if (v->type == EV_KEY && v->value != 2) {
                 if (v->value)
                     input_start_autorepeat(dev, v->code);
                 else
                     input_stop_autorepeat(dev);
             }
         }
     }
 }
 
 #define INPUT_IGNORE_EVENT  0
 #define INPUT_PASS_TO_HANDLERS  1
 #define INPUT_PASS_TO_DEVICE    2
 #define INPUT_SLOT      4
 #define INPUT_FLUSH     8
 #define INPUT_PASS_TO_ALL   (INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)
 
 static int input_handle_abs_event(struct input_dev *dev,
                   unsigned int code, int *pval)
 {
     struct input_mt *mt = dev->mt;
     bool is_mt_event;
     int *pold;
 
     if (code == ABS_MT_SLOT) {
         /*
          * "Stage" the event; we'll flush it later, when we
          * get actual touch data.
          */
         if (mt && *pval >= 0 && *pval < mt->num_slots)
             mt->slot = *pval;
 
         return INPUT_IGNORE_EVENT;
     }
 
     is_mt_event = input_is_mt_value(code);
 
     if (!is_mt_event) {
         pold = &dev->absinfo[code].value;
     } else if (mt) {
         pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST];
     } else {
         /*
          * Bypass filtering for multi-touch events when
          * not employing slots.
          */
         pold = NULL;
     }
 
     if (pold) {
         *pval = input_defuzz_abs_event(*pval, *pold,
                         dev->absinfo[code].fuzz);
         if (*pold == *pval)
             return INPUT_IGNORE_EVENT;
 
         *pold = *pval;
     }
 
     /* Flush pending "slot" event */
     if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
         input_abs_set_val(dev, ABS_MT_SLOT, mt->slot);
         return INPUT_PASS_TO_HANDLERS | INPUT_SLOT;
     }
 
     return INPUT_PASS_TO_HANDLERS;
 }
 
 static int input_get_disposition(struct input_dev *dev,
               unsigned int type, unsigned int code, int *pval)
 {
     int disposition = INPUT_IGNORE_EVENT;
     int value = *pval;
 
     /* filter-out events from inhibited devices */
     if (dev->inhibited)
         return INPUT_IGNORE_EVENT;
 
     switch (type) {
 
     case EV_SYN:
         switch (code) {
         case SYN_CONFIG:
             disposition = INPUT_PASS_TO_ALL;
             break;
 
         case SYN_REPORT:
             disposition = INPUT_PASS_TO_HANDLERS | INPUT_FLUSH;
             break;
         case SYN_MT_REPORT:
             disposition = INPUT_PASS_TO_HANDLERS;
             break;
         }
         break;
 
     case EV_KEY:
         if (is_event_supported(code, dev->keybit, KEY_MAX)) {
 
             /* auto-repeat bypasses state updates */
             if (value == 2) {
                 disposition = INPUT_PASS_TO_HANDLERS;
                 break;
             }
 
             if (!!test_bit(code, dev->key) != !!value) {
 
                 __change_bit(code, dev->key);
                 disposition = INPUT_PASS_TO_HANDLERS;
             }
         }
         break;
 
     case EV_SW:
         if (is_event_supported(code, dev->swbit, SW_MAX) &&
             !!test_bit(code, dev->sw) != !!value) {
 
             __change_bit(code, dev->sw);
             disposition = INPUT_PASS_TO_HANDLERS;
         }
         break;
 
     case EV_ABS:
         if (is_event_supported(code, dev->absbit, ABS_MAX))
             disposition = input_handle_abs_event(dev, code, &value);
 
         break;
 
     case EV_REL:
         if (is_event_supported(code, dev->relbit, REL_MAX) && value)
             disposition = INPUT_PASS_TO_HANDLERS;
 
         break;
 
     case EV_MSC:
         if (is_event_supported(code, dev->mscbit, MSC_MAX))
             disposition = INPUT_PASS_TO_ALL;
 
         break;
 
     case EV_LED:
         if (is_event_supported(code, dev->ledbit, LED_MAX) &&
             !!test_bit(code, dev->led) != !!value) {
 
             __change_bit(code, dev->led);
             disposition = INPUT_PASS_TO_ALL;
         }
         break;
 
     case EV_SND:
         if (is_event_supported(code, dev->sndbit, SND_MAX)) {
 
             if (!!test_bit(code, dev->snd) != !!value)
                 __change_bit(code, dev->snd);
             disposition = INPUT_PASS_TO_ALL;
         }
         break;
 
     case EV_REP:
         if (code <= REP_MAX && value >= 0 && dev->rep[code] != value) {
             dev->rep[code] = value;
             disposition = INPUT_PASS_TO_ALL;
         }
         break;
 
     case EV_FF:
         if (value >= 0)
             disposition = INPUT_PASS_TO_ALL;
         break;
 
     case EV_PWR:
         disposition = INPUT_PASS_TO_ALL;
         break;
     }
 
     *pval = value;
     return disposition;
 }
 
 static void input_event_dispose(struct input_dev *dev, int disposition,
                 unsigned int type, unsigned int code, int value)
 {
     if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event)
         dev->event(dev, type, code, value);
 
     if (!dev->vals)
         return;
 
     if (disposition & INPUT_PASS_TO_HANDLERS) {
         struct input_value *v;
 
         if (disposition & INPUT_SLOT) {
             v = &dev->vals[dev->num_vals++];
             v->type = EV_ABS;
             v->code = ABS_MT_SLOT;
             v->value = dev->mt->slot;
         }
 
         v = &dev->vals[dev->num_vals++];
         v->type = type;
         v->code = code;
         v->value = value;
     }
 
     if (disposition & INPUT_FLUSH) {
         if (dev->num_vals >= 2)
             input_pass_values(dev, dev->vals, dev->num_vals);
         dev->num_vals = 0;
         /*
          * Reset the timestamp on flush so we won't end up
          * with a stale one. Note we only need to reset the
          * monolithic one as we use its presence when deciding
          * whether to generate a synthetic timestamp.
          */
         dev->timestamp[INPUT_CLK_MONO] = ktime_set(0, 0);
     } else if (dev->num_vals >= dev->max_vals - 2) {
         dev->vals[dev->num_vals++] = input_value_sync;
         input_pass_values(dev, dev->vals, dev->num_vals);
         dev->num_vals = 0;
     }
 }
 
 void input_handle_event(struct input_dev *dev,
             unsigned int type, unsigned int code, int value)
 {
     int disposition;
 
     lockdep_assert_held(&dev->event_lock);
 
     disposition = input_get_disposition(dev, type, code, &value);
     if (disposition != INPUT_IGNORE_EVENT) {
         if (type != EV_SYN)
             add_input_randomness(type, code, value);
 
         input_event_dispose(dev, disposition, type, code, value);
     }
 }
 
 /**
  * input_event() - report new input event
  * @dev: device that generated the event
  * @type: type of the event
  * @code: event code
  * @value: value of the event
  *
  * This function should be used by drivers implementing various input
  * devices to report input events. See also input_inject_event().
  *
  * NOTE: input_event() may be safely used right after input device was
  * allocated with input_allocate_device(), even before it is registered
  * with input_register_device(), but the event will not reach any of the
  * input handlers. Such early invocation of input_event() may be used
  * to 'seed' initial state of a switch or initial position of absolute
  * axis, etc.
  */
 void input_event(struct input_dev *dev,
          unsigned int type, unsigned int code, int value)
 {
     unsigned long flags;
 
     if (is_event_supported(type, dev->evbit, EV_MAX)) {
 
         spin_lock_irqsave(&dev->event_lock, flags);
         input_handle_event(dev, type, code, value);
         spin_unlock_irqrestore(&dev->event_lock, flags);
     }
 }
 EXPORT_SYMBOL(input_event);
 
 /**
  * input_inject_event() - send input event from input handler
  * @handle: input handle to send event through
  * @type: type of the event
  * @code: event code
  * @value: value of the event
  *
  * Similar to input_event() but will ignore event if device is
  * "grabbed" and handle injecting event is not the one that owns
  * the device.
  */
 void input_inject_event(struct input_handle *handle,
             unsigned int type, unsigned int code, int value)
 {
     struct input_dev *dev = handle->dev;
     struct input_handle *grab;
     unsigned long flags;
 
     if (is_event_supported(type, dev->evbit, EV_MAX)) {
         spin_lock_irqsave(&dev->event_lock, flags);
 
         rcu_read_lock();
         grab = rcu_dereference(dev->grab);
         if (!grab || grab == handle)
             input_handle_event(dev, type, code, value);
         rcu_read_unlock();
 
         spin_unlock_irqrestore(&dev->event_lock, flags);
     }
 }
 EXPORT_SYMBOL(input_inject_event);
 
 /**
  * input_alloc_absinfo - allocates array of input_absinfo structs
  * @dev: the input device emitting absolute events
  *
  * If the absinfo struct the caller asked for is already allocated, this
  * functions will not do anything.
  */
 void input_alloc_absinfo(struct input_dev *dev)
 {
     if (dev->absinfo)
         return;
 
     dev->absinfo = kcalloc(ABS_CNT, sizeof(*dev->absinfo), GFP_KERNEL);
     if (!dev->absinfo) {
         dev_err(dev->dev.parent ?: &dev->dev,
             "%s: unable to allocate memory\n", __func__);
         /*
          * We will handle this allocation failure in
          * input_register_device() when we refuse to register input
          * device with ABS bits but without absinfo.
          */
     }
 }
 EXPORT_SYMBOL(input_alloc_absinfo);
 
 void input_set_abs_params(struct input_dev *dev, unsigned int axis,
               int min, int max, int fuzz, int flat)
 {
     struct input_absinfo *absinfo;
 
     __set_bit(EV_ABS, dev->evbit);
     __set_bit(axis, dev->absbit);
 
     input_alloc_absinfo(dev);
     if (!dev->absinfo)
         return;
 
     absinfo = &dev->absinfo[axis];
     absinfo->minimum = min;
     absinfo->maximum = max;
     absinfo->fuzz = fuzz;
     absinfo->flat = flat;
 }
 EXPORT_SYMBOL(input_set_abs_params);
 
 /**
  * input_copy_abs - Copy absinfo from one input_dev to another
  * @dst: Destination input device to copy the abs settings to
  * @dst_axis: ABS_* value selecting the destination axis
  * @src: Source input device to copy the abs settings from
  * @src_axis: ABS_* value selecting the source axis
  *
  * Set absinfo for the selected destination axis by copying it from
  * the specified source input device's source axis.
  * This is useful to e.g. setup a pen/stylus input-device for combined
  * touchscreen/pen hardware where the pen uses the same coordinates as
  * the touchscreen.
  */
 void input_copy_abs(struct input_dev *dst, unsigned int dst_axis,
             const struct input_dev *src, unsigned int src_axis)
 {
     /* src must have EV_ABS and src_axis set */
     if (WARN_ON(!(test_bit(EV_ABS, src->evbit) &&
               test_bit(src_axis, src->absbit))))
         return;
 
     /*
      * input_alloc_absinfo() may have failed for the source. Our caller is
      * expected to catch this when registering the input devices, which may
      * happen after the input_copy_abs() call.
      */
     if (!src->absinfo)
         return;
 
     input_set_capability(dst, EV_ABS, dst_axis);
     if (!dst->absinfo)
         return;
 
     dst->absinfo[dst_axis] = src->absinfo[src_axis];
 }
 EXPORT_SYMBOL(input_copy_abs);
 
 /**
  * input_grab_device - grabs device for exclusive use
  * @handle: input handle that wants to own the device
  *
  * When a device is grabbed by an input handle all events generated by
  * the device are delivered only to this handle. Also events injected
  * by other input handles are ignored while device is grabbed.
  */
 int input_grab_device(struct input_handle *handle)
 {
     struct input_dev *dev = handle->dev;
     int retval;
 
     retval = mutex_lock_interruptible(&dev->mutex);
     if (retval)
         return retval;
 
     if (dev->grab) {
         retval = -EBUSY;
         goto out;
     }
 
     rcu_assign_pointer(dev->grab, handle);
 
  out:
     mutex_unlock(&dev->mutex);
     return retval;
 }
 EXPORT_SYMBOL(input_grab_device);
 
 static void __input_release_device(struct input_handle *handle)
 {
     struct input_dev *dev = handle->dev;
     struct input_handle *grabber;
 
     grabber = rcu_dereference_protected(dev->grab,
                         lockdep_is_held(&dev->mutex));
     if (grabber == handle) {
         rcu_assign_pointer(dev->grab, NULL);
         /* Make sure input_pass_values() notices that grab is gone */
         synchronize_rcu();
 
         list_for_each_entry(handle, &dev->h_list, d_node)
             if (handle->open && handle->handler->start)
                 handle->handler->start(handle);
     }
 }
 
 /**
  * input_release_device - release previously grabbed device
  * @handle: input handle that owns the device
  *
  * Releases previously grabbed device so that other input handles can
  * start receiving input events. Upon release all handlers attached
  * to the device have their start() method called so they have a change
  * to synchronize device state with the rest of the system.
  */
 void input_release_device(struct input_handle *handle)
 {
     struct input_dev *dev = handle->dev;
 
     mutex_lock(&dev->mutex);
     __input_release_device(handle);
     mutex_unlock(&dev->mutex);
 }
 EXPORT_SYMBOL(input_release_device);
 
 /**
  * input_open_device - open input device
  * @handle: handle through which device is being accessed
  *
  * This function should be called by input handlers when they
  * want to start receive events from given input device.
  */
 int input_open_device(struct input_handle *handle)
 {
     struct input_dev *dev = handle->dev;
     int retval;
 
     retval = mutex_lock_interruptible(&dev->mutex);
     if (retval)
         return retval;
 
     if (dev->going_away) {
         retval = -ENODEV;
         goto out;
     }
 
     handle->open++;
 
     if (dev->users++ || dev->inhibited) {
         /*
          * Device is already opened and/or inhibited,
          * so we can exit immediately and report success.
          */
         goto out;
     }
 
     if (dev->open) {
         retval = dev->open(dev);
         if (retval) {
             dev->users--;
             handle->open--;
             /*
              * Make sure we are not delivering any more events
              * through this handle
              */
             synchronize_rcu();
             goto out;
         }
     }
 
     if (dev->poller)
         input_dev_poller_start(dev->poller);
 
  out:
     mutex_unlock(&dev->mutex);
     return retval;
 }
 EXPORT_SYMBOL(input_open_device);
 
 int input_flush_device(struct input_handle *handle, struct file *file)
 {
     struct input_dev *dev = handle->dev;
     int retval;
 
     retval = mutex_lock_interruptible(&dev->mutex);
     if (retval)
         return retval;
 
     if (dev->flush)
         retval = dev->flush(dev, file);
 
     mutex_unlock(&dev->mutex);
     return retval;
 }
 EXPORT_SYMBOL(input_flush_device);
 
 /**
  * input_close_device - close input device
  * @handle: handle through which device is being accessed
  *
  * This function should be called by input handlers when they
  * want to stop receive events from given input device.
  */
 void input_close_device(struct input_handle *handle)
 {
     struct input_dev *dev = handle->dev;
 
     mutex_lock(&dev->mutex);
 
     __input_release_device(handle);
 
     if (!dev->inhibited && !--dev->users) {
         if (dev->poller)
             input_dev_poller_stop(dev->poller);
         if (dev->close)
             dev->close(dev);
     }
 
     if (!--handle->open) {
         /*
          * synchronize_rcu() makes sure that input_pass_values()
          * completed and that no more input events are delivered
          * through this handle
          */
         synchronize_rcu();
     }
 
     mutex_unlock(&dev->mutex);
 }
 EXPORT_SYMBOL(input_close_device);
 
 /*
  * Simulate keyup events for all keys that are marked as pressed.
  * The function must be called with dev->event_lock held.
  */
 static bool input_dev_release_keys(struct input_dev *dev)
 {
     bool need_sync = false;
     int code;
 
     lockdep_assert_held(&dev->event_lock);
 
     if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
         for_each_set_bit(code, dev->key, KEY_CNT) {
             input_handle_event(dev, EV_KEY, code, 0);
             need_sync = true;
         }
     }
 
     return need_sync;
 }
 
 /*
  * Prepare device for unregistering
  */
 static void input_disconnect_device(struct input_dev *dev)
 {
     struct input_handle *handle;
 
     /*
      * Mark device as going away. Note that we take dev->mutex here
      * not to protect access to dev->going_away but rather to ensure
      * that there are no threads in the middle of input_open_device()
      */
     mutex_lock(&dev->mutex);
     dev->going_away = true;
     mutex_unlock(&dev->mutex);
 
     spin_lock_irq(&dev->event_lock);
 
     /*
      * Simulate keyup events for all pressed keys so that handlers
      * are not left with "stuck" keys. The driver may continue
      * generate events even after we done here but they will not
      * reach any handlers.
      */
     if (input_dev_release_keys(dev))
         input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
 
     list_for_each_entry(handle, &dev->h_list, d_node)
         handle->open = 0;
 
     spin_unlock_irq(&dev->event_lock);
 }
 
 /**
  * input_scancode_to_scalar() - converts scancode in &struct input_keymap_entry
  * @ke: keymap entry containing scancode to be converted.
  * @scancode: pointer to the location where converted scancode should
  *  be stored.
  *
  * This function is used to convert scancode stored in &struct keymap_entry
  * into scalar form understood by legacy keymap handling methods. These
  * methods expect scancodes to be represented as 'unsigned int'.
  */
 int input_scancode_to_scalar(const struct input_keymap_entry *ke,
                  unsigned int *scancode)
 {
     switch (ke->len) {
     case 1:
         *scancode = *((u8 *)ke->scancode);
         break;
 
     case 2:
         *scancode = *((u16 *)ke->scancode);
         break;
 
     case 4:
         *scancode = *((u32 *)ke->scancode);
         break;
 
     default:
         return -EINVAL;
     }
 
     return 0;
 }
 EXPORT_SYMBOL(input_scancode_to_scalar);
 
 /*
  * Those routines handle the default case where no [gs]etkeycode() is
  * defined. In this case, an array indexed by the scancode is used.
  */
 
 static unsigned int input_fetch_keycode(struct input_dev *dev,
                     unsigned int index)
 {
     switch (dev->keycodesize) {
     case 1:
         return ((u8 *)dev->keycode)[index];
 
     case 2:
         return ((u16 *)dev->keycode)[index];
 
     default:
         return ((u32 *)dev->keycode)[index];
     }
 }
 
 static int input_default_getkeycode(struct input_dev *dev,
                     struct input_keymap_entry *ke)
 {
     unsigned int index;
     int error;
 
     if (!dev->keycodesize)
         return -EINVAL;
 
     if (ke->flags & INPUT_KEYMAP_BY_INDEX)
         index = ke->index;
     else {
         error = input_scancode_to_scalar(ke, &index);
         if (error)
             return error;
     }
 
     if (index >= dev->keycodemax)
         return -EINVAL;
 
     ke->keycode = input_fetch_keycode(dev, index);
     ke->index = index;
     ke->len = sizeof(index);
     memcpy(ke->scancode, &index, sizeof(index));
 
     return 0;
 }
 
 static int input_default_setkeycode(struct input_dev *dev,
                     const struct input_keymap_entry *ke,
                     unsigned int *old_keycode)
 {
     unsigned int index;
     int error;
     int i;
 
     if (!dev->keycodesize)
         return -EINVAL;
 
     if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
         index = ke->index;
     } else {
         error = input_scancode_to_scalar(ke, &index);
         if (error)
             return error;
     }
 
     if (index >= dev->keycodemax)
         return -EINVAL;
 
     if (dev->keycodesize < sizeof(ke->keycode) &&
             (ke->keycode >> (dev->keycodesize * 8)))
         return -EINVAL;
 
     switch (dev->keycodesize) {
         case 1: {
             u8 *k = (u8 *)dev->keycode;
             *old_keycode = k[index];
             k[index] = ke->keycode;
             break;
         }
         case 2: {
             u16 *k = (u16 *)dev->keycode;
             *old_keycode = k[index];
             k[index] = ke->keycode;
             break;
         }
         default: {
             u32 *k = (u32 *)dev->keycode;
             *old_keycode = k[index];
             k[index] = ke->keycode;
             break;
         }
     }
 
     if (*old_keycode <= KEY_MAX) {
         __clear_bit(*old_keycode, dev->keybit);
         for (i = 0; i < dev->keycodemax; i++) {
             if (input_fetch_keycode(dev, i) == *old_keycode) {
                 __set_bit(*old_keycode, dev->keybit);
                 /* Setting the bit twice is useless, so break */
                 break;
             }
         }
     }
 
     __set_bit(ke->keycode, dev->keybit);
     return 0;
 }
 
 /**
  * input_get_keycode - retrieve keycode currently mapped to a given scancode
  * @dev: input device which keymap is being queried
  * @ke: keymap entry
  *
  * This function should be called by anyone interested in retrieving current
  * keymap. Presently evdev handlers use it.
  */
 int input_get_keycode(struct input_dev *dev, struct input_keymap_entry *ke)
 {
     unsigned long flags;
     int retval;
 
     spin_lock_irqsave(&dev->event_lock, flags);
     retval = dev->getkeycode(dev, ke);
     spin_unlock_irqrestore(&dev->event_lock, flags);
 
     return retval;
 }
 EXPORT_SYMBOL(input_get_keycode);
 
 /**
  * input_set_keycode - attribute a keycode to a given scancode
  * @dev: input device which keymap is being updated
  * @ke: new keymap entry
  *
  * This function should be called by anyone needing to update current
  * keymap. Presently keyboard and evdev handlers use it.
  */
 int input_set_keycode(struct input_dev *dev,
               const struct input_keymap_entry *ke)
 {
     unsigned long flags;
     unsigned int old_keycode;
     int retval;
 
     if (ke->keycode > KEY_MAX)
         return -EINVAL;
 
     spin_lock_irqsave(&dev->event_lock, flags);
 
     retval = dev->setkeycode(dev, ke, &old_keycode);
     if (retval)
         goto out;
 
     /* Make sure KEY_RESERVED did not get enabled. */
     __clear_bit(KEY_RESERVED, dev->keybit);
 
     /*
      * Simulate keyup event if keycode is not present
      * in the keymap anymore
      */
     if (old_keycode > KEY_MAX) {
         dev_warn(dev->dev.parent ?: &dev->dev,
              "%s: got too big old keycode %#x\n",
              __func__, old_keycode);
     } else if (test_bit(EV_KEY, dev->evbit) &&
            !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
            __test_and_clear_bit(old_keycode, dev->key)) {
         /*
          * We have to use input_event_dispose() here directly instead
          * of input_handle_event() because the key we want to release
          * here is considered no longer supported by the device and
          * input_handle_event() will ignore it.
          */
         input_event_dispose(dev, INPUT_PASS_TO_HANDLERS,
                     EV_KEY, old_keycode, 0);
         input_event_dispose(dev, INPUT_PASS_TO_HANDLERS | INPUT_FLUSH,
                     EV_SYN, SYN_REPORT, 1);
     }
 
  out:
     spin_unlock_irqrestore(&dev->event_lock, flags);
 
     return retval;
 }
 EXPORT_SYMBOL(input_set_keycode);
 
 bool input_match_device_id(const struct input_dev *dev,
                const struct input_device_id *id)
 {
     if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)
         if (id->bustype != dev->id.bustype)
             return false;
 
     if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
         if (id->vendor != dev->id.vendor)
             return false;
 
     if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
         if (id->product != dev->id.product)
             return false;
 
     if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
         if (id->version != dev->id.version)
             return false;
 
     if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX) ||
         !bitmap_subset(id->keybit, dev->keybit, KEY_MAX) ||
         !bitmap_subset(id->relbit, dev->relbit, REL_MAX) ||
         !bitmap_subset(id->absbit, dev->absbit, ABS_MAX) ||
         !bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX) ||
         !bitmap_subset(id->ledbit, dev->ledbit, LED_MAX) ||
         !bitmap_subset(id->sndbit, dev->sndbit, SND_MAX) ||
         !bitmap_subset(id->ffbit, dev->ffbit, FF_MAX) ||
         !bitmap_subset(id->swbit, dev->swbit, SW_MAX) ||
         !bitmap_subset(id->propbit, dev->propbit, INPUT_PROP_MAX)) {
         return false;
     }
 
     return true;
 }
 EXPORT_SYMBOL(input_match_device_id);
 
 static const struct input_device_id *input_match_device(struct input_handler *handler,
                             struct input_dev *dev)
 {
     const struct input_device_id *id;
 
     for (id = handler->id_table; id->flags || id->driver_info; id++) {
         if (input_match_device_id(dev, id) &&
             (!handler->match || handler->match(handler, dev))) {
             return id;
         }
     }
 
     return NULL;
 }
 
 static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
 {
     const struct input_device_id *id;
     int error;
 
     id = input_match_device(handler, dev);
     if (!id)
         return -ENODEV;
 
     error = handler->connect(handler, dev, id);
     if (error && error != -ENODEV)
         pr_err("failed to attach handler %s to device %s, error: %d\n",
                handler->name, kobject_name(&dev->dev.kobj), error);
 
     return error;
 }
 
 #ifdef CONFIG_COMPAT
 
 static int input_bits_to_string(char *buf, int buf_size,
                 unsigned long bits, bool skip_empty)
 {
     int len = 0;
 
     if (in_compat_syscall()) {
         u32 dword = bits >> 32;
         if (dword || !skip_empty)
             len += snprintf(buf, buf_size, "%x ", dword);
 
         dword = bits & 0xffffffffUL;
         if (dword || !skip_empty || len)
             len += snprintf(buf + len, max(buf_size - len, 0),
                     "%x", dword);
     } else {
         if (bits || !skip_empty)
             len += snprintf(buf, buf_size, "%lx", bits);
     }
 
     return len;
 }
 
 #else /* !CONFIG_COMPAT */
 
 static int input_bits_to_string(char *buf, int buf_size,
                 unsigned long bits, bool skip_empty)
 {
     return bits || !skip_empty ?
         snprintf(buf, buf_size, "%lx", bits) : 0;
 }
 
 #endif
 
 #ifdef CONFIG_PROC_FS
 
 static struct proc_dir_entry *proc_bus_input_dir;
 static DECLARE_WAIT_QUEUE_HEAD(input_devices_poll_wait);
 static int input_devices_state;
 
 static inline void input_wakeup_procfs_readers(void)
 {
     input_devices_state++;
     wake_up(&input_devices_poll_wait);
 }
 
 static __poll_t input_proc_devices_poll(struct file *file, poll_table *wait)
 {
     poll_wait(file, &input_devices_poll_wait, wait);
     if (file->f_version != input_devices_state) {
         file->f_version = input_devices_state;
         return EPOLLIN | EPOLLRDNORM;
     }
 
     return 0;
 }
 
 union input_seq_state {
     struct {
         unsigned short pos;
         bool mutex_acquired;
     };
     void *p;
 };
 
 static void *input_devices_seq_start(struct seq_file *seq, loff_t *pos)
 {
     union input_seq_state *state = (union input_seq_state *)&seq->private;
     int error;
 
     /* We need to fit into seq->private pointer */
     BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
 
     error = mutex_lock_interruptible(&input_mutex);
     if (error) {
         state->mutex_acquired = false;
         return ERR_PTR(error);
     }
 
     state->mutex_acquired = true;
 
     return seq_list_start(&input_dev_list, *pos);
 }
 
 static void *input_devices_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
     return seq_list_next(v, &input_dev_list, pos);
 }
 
 static void input_seq_stop(struct seq_file *seq, void *v)
 {
     union input_seq_state *state = (union input_seq_state *)&seq->private;
 
     if (state->mutex_acquired)
         mutex_unlock(&input_mutex);
 }
 
 static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
                    unsigned long *bitmap, int max)
 {
     int i;
     bool skip_empty = true;
     char buf[18];
 
     seq_printf(seq, "B: %s=", name);
 
     for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
         if (input_bits_to_string(buf, sizeof(buf),
                      bitmap[i], skip_empty)) {
             skip_empty = false;
             seq_printf(seq, "%s%s", buf, i > 0 ? " " : "");
         }
     }
 
     /*
      * If no output was produced print a single 0.
      */
     if (skip_empty)
         seq_putc(seq, '0');
 
     seq_putc(seq, '\n');
 }
 
 static int input_devices_seq_show(struct seq_file *seq, void *v)
 {
     struct input_dev *dev = container_of(v, struct input_dev, node);
     const char *path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
     struct input_handle *handle;
 
     seq_printf(seq, "I: Bus=%04x Vendor=%04x Product=%04x Version=%04x\n",
            dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version);
 
     seq_printf(seq, "N: Name=\"%s\"\n", dev->name ? dev->name : "");
     seq_printf(seq, "P: Phys=%s\n", dev->phys ? dev->phys : "");
     seq_printf(seq, "S: Sysfs=%s\n", path ? path : "");
     seq_printf(seq, "U: Uniq=%s\n", dev->uniq ? dev->uniq : "");
     seq_puts(seq, "H: Handlers=");
 
     list_for_each_entry(handle, &dev->h_list, d_node)
         seq_printf(seq, "%s ", handle->name);
     seq_putc(seq, '\n');
 
     input_seq_print_bitmap(seq, "PROP", dev->propbit, INPUT_PROP_MAX);
 
     input_seq_print_bitmap(seq, "EV", dev->evbit, EV_MAX);
     if (test_bit(EV_KEY, dev->evbit))
         input_seq_print_bitmap(seq, "KEY", dev->keybit, KEY_MAX);
     if (test_bit(EV_REL, dev->evbit))
         input_seq_print_bitmap(seq, "REL", dev->relbit, REL_MAX);
     if (test_bit(EV_ABS, dev->evbit))
         input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX);
     if (test_bit(EV_MSC, dev->evbit))
         input_seq_print_bitmap(seq, "MSC", dev->mscbit, MSC_MAX);
     if (test_bit(EV_LED, dev->evbit))
         input_seq_print_bitmap(seq, "LED", dev->ledbit, LED_MAX);
     if (test_bit(EV_SND, dev->evbit))
         input_seq_print_bitmap(seq, "SND", dev->sndbit, SND_MAX);
     if (test_bit(EV_FF, dev->evbit))
         input_seq_print_bitmap(seq, "FF", dev->ffbit, FF_MAX);
     if (test_bit(EV_SW, dev->evbit))
         input_seq_print_bitmap(seq, "SW", dev->swbit, SW_MAX);
 
     seq_putc(seq, '\n');
 
     kfree(path);
     return 0;
 }
 
 static const struct seq_operations input_devices_seq_ops = {
     .start  = input_devices_seq_start,
     .next   = input_devices_seq_next,
     .stop   = input_seq_stop,
     .show   = input_devices_seq_show,
 };
 
 static int input_proc_devices_open(struct inode *inode, struct file *file)
 {
     return seq_open(file, &input_devices_seq_ops);
 }
 
 static const struct proc_ops input_devices_proc_ops = {
     .proc_open  = input_proc_devices_open,
     .proc_poll  = input_proc_devices_poll,
     .proc_read  = seq_read,
     .proc_lseek = seq_lseek,
     .proc_release   = seq_release,
 };
 
 static void *input_handlers_seq_start(struct seq_file *seq, loff_t *pos)
 {
     union input_seq_state *state = (union input_seq_state *)&seq->private;
     int error;
 
     /* We need to fit into seq->private pointer */
     BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
 
     error = mutex_lock_interruptible(&input_mutex);
     if (error) {
         state->mutex_acquired = false;
         return ERR_PTR(error);
     }
 
     state->mutex_acquired = true;
     state->pos = *pos;
 
     return seq_list_start(&input_handler_list, *pos);
 }
 
 static void *input_handlers_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
     union input_seq_state *state = (union input_seq_state *)&seq->private;
 
     state->pos = *pos + 1;
     return seq_list_next(v, &input_handler_list, pos);
 }
 
 static int input_handlers_seq_show(struct seq_file *seq, void *v)
 {
     struct input_handler *handler = container_of(v, struct input_handler, node);
     union input_seq_state *state = (union input_seq_state *)&seq->private;
 
     seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
     if (handler->filter)
         seq_puts(seq, " (filter)");
     if (handler->legacy_minors)
         seq_printf(seq, " Minor=%d", handler->minor);
     seq_putc(seq, '\n');
 
     return 0;
 }
 
 static const struct seq_operations input_handlers_seq_ops = {
     .start  = input_handlers_seq_start,
     .next   = input_handlers_seq_next,
     .stop   = input_seq_stop,
     .show   = input_handlers_seq_show,
 };
 
 static int input_proc_handlers_open(struct inode *inode, struct file *file)
 {
     return seq_open(file, &input_handlers_seq_ops);
 }
 
 static const struct proc_ops input_handlers_proc_ops = {
     .proc_open  = input_proc_handlers_open,
     .proc_read  = seq_read,
     .proc_lseek = seq_lseek,
     .proc_release   = seq_release,
 };
 
 static int __init input_proc_init(void)
 {
     struct proc_dir_entry *entry;
 
     proc_bus_input_dir = proc_mkdir("bus/input", NULL);
     if (!proc_bus_input_dir)
         return -ENOMEM;
 
     entry = proc_create("devices", 0, proc_bus_input_dir,
                 &input_devices_proc_ops);
     if (!entry)
         goto fail1;
 
     entry = proc_create("handlers", 0, proc_bus_input_dir,
                 &input_handlers_proc_ops);
     if (!entry)
         goto fail2;
 
     return 0;
 
  fail2: remove_proc_entry("devices", proc_bus_input_dir);
  fail1: remove_proc_entry("bus/input", NULL);
     return -ENOMEM;
 }
 
 static void input_proc_exit(void)
 {
     remove_proc_entry("devices", proc_bus_input_dir);
     remove_proc_entry("handlers", proc_bus_input_dir);
     remove_proc_entry("bus/input", NULL);
 }
 
 #else /* !CONFIG_PROC_FS */
 static inline void input_wakeup_procfs_readers(void) { }
 static inline int input_proc_init(void) { return 0; }
 static inline void input_proc_exit(void) { }
 #endif
 
 #define INPUT_DEV_STRING_ATTR_SHOW(name)                \
 static ssize_t input_dev_show_##name(struct device *dev,        \
                      struct device_attribute *attr, \
                      char *buf)             \
 {                                   \
     struct input_dev *input_dev = to_input_dev(dev);        \
                                     \
     return scnprintf(buf, PAGE_SIZE, "%s\n",            \
              input_dev->name ? input_dev->name : "");   \
 }                                   \
 static DEVICE_ATTR(name, S_IRUGO, input_dev_show_##name, NULL)
 
 INPUT_DEV_STRING_ATTR_SHOW(name);
 INPUT_DEV_STRING_ATTR_SHOW(phys);
 INPUT_DEV_STRING_ATTR_SHOW(uniq);
 
 static int input_print_modalias_bits(char *buf, int size,
                      char name, unsigned long *bm,
                      unsigned int min_bit, unsigned int max_bit)
 {
     int len = 0, i;
 
     len += snprintf(buf, max(size, 0), "%c", name);
     for (i = min_bit; i < max_bit; i++)
         if (bm[BIT_WORD(i)] & BIT_MASK(i))
             len += snprintf(buf + len, max(size - len, 0), "%X,", i);
     return len;
 }
 
 static int input_print_modalias(char *buf, int size, struct input_dev *id,
                 int add_cr)
 {
     int len;
 
     len = snprintf(buf, max(size, 0),
                "input:b%04Xv%04Xp%04Xe%04X-",
                id->id.bustype, id->id.vendor,
                id->id.product, id->id.version);
 
     len += input_print_modalias_bits(buf + len, size - len,
                 'e', id->evbit, 0, EV_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 'k', id->keybit, KEY_MIN_INTERESTING, KEY_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 'r', id->relbit, 0, REL_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 'a', id->absbit, 0, ABS_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 'm', id->mscbit, 0, MSC_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 'l', id->ledbit, 0, LED_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 's', id->sndbit, 0, SND_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 'f', id->ffbit, 0, FF_MAX);
     len += input_print_modalias_bits(buf + len, size - len,
                 'w', id->swbit, 0, SW_MAX);
 
     if (add_cr)
         len += snprintf(buf + len, max(size - len, 0), "\n");
 
     return len;
 }
 
 static ssize_t input_dev_show_modalias(struct device *dev,
                        struct device_attribute *attr,
                        char *buf)
 {
     struct input_dev *id = to_input_dev(dev);
     ssize_t len;
 
     len = input_print_modalias(buf, PAGE_SIZE, id, 1);
 
     return min_t(int, len, PAGE_SIZE);
 }
 static DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);
 
 static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
                   int max, int add_cr);
 
 static ssize_t input_dev_show_properties(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
 {
     struct input_dev *input_dev = to_input_dev(dev);
     int len = input_print_bitmap(buf, PAGE_SIZE, input_dev->propbit,
                      INPUT_PROP_MAX, true);
     return min_t(int, len, PAGE_SIZE);
 }
 static DEVICE_ATTR(properties, S_IRUGO, input_dev_show_properties, NULL);
 
 static int input_inhibit_device(struct input_dev *dev);
 static int input_uninhibit_device(struct input_dev *dev);
 
 static ssize_t inhibited_show(struct device *dev,
                   struct device_attribute *attr,
                   char *buf)
 {
     struct input_dev *input_dev = to_input_dev(dev);
 
     return scnprintf(buf, PAGE_SIZE, "%d\n", input_dev->inhibited);
 }
 
 static ssize_t inhibited_store(struct device *dev,
                    struct device_attribute *attr, const char *buf,
                    size_t len)
 {
     struct input_dev *input_dev = to_input_dev(dev);
     ssize_t rv;
     bool inhibited;
 
     if (strtobool(buf, &inhibited))
         return -EINVAL;
 
     if (inhibited)
         rv = input_inhibit_device(input_dev);
     else
         rv = input_uninhibit_device(input_dev);
 
     if (rv != 0)
         return rv;
 
     return len;
 }
 
 static DEVICE_ATTR_RW(inhibited);
 
 static struct attribute *input_dev_attrs[] = {
     &dev_attr_name.attr,
     &dev_attr_phys.attr,
     &dev_attr_uniq.attr,
     &dev_attr_modalias.attr,
     &dev_attr_properties.attr,
     &dev_attr_inhibited.attr,
     NULL
 };
 
 static const struct attribute_group input_dev_attr_group = {
     .attrs  = input_dev_attrs,
 };
 
 #define INPUT_DEV_ID_ATTR(name)                     \
 static ssize_t input_dev_show_id_##name(struct device *dev,     \
                     struct device_attribute *attr,  \
                     char *buf)          \
 {                                   \
     struct input_dev *input_dev = to_input_dev(dev);        \
     return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name); \
 }                                   \
 static DEVICE_ATTR(name, S_IRUGO, input_dev_show_id_##name, NULL)
 
 INPUT_DEV_ID_ATTR(bustype);
 INPUT_DEV_ID_ATTR(vendor);
 INPUT_DEV_ID_ATTR(product);
 INPUT_DEV_ID_ATTR(version);
 
 static struct attribute *input_dev_id_attrs[] = {
     &dev_attr_bustype.attr,
     &dev_attr_vendor.attr,
     &dev_attr_product.attr,
     &dev_attr_version.attr,
     NULL
 };
 
 static const struct attribute_group input_dev_id_attr_group = {
     .name   = "id",
     .attrs  = input_dev_id_attrs,
 };
 
 static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
                   int max, int add_cr)
 {
     int i;
     int len = 0;
     bool skip_empty = true;
 
     for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
         len += input_bits_to_string(buf + len, max(buf_size - len, 0),
                         bitmap[i], skip_empty);
         if (len) {
             skip_empty = false;
             if (i > 0)
                 len += snprintf(buf + len, max(buf_size - len, 0), " ");
         }
     }
 
     /*
      * If no output was produced print a single 0.
      */
     if (len == 0)
         len = snprintf(buf, buf_size, "%d", 0);
 
     if (add_cr)
         len += snprintf(buf + len, max(buf_size - len, 0), "\n");
 
     return len;
 }
 
 #define INPUT_DEV_CAP_ATTR(ev, bm)                  \
 static ssize_t input_dev_show_cap_##bm(struct device *dev,      \
                        struct device_attribute *attr,   \
                        char *buf)           \
 {                                   \
     struct input_dev *input_dev = to_input_dev(dev);        \
     int len = input_print_bitmap(buf, PAGE_SIZE,            \
                      input_dev->bm##bit, ev##_MAX,  \
                      true);             \
     return min_t(int, len, PAGE_SIZE);              \
 }                                   \
 static DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL)
 
 INPUT_DEV_CAP_ATTR(EV, ev);
 INPUT_DEV_CAP_ATTR(KEY, key);
 INPUT_DEV_CAP_ATTR(REL, rel);
 INPUT_DEV_CAP_ATTR(ABS, abs);
 INPUT_DEV_CAP_ATTR(MSC, msc);
 INPUT_DEV_CAP_ATTR(LED, led);
 INPUT_DEV_CAP_ATTR(SND, snd);
 INPUT_DEV_CAP_ATTR(FF, ff);
 INPUT_DEV_CAP_ATTR(SW, sw);
 
 static struct attribute *input_dev_caps_attrs[] = {
     &dev_attr_ev.attr,
     &dev_attr_key.attr,
     &dev_attr_rel.attr,
     &dev_attr_abs.attr,
     &dev_attr_msc.attr,
     &dev_attr_led.attr,
     &dev_attr_snd.attr,
     &dev_attr_ff.attr,
     &dev_attr_sw.attr,
     NULL
 };
 
 static const struct attribute_group input_dev_caps_attr_group = {
     .name   = "capabilities",
     .attrs  = input_dev_caps_attrs,
 };
 
 static const struct attribute_group *input_dev_attr_groups[] = {
     &input_dev_attr_group,
     &input_dev_id_attr_group,
     &input_dev_caps_attr_group,
     &input_poller_attribute_group,
     NULL
 };
 
 static void input_dev_release(struct device *device)
 {
     struct input_dev *dev = to_input_dev(device);
 
     input_ff_destroy(dev);
     input_mt_destroy_slots(dev);
     kfree(dev->poller);
     kfree(dev->absinfo);
     kfree(dev->vals);
     kfree(dev);
 
     module_put(THIS_MODULE);
 }
 
 /*
  * Input uevent interface - loading event handlers based on
  * device bitfields.
  */
 static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
                    const char *name, unsigned long *bitmap, int max)
 {
     int len;
 
     if (add_uevent_var(env, "%s", name))
         return -ENOMEM;
 
     len = input_print_bitmap(&env->buf[env->buflen - 1],
                  sizeof(env->buf) - env->buflen,
                  bitmap, max, false);
     if (len >= (sizeof(env->buf) - env->buflen))
         return -ENOMEM;
 
     env->buflen += len;
     return 0;
 }
 
 static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
                      struct input_dev *dev)
 {
     int len;
 
     if (add_uevent_var(env, "MODALIAS="))
         return -ENOMEM;
 
     len = input_print_modalias(&env->buf[env->buflen - 1],
                    sizeof(env->buf) - env->buflen,
                    dev, 0);
     if (len >= (sizeof(env->buf) - env->buflen))
         return -ENOMEM;
 
     env->buflen += len;
     return 0;
 }
 
 #define INPUT_ADD_HOTPLUG_VAR(fmt, val...)              \
     do {                                \
         int err = add_uevent_var(env, fmt, val);        \
         if (err)                        \
             return err;                 \
     } while (0)
 
 #define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max)             \
     do {                                \
         int err = input_add_uevent_bm_var(env, name, bm, max);  \
         if (err)                        \
             return err;                 \
     } while (0)
 
 #define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev)             \
     do {                                \
         int err = input_add_uevent_modalias_var(env, dev);  \
         if (err)                        \
             return err;                 \
     } while (0)
 
 static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
 {
     struct input_dev *dev = to_input_dev(device);
 
     INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
                 dev->id.bustype, dev->id.vendor,
                 dev->id.product, dev->id.version);
     if (dev->name)
         INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name);
     if (dev->phys)
         INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys);
     if (dev->uniq)
         INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq);
 
     INPUT_ADD_HOTPLUG_BM_VAR("PROP=", dev->propbit, INPUT_PROP_MAX);
 
     INPUT_ADD_HOTPLUG_BM_VAR("EV=", dev->evbit, EV_MAX);
     if (test_bit(EV_KEY, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("KEY=", dev->keybit, KEY_MAX);
     if (test_bit(EV_REL, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
     if (test_bit(EV_ABS, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
     if (test_bit(EV_MSC, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
     if (test_bit(EV_LED, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("LED=", dev->ledbit, LED_MAX);
     if (test_bit(EV_SND, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("SND=", dev->sndbit, SND_MAX);
     if (test_bit(EV_FF, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("FF=", dev->ffbit, FF_MAX);
     if (test_bit(EV_SW, dev->evbit))
         INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);
 
     INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
 
     return 0;
 }
 
 #define INPUT_DO_TOGGLE(dev, type, bits, on)                \
     do {                                \
         int i;                          \
         bool active;                        \
                                     \
         if (!test_bit(EV_##type, dev->evbit))           \
             break;                      \
                                     \
         for_each_set_bit(i, dev->bits##bit, type##_CNT) {   \
             active = test_bit(i, dev->bits);        \
             if (!active && !on)             \
                 continue;               \
                                     \
             dev->event(dev, EV_##type, i, on ? active : 0); \
         }                           \
     } while (0)
 
 static void input_dev_toggle(struct input_dev *dev, bool activate)
 {
     if (!dev->event)
         return;
 
     INPUT_DO_TOGGLE(dev, LED, led, activate);
     INPUT_DO_TOGGLE(dev, SND, snd, activate);
 
     if (activate && test_bit(EV_REP, dev->evbit)) {
         dev->event(dev, EV_REP, REP_PERIOD, dev->rep[REP_PERIOD]);
         dev->event(dev, EV_REP, REP_DELAY, dev->rep[REP_DELAY]);
     }
 }
 
 /**
  * input_reset_device() - reset/restore the state of input device
  * @dev: input device whose state needs to be reset
  *
  * This function tries to reset the state of an opened input device and
  * bring internal state and state if the hardware in sync with each other.
  * We mark all keys as released, restore LED state, repeat rate, etc.
  */
 void input_reset_device(struct input_dev *dev)
 {
     unsigned long flags;
 
     mutex_lock(&dev->mutex);
     spin_lock_irqsave(&dev->event_lock, flags);
 
     input_dev_toggle(dev, true);
     if (input_dev_release_keys(dev))
         input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
 
     spin_unlock_irqrestore(&dev->event_lock, flags);
     mutex_unlock(&dev->mutex);
 }
 EXPORT_SYMBOL(input_reset_device);
 
 static int input_inhibit_device(struct input_dev *dev)
 {
     mutex_lock(&dev->mutex);
 
     if (dev->inhibited)
         goto out;
 
     if (dev->users) {
         if (dev->close)
             dev->close(dev);
         if (dev->poller)
             input_dev_poller_stop(dev->poller);
     }
 
     spin_lock_irq(&dev->event_lock);
     input_mt_release_slots(dev);
     input_dev_release_keys(dev);
     input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
     input_dev_toggle(dev, false);
     spin_unlock_irq(&dev->event_lock);
 
     dev->inhibited = true;
 
 out:
     mutex_unlock(&dev->mutex);
     return 0;
 }
 
 static int input_uninhibit_device(struct input_dev *dev)
 {
     int ret = 0;
 
     mutex_lock(&dev->mutex);
 
     if (!dev->inhibited)
         goto out;
 
     if (dev->users) {
         if (dev->open) {
             ret = dev->open(dev);
             if (ret)
                 goto out;
         }
         if (dev->poller)
             input_dev_poller_start(dev->poller);
     }
 
     dev->inhibited = false;
     spin_lock_irq(&dev->event_lock);
     input_dev_toggle(dev, true);
     spin_unlock_irq(&dev->event_lock);
 
 out:
     mutex_unlock(&dev->mutex);
     return ret;
 }
 
 #ifdef CONFIG_PM_SLEEP
 static int input_dev_suspend(struct device *dev)
 {
     struct input_dev *input_dev = to_input_dev(dev);
 
     spin_lock_irq(&input_dev->event_lock);
 
     /*
      * Keys that are pressed now are unlikely to be
      * still pressed when we resume.
      */
     if (input_dev_release_keys(input_dev))
         input_handle_event(input_dev, EV_SYN, SYN_REPORT, 1);
 
     /* Turn off LEDs and sounds, if any are active. */
     input_dev_toggle(input_dev, false);
 
     spin_unlock_irq(&input_dev->event_lock);
 
     return 0;
 }
 
 static int input_dev_resume(struct device *dev)
 {
     struct input_dev *input_dev = to_input_dev(dev);
 
     spin_lock_irq(&input_dev->event_lock);
 
     /* Restore state of LEDs and sounds, if any were active. */
     input_dev_toggle(input_dev, true);
 
     spin_unlock_irq(&input_dev->event_lock);
 
     return 0;
 }
 
 static int input_dev_freeze(struct device *dev)
 {
     struct input_dev *input_dev = to_input_dev(dev);
 
     spin_lock_irq(&input_dev->event_lock);
 
     /*
      * Keys that are pressed now are unlikely to be
      * still pressed when we resume.
      */
     if (input_dev_release_keys(input_dev))
         input_handle_event(input_dev, EV_SYN, SYN_REPORT, 1);
 
     spin_unlock_irq(&input_dev->event_lock);
 
     return 0;
 }
 
 static int input_dev_poweroff(struct device *dev)
 {
     struct input_dev *input_dev = to_input_dev(dev);
 
     spin_lock_irq(&input_dev->event_lock);
 
     /* Turn off LEDs and sounds, if any are active. */
     input_dev_toggle(input_dev, false);
 
     spin_unlock_irq(&input_dev->event_lock);
 
     return 0;
 }
 
 static const struct dev_pm_ops input_dev_pm_ops = {
     .suspend    = input_dev_suspend,
     .resume     = input_dev_resume,
     .freeze     = input_dev_freeze,
     .poweroff   = input_dev_poweroff,
     .restore    = input_dev_resume,
 };
 #endif /* CONFIG_PM */
 
 static const struct device_type input_dev_type = {
     .groups     = input_dev_attr_groups,
     .release    = input_dev_release,
     .uevent     = input_dev_uevent,
 #ifdef CONFIG_PM_SLEEP
     .pm     = &input_dev_pm_ops,
 #endif
 };
 
 static char *input_devnode(struct device *dev, umode_t *mode)
 {
     return kasprintf(GFP_KERNEL, "input/%s", dev_name(dev));
 }
 
 struct class input_class = {
     .name       = "input",
     .devnode    = input_devnode,
 };
 EXPORT_SYMBOL_GPL(input_class);
 
 /**
  * input_allocate_device - allocate memory for new input device
  *
  * Returns prepared struct input_dev or %NULL.
  *
  * NOTE: Use input_free_device() to free devices that have not been
  * registered; input_unregister_device() should be used for already
  * registered devices.
  */
 struct input_dev *input_allocate_device(void)
 {
     static atomic_t input_no = ATOMIC_INIT(-1);
     struct input_dev *dev;
 
     dev = kzalloc(sizeof(*dev), GFP_KERNEL);
     if (dev) {
         dev->dev.type = &input_dev_type;
         dev->dev.class = &input_class;
         device_initialize(&dev->dev);
         mutex_init(&dev->mutex);
         spin_lock_init(&dev->event_lock);
         timer_setup(&dev->timer, NULL, 0);
         INIT_LIST_HEAD(&dev->h_list);
         INIT_LIST_HEAD(&dev->node);
 
         dev_set_name(&dev->dev, "input%lu",
                  (unsigned long)atomic_inc_return(&input_no));
 
         __module_get(THIS_MODULE);
     }
 
     return dev;
 }
 EXPORT_SYMBOL(input_allocate_device);
 
 struct input_devres {
     struct input_dev *input;
 };
 
 static int devm_input_device_match(struct device *dev, void *res, void *data)
 {
     struct input_devres *devres = res;
 
     return devres->input == data;
 }
 
 static void devm_input_device_release(struct device *dev, void *res)
 {
     struct input_devres *devres = res;
     struct input_dev *input = devres->input;
 
     dev_dbg(dev, "%s: dropping reference to %s\n",
         __func__, dev_name(&input->dev));
     input_put_device(input);
 }
 
 /**
  * devm_input_allocate_device - allocate managed input device
  * @dev: device owning the input device being created
  *
  * Returns prepared struct input_dev or %NULL.
  *
  * Managed input devices do not need to be explicitly unregistered or
  * freed as it will be done automatically when owner device unbinds from
  * its driver (or binding fails). Once managed input device is allocated,
  * it is ready to be set up and registered in the same fashion as regular
  * input device. There are no special devm_input_device_[un]register()
  * variants, regular ones work with both managed and unmanaged devices,
  * should you need them. In most cases however, managed input device need
  * not be explicitly unregistered or freed.
  *
  * NOTE: the owner device is set up as parent of input device and users
  * should not override it.
  */
 struct input_dev *devm_input_allocate_device(struct device *dev)
 {
     struct input_dev *input;
     struct input_devres *devres;
 
     devres = devres_alloc(devm_input_device_release,
                   sizeof(*devres), GFP_KERNEL);
     if (!devres)
         return NULL;
 
     input = input_allocate_device();
     if (!input) {
         devres_free(devres);
         return NULL;
     }
 
     input->dev.parent = dev;
     input->devres_managed = true;
 
     devres->input = input;
     devres_add(dev, devres);
 
     return input;
 }
 EXPORT_SYMBOL(devm_input_allocate_device);
 
 /**
  * input_free_device - free memory occupied by input_dev structure
  * @dev: input device to free
  *
  * This function should only be used if input_register_device()
  * was not called yet or if it failed. Once device was registered
  * use input_unregister_device() and memory will be freed once last
  * reference to the device is dropped.
  *
  * Device should be allocated by input_allocate_device().
  *
  * NOTE: If there are references to the input device then memory
  * will not be freed until last reference is dropped.
  */
 void input_free_device(struct input_dev *dev)
 {
     if (dev) {
         if (dev->devres_managed)
             WARN_ON(devres_destroy(dev->dev.parent,
                         devm_input_device_release,
                         devm_input_device_match,
                         dev));
         input_put_device(dev);
     }
 }
 EXPORT_SYMBOL(input_free_device);
 
 /**
  * input_set_timestamp - set timestamp for input events
  * @dev: input device to set timestamp for
  * @timestamp: the time at which the event has occurred
  *   in CLOCK_MONOTONIC
  *
  * This function is intended to provide to the input system a more
  * accurate time of when an event actually occurred. The driver should
  * call this function as soon as a timestamp is acquired ensuring
  * clock conversions in input_set_timestamp are done correctly.
  *
  * The system entering suspend state between timestamp acquisition and
  * calling input_set_timestamp can result in inaccurate conversions.
  */
 void input_set_timestamp(struct input_dev *dev, ktime_t timestamp)
 {
     dev->timestamp[INPUT_CLK_MONO] = timestamp;
     dev->timestamp[INPUT_CLK_REAL] = ktime_mono_to_real(timestamp);
     dev->timestamp[INPUT_CLK_BOOT] = ktime_mono_to_any(timestamp,
                                TK_OFFS_BOOT);
 }
 EXPORT_SYMBOL(input_set_timestamp);
 
 /**
  * input_get_timestamp - get timestamp for input events
  * @dev: input device to get timestamp from
  *
  * A valid timestamp is a timestamp of non-zero value.
  */
 ktime_t *input_get_timestamp(struct input_dev *dev)
 {
     const ktime_t invalid_timestamp = ktime_set(0, 0);
 
     if (!ktime_compare(dev->timestamp[INPUT_CLK_MONO], invalid_timestamp))
         input_set_timestamp(dev, ktime_get());
 
     return dev->timestamp;
 }
 EXPORT_SYMBOL(input_get_timestamp);
 
 /**
  * input_set_capability - mark device as capable of a certain event
  * @dev: device that is capable of emitting or accepting event
  * @type: type of the event (EV_KEY, EV_REL, etc...)
  * @code: event code
  *
  * In addition to setting up corresponding bit in appropriate capability
  * bitmap the function also adjusts dev->evbit.
  */
 void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
 {
     if (type < EV_CNT && input_max_code[type] &&
         code > input_max_code[type]) {
         pr_err("%s: invalid code %u for type %u\n", __func__, code,
                type);
         dump_stack();
         return;
     }
 
     switch (type) {
     case EV_KEY:
         __set_bit(code, dev->keybit);
         break;
 
     case EV_REL:
         __set_bit(code, dev->relbit);
         break;
 
     case EV_ABS:
         input_alloc_absinfo(dev);
         __set_bit(code, dev->absbit);
         break;
 
     case EV_MSC:
         __set_bit(code, dev->mscbit);
         break;
 
     case EV_SW:
         __set_bit(code, dev->swbit);
         break;
 
     case EV_LED:
         __set_bit(code, dev->ledbit);
         break;
 
     case EV_SND:
         __set_bit(code, dev->sndbit);
         break;
 
     case EV_FF:
         __set_bit(code, dev->ffbit);
         break;
 
     case EV_PWR:
         /* do nothing */
         break;
 
     default:
         pr_err("%s: unknown type %u (code %u)\n", __func__, type, code);
         dump_stack();
         return;
     }
 
     __set_bit(type, dev->evbit);
 }
 EXPORT_SYMBOL(input_set_capability);
 
 static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
 {
     int mt_slots;
     int i;
     unsigned int events;
 
     if (dev->mt) {
         mt_slots = dev->mt->num_slots;
     } else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit)) {
         mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
                dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1,
         mt_slots = clamp(mt_slots, 2, 32);
     } else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
         mt_slots = 2;
     } else {
         mt_slots = 0;
     }
 
     events = mt_slots + 1; /* count SYN_MT_REPORT and SYN_REPORT */
 
     if (test_bit(EV_ABS, dev->evbit))
         for_each_set_bit(i, dev->absbit, ABS_CNT)
             events += input_is_mt_axis(i) ? mt_slots : 1;
 
     if (test_bit(EV_REL, dev->evbit))
         events += bitmap_weight(dev->relbit, REL_CNT);
 
     /* Make room for KEY and MSC events */
     events += 7;
 
     return events;
 }
 
 #define INPUT_CLEANSE_BITMASK(dev, type, bits)              \
     do {                                \
         if (!test_bit(EV_##type, dev->evbit))           \
             memset(dev->bits##bit, 0,           \
                 sizeof(dev->bits##bit));        \
     } while (0)
 
 static void input_cleanse_bitmasks(struct input_dev *dev)
 {
     INPUT_CLEANSE_BITMASK(dev, KEY, key);
     INPUT_CLEANSE_BITMASK(dev, REL, rel);
     INPUT_CLEANSE_BITMASK(dev, ABS, abs);
     INPUT_CLEANSE_BITMASK(dev, MSC, msc);
     INPUT_CLEANSE_BITMASK(dev, LED, led);
     INPUT_CLEANSE_BITMASK(dev, SND, snd);
     INPUT_CLEANSE_BITMASK(dev, FF, ff);
     INPUT_CLEANSE_BITMASK(dev, SW, sw);
 }
 
 static void __input_unregister_device(struct input_dev *dev)
 {
     struct input_handle *handle, *next;
 
     input_disconnect_device(dev);
 
     mutex_lock(&input_mutex);
 
     list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
         handle->handler->disconnect(handle);
     WARN_ON(!list_empty(&dev->h_list));
 
     del_timer_sync(&dev->timer);
     list_del_init(&dev->node);
 
     input_wakeup_procfs_readers();
 
     mutex_unlock(&input_mutex);
 
     device_del(&dev->dev);
 }
 
 static void devm_input_device_unregister(struct device *dev, void *res)
 {
     struct input_devres *devres = res;
     struct input_dev *input = devres->input;
 
     dev_dbg(dev, "%s: unregistering device %s\n",
         __func__, dev_name(&input->dev));
     __input_unregister_device(input);
 }
 
 /*
  * Generate software autorepeat event. Note that we take
  * dev->event_lock here to avoid racing with input_event
  * which may cause keys get "stuck".
  */
 static void input_repeat_key(struct timer_list *t)
 {
     struct input_dev *dev = from_timer(dev, t, timer);
     unsigned long flags;
 
     spin_lock_irqsave(&dev->event_lock, flags);
 
     if (!dev->inhibited &&
         test_bit(dev->repeat_key, dev->key) &&
         is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {
 
         input_set_timestamp(dev, ktime_get());
         input_handle_event(dev, EV_KEY, dev->repeat_key, 2);
         input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
 
         if (dev->rep[REP_PERIOD])
             mod_timer(&dev->timer, jiffies +
                     msecs_to_jiffies(dev->rep[REP_PERIOD]));
     }
 
     spin_unlock_irqrestore(&dev->event_lock, flags);
 }
 
 /**
  * input_enable_softrepeat - enable software autorepeat
  * @dev: input device
  * @delay: repeat delay
  * @period: repeat period
  *
  * Enable software autorepeat on the input device.
  */
 void input_enable_softrepeat(struct input_dev *dev, int delay, int period)
 {
     dev->timer.function = input_repeat_key;
     dev->rep[REP_DELAY] = delay;
     dev->rep[REP_PERIOD] = period;
 }
 EXPORT_SYMBOL(input_enable_softrepeat);
 
 bool input_device_enabled(struct input_dev *dev)
 {
     lockdep_assert_held(&dev->mutex);
 
     return !dev->inhibited && dev->users > 0;
 }
 EXPORT_SYMBOL_GPL(input_device_enabled);
 
 /**
  * input_register_device - register device with input core
  * @dev: device to be registered
  *
  * This function registers device with input core. The device must be
  * allocated with input_allocate_device() and all it's capabilities
  * set up before registering.
  * If function fails the device must be freed with input_free_device().
  * Once device has been successfully registered it can be unregistered
  * with input_unregister_device(); input_free_device() should not be
  * called in this case.
  *
  * Note that this function is also used to register managed input devices
  * (ones allocated with devm_input_allocate_device()). Such managed input
  * devices need not be explicitly unregistered or freed, their tear down
  * is controlled by the devres infrastructure. It is also worth noting
  * that tear down of managed input devices is internally a 2-step process:
  * registered managed input device is first unregistered, but stays in
  * memory and can still handle input_event() calls (although events will
  * not be delivered anywhere). The freeing of managed input device will
  * happen later, when devres stack is unwound to the point where device
  * allocation was made.
  */
 int input_register_device(struct input_dev *dev)
 {
     struct input_devres *devres = NULL;
     struct input_handler *handler;
     unsigned int packet_size;
     const char *path;
     int error;
 
     if (test_bit(EV_ABS, dev->evbit) && !dev->absinfo) {
         dev_err(&dev->dev,
             "Absolute device without dev->absinfo, refusing to register\n");
         return -EINVAL;
     }
 
     if (dev->devres_managed) {
         devres = devres_alloc(devm_input_device_unregister,
                       sizeof(*devres), GFP_KERNEL);
         if (!devres)
             return -ENOMEM;
 
         devres->input = dev;
     }
 
     /* Every input device generates EV_SYN/SYN_REPORT events. */
     __set_bit(EV_SYN, dev->evbit);
 
     /* KEY_RESERVED is not supposed to be transmitted to userspace. */
     __clear_bit(KEY_RESERVED, dev->keybit);
 
     /* Make sure that bitmasks not mentioned in dev->evbit are clean. */
     input_cleanse_bitmasks(dev);
 
     packet_size = input_estimate_events_per_packet(dev);
     if (dev->hint_events_per_packet < packet_size)
         dev->hint_events_per_packet = packet_size;
 
     dev->max_vals = dev->hint_events_per_packet + 2;
     dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
     if (!dev->vals) {
         error = -ENOMEM;
         goto err_devres_free;
     }
 
     /*
      * If delay and period are pre-set by the driver, then autorepeating
      * is handled by the driver itself and we don't do it in input.c.
      */
     if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD])
         input_enable_softrepeat(dev, 250, 33);
 
     if (!dev->getkeycode)
         dev->getkeycode = input_default_getkeycode;
 
     if (!dev->setkeycode)
         dev->setkeycode = input_default_setkeycode;
 
     if (dev->poller)
         input_dev_poller_finalize(dev->poller);
 
     error = device_add(&dev->dev);
     if (error)
         goto err_free_vals;
 
     path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
     pr_info("%s as %s\n",
         dev->name ? dev->name : "Unspecified device",
         path ? path : "N/A");
     kfree(path);
 
     error = mutex_lock_interruptible(&input_mutex);
     if (error)
         goto err_device_del;
 
     list_add_tail(&dev->node, &input_dev_list);
 
     list_for_each_entry(handler, &input_handler_list, node)
         input_attach_handler(dev, handler);
 
     input_wakeup_procfs_readers();
 
     mutex_unlock(&input_mutex);
 
     if (dev->devres_managed) {
         dev_dbg(dev->dev.parent, "%s: registering %s with devres.\n",
             __func__, dev_name(&dev->dev));
         devres_add(dev->dev.parent, devres);
     }
     return 0;
 
 err_device_del:
     device_del(&dev->dev);
 err_free_vals:
     kfree(dev->vals);
     dev->vals = NULL;
 err_devres_free:
     devres_free(devres);
     return error;
 }
 EXPORT_SYMBOL(input_register_device);
 
 /**
  * input_unregister_device - unregister previously registered device
  * @dev: device to be unregistered
  *
  * This function unregisters an input device. Once device is unregistered
  * the caller should not try to access it as it may get freed at any moment.
  */
 void input_unregister_device(struct input_dev *dev)
 {
     if (dev->devres_managed) {
         WARN_ON(devres_destroy(dev->dev.parent,
                     devm_input_device_unregister,
                     devm_input_device_match,
                     dev));
         __input_unregister_device(dev);
         /*
          * We do not do input_put_device() here because it will be done
          * when 2nd devres fires up.
          */
     } else {
         __input_unregister_device(dev);
         input_put_device(dev);
     }
 }
 EXPORT_SYMBOL(input_unregister_device);
 
 /**
  * input_register_handler - register a new input handler
  * @handler: handler to be registered
  *
  * This function registers a new input handler (interface) for input
  * devices in the system and attaches it to all input devices that
  * are compatible with the handler.
  */
 int input_register_handler(struct input_handler *handler)
 {
     struct input_dev *dev;
     int error;
 
     error = mutex_lock_interruptible(&input_mutex);
     if (error)
         return error;
 
     INIT_LIST_HEAD(&handler->h_list);
 
     list_add_tail(&handler->node, &input_handler_list);
 
     list_for_each_entry(dev, &input_dev_list, node)
         input_attach_handler(dev, handler);
 
     input_wakeup_procfs_readers();
 
     mutex_unlock(&input_mutex);
     return 0;
 }
 EXPORT_SYMBOL(input_register_handler);
 
 /**
  * input_unregister_handler - unregisters an input handler
  * @handler: handler to be unregistered
  *
  * This function disconnects a handler from its input devices and
  * removes it from lists of known handlers.
  */
 void input_unregister_handler(struct input_handler *handler)
 {
     struct input_handle *handle, *next;
 
     mutex_lock(&input_mutex);
 
     list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
         handler->disconnect(handle);
     WARN_ON(!list_empty(&handler->h_list));
 
     list_del_init(&handler->node);
 
     input_wakeup_procfs_readers();
 
     mutex_unlock(&input_mutex);
 }
 EXPORT_SYMBOL(input_unregister_handler);
 
 /**
  * input_handler_for_each_handle - handle iterator
  * @handler: input handler to iterate
  * @data: data for the callback
  * @fn: function to be called for each handle
  *
  * Iterate over @bus's list of devices, and call @fn for each, passing
  * it @data and stop when @fn returns a non-zero value. The function is
  * using RCU to traverse the list and therefore may be using in atomic
  * contexts. The @fn callback is invoked from RCU critical section and
  * thus must not sleep.
  */
 int input_handler_for_each_handle(struct input_handler *handler, void *data,
                   int (*fn)(struct input_handle *, void *))
 {
     struct input_handle *handle;
     int retval = 0;
 
     rcu_read_lock();
 
     list_for_each_entry_rcu(handle, &handler->h_list, h_node) {
         retval = fn(handle, data);
         if (retval)
             break;
     }
 
     rcu_read_unlock();
 
     return retval;
 }
 EXPORT_SYMBOL(input_handler_for_each_handle);
 
 /**
  * input_register_handle - register a new input handle
  * @handle: handle to register
  *
  * This function puts a new input handle onto device's
  * and handler's lists so that events can flow through
  * it once it is opened using input_open_device().
  *
  * This function is supposed to be called from handler's
  * connect() method.
  */
 int input_register_handle(struct input_handle *handle)
 {
     struct input_handler *handler = handle->handler;
     struct input_dev *dev = handle->dev;
     int error;
 
     /*
      * We take dev->mutex here to prevent race with
      * input_release_device().
      */
     error = mutex_lock_interruptible(&dev->mutex);
     if (error)
         return error;
 
     /*
      * Filters go to the head of the list, normal handlers
      * to the tail.
      */
     if (handler->filter)
         list_add_rcu(&handle->d_node, &dev->h_list);
     else
         list_add_tail_rcu(&handle->d_node, &dev->h_list);
 
     mutex_unlock(&dev->mutex);
 
     /*
      * Since we are supposed to be called from ->connect()
      * which is mutually exclusive with ->disconnect()
      * we can't be racing with input_unregister_handle()
      * and so separate lock is not needed here.
      */
     list_add_tail_rcu(&handle->h_node, &handler->h_list);
 
     if (handler->start)
         handler->start(handle);
 
     return 0;
 }
 EXPORT_SYMBOL(input_register_handle);
 
 /**
  * input_unregister_handle - unregister an input handle
  * @handle: handle to unregister
  *
  * This function removes input handle from device's
  * and handler's lists.
  *
  * This function is supposed to be called from handler's
  * disconnect() method.
  */
 void input_unregister_handle(struct input_handle *handle)
 {
     struct input_dev *dev = handle->dev;
 
     list_del_rcu(&handle->h_node);
 
     /*
      * Take dev->mutex to prevent race with input_release_device().
      */
     mutex_lock(&dev->mutex);
     list_del_rcu(&handle->d_node);
     mutex_unlock(&dev->mutex);
 
     synchronize_rcu();
 }
 EXPORT_SYMBOL(input_unregister_handle);
 
 /**
  * input_get_new_minor - allocates a new input minor number
  * @legacy_base: beginning or the legacy range to be searched
  * @legacy_num: size of legacy range
  * @allow_dynamic: whether we can also take ID from the dynamic range
  *
  * This function allocates a new device minor for from input major namespace.
  * Caller can request legacy minor by specifying @legacy_base and @legacy_num
  * parameters and whether ID can be allocated from dynamic range if there are
  * no free IDs in legacy range.
  */
 int input_get_new_minor(int legacy_base, unsigned int legacy_num,
             bool allow_dynamic)
 {
     /*
      * This function should be called from input handler's ->connect()
      * methods, which are serialized with input_mutex, so no additional
      * locking is needed here.
      */
     if (legacy_base >= 0) {
         int minor = ida_simple_get(&input_ida,
                        legacy_base,
                        legacy_base + legacy_num,
                        GFP_KERNEL);
         if (minor >= 0 || !allow_dynamic)
             return minor;
     }
 
     return ida_simple_get(&input_ida,
                   INPUT_FIRST_DYNAMIC_DEV, INPUT_MAX_CHAR_DEVICES,
                   GFP_KERNEL);
 }
 EXPORT_SYMBOL(input_get_new_minor);
 
 /**
  * input_free_minor - release previously allocated minor
  * @minor: minor to be released
  *
  * This function releases previously allocated input minor so that it can be
  * reused later.
  */
 void input_free_minor(unsigned int minor)
 {
     ida_simple_remove(&input_ida, minor);
 }
 EXPORT_SYMBOL(input_free_minor);
 
 static int __init input_init(void)
 {
     int err;
 
     err = class_register(&input_class);
     if (err) {
         pr_err("unable to register input_dev class\n");
         return err;
     }
 
     err = input_proc_init();
     if (err)
         goto fail1;
 
     err = register_chrdev_region(MKDEV(INPUT_MAJOR, 0),
                      INPUT_MAX_CHAR_DEVICES, "input");
     if (err) {
         pr_err("unable to register char major %d", INPUT_MAJOR);
         goto fail2;
     }
 
     return 0;
 
  fail2: input_proc_exit();
  fail1: class_unregister(&input_class);
     return err;
 }
 
 static void __exit input_exit(void)
 {
     input_proc_exit();
     unregister_chrdev_region(MKDEV(INPUT_MAJOR, 0),
                  INPUT_MAX_CHAR_DEVICES);
     class_unregister(&input_class);
 }
 
 subsys_initcall(input_init);
 module_exit(input_exit);