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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
 /*
  * Multiplexer subsystem
  *
  * Copyright (C) 2017 Axentia Technologies AB
  *
  * Author: Peter Rosin <peda@axentia.se>
  */
 
 #define pr_fmt(fmt) "mux-core: " fmt
 
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/export.h>
 #include <linux/idr.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mux/consumer.h>
 #include <linux/mux/driver.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
 
 /*
  * The idle-as-is "state" is not an actual state that may be selected, it
  * only implies that the state should not be changed. So, use that state
  * as indication that the cached state of the multiplexer is unknown.
  */
 #define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS
 
 /**
  * struct mux_state -   Represents a mux controller state specific to a given
  *          consumer.
  * @mux:        Pointer to a mux controller.
  * @state:      State of the mux to be selected.
  *
  * This structure is specific to the consumer that acquires it and has
  * information specific to that consumer.
  */
 struct mux_state {
     struct mux_control *mux;
     unsigned int state;
 };
 
 static struct class mux_class = {
     .name = "mux",
     .owner = THIS_MODULE,
 };
 
 static DEFINE_IDA(mux_ida);
 
 static int __init mux_init(void)
 {
     ida_init(&mux_ida);
     return class_register(&mux_class);
 }
 
 static void __exit mux_exit(void)
 {
     class_unregister(&mux_class);
     ida_destroy(&mux_ida);
 }
 
 static void mux_chip_release(struct device *dev)
 {
     struct mux_chip *mux_chip = to_mux_chip(dev);
 
     ida_simple_remove(&mux_ida, mux_chip->id);
     kfree(mux_chip);
 }
 
 static const struct device_type mux_type = {
     .name = "mux-chip",
     .release = mux_chip_release,
 };
 
 /**
  * mux_chip_alloc() - Allocate a mux-chip.
  * @dev: The parent device implementing the mux interface.
  * @controllers: The number of mux controllers to allocate for this chip.
  * @sizeof_priv: Size of extra memory area for private use by the caller.
  *
  * After allocating the mux-chip with the desired number of mux controllers
  * but before registering the chip, the mux driver is required to configure
  * the number of valid mux states in the mux_chip->mux[N].states members and
  * the desired idle state in the returned mux_chip->mux[N].idle_state members.
  * The default idle state is MUX_IDLE_AS_IS. The mux driver also needs to
  * provide a pointer to the operations struct in the mux_chip->ops member
  * before registering the mux-chip with mux_chip_register.
  *
  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
  */
 struct mux_chip *mux_chip_alloc(struct device *dev,
                 unsigned int controllers, size_t sizeof_priv)
 {
     struct mux_chip *mux_chip;
     int i;
 
     if (WARN_ON(!dev || !controllers))
         return ERR_PTR(-EINVAL);
 
     mux_chip = kzalloc(sizeof(*mux_chip) +
                controllers * sizeof(*mux_chip->mux) +
                sizeof_priv, GFP_KERNEL);
     if (!mux_chip)
         return ERR_PTR(-ENOMEM);
 
     mux_chip->mux = (struct mux_control *)(mux_chip + 1);
     mux_chip->dev.class = &mux_class;
     mux_chip->dev.type = &mux_type;
     mux_chip->dev.parent = dev;
     mux_chip->dev.of_node = dev->of_node;
     dev_set_drvdata(&mux_chip->dev, mux_chip);
 
     mux_chip->id = ida_simple_get(&mux_ida, 0, 0, GFP_KERNEL);
     if (mux_chip->id < 0) {
         int err = mux_chip->id;
 
         pr_err("muxchipX failed to get a device id\n");
         kfree(mux_chip);
         return ERR_PTR(err);
     }
     dev_set_name(&mux_chip->dev, "muxchip%d", mux_chip->id);
 
     mux_chip->controllers = controllers;
     for (i = 0; i < controllers; ++i) {
         struct mux_control *mux = &mux_chip->mux[i];
 
         mux->chip = mux_chip;
         sema_init(&mux->lock, 1);
         mux->cached_state = MUX_CACHE_UNKNOWN;
         mux->idle_state = MUX_IDLE_AS_IS;
         mux->last_change = ktime_get();
     }
 
     device_initialize(&mux_chip->dev);
 
     return mux_chip;
 }
 EXPORT_SYMBOL_GPL(mux_chip_alloc);
 
 static int mux_control_set(struct mux_control *mux, int state)
 {
     int ret = mux->chip->ops->set(mux, state);
 
     mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;
     if (ret >= 0)
         mux->last_change = ktime_get();
 
     return ret;
 }
 
 /**
  * mux_chip_register() - Register a mux-chip, thus readying the controllers
  *           for use.
  * @mux_chip: The mux-chip to register.
  *
  * Do not retry registration of the same mux-chip on failure. You should
  * instead put it away with mux_chip_free() and allocate a new one, if you
  * for some reason would like to retry registration.
  *
  * Return: Zero on success or a negative errno on error.
  */
 int mux_chip_register(struct mux_chip *mux_chip)
 {
     int i;
     int ret;
 
     for (i = 0; i < mux_chip->controllers; ++i) {
         struct mux_control *mux = &mux_chip->mux[i];
 
         if (mux->idle_state == mux->cached_state)
             continue;
 
         ret = mux_control_set(mux, mux->idle_state);
         if (ret < 0) {
             dev_err(&mux_chip->dev, "unable to set idle state\n");
             return ret;
         }
     }
 
     ret = device_add(&mux_chip->dev);
     if (ret < 0)
         dev_err(&mux_chip->dev,
             "device_add failed in %s: %d\n", __func__, ret);
     return ret;
 }
 EXPORT_SYMBOL_GPL(mux_chip_register);
 
 /**
  * mux_chip_unregister() - Take the mux-chip off-line.
  * @mux_chip: The mux-chip to unregister.
  *
  * mux_chip_unregister() reverses the effects of mux_chip_register().
  * But not completely, you should not try to call mux_chip_register()
  * on a mux-chip that has been registered before.
  */
 void mux_chip_unregister(struct mux_chip *mux_chip)
 {
     device_del(&mux_chip->dev);
 }
 EXPORT_SYMBOL_GPL(mux_chip_unregister);
 
 /**
  * mux_chip_free() - Free the mux-chip for good.
  * @mux_chip: The mux-chip to free.
  *
  * mux_chip_free() reverses the effects of mux_chip_alloc().
  */
 void mux_chip_free(struct mux_chip *mux_chip)
 {
     if (!mux_chip)
         return;
 
     put_device(&mux_chip->dev);
 }
 EXPORT_SYMBOL_GPL(mux_chip_free);
 
 static void devm_mux_chip_release(struct device *dev, void *res)
 {
     struct mux_chip *mux_chip = *(struct mux_chip **)res;
 
     mux_chip_free(mux_chip);
 }
 
 /**
  * devm_mux_chip_alloc() - Resource-managed version of mux_chip_alloc().
  * @dev: The parent device implementing the mux interface.
  * @controllers: The number of mux controllers to allocate for this chip.
  * @sizeof_priv: Size of extra memory area for private use by the caller.
  *
  * See mux_chip_alloc() for more details.
  *
  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
  */
 struct mux_chip *devm_mux_chip_alloc(struct device *dev,
                      unsigned int controllers,
                      size_t sizeof_priv)
 {
     struct mux_chip **ptr, *mux_chip;
 
     ptr = devres_alloc(devm_mux_chip_release, sizeof(*ptr), GFP_KERNEL);
     if (!ptr)
         return ERR_PTR(-ENOMEM);
 
     mux_chip = mux_chip_alloc(dev, controllers, sizeof_priv);
     if (IS_ERR(mux_chip)) {
         devres_free(ptr);
         return mux_chip;
     }
 
     *ptr = mux_chip;
     devres_add(dev, ptr);
 
     return mux_chip;
 }
 EXPORT_SYMBOL_GPL(devm_mux_chip_alloc);
 
 static void devm_mux_chip_reg_release(struct device *dev, void *res)
 {
     struct mux_chip *mux_chip = *(struct mux_chip **)res;
 
     mux_chip_unregister(mux_chip);
 }
 
 /**
  * devm_mux_chip_register() - Resource-managed version mux_chip_register().
  * @dev: The parent device implementing the mux interface.
  * @mux_chip: The mux-chip to register.
  *
  * See mux_chip_register() for more details.
  *
  * Return: Zero on success or a negative errno on error.
  */
 int devm_mux_chip_register(struct device *dev,
                struct mux_chip *mux_chip)
 {
     struct mux_chip **ptr;
     int res;
 
     ptr = devres_alloc(devm_mux_chip_reg_release, sizeof(*ptr), GFP_KERNEL);
     if (!ptr)
         return -ENOMEM;
 
     res = mux_chip_register(mux_chip);
     if (res) {
         devres_free(ptr);
         return res;
     }
 
     *ptr = mux_chip;
     devres_add(dev, ptr);
 
     return res;
 }
 EXPORT_SYMBOL_GPL(devm_mux_chip_register);
 
 /**
  * mux_control_states() - Query the number of multiplexer states.
  * @mux: The mux-control to query.
  *
  * Return: The number of multiplexer states.
  */
 unsigned int mux_control_states(struct mux_control *mux)
 {
     return mux->states;
 }
 EXPORT_SYMBOL_GPL(mux_control_states);
 
 /*
  * The mux->lock must be down when calling this function.
  */
 static int __mux_control_select(struct mux_control *mux, int state)
 {
     int ret;
 
     if (WARN_ON(state < 0 || state >= mux->states))
         return -EINVAL;
 
     if (mux->cached_state == state)
         return 0;
 
     ret = mux_control_set(mux, state);
     if (ret >= 0)
         return 0;
 
     /* The mux update failed, try to revert if appropriate... */
     if (mux->idle_state != MUX_IDLE_AS_IS)
         mux_control_set(mux, mux->idle_state);
 
     return ret;
 }
 
 static void mux_control_delay(struct mux_control *mux, unsigned int delay_us)
 {
     ktime_t delayend;
     s64 remaining;
 
     if (!delay_us)
         return;
 
     delayend = ktime_add_us(mux->last_change, delay_us);
     remaining = ktime_us_delta(delayend, ktime_get());
     if (remaining > 0)
         fsleep(remaining);
 }
 
 /**
  * mux_control_select_delay() - Select the given multiplexer state.
  * @mux: The mux-control to request a change of state from.
  * @state: The new requested state.
  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
  *
  * On successfully selecting the mux-control state, it will be locked until
  * there is a call to mux_control_deselect(). If the mux-control is already
  * selected when mux_control_select() is called, the caller will be blocked
  * until mux_control_deselect() or mux_state_deselect() is called (by someone
  * else).
  *
  * Therefore, make sure to call mux_control_deselect() when the operation is
  * complete and the mux-control is free for others to use, but do not call
  * mux_control_deselect() if mux_control_select() fails.
  *
  * Return: 0 when the mux-control state has the requested state or a negative
  * errno on error.
  */
 int mux_control_select_delay(struct mux_control *mux, unsigned int state,
                  unsigned int delay_us)
 {
     int ret;
 
     ret = down_killable(&mux->lock);
     if (ret < 0)
         return ret;
 
     ret = __mux_control_select(mux, state);
     if (ret >= 0)
         mux_control_delay(mux, delay_us);
 
     if (ret < 0)
         up(&mux->lock);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(mux_control_select_delay);
 
 /**
  * mux_state_select_delay() - Select the given multiplexer state.
  * @mstate: The mux-state to select.
  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
  *
  * On successfully selecting the mux-state, its mux-control will be locked
  * until there is a call to mux_state_deselect(). If the mux-control is already
  * selected when mux_state_select() is called, the caller will be blocked
  * until mux_state_deselect() or mux_control_deselect() is called (by someone
  * else).
  *
  * Therefore, make sure to call mux_state_deselect() when the operation is
  * complete and the mux-control is free for others to use, but do not call
  * mux_state_deselect() if mux_state_select() fails.
  *
  * Return: 0 when the mux-state has been selected or a negative
  * errno on error.
  */
 int mux_state_select_delay(struct mux_state *mstate, unsigned int delay_us)
 {
     return mux_control_select_delay(mstate->mux, mstate->state, delay_us);
 }
 EXPORT_SYMBOL_GPL(mux_state_select_delay);
 
 /**
  * mux_control_try_select_delay() - Try to select the given multiplexer state.
  * @mux: The mux-control to request a change of state from.
  * @state: The new requested state.
  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
  *
  * On successfully selecting the mux-control state, it will be locked until
  * mux_control_deselect() is called.
  *
  * Therefore, make sure to call mux_control_deselect() when the operation is
  * complete and the mux-control is free for others to use, but do not call
  * mux_control_deselect() if mux_control_try_select() fails.
  *
  * Return: 0 when the mux-control state has the requested state or a negative
  * errno on error. Specifically -EBUSY if the mux-control is contended.
  */
 int mux_control_try_select_delay(struct mux_control *mux, unsigned int state,
                  unsigned int delay_us)
 {
     int ret;
 
     if (down_trylock(&mux->lock))
         return -EBUSY;
 
     ret = __mux_control_select(mux, state);
     if (ret >= 0)
         mux_control_delay(mux, delay_us);
 
     if (ret < 0)
         up(&mux->lock);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(mux_control_try_select_delay);
 
 /**
  * mux_state_try_select_delay() - Try to select the given multiplexer state.
  * @mstate: The mux-state to select.
  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
  *
  * On successfully selecting the mux-state, its mux-control will be locked
  * until mux_state_deselect() is called.
  *
  * Therefore, make sure to call mux_state_deselect() when the operation is
  * complete and the mux-control is free for others to use, but do not call
  * mux_state_deselect() if mux_state_try_select() fails.
  *
  * Return: 0 when the mux-state has been selected or a negative errno on
  * error. Specifically -EBUSY if the mux-control is contended.
  */
 int mux_state_try_select_delay(struct mux_state *mstate, unsigned int delay_us)
 {
     return mux_control_try_select_delay(mstate->mux, mstate->state, delay_us);
 }
 EXPORT_SYMBOL_GPL(mux_state_try_select_delay);
 
 /**
  * mux_control_deselect() - Deselect the previously selected multiplexer state.
  * @mux: The mux-control to deselect.
  *
  * It is required that a single call is made to mux_control_deselect() for
  * each and every successful call made to either of mux_control_select() or
  * mux_control_try_select().
  *
  * Return: 0 on success and a negative errno on error. An error can only
  * occur if the mux has an idle state. Note that even if an error occurs, the
  * mux-control is unlocked and is thus free for the next access.
  */
 int mux_control_deselect(struct mux_control *mux)
 {
     int ret = 0;
 
     if (mux->idle_state != MUX_IDLE_AS_IS &&
         mux->idle_state != mux->cached_state)
         ret = mux_control_set(mux, mux->idle_state);
 
     up(&mux->lock);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(mux_control_deselect);
 
 /**
  * mux_state_deselect() - Deselect the previously selected multiplexer state.
  * @mstate: The mux-state to deselect.
  *
  * It is required that a single call is made to mux_state_deselect() for
  * each and every successful call made to either of mux_state_select() or
  * mux_state_try_select().
  *
  * Return: 0 on success and a negative errno on error. An error can only
  * occur if the mux has an idle state. Note that even if an error occurs, the
  * mux-control is unlocked and is thus free for the next access.
  */
 int mux_state_deselect(struct mux_state *mstate)
 {
     return mux_control_deselect(mstate->mux);
 }
 EXPORT_SYMBOL_GPL(mux_state_deselect);
 
 /* Note this function returns a reference to the mux_chip dev. */
 static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np)
 {
     struct device *dev;
 
     dev = class_find_device_by_of_node(&mux_class, np);
 
     return dev ? to_mux_chip(dev) : NULL;
 }
 
 /*
  * mux_get() - Get the mux-control for a device.
  * @dev: The device that needs a mux-control.
  * @mux_name: The name identifying the mux-control.
  * @state: Pointer to where the requested state is returned, or NULL when
  *         the required multiplexer states are handled by other means.
  *
  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
  */
 static struct mux_control *mux_get(struct device *dev, const char *mux_name,
                    unsigned int *state)
 {
     struct device_node *np = dev->of_node;
     struct of_phandle_args args;
     struct mux_chip *mux_chip;
     unsigned int controller;
     int index = 0;
     int ret;
 
     if (mux_name) {
         if (state)
             index = of_property_match_string(np, "mux-state-names",
                              mux_name);
         else
             index = of_property_match_string(np, "mux-control-names",
                              mux_name);
         if (index < 0) {
             dev_err(dev, "mux controller '%s' not found\n",
                 mux_name);
             return ERR_PTR(index);
         }
     }
 
     if (state)
         ret = of_parse_phandle_with_args(np,
                          "mux-states", "#mux-state-cells",
                          index, &args);
     else
         ret = of_parse_phandle_with_args(np,
                          "mux-controls", "#mux-control-cells",
                          index, &args);
     if (ret) {
         dev_err(dev, "%pOF: failed to get mux-%s %s(%i)\n",
             np, state ? "state" : "control", mux_name ?: "", index);
         return ERR_PTR(ret);
     }
 
     mux_chip = of_find_mux_chip_by_node(args.np);
     of_node_put(args.np);
     if (!mux_chip)
         return ERR_PTR(-EPROBE_DEFER);
 
     controller = 0;
     if (state) {
         if (args.args_count > 2 || args.args_count == 0 ||
             (args.args_count < 2 && mux_chip->controllers > 1)) {
             dev_err(dev, "%pOF: wrong #mux-state-cells for %pOF\n",
                 np, args.np);
             put_device(&mux_chip->dev);
             return ERR_PTR(-EINVAL);
         }
 
         if (args.args_count == 2) {
             controller = args.args[0];
             *state = args.args[1];
         } else {
             *state = args.args[0];
         }
 
     } else {
         if (args.args_count > 1 ||
             (!args.args_count && mux_chip->controllers > 1)) {
             dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",
                 np, args.np);
             put_device(&mux_chip->dev);
             return ERR_PTR(-EINVAL);
         }
 
         if (args.args_count)
             controller = args.args[0];
     }
 
     if (controller >= mux_chip->controllers) {
         dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n",
             np, controller, args.np);
         put_device(&mux_chip->dev);
         return ERR_PTR(-EINVAL);
     }
 
     return &mux_chip->mux[controller];
 }
 
 /**
  * mux_control_get() - Get the mux-control for a device.
  * @dev: The device that needs a mux-control.
  * @mux_name: The name identifying the mux-control.
  *
  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
  */
 struct mux_control *mux_control_get(struct device *dev, const char *mux_name)
 {
     return mux_get(dev, mux_name, NULL);
 }
 EXPORT_SYMBOL_GPL(mux_control_get);
 
 /**
  * mux_control_put() - Put away the mux-control for good.
  * @mux: The mux-control to put away.
  *
  * mux_control_put() reverses the effects of mux_control_get().
  */
 void mux_control_put(struct mux_control *mux)
 {
     put_device(&mux->chip->dev);
 }
 EXPORT_SYMBOL_GPL(mux_control_put);
 
 static void devm_mux_control_release(struct device *dev, void *res)
 {
     struct mux_control *mux = *(struct mux_control **)res;
 
     mux_control_put(mux);
 }
 
 /**
  * devm_mux_control_get() - Get the mux-control for a device, with resource
  *              management.
  * @dev: The device that needs a mux-control.
  * @mux_name: The name identifying the mux-control.
  *
  * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno.
  */
 struct mux_control *devm_mux_control_get(struct device *dev,
                      const char *mux_name)
 {
     struct mux_control **ptr, *mux;
 
     ptr = devres_alloc(devm_mux_control_release, sizeof(*ptr), GFP_KERNEL);
     if (!ptr)
         return ERR_PTR(-ENOMEM);
 
     mux = mux_control_get(dev, mux_name);
     if (IS_ERR(mux)) {
         devres_free(ptr);
         return mux;
     }
 
     *ptr = mux;
     devres_add(dev, ptr);
 
     return mux;
 }
 EXPORT_SYMBOL_GPL(devm_mux_control_get);
 
 /*
  * mux_state_get() - Get the mux-state for a device.
  * @dev: The device that needs a mux-state.
  * @mux_name: The name identifying the mux-state.
  *
  * Return: A pointer to the mux-state, or an ERR_PTR with a negative errno.
  */
 static struct mux_state *mux_state_get(struct device *dev, const char *mux_name)
 {
     struct mux_state *mstate;
 
     mstate = kzalloc(sizeof(*mstate), GFP_KERNEL);
     if (!mstate)
         return ERR_PTR(-ENOMEM);
 
     mstate->mux = mux_get(dev, mux_name, &mstate->state);
     if (IS_ERR(mstate->mux)) {
         int err = PTR_ERR(mstate->mux);
 
         kfree(mstate);
         return ERR_PTR(err);
     }
 
     return mstate;
 }
 
 /*
  * mux_state_put() - Put away the mux-state for good.
  * @mstate: The mux-state to put away.
  *
  * mux_state_put() reverses the effects of mux_state_get().
  */
 static void mux_state_put(struct mux_state *mstate)
 {
     mux_control_put(mstate->mux);
     kfree(mstate);
 }
 
 static void devm_mux_state_release(struct device *dev, void *res)
 {
     struct mux_state *mstate = *(struct mux_state **)res;
 
     mux_state_put(mstate);
 }
 
 /**
  * devm_mux_state_get() - Get the mux-state for a device, with resource
  *            management.
  * @dev: The device that needs a mux-control.
  * @mux_name: The name identifying the mux-control.
  *
  * Return: Pointer to the mux-state, or an ERR_PTR with a negative errno.
  */
 struct mux_state *devm_mux_state_get(struct device *dev,
                      const char *mux_name)
 {
     struct mux_state **ptr, *mstate;
 
     ptr = devres_alloc(devm_mux_state_release, sizeof(*ptr), GFP_KERNEL);
     if (!ptr)
         return ERR_PTR(-ENOMEM);
 
     mstate = mux_state_get(dev, mux_name);
     if (IS_ERR(mstate)) {
         devres_free(ptr);
         return mstate;
     }
 
     *ptr = mstate;
     devres_add(dev, ptr);
 
     return mstate;
 }
 EXPORT_SYMBOL_GPL(devm_mux_state_get);
 
 /*
  * Using subsys_initcall instead of module_init here to try to ensure - for
  * the non-modular case - that the subsystem is initialized when mux consumers
  * and mux controllers start to use it.
  * For the modular case, the ordering is ensured with module dependencies.
  */
 subsys_initcall(mux_init);
 module_exit(mux_exit);
 
 MODULE_DESCRIPTION("Multiplexer subsystem");
 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
 MODULE_LICENSE("GPL v2");

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