drivers/leds/led-triggers.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * LED Triggers Core
  *
  * Copyright 2005-2007 Openedhand Ltd.
  *
  * Author: Richard Purdie <rpurdie@openedhand.com>
  */

 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/spinlock.h>
 #include <linux/device.h>
 #include <linux/timer.h>
 #include <linux/rwsem.h>
 #include <linux/leds.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include "leds.h"

 /*
  * Nests outside led_cdev->trigger_lock
  */
 static DECLARE_RWSEM(triggers_list_lock);
 static LIST_HEAD(trigger_list);

  /* Used by LED Class */

 static inline bool
 trigger_relevant(struct led_classdev *led_cdev, struct led_trigger *trig)
 {
 	return !trig->trigger_type || trig->trigger_type == led_cdev->trigger_type;
 }

 ssize_t led_trigger_write(struct file *filp, struct kobject *kobj,
 			  struct bin_attribute *bin_attr, char *buf,
 			  loff_t pos, size_t count)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
 	struct led_trigger *trig;
 	int ret = count;

 	mutex_lock(&led_cdev->led_access);

 	if (led_sysfs_is_disabled(led_cdev)) {
 		ret = -EBUSY;
 		goto unlock;
 	}

 	if (sysfs_streq(buf, "none")) {
 		led_trigger_remove(led_cdev);
 		goto unlock;
 	}

 	down_read(&triggers_list_lock);
 	list_for_each_entry(trig, &trigger_list, next_trig) {
 		if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
 			down_write(&led_cdev->trigger_lock);
 			led_trigger_set(led_cdev, trig);
 			up_write(&led_cdev->trigger_lock);

 			up_read(&triggers_list_lock);
 			goto unlock;
 		}
 	}
 	/* we come here only if buf matches no trigger */
 	ret = -EINVAL;
 	up_read(&triggers_list_lock);

 unlock:
 	mutex_unlock(&led_cdev->led_access);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(led_trigger_write);

 __printf(3, 4)
 static int led_trigger_snprintf(char *buf, ssize_t size, const char *fmt, ...)
 {
 	va_list args;
 	int i;

 	va_start(args, fmt);
 	if (size <= 0)
 		i = vsnprintf(NULL, 0, fmt, args);
 	else
 		i = vscnprintf(buf, size, fmt, args);
 	va_end(args);

 	return i;
 }

 static int led_trigger_format(char *buf, size_t size,
 			      struct led_classdev *led_cdev)
 {
 	struct led_trigger *trig;
 	int len = led_trigger_snprintf(buf, size, "%s",
 				       led_cdev->trigger ? "none" : "[none]");

 	list_for_each_entry(trig, &trigger_list, next_trig) {
 		bool hit;

 		if (!trigger_relevant(led_cdev, trig))
 			continue;

 		hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);

 		len += led_trigger_snprintf(buf + len, size - len,
 					    " %s%s%s", hit ? "[" : "",
 					    trig->name, hit ? "]" : "");
 	}

 	len += led_trigger_snprintf(buf + len, size - len, "\n");

 	return len;
 }

 /*
  * It was stupid to create 10000 cpu triggers, but we are stuck with it now.
  * Don't make that mistake again. We work around it here by creating binary
  * attribute, which is not limited by length. This is _not_ good design, do not
  * copy it.
  */
 ssize_t led_trigger_read(struct file *filp, struct kobject *kobj,
 			struct bin_attribute *attr, char *buf,
 			loff_t pos, size_t count)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
 	void *data;
 	int len;

 	down_read(&triggers_list_lock);
 	down_read(&led_cdev->trigger_lock);

 	len = led_trigger_format(NULL, 0, led_cdev);
 	data = kvmalloc(len + 1, GFP_KERNEL);
 	if (!data) {
 		up_read(&led_cdev->trigger_lock);
 		up_read(&triggers_list_lock);
 		return -ENOMEM;
 	}
 	len = led_trigger_format(data, len + 1, led_cdev);

 	up_read(&led_cdev->trigger_lock);
 	up_read(&triggers_list_lock);

 	len = memory_read_from_buffer(buf, count, &pos, data, len);

 	kvfree(data);

 	return len;
 }
 EXPORT_SYMBOL_GPL(led_trigger_read);

 /* Caller must ensure led_cdev->trigger_lock held */
 int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
 {
 	char *event = NULL;
 	char *envp[2];
 	const char *name;
 	int ret;

 	if (!led_cdev->trigger && !trig)
 		return 0;

 	name = trig ? trig->name : "none";
 	event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);

 	/* Remove any existing trigger */
 	if (led_cdev->trigger) {
 		spin_lock(&led_cdev->trigger->leddev_list_lock);
 		list_del_rcu(&led_cdev->trig_list);
 		spin_unlock(&led_cdev->trigger->leddev_list_lock);

 		/* ensure it's no longer visible on the led_cdevs list */
 		synchronize_rcu();

 		cancel_work_sync(&led_cdev->set_brightness_work);
 		led_stop_software_blink(led_cdev);
 		device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
 		if (led_cdev->trigger->deactivate)
 			led_cdev->trigger->deactivate(led_cdev);
 		led_cdev->trigger = NULL;
 		led_cdev->trigger_data = NULL;
 		led_cdev->activated = false;
 		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
 		led_set_brightness(led_cdev, LED_OFF);
 	}
 	if (trig) {
 		spin_lock(&trig->leddev_list_lock);
 		list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);
 		spin_unlock(&trig->leddev_list_lock);
 		led_cdev->trigger = trig;

 		/*
 		 * Some activate() calls use led_trigger_event() to initialize
 		 * the brightness of the LED for which the trigger is being set.
 		 * Ensure the led_cdev is visible on trig->led_cdevs for this.
 		 */
 		synchronize_rcu();

 		/*
 		 * If "set brightness to 0" is pending in workqueue,
 		 * we don't want that to be reordered after ->activate()
 		 */
 		flush_work(&led_cdev->set_brightness_work);

 		ret = 0;
 		if (trig->activate)
 			ret = trig->activate(led_cdev);
 		else
 			led_set_brightness(led_cdev, trig->brightness);
 		if (ret)
 			goto err_activate;

 		ret = device_add_groups(led_cdev->dev, trig->groups);
 		if (ret) {
 			dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
 			goto err_add_groups;
 		}
 	}

 	if (event) {
 		envp[0] = event;
 		envp[1] = NULL;
 		if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
 			dev_err(led_cdev->dev,
 				"%s: Error sending uevent\n", __func__);
 		kfree(event);
 	}

 	return 0;

 err_add_groups:

 	if (trig->deactivate)
 		trig->deactivate(led_cdev);
 err_activate:

 	spin_lock(&led_cdev->trigger->leddev_list_lock);
 	list_del_rcu(&led_cdev->trig_list);
 	spin_unlock(&led_cdev->trigger->leddev_list_lock);
 	synchronize_rcu();
 	led_cdev->trigger = NULL;
 	led_cdev->trigger_data = NULL;
 	led_set_brightness(led_cdev, LED_OFF);
 	kfree(event);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(led_trigger_set);

 void led_trigger_remove(struct led_classdev *led_cdev)
 {
 	down_write(&led_cdev->trigger_lock);
 	led_trigger_set(led_cdev, NULL);
 	up_write(&led_cdev->trigger_lock);
 }
 EXPORT_SYMBOL_GPL(led_trigger_remove);

 static bool led_match_default_trigger(struct led_classdev *led_cdev,
 				      struct led_trigger *trig)
 {
 	if (!strcmp(led_cdev->default_trigger, trig->name) &&
 	    trigger_relevant(led_cdev, trig)) {
 		led_cdev->flags |= LED_INIT_DEFAULT_TRIGGER;
 		led_trigger_set(led_cdev, trig);
 		return true;
 	}

 	return false;
 }

 void led_trigger_set_default(struct led_classdev *led_cdev)
 {
 	struct led_trigger *trig;
 	bool found = false;

 	if (!led_cdev->default_trigger)
 		return;

 	down_read(&triggers_list_lock);
 	down_write(&led_cdev->trigger_lock);
 	list_for_each_entry(trig, &trigger_list, next_trig) {
 		found = led_match_default_trigger(led_cdev, trig);
 		if (found)
 			break;
 	}
 	up_write(&led_cdev->trigger_lock);
 	up_read(&triggers_list_lock);

 	/*
 	 * If default trigger wasn't found, maybe trigger module isn't loaded yet.
 	 * Once loaded it will re-probe with all led_cdev's.
 	 */
 	if (!found)
 		request_module_nowait("ledtrig:%s", led_cdev->default_trigger);
 }
 EXPORT_SYMBOL_GPL(led_trigger_set_default);

 /* LED Trigger Interface */

 int led_trigger_register(struct led_trigger *trig)
 {
 	struct led_classdev *led_cdev;
 	struct led_trigger *_trig;

 	spin_lock_init(&trig->leddev_list_lock);
 	INIT_LIST_HEAD(&trig->led_cdevs);

 	down_write(&triggers_list_lock);
 	/* Make sure the trigger's name isn't already in use */
 	list_for_each_entry(_trig, &trigger_list, next_trig) {
 		if (!strcmp(_trig->name, trig->name) &&
 		    (trig->trigger_type == _trig->trigger_type ||
 		     !trig->trigger_type || !_trig->trigger_type)) {
 			up_write(&triggers_list_lock);
 			return -EEXIST;
 		}
 	}
 	/* Add to the list of led triggers */
 	list_add_tail(&trig->next_trig, &trigger_list);
 	up_write(&triggers_list_lock);

 	/* Register with any LEDs that have this as a default trigger */
 	down_read(&leds_list_lock);
 	list_for_each_entry(led_cdev, &leds_list, node) {
 		down_write(&led_cdev->trigger_lock);
 		if (!led_cdev->trigger && led_cdev->default_trigger)
 			led_match_default_trigger(led_cdev, trig);
 		up_write(&led_cdev->trigger_lock);
 	}
 	up_read(&leds_list_lock);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(led_trigger_register);

 void led_trigger_unregister(struct led_trigger *trig)
 {
 	struct led_classdev *led_cdev;

 	if (list_empty_careful(&trig->next_trig))
 		return;

 	/* Remove from the list of led triggers */
 	down_write(&triggers_list_lock);
 	list_del_init(&trig->next_trig);
 	up_write(&triggers_list_lock);

 	/* Remove anyone actively using this trigger */
 	down_read(&leds_list_lock);
 	list_for_each_entry(led_cdev, &leds_list, node) {
 		down_write(&led_cdev->trigger_lock);
 		if (led_cdev->trigger == trig)
 			led_trigger_set(led_cdev, NULL);
 		up_write(&led_cdev->trigger_lock);
 	}
 	up_read(&leds_list_lock);
 }
 EXPORT_SYMBOL_GPL(led_trigger_unregister);

 static void devm_led_trigger_release(struct device *dev, void *res)
 {
 	led_trigger_unregister(*(struct led_trigger **)res);
 }

 int devm_led_trigger_register(struct device *dev,
 			      struct led_trigger *trig)
 {
 	struct led_trigger **dr;
 	int rc;

 	dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
 			  GFP_KERNEL);
 	if (!dr)
 		return -ENOMEM;

 	*dr = trig;

 	rc = led_trigger_register(trig);
 	if (rc)
 		devres_free(dr);
 	else
 		devres_add(dev, dr);

 	return rc;
 }
 EXPORT_SYMBOL_GPL(devm_led_trigger_register);

 /* Simple LED Trigger Interface */

 void led_trigger_event(struct led_trigger *trig,
 			enum led_brightness brightness)
 {
 	struct led_classdev *led_cdev;

 	if (!trig)
 		return;

 	trig->brightness = brightness;

 	rcu_read_lock();
 	list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
 		led_set_brightness(led_cdev, brightness);
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(led_trigger_event);

 void led_mc_trigger_event(struct led_trigger *trig,
 			  unsigned int *intensity_value, unsigned int num_colors,
 			  enum led_brightness brightness)
 {
 	struct led_classdev *led_cdev;

 	if (!trig)
 		return;

 	rcu_read_lock();
 	list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
 		if (!(led_cdev->flags & LED_MULTI_COLOR))
 			continue;

 		led_mc_set_brightness(led_cdev, intensity_value, num_colors, brightness);
 	}
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(led_mc_trigger_event);

 static void led_trigger_blink_setup(struct led_trigger *trig,
 			     unsigned long delay_on,
 			     unsigned long delay_off,
 			     int oneshot,
 			     int invert)
 {
 	struct led_classdev *led_cdev;

 	if (!trig)
 		return;

 	rcu_read_lock();
 	list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
 		if (oneshot)
 			led_blink_set_oneshot(led_cdev, &delay_on, &delay_off,
 					      invert);
 		else
 			led_blink_set_nosleep(led_cdev, delay_on, delay_off);
 	}
 	rcu_read_unlock();
 }

 void led_trigger_blink(struct led_trigger *trig,
 		       unsigned long delay_on,
 		       unsigned long delay_off)
 {
 	led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
 }
 EXPORT_SYMBOL_GPL(led_trigger_blink);

 void led_trigger_blink_oneshot(struct led_trigger *trig,
 			       unsigned long delay_on,
 			       unsigned long delay_off,
 			       int invert)
 {
 	led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
 }
 EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);

 void led_trigger_register_simple(const char *name, struct led_trigger **tp)
 {
 	struct led_trigger *trig;
 	int err;

 	trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);

 	if (trig) {
 		trig->name = name;
 		err = led_trigger_register(trig);
 		if (err < 0) {
 			kfree(trig);
 			trig = NULL;
 			pr_warn("LED trigger %s failed to register (%d)\n",
 				name, err);
 		}
 	} else {
 		pr_warn("LED trigger %s failed to register (no memory)\n",
 			name);
 	}
 	*tp = trig;
 }
 EXPORT_SYMBOL_GPL(led_trigger_register_simple);

 void led_trigger_unregister_simple(struct led_trigger *trig)
 {
 	if (trig)
 		led_trigger_unregister(trig);
 	kfree(trig);
 }
 EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* LED Triggers Core
	*
	* Copyright 2005-2007 Openedhand Ltd.
	*
	* Author: Richard Purdie <rpurdie@openedhand.com>
	*/

	#include <linux/export.h>
	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/spinlock.h>
	#include <linux/device.h>
	#include <linux/timer.h>
	#include <linux/rwsem.h>
	#include <linux/leds.h>
	#include <linux/slab.h>
	#include <linux/mm.h>
	#include "leds.h"

	/*
	* Nests outside led_cdev->trigger_lock
	*/
	static DECLARE_RWSEM(triggers_list_lock);
	static LIST_HEAD(trigger_list);

	/* Used by LED Class */

	static inline bool
	trigger_relevant(struct led_classdev led_cdev, struct led_trigger trig)
	{
	return !trig->trigger_type \|\| trig->trigger_type == led_cdev->trigger_type;
	}

	ssize_t led_trigger_write(struct file filp, struct kobject kobj,
	struct bin_attribute bin_attr, char buf,
	loff_t pos, size_t count)
	{
	struct device *dev = kobj_to_dev(kobj);
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_trigger *trig;
	int ret = count;

	mutex_lock(&led_cdev->led_access);

	if (led_sysfs_is_disabled(led_cdev)) {
	ret = -EBUSY;
	goto unlock;
	}

	if (sysfs_streq(buf, "none")) {
	led_trigger_remove(led_cdev);
	goto unlock;
	}

	down_read(&triggers_list_lock);
	list_for_each_entry(trig, &trigger_list, next_trig) {
	if (sysfs_streq(buf, trig->name) && trigger_relevant(led_cdev, trig)) {
	down_write(&led_cdev->trigger_lock);
	led_trigger_set(led_cdev, trig);
	up_write(&led_cdev->trigger_lock);

	up_read(&triggers_list_lock);
	goto unlock;
	}
	}
	/* we come here only if buf matches no trigger */
	ret = -EINVAL;
	up_read(&triggers_list_lock);

	unlock:
	mutex_unlock(&led_cdev->led_access);
	return ret;
	}
	EXPORT_SYMBOL_GPL(led_trigger_write);

	__printf(3, 4)
	static int led_trigger_snprintf(char buf, ssize_t size, const char fmt, ...)
	{
	va_list args;
	int i;

	va_start(args, fmt);
	if (size <= 0)
	i = vsnprintf(NULL, 0, fmt, args);
	else
	i = vscnprintf(buf, size, fmt, args);
	va_end(args);

	return i;
	}

	static int led_trigger_format(char *buf, size_t size,
	struct led_classdev *led_cdev)
	{
	struct led_trigger *trig;
	int len = led_trigger_snprintf(buf, size, "%s",
	led_cdev->trigger ? "none" : "[none]");

	list_for_each_entry(trig, &trigger_list, next_trig) {
	bool hit;

	if (!trigger_relevant(led_cdev, trig))
	continue;

	hit = led_cdev->trigger && !strcmp(led_cdev->trigger->name, trig->name);

	len += led_trigger_snprintf(buf + len, size - len,
	" %s%s%s", hit ? "[" : "",
	trig->name, hit ? "]" : "");
	}

	len += led_trigger_snprintf(buf + len, size - len, "\n");

	return len;
	}

	/*
	* It was stupid to create 10000 cpu triggers, but we are stuck with it now.
	* Don't make that mistake again. We work around it here by creating binary
	* attribute, which is not limited by length. This is _not_ good design, do not
	* copy it.
	*/
	ssize_t led_trigger_read(struct file filp, struct kobject kobj,
	struct bin_attribute attr, char buf,
	loff_t pos, size_t count)
	{
	struct device *dev = kobj_to_dev(kobj);
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	void *data;
	int len;

	down_read(&triggers_list_lock);
	down_read(&led_cdev->trigger_lock);

	len = led_trigger_format(NULL, 0, led_cdev);
	data = kvmalloc(len + 1, GFP_KERNEL);
	if (!data) {
	up_read(&led_cdev->trigger_lock);
	up_read(&triggers_list_lock);
	return -ENOMEM;
	}
	len = led_trigger_format(data, len + 1, led_cdev);

	up_read(&led_cdev->trigger_lock);
	up_read(&triggers_list_lock);

	len = memory_read_from_buffer(buf, count, &pos, data, len);

	kvfree(data);

	return len;
	}
	EXPORT_SYMBOL_GPL(led_trigger_read);

	/* Caller must ensure led_cdev->trigger_lock held */
	int led_trigger_set(struct led_classdev led_cdev, struct led_trigger trig)
	{
	char *event = NULL;
	char *envp[2];
	const char *name;
	int ret;

	if (!led_cdev->trigger && !trig)
	return 0;

	name = trig ? trig->name : "none";
	event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);

	/* Remove any existing trigger */
	if (led_cdev->trigger) {
	spin_lock(&led_cdev->trigger->leddev_list_lock);
	list_del_rcu(&led_cdev->trig_list);
	spin_unlock(&led_cdev->trigger->leddev_list_lock);

	/* ensure it's no longer visible on the led_cdevs list */
	synchronize_rcu();

	cancel_work_sync(&led_cdev->set_brightness_work);
	led_stop_software_blink(led_cdev);
	device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
	if (led_cdev->trigger->deactivate)
	led_cdev->trigger->deactivate(led_cdev);
	led_cdev->trigger = NULL;
	led_cdev->trigger_data = NULL;
	led_cdev->activated = false;
	led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
	led_set_brightness(led_cdev, LED_OFF);
	}
	if (trig) {
	spin_lock(&trig->leddev_list_lock);
	list_add_tail_rcu(&led_cdev->trig_list, &trig->led_cdevs);
	spin_unlock(&trig->leddev_list_lock);
	led_cdev->trigger = trig;

	/*
	* Some activate() calls use led_trigger_event() to initialize
	* the brightness of the LED for which the trigger is being set.
	* Ensure the led_cdev is visible on trig->led_cdevs for this.
	*/
	synchronize_rcu();

	/*
	* If "set brightness to 0" is pending in workqueue,
	* we don't want that to be reordered after ->activate()
	*/
	flush_work(&led_cdev->set_brightness_work);

	ret = 0;
	if (trig->activate)
	ret = trig->activate(led_cdev);
	else
	led_set_brightness(led_cdev, trig->brightness);
	if (ret)
	goto err_activate;

	ret = device_add_groups(led_cdev->dev, trig->groups);
	if (ret) {
	dev_err(led_cdev->dev, "Failed to add trigger attributes\n");
	goto err_add_groups;
	}
	}

	if (event) {
	envp[0] = event;
	envp[1] = NULL;
	if (kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp))
	dev_err(led_cdev->dev,
	"%s: Error sending uevent\n", __func__);
	kfree(event);
	}

	return 0;

	err_add_groups:

	if (trig->deactivate)
	trig->deactivate(led_cdev);
	err_activate:

	spin_lock(&led_cdev->trigger->leddev_list_lock);
	list_del_rcu(&led_cdev->trig_list);
	spin_unlock(&led_cdev->trigger->leddev_list_lock);
	synchronize_rcu();
	led_cdev->trigger = NULL;
	led_cdev->trigger_data = NULL;
	led_set_brightness(led_cdev, LED_OFF);
	kfree(event);

	return ret;
	}
	EXPORT_SYMBOL_GPL(led_trigger_set);

	void led_trigger_remove(struct led_classdev *led_cdev)
	{
	down_write(&led_cdev->trigger_lock);
	led_trigger_set(led_cdev, NULL);
	up_write(&led_cdev->trigger_lock);
	}
	EXPORT_SYMBOL_GPL(led_trigger_remove);

	static bool led_match_default_trigger(struct led_classdev *led_cdev,
	struct led_trigger *trig)
	{
	if (!strcmp(led_cdev->default_trigger, trig->name) &&
	trigger_relevant(led_cdev, trig)) {
	led_cdev->flags \|= LED_INIT_DEFAULT_TRIGGER;
	led_trigger_set(led_cdev, trig);
	return true;
	}

	return false;
	}

	void led_trigger_set_default(struct led_classdev *led_cdev)
	{
	struct led_trigger *trig;
	bool found = false;

	if (!led_cdev->default_trigger)
	return;

	down_read(&triggers_list_lock);
	down_write(&led_cdev->trigger_lock);
	list_for_each_entry(trig, &trigger_list, next_trig) {
	found = led_match_default_trigger(led_cdev, trig);
	if (found)
	break;
	}
	up_write(&led_cdev->trigger_lock);
	up_read(&triggers_list_lock);

	/*
	* If default trigger wasn't found, maybe trigger module isn't loaded yet.
	* Once loaded it will re-probe with all led_cdev's.
	*/
	if (!found)
	request_module_nowait("ledtrig:%s", led_cdev->default_trigger);
	}
	EXPORT_SYMBOL_GPL(led_trigger_set_default);

	/* LED Trigger Interface */

	int led_trigger_register(struct led_trigger *trig)
	{
	struct led_classdev *led_cdev;
	struct led_trigger *_trig;

	spin_lock_init(&trig->leddev_list_lock);
	INIT_LIST_HEAD(&trig->led_cdevs);

	down_write(&triggers_list_lock);
	/* Make sure the trigger's name isn't already in use */
	list_for_each_entry(_trig, &trigger_list, next_trig) {
	if (!strcmp(_trig->name, trig->name) &&
	(trig->trigger_type == _trig->trigger_type \|\|
	!trig->trigger_type \|\| !_trig->trigger_type)) {
	up_write(&triggers_list_lock);
	return -EEXIST;
	}
	}
	/* Add to the list of led triggers */
	list_add_tail(&trig->next_trig, &trigger_list);
	up_write(&triggers_list_lock);

	/* Register with any LEDs that have this as a default trigger */
	down_read(&leds_list_lock);
	list_for_each_entry(led_cdev, &leds_list, node) {
	down_write(&led_cdev->trigger_lock);
	if (!led_cdev->trigger && led_cdev->default_trigger)
	led_match_default_trigger(led_cdev, trig);
	up_write(&led_cdev->trigger_lock);
	}
	up_read(&leds_list_lock);

	return 0;
	}
	EXPORT_SYMBOL_GPL(led_trigger_register);

	void led_trigger_unregister(struct led_trigger *trig)
	{
	struct led_classdev *led_cdev;

	if (list_empty_careful(&trig->next_trig))
	return;

	/* Remove from the list of led triggers */
	down_write(&triggers_list_lock);
	list_del_init(&trig->next_trig);
	up_write(&triggers_list_lock);

	/* Remove anyone actively using this trigger */
	down_read(&leds_list_lock);
	list_for_each_entry(led_cdev, &leds_list, node) {
	down_write(&led_cdev->trigger_lock);
	if (led_cdev->trigger == trig)
	led_trigger_set(led_cdev, NULL);
	up_write(&led_cdev->trigger_lock);
	}
	up_read(&leds_list_lock);
	}
	EXPORT_SYMBOL_GPL(led_trigger_unregister);

	static void devm_led_trigger_release(struct device dev, void res)
	{
	led_trigger_unregister((struct led_trigger *)res);
	}

	int devm_led_trigger_register(struct device *dev,
	struct led_trigger *trig)
	{
	struct led_trigger **dr;
	int rc;

	dr = devres_alloc(devm_led_trigger_release, sizeof(*dr),
	GFP_KERNEL);
	if (!dr)
	return -ENOMEM;

	*dr = trig;

	rc = led_trigger_register(trig);
	if (rc)
	devres_free(dr);
	else
	devres_add(dev, dr);

	return rc;
	}
	EXPORT_SYMBOL_GPL(devm_led_trigger_register);

	/* Simple LED Trigger Interface */

	void led_trigger_event(struct led_trigger *trig,
	enum led_brightness brightness)
	{
	struct led_classdev *led_cdev;

	if (!trig)
	return;

	trig->brightness = brightness;

	rcu_read_lock();
	list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
	led_set_brightness(led_cdev, brightness);
	rcu_read_unlock();
	}
	EXPORT_SYMBOL_GPL(led_trigger_event);

	void led_mc_trigger_event(struct led_trigger *trig,
	unsigned int *intensity_value, unsigned int num_colors,
	enum led_brightness brightness)
	{
	struct led_classdev *led_cdev;

	if (!trig)
	return;

	rcu_read_lock();
	list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
	if (!(led_cdev->flags & LED_MULTI_COLOR))
	continue;

	led_mc_set_brightness(led_cdev, intensity_value, num_colors, brightness);
	}
	rcu_read_unlock();
	}
	EXPORT_SYMBOL_GPL(led_mc_trigger_event);

	static void led_trigger_blink_setup(struct led_trigger *trig,
	unsigned long delay_on,
	unsigned long delay_off,
	int oneshot,
	int invert)
	{
	struct led_classdev *led_cdev;

	if (!trig)
	return;

	rcu_read_lock();
	list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) {
	if (oneshot)
	led_blink_set_oneshot(led_cdev, &delay_on, &delay_off,
	invert);
	else
	led_blink_set_nosleep(led_cdev, delay_on, delay_off);
	}
	rcu_read_unlock();
	}

	void led_trigger_blink(struct led_trigger *trig,
	unsigned long delay_on,
	unsigned long delay_off)
	{
	led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0);
	}
	EXPORT_SYMBOL_GPL(led_trigger_blink);

	void led_trigger_blink_oneshot(struct led_trigger *trig,
	unsigned long delay_on,
	unsigned long delay_off,
	int invert)
	{
	led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert);
	}
	EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot);

	void led_trigger_register_simple(const char name, struct led_trigger *tp)
	{
	struct led_trigger *trig;
	int err;

	trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);

	if (trig) {
	trig->name = name;
	err = led_trigger_register(trig);
	if (err < 0) {
	kfree(trig);
	trig = NULL;
	pr_warn("LED trigger %s failed to register (%d)\n",
	name, err);
	}
	} else {
	pr_warn("LED trigger %s failed to register (no memory)\n",
	name);
	}
	*tp = trig;
	}
	EXPORT_SYMBOL_GPL(led_trigger_register_simple);

	void led_trigger_unregister_simple(struct led_trigger *trig)
	{
	if (trig)
	led_trigger_unregister(trig);
	kfree(trig);
	}
	EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);