drivers/leds/led-triggers.c - kernel/mindspeed - Git at Google

 /*
  * LED Triggers Core
  *
  * Copyright 2005-2007 Openedhand Ltd.
  *
  * Author: Richard Purdie <rpurdie@openedhand.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  */

 #include <linux/module.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 "leds.h"

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

  /* Used by LED Class */

 ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr,
 		const char *buf, size_t count)
 {
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
 	char trigger_name[TRIG_NAME_MAX];
 	struct led_trigger *trig;
 	size_t len;
 	int ret = count;

 	mutex_lock(&led_cdev->led_access);

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

 	trigger_name[sizeof(trigger_name) - 1] = '\0';
 	strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
 	len = strlen(trigger_name);

 	if (len && trigger_name[len - 1] == '\n')
 		trigger_name[len - 1] = '\0';

 	if (!strcmp(trigger_name, "none")) {
 		led_trigger_remove(led_cdev);
 		goto unlock;
 	}

 	down_read(&triggers_list_lock);
 	list_for_each_entry(trig, &trigger_list, next_trig) {
 		if (!strcmp(trigger_name, trig->name)) {
 			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;
 		}
 	}
 	up_read(&triggers_list_lock);

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

 ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
 		char *buf)
 {
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
 	struct led_trigger *trig;
 	int len = 0;

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

 	if (!led_cdev->trigger)
 		len += sprintf(buf+len, "[none] ");
 	else
 		len += sprintf(buf+len, "none ");

 	list_for_each_entry(trig, &trigger_list, next_trig) {
 		if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
 							trig->name))
 			len += sprintf(buf+len, "[%s] ", trig->name);
 		else
 			len += sprintf(buf+len, "%s ", trig->name);
 	}
 	up_read(&led_cdev->trigger_lock);
 	up_read(&triggers_list_lock);

 	len += sprintf(len+buf, "\n");
 	return len;
 }
 EXPORT_SYMBOL_GPL(led_trigger_show);

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

 	if (trig != led_cdev->trigger) {
 		name = trig ? trig->name : "none";
 		event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
 	}

 	/* Remove any existing trigger */
 	if (led_cdev->trigger) {
 		write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
 		list_del(&led_cdev->trig_list);
 		write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
 			flags);
 		cancel_work_sync(&led_cdev->set_brightness_work);
 		led_stop_software_blink(led_cdev);
 		if (led_cdev->trigger->deactivate)
 			led_cdev->trigger->deactivate(led_cdev);
 		led_cdev->trigger = NULL;
 		led_set_brightness(led_cdev, LED_OFF);
 	}
 	if (trig) {
 		write_lock_irqsave(&trig->leddev_list_lock, flags);
 		list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
 		write_unlock_irqrestore(&trig->leddev_list_lock, flags);
 		led_cdev->trigger = trig;
 		if (trig->activate)
 			trig->activate(led_cdev);
 	}

 	if (event) {
 		envp[0] = event;
 		envp[1] = NULL;
 		kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp);
 		kfree(event);
 	}
 }
 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);

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

 	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) {
 		if (!strcmp(led_cdev->default_trigger, trig->name))
 			led_trigger_set(led_cdev, trig);
 	}
 	up_write(&led_cdev->trigger_lock);
 	up_read(&triggers_list_lock);
 }
 EXPORT_SYMBOL_GPL(led_trigger_set_default);

 void led_trigger_rename_static(const char *name, struct led_trigger *trig)
 {
 	/* new name must be on a temporary string to prevent races */
 	BUG_ON(name == trig->name);

 	down_write(&triggers_list_lock);
 	/* this assumes that trig->name was originaly allocated to
 	 * non constant storage */
 	strcpy((char *)trig->name, name);
 	up_write(&triggers_list_lock);
 }
 EXPORT_SYMBOL_GPL(led_trigger_rename_static);

 /* LED Trigger Interface */

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

 	rwlock_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)) {
 			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 &&
 			    !strcmp(led_cdev->default_trigger, trig->name))
 			led_trigger_set(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);

 /* Simple LED Tigger Interface */

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

 	if (!trig)
 		return;

 	read_lock(&trig->leddev_list_lock);
 	list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
 		led_set_brightness(led_cdev, brightness);
 	read_unlock(&trig->leddev_list_lock);
 }
 EXPORT_SYMBOL_GPL(led_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;

 	read_lock(&trig->leddev_list_lock);
 	list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
 		if (oneshot)
 			led_blink_set_oneshot(led_cdev, delay_on, delay_off,
 					      invert);
 		else
 			led_blink_set(led_cdev, delay_on, delay_off);
 	}
 	read_unlock(&trig->leddev_list_lock);
 }

 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);

 MODULE_AUTHOR("Richard Purdie");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("LED Triggers Core");
	/*
	* LED Triggers Core
	*
	* Copyright 2005-2007 Openedhand Ltd.
	*
	* Author: Richard Purdie <rpurdie@openedhand.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	*/

	#include <linux/module.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 "leds.h"

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

	/* Used by LED Class */

	ssize_t led_trigger_store(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	char trigger_name[TRIG_NAME_MAX];
	struct led_trigger *trig;
	size_t len;
	int ret = count;

	mutex_lock(&led_cdev->led_access);

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

	trigger_name[sizeof(trigger_name) - 1] = '\0';
	strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
	len = strlen(trigger_name);

	if (len && trigger_name[len - 1] == '\n')
	trigger_name[len - 1] = '\0';

	if (!strcmp(trigger_name, "none")) {
	led_trigger_remove(led_cdev);
	goto unlock;
	}

	down_read(&triggers_list_lock);
	list_for_each_entry(trig, &trigger_list, next_trig) {
	if (!strcmp(trigger_name, trig->name)) {
	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;
	}
	}
	up_read(&triggers_list_lock);

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

	ssize_t led_trigger_show(struct device dev, struct device_attribute attr,
	char *buf)
	{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_trigger *trig;
	int len = 0;

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

	if (!led_cdev->trigger)
	len += sprintf(buf+len, "[none] ");
	else
	len += sprintf(buf+len, "none ");

	list_for_each_entry(trig, &trigger_list, next_trig) {
	if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
	trig->name))
	len += sprintf(buf+len, "[%s] ", trig->name);
	else
	len += sprintf(buf+len, "%s ", trig->name);
	}
	up_read(&led_cdev->trigger_lock);
	up_read(&triggers_list_lock);

	len += sprintf(len+buf, "\n");
	return len;
	}
	EXPORT_SYMBOL_GPL(led_trigger_show);

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

	if (trig != led_cdev->trigger) {
	name = trig ? trig->name : "none";
	event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
	}

	/* Remove any existing trigger */
	if (led_cdev->trigger) {
	write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
	list_del(&led_cdev->trig_list);
	write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock,
	flags);
	cancel_work_sync(&led_cdev->set_brightness_work);
	led_stop_software_blink(led_cdev);
	if (led_cdev->trigger->deactivate)
	led_cdev->trigger->deactivate(led_cdev);
	led_cdev->trigger = NULL;
	led_set_brightness(led_cdev, LED_OFF);
	}
	if (trig) {
	write_lock_irqsave(&trig->leddev_list_lock, flags);
	list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
	write_unlock_irqrestore(&trig->leddev_list_lock, flags);
	led_cdev->trigger = trig;
	if (trig->activate)
	trig->activate(led_cdev);
	}

	if (event) {
	envp[0] = event;
	envp[1] = NULL;
	kobject_uevent_env(&led_cdev->dev->kobj, KOBJ_CHANGE, envp);
	kfree(event);
	}
	}
	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);

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

	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) {
	if (!strcmp(led_cdev->default_trigger, trig->name))
	led_trigger_set(led_cdev, trig);
	}
	up_write(&led_cdev->trigger_lock);
	up_read(&triggers_list_lock);
	}
	EXPORT_SYMBOL_GPL(led_trigger_set_default);

	void led_trigger_rename_static(const char name, struct led_trigger trig)
	{
	/* new name must be on a temporary string to prevent races */
	BUG_ON(name == trig->name);

	down_write(&triggers_list_lock);
	/* this assumes that trig->name was originaly allocated to
	* non constant storage */
	strcpy((char *)trig->name, name);
	up_write(&triggers_list_lock);
	}
	EXPORT_SYMBOL_GPL(led_trigger_rename_static);

	/* LED Trigger Interface */

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

	rwlock_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)) {
	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 &&
	!strcmp(led_cdev->default_trigger, trig->name))
	led_trigger_set(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);

	/* Simple LED Tigger Interface */

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

	if (!trig)
	return;

	read_lock(&trig->leddev_list_lock);
	list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list)
	led_set_brightness(led_cdev, brightness);
	read_unlock(&trig->leddev_list_lock);
	}
	EXPORT_SYMBOL_GPL(led_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;

	read_lock(&trig->leddev_list_lock);
	list_for_each_entry(led_cdev, &trig->led_cdevs, trig_list) {
	if (oneshot)
	led_blink_set_oneshot(led_cdev, delay_on, delay_off,
	invert);
	else
	led_blink_set(led_cdev, delay_on, delay_off);
	}
	read_unlock(&trig->leddev_list_lock);
	}

	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);

	MODULE_AUTHOR("Richard Purdie");
	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("LED Triggers Core");