[deliverable/linux.git] / drivers / leds / led-triggers.c

/*
 * 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/init.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/sysdev.h>
#include <linux/timer.h>
#include <linux/rwsem.h>
#include <linux/leds.h>
#include "leds.h"

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

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;

	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")) {
		down_write(&led_cdev->trigger_lock);
		led_trigger_set(led_cdev, NULL);
		up_write(&led_cdev->trigger_lock);
		return count;
	}

	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);
			return count;
		}
	}
	up_read(&triggers_list_lock);

	return -EINVAL;
}


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;
}

void led_trigger_event(struct led_trigger *trigger,
			enum led_brightness brightness)
{
	struct list_head *entry;

	if (!trigger)
		return;

	read_lock(&trigger->leddev_list_lock);
	list_for_each(entry, &trigger->led_cdevs) {
		struct led_classdev *led_cdev;

		led_cdev = list_entry(entry, struct led_classdev, trig_list);
		led_set_brightness(led_cdev, brightness);
	}
	read_unlock(&trigger->leddev_list_lock);
}

/* Caller must ensure led_cdev->trigger_lock held */
void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
{
	unsigned long flags;

	/* 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);
		if (led_cdev->trigger->deactivate)
			led_cdev->trigger->deactivate(led_cdev);
		led_set_brightness(led_cdev, LED_OFF);
	}
	if (trigger) {
		write_lock_irqsave(&trigger->leddev_list_lock, flags);
		list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
		write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
		if (trigger->activate)
			trigger->activate(led_cdev);
	}
	led_cdev->trigger = trigger;
}

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);
}

int led_trigger_register(struct led_trigger *trigger)
{
	struct led_classdev *led_cdev;

	rwlock_init(&trigger->leddev_list_lock);
	INIT_LIST_HEAD(&trigger->led_cdevs);

	/* Add to the list of led triggers */
	down_write(&triggers_list_lock);
	list_add_tail(&trigger->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, trigger->name))
			led_trigger_set(led_cdev, trigger);
		up_write(&led_cdev->trigger_lock);
	}
	up_read(&leds_list_lock);

	return 0;
}

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

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

	if (trigger) {
		trigger->name = name;
		err = led_trigger_register(trigger);
		if (err < 0)
			printk(KERN_WARNING "LED trigger %s failed to register"
				" (%d)\n", name, err);
	} else
		printk(KERN_WARNING "LED trigger %s failed to register"
			" (no memory)\n", name);

	*tp = trigger;
}

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

	/* Remove from the list of led triggers */
	down_write(&triggers_list_lock);
	list_del(&trigger->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 == trigger)
			led_trigger_set(led_cdev, NULL);
		up_write(&led_cdev->trigger_lock);
	}
	up_read(&leds_list_lock);
}

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

/* Used by LED Class */
EXPORT_SYMBOL_GPL(led_trigger_set);
EXPORT_SYMBOL_GPL(led_trigger_set_default);
EXPORT_SYMBOL_GPL(led_trigger_show);
EXPORT_SYMBOL_GPL(led_trigger_store);

/* LED Trigger Interface */
EXPORT_SYMBOL_GPL(led_trigger_register);
EXPORT_SYMBOL_GPL(led_trigger_unregister);

/* Simple LED Tigger Interface */
EXPORT_SYMBOL_GPL(led_trigger_register_simple);
EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
EXPORT_SYMBOL_GPL(led_trigger_event);

MODULE_AUTHOR("Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Triggers Core");
Commit	Line	Data
	1	/*
	2	* LED Triggers Core
	3	*
	4	* Copyright 2005-2007 Openedhand Ltd.
	5	*
	6	* Author: Richard Purdie <rpurdie@openedhand.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	*/
	13
	14	#include <linux/module.h>
	15	#include <linux/kernel.h>
	16	#include <linux/init.h>
	17	#include <linux/list.h>
	18	#include <linux/spinlock.h>
	19	#include <linux/device.h>
	20	#include <linux/sysdev.h>
	21	#include <linux/timer.h>
	22	#include <linux/rwsem.h>
	23	#include <linux/leds.h>
	24	#include "leds.h"
	25
	26	/*
	27	* Nests outside led_cdev->trigger_lock
	28	*/
	29	static DECLARE_RWSEM(triggers_list_lock);
	30	static LIST_HEAD(trigger_list);
	31
	32	ssize_t led_trigger_store(struct device dev, struct device_attribute attr,
	33	const char *buf, size_t count)
	34	{
	35	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	36	char trigger_name[TRIG_NAME_MAX];
	37	struct led_trigger *trig;
	38	size_t len;
	39
	40	trigger_name[sizeof(trigger_name) - 1] = '\0';
	41	strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
	42	len = strlen(trigger_name);
	43
	44	if (len && trigger_name[len - 1] == '\n')
	45	trigger_name[len - 1] = '\0';
	46
	47	if (!strcmp(trigger_name, "none")) {
	48	down_write(&led_cdev->trigger_lock);
	49	led_trigger_set(led_cdev, NULL);
	50	up_write(&led_cdev->trigger_lock);
	51	return count;
	52	}
	53
	54	down_read(&triggers_list_lock);
	55	list_for_each_entry(trig, &trigger_list, next_trig) {
	56	if (!strcmp(trigger_name, trig->name)) {
	57	down_write(&led_cdev->trigger_lock);
	58	led_trigger_set(led_cdev, trig);
	59	up_write(&led_cdev->trigger_lock);
	60
	61	up_read(&triggers_list_lock);
	62	return count;
	63	}
	64	}
	65	up_read(&triggers_list_lock);
	66
	67	return -EINVAL;
	68	}
	69
	70
	71	ssize_t led_trigger_show(struct device dev, struct device_attribute attr,
	72	char *buf)
	73	{
	74	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	75	struct led_trigger *trig;
	76	int len = 0;
	77
	78	down_read(&triggers_list_lock);
	79	down_read(&led_cdev->trigger_lock);
	80
	81	if (!led_cdev->trigger)
	82	len += sprintf(buf+len, "[none] ");
	83	else
	84	len += sprintf(buf+len, "none ");
	85
	86	list_for_each_entry(trig, &trigger_list, next_trig) {
	87	if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
	88	trig->name))
	89	len += sprintf(buf+len, "[%s] ", trig->name);
	90	else
	91	len += sprintf(buf+len, "%s ", trig->name);
	92	}
	93	up_read(&led_cdev->trigger_lock);
	94	up_read(&triggers_list_lock);
	95
	96	len += sprintf(len+buf, "\n");
	97	return len;
	98	}
	99
	100	void led_trigger_event(struct led_trigger *trigger,
	101	enum led_brightness brightness)
	102	{
	103	struct list_head *entry;
	104
	105	if (!trigger)
	106	return;
	107
	108	read_lock(&trigger->leddev_list_lock);
	109	list_for_each(entry, &trigger->led_cdevs) {
	110	struct led_classdev *led_cdev;
	111
	112	led_cdev = list_entry(entry, struct led_classdev, trig_list);
	113	led_set_brightness(led_cdev, brightness);
	114	}
	115	read_unlock(&trigger->leddev_list_lock);
	116	}
	117
	118	/* Caller must ensure led_cdev->trigger_lock held */
	119	void led_trigger_set(struct led_classdev led_cdev, struct led_trigger trigger)
	120	{
	121	unsigned long flags;
	122
	123	/* Remove any existing trigger */
	124	if (led_cdev->trigger) {
	125	write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
	126	list_del(&led_cdev->trig_list);
	127	write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
	128	if (led_cdev->trigger->deactivate)
	129	led_cdev->trigger->deactivate(led_cdev);
	130	led_set_brightness(led_cdev, LED_OFF);
	131	}
	132	if (trigger) {
	133	write_lock_irqsave(&trigger->leddev_list_lock, flags);
	134	list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
	135	write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
	136	if (trigger->activate)
	137	trigger->activate(led_cdev);
	138	}
	139	led_cdev->trigger = trigger;
	140	}
	141
	142	void led_trigger_set_default(struct led_classdev *led_cdev)
	143	{
	144	struct led_trigger *trig;
	145
	146	if (!led_cdev->default_trigger)
	147	return;
	148
	149	down_read(&triggers_list_lock);
	150	down_write(&led_cdev->trigger_lock);
	151	list_for_each_entry(trig, &trigger_list, next_trig) {
	152	if (!strcmp(led_cdev->default_trigger, trig->name))
	153	led_trigger_set(led_cdev, trig);
	154	}
	155	up_write(&led_cdev->trigger_lock);
	156	up_read(&triggers_list_lock);
	157	}
	158
	159	int led_trigger_register(struct led_trigger *trigger)
	160	{
	161	struct led_classdev *led_cdev;
	162
	163	rwlock_init(&trigger->leddev_list_lock);
	164	INIT_LIST_HEAD(&trigger->led_cdevs);
	165
	166	/* Add to the list of led triggers */
	167	down_write(&triggers_list_lock);
	168	list_add_tail(&trigger->next_trig, &trigger_list);
	169	up_write(&triggers_list_lock);
	170
	171	/* Register with any LEDs that have this as a default trigger */
	172	down_read(&leds_list_lock);
	173	list_for_each_entry(led_cdev, &leds_list, node) {
	174	down_write(&led_cdev->trigger_lock);
	175	if (!led_cdev->trigger && led_cdev->default_trigger &&
	176	!strcmp(led_cdev->default_trigger, trigger->name))
	177	led_trigger_set(led_cdev, trigger);
	178	up_write(&led_cdev->trigger_lock);
	179	}
	180	up_read(&leds_list_lock);
	181
	182	return 0;
	183	}
	184
	185	void led_trigger_register_simple(const char name, struct led_trigger *tp)
	186	{
	187	struct led_trigger *trigger;
	188	int err;
	189
	190	trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
	191
	192	if (trigger) {
	193	trigger->name = name;
	194	err = led_trigger_register(trigger);
	195	if (err < 0)
	196	printk(KERN_WARNING "LED trigger %s failed to register"
	197	" (%d)\n", name, err);
	198	} else
	199	printk(KERN_WARNING "LED trigger %s failed to register"
	200	" (no memory)\n", name);
	201
	202	*tp = trigger;
	203	}
	204
	205	void led_trigger_unregister(struct led_trigger *trigger)
	206	{
	207	struct led_classdev *led_cdev;
	208
	209	/* Remove from the list of led triggers */
	210	down_write(&triggers_list_lock);
	211	list_del(&trigger->next_trig);
	212	up_write(&triggers_list_lock);
	213
	214	/* Remove anyone actively using this trigger */
	215	down_read(&leds_list_lock);
	216	list_for_each_entry(led_cdev, &leds_list, node) {
	217	down_write(&led_cdev->trigger_lock);
	218	if (led_cdev->trigger == trigger)
	219	led_trigger_set(led_cdev, NULL);
	220	up_write(&led_cdev->trigger_lock);
	221	}
	222	up_read(&leds_list_lock);
	223	}
	224
	225	void led_trigger_unregister_simple(struct led_trigger *trigger)
	226	{
	227	if (trigger)
	228	led_trigger_unregister(trigger);
	229	kfree(trigger);
	230	}
	231
	232	/* Used by LED Class */
	233	EXPORT_SYMBOL_GPL(led_trigger_set);
	234	EXPORT_SYMBOL_GPL(led_trigger_set_default);
	235	EXPORT_SYMBOL_GPL(led_trigger_show);
	236	EXPORT_SYMBOL_GPL(led_trigger_store);
	237
	238	/* LED Trigger Interface */
	239	EXPORT_SYMBOL_GPL(led_trigger_register);
	240	EXPORT_SYMBOL_GPL(led_trigger_unregister);
	241
	242	/* Simple LED Tigger Interface */
	243	EXPORT_SYMBOL_GPL(led_trigger_register_simple);
	244	EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
	245	EXPORT_SYMBOL_GPL(led_trigger_event);
	246
	247	MODULE_AUTHOR("Richard Purdie");
	248	MODULE_LICENSE("GPL");
	249	MODULE_DESCRIPTION("LED Triggers Core");