Commit c3bc9956 authored by Richard Purdie's avatar Richard Purdie Committed by Linus Torvalds
Browse files

[PATCH] LED: add LED trigger tupport 



Add support for LED triggers to the LED subsystem.  "Triggers" are events
which change the state of an LED.  Two kinds of trigger are available, simple
ones which can be added to exising code with minimum disruption and complex
ones for implementing new or more complex functionality.

Signed-off-by: default avatarRichard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c72a1d60

drivers/leds/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -14,5 +14,13 @@ config LEDS_CLASS 
	  This option enables the led sysfs class in /sys/class/leds.  You'll

	  need this to do anything useful with LEDs.  If unsure, say N.



config LEDS_TRIGGERS

	bool "LED Trigger support"

	depends NEW_LEDS

	help

	  This option enables trigger support for the leds class.

	  These triggers allow kernel events to drive the LEDs and can

	  be configured via sysfs. If unsure, say Y.



endmenu

drivers/leds/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -2,3 +2,4 @@ 
# LED Core

obj-$(CONFIG_NEW_LEDS)			+= led-core.o

obj-$(CONFIG_LEDS_CLASS)		+= led-class.o

obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o

drivers/leds/led-class.c

+20 −0
Original line number Diff line number Diff line
@@ -54,6 +54,9 @@ static ssize_t led_brightness_store(struct class_device *dev, 


static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,

			led_brightness_store);

#ifdef CONFIG_LEDS_TRIGGERS

static CLASS_DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);

#endif



/**

 * led_classdev_suspend - suspend an led_classdev.
@@ -100,6 +103,15 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 
	list_add_tail(&led_cdev->node, &leds_list);

	write_unlock(&leds_list_lock);



#ifdef CONFIG_LEDS_TRIGGERS

	rwlock_init(&led_cdev->trigger_lock);



	led_trigger_set_default(led_cdev);



	class_device_create_file(led_cdev->class_dev,

				&class_device_attr_trigger);

#endif



	printk(KERN_INFO "Registered led device: %s\n",

			led_cdev->class_dev->class_id);
@@ -117,6 +129,14 @@ void led_classdev_unregister(struct led_classdev *led_cdev) 
{

	class_device_remove_file(led_cdev->class_dev,

				&class_device_attr_brightness);

#ifdef CONFIG_LEDS_TRIGGERS

	class_device_remove_file(led_cdev->class_dev,

				&class_device_attr_trigger);

	write_lock(&led_cdev->trigger_lock);

	if (led_cdev->trigger)

		led_trigger_set(led_cdev, NULL);

	write_unlock(&led_cdev->trigger_lock);

#endif



	class_device_unregister(led_cdev->class_dev);

drivers/leds/led-triggers.c

0 → 100644
+239 −0
Original line number Diff line number Diff line 
/*

 * LED Triggers Core

 *

 * Copyright 2005-2006 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/config.h>

#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/leds.h>

#include "leds.h"



/*

 * Nests outside led_cdev->trigger_lock

 */

static rwlock_t triggers_list_lock = RW_LOCK_UNLOCKED;

static LIST_HEAD(trigger_list);



ssize_t led_trigger_store(struct class_device *dev, const char *buf,

			size_t count)

{

	struct led_classdev *led_cdev = class_get_devdata(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")) {

		write_lock(&led_cdev->trigger_lock);

		led_trigger_set(led_cdev, NULL);

		write_unlock(&led_cdev->trigger_lock);

		return count;

	}



	read_lock(&triggers_list_lock);

	list_for_each_entry(trig, &trigger_list, next_trig) {

		if (!strcmp(trigger_name, trig->name)) {

			write_lock(&led_cdev->trigger_lock);

			led_trigger_set(led_cdev, trig);

			write_unlock(&led_cdev->trigger_lock);



			read_unlock(&triggers_list_lock);

			return count;

		}

	}

	read_unlock(&triggers_list_lock);



	return -EINVAL;

}





ssize_t led_trigger_show(struct class_device *dev, char *buf)

{

	struct led_classdev *led_cdev = class_get_devdata(dev);

	struct led_trigger *trig;

	int len = 0;



	read_lock(&triggers_list_lock);

	read_lock(&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);

	}

	read_unlock(&led_cdev->trigger_lock);

	read_unlock(&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);

	}

	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;



	read_lock(&triggers_list_lock);

	write_lock(&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);

	}

	write_unlock(&led_cdev->trigger_lock);

	read_unlock(&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 */

	write_lock(&triggers_list_lock);

	list_add_tail(&trigger->next_trig, &trigger_list);

	write_unlock(&triggers_list_lock);



	/* Register with any LEDs that have this as a default trigger */

	read_lock(&leds_list_lock);

	list_for_each_entry(led_cdev, &leds_list, node) {

		write_lock(&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);

		write_unlock(&led_cdev->trigger_lock);

	}

	read_unlock(&leds_list_lock);



	return 0;

}



void led_trigger_register_simple(const char *name, struct led_trigger **tp)

{

	struct led_trigger *trigger;



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



	if (trigger) {

		trigger->name = name;

		led_trigger_register(trigger);

	}

	*tp = trigger;

}



void led_trigger_unregister(struct led_trigger *trigger)

{

	struct led_classdev *led_cdev;



	/* Remove from the list of led triggers */

	write_lock(&triggers_list_lock);

	list_del(&trigger->next_trig);

	write_unlock(&triggers_list_lock);



	/* Remove anyone actively using this trigger */

	read_lock(&leds_list_lock);

	list_for_each_entry(led_cdev, &leds_list, node) {

		write_lock(&led_cdev->trigger_lock);

		if (led_cdev->trigger == trigger)

			led_trigger_set(led_cdev, NULL);

		write_unlock(&led_cdev->trigger_lock);

	}

	read_unlock(&leds_list_lock);

}



void led_trigger_unregister_simple(struct led_trigger *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");

drivers/leds/leds.h

+13 −0
Original line number Diff line number Diff line
@@ -28,4 +28,17 @@ static inline void led_set_brightness(struct led_classdev *led_cdev, 
extern rwlock_t leds_list_lock;

extern struct list_head leds_list;



#ifdef CONFIG_LEDS_TRIGGERS

void led_trigger_set_default(struct led_classdev *led_cdev);

void led_trigger_set(struct led_classdev *led_cdev,

			struct led_trigger *trigger);

#else

#define led_trigger_set_default(x) do {} while(0)

#define led_trigger_set(x, y) do {} while(0)

#endif



ssize_t led_trigger_store(struct class_device *dev, const char *buf,

			size_t count);

ssize_t led_trigger_show(struct class_device *dev, char *buf);



#endif	/* __LEDS_H_INCLUDED */

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