[PATCH] LED: add LED timer trigger

Add an example of a complex LED trigger in the form of a generic timer which
triggers the LED its attached to at a user specified frequency and duty cycle.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Richard Purdie 2006-03-31 02:31:07 -08:00 committed by Linus Torvalds
parent c3bc9956ec
commit 6655c6fe57
3 changed files with 180 additions and 0 deletions

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@ -22,5 +22,12 @@ config LEDS_TRIGGERS
These triggers allow kernel events to drive the LEDs and can
be configured via sysfs. If unsure, say Y.
config LEDS_TRIGGER_TIMER
tristate "LED Timer Trigger"
depends LEDS_TRIGGERS
help
This allows LEDs to be controlled by a programmable timer
via sysfs. If unsure, say Y.
endmenu

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@ -3,3 +3,6 @@
obj-$(CONFIG_NEW_LEDS) += led-core.o
obj-$(CONFIG_LEDS_CLASS) += led-class.o
obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o
# LED Triggers
obj-$(CONFIG_LEDS_TRIGGER_TIMER) += ledtrig-timer.o

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@ -0,0 +1,170 @@
/*
* LED Kernel Timer Trigger
*
* 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"
struct timer_trig_data {
unsigned long delay_on; /* milliseconds on */
unsigned long delay_off; /* milliseconds off */
struct timer_list timer;
};
static void led_timer_function(unsigned long data)
{
struct led_classdev *led_cdev = (struct led_classdev *) data;
struct timer_trig_data *timer_data = led_cdev->trigger_data;
unsigned long brightness = LED_OFF;
unsigned long delay = timer_data->delay_off;
if (!timer_data->delay_on || !timer_data->delay_off) {
led_set_brightness(led_cdev, LED_OFF);
return;
}
if (!led_cdev->brightness) {
brightness = LED_FULL;
delay = timer_data->delay_on;
}
led_set_brightness(led_cdev, brightness);
mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
}
static ssize_t led_delay_on_show(struct class_device *dev, char *buf)
{
struct led_classdev *led_cdev = class_get_devdata(dev);
struct timer_trig_data *timer_data = led_cdev->trigger_data;
sprintf(buf, "%lu\n", timer_data->delay_on);
return strlen(buf) + 1;
}
static ssize_t led_delay_on_store(struct class_device *dev, const char *buf,
size_t size)
{
struct led_classdev *led_cdev = class_get_devdata(dev);
struct timer_trig_data *timer_data = led_cdev->trigger_data;
int ret = -EINVAL;
char *after;
unsigned long state = simple_strtoul(buf, &after, 10);
if (after - buf > 0) {
timer_data->delay_on = state;
mod_timer(&timer_data->timer, jiffies + 1);
ret = after - buf;
}
return ret;
}
static ssize_t led_delay_off_show(struct class_device *dev, char *buf)
{
struct led_classdev *led_cdev = class_get_devdata(dev);
struct timer_trig_data *timer_data = led_cdev->trigger_data;
sprintf(buf, "%lu\n", timer_data->delay_off);
return strlen(buf) + 1;
}
static ssize_t led_delay_off_store(struct class_device *dev, const char *buf,
size_t size)
{
struct led_classdev *led_cdev = class_get_devdata(dev);
struct timer_trig_data *timer_data = led_cdev->trigger_data;
int ret = -EINVAL;
char *after;
unsigned long state = simple_strtoul(buf, &after, 10);
if (after - buf > 0) {
timer_data->delay_off = state;
mod_timer(&timer_data->timer, jiffies + 1);
ret = after - buf;
}
return ret;
}
static CLASS_DEVICE_ATTR(delay_on, 0644, led_delay_on_show,
led_delay_on_store);
static CLASS_DEVICE_ATTR(delay_off, 0644, led_delay_off_show,
led_delay_off_store);
static void timer_trig_activate(struct led_classdev *led_cdev)
{
struct timer_trig_data *timer_data;
timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
if (!timer_data)
return;
led_cdev->trigger_data = timer_data;
init_timer(&timer_data->timer);
timer_data->timer.function = led_timer_function;
timer_data->timer.data = (unsigned long) led_cdev;
class_device_create_file(led_cdev->class_dev,
&class_device_attr_delay_on);
class_device_create_file(led_cdev->class_dev,
&class_device_attr_delay_off);
}
static void timer_trig_deactivate(struct led_classdev *led_cdev)
{
struct timer_trig_data *timer_data = led_cdev->trigger_data;
if (timer_data) {
class_device_remove_file(led_cdev->class_dev,
&class_device_attr_delay_on);
class_device_remove_file(led_cdev->class_dev,
&class_device_attr_delay_off);
del_timer_sync(&timer_data->timer);
kfree(timer_data);
}
}
static struct led_trigger timer_led_trigger = {
.name = "timer",
.activate = timer_trig_activate,
.deactivate = timer_trig_deactivate,
};
static int __init timer_trig_init(void)
{
return led_trigger_register(&timer_led_trigger);
}
static void __exit timer_trig_exit(void)
{
led_trigger_unregister(&timer_led_trigger);
}
module_init(timer_trig_init);
module_exit(timer_trig_exit);
MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
MODULE_DESCRIPTION("Timer LED trigger");
MODULE_LICENSE("GPL");