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ledtrig-timer.c

/*
 * 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/module.h>
#include <linux/jiffies.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/ctype.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 device *dev, 
            struct device_attribute *attr, char *buf)
{
      struct led_classdev *led_cdev = dev_get_drvdata(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 device *dev, 
            struct device_attribute *attr, const char *buf, size_t size)
{
      struct led_classdev *led_cdev = dev_get_drvdata(dev);
      struct timer_trig_data *timer_data = led_cdev->trigger_data;
      int ret = -EINVAL;
      char *after;
      unsigned long state = simple_strtoul(buf, &after, 10);
      size_t count = after - buf;

      if (*after && isspace(*after))
            count++;

      if (count == size) {
            timer_data->delay_on = state;
            mod_timer(&timer_data->timer, jiffies + 1);
            ret = count;
      }

      return ret;
}

static ssize_t led_delay_off_show(struct device *dev, 
            struct device_attribute *attr, char *buf)
{
      struct led_classdev *led_cdev = dev_get_drvdata(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 device *dev, 
            struct device_attribute *attr, const char *buf, size_t size)
{
      struct led_classdev *led_cdev = dev_get_drvdata(dev);
      struct timer_trig_data *timer_data = led_cdev->trigger_data;
      int ret = -EINVAL;
      char *after;
      unsigned long state = simple_strtoul(buf, &after, 10);
      size_t count = after - buf;

      if (*after && isspace(*after))
            count++;

      if (count == size) {
            timer_data->delay_off = state;
            mod_timer(&timer_data->timer, jiffies + 1);
            ret = count;
      }

      return ret;
}

static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
static 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;
      int rc;

      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;

      rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
      if (rc)
            goto err_out;
      rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
      if (rc)
            goto err_out_delayon;

      return;

err_out_delayon:
      device_remove_file(led_cdev->dev, &dev_attr_delay_on);
err_out:
      led_cdev->trigger_data = NULL;
      kfree(timer_data);
}

static void timer_trig_deactivate(struct led_classdev *led_cdev)
{
      struct timer_trig_data *timer_data = led_cdev->trigger_data;

      if (timer_data) {
            device_remove_file(led_cdev->dev, &dev_attr_delay_on);
            device_remove_file(led_cdev->dev, &dev_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");

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