Eric Lee / smarc-fsl-linux-kernel

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drivers/leds/ledtrig-heartbeat.c 3.13 KB
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891c668b9   Atsushi Nemoto   [PATCH] LED: add ... 
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  /*
   * LED Heartbeat Trigger
   *
   * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   *
   * Based on Richard Purdie's ledtrig-timer.c and some arch's
   * CONFIG_HEARTBEAT code.
   *
   * 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>
5a0e3ad6a   Tejun Heo   include cleanup: ... 
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  #include <linux/slab.h>
891c668b9   Atsushi Nemoto   [PATCH] LED: add ... 
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  #include <linux/timer.h>
  #include <linux/sched.h>
  #include <linux/leds.h>
  #include "leds.h"
  
  struct heartbeat_trig_data {
  	unsigned int phase;
  	unsigned int period;
  	struct timer_list timer;
  };
  
  static void led_heartbeat_function(unsigned long data)
  {
  	struct led_classdev *led_cdev = (struct led_classdev *) data;
  	struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
  	unsigned long brightness = LED_OFF;
  	unsigned long delay = 0;
  
  	/* acts like an actual heart beat -- ie thump-thump-pause... */
  	switch (heartbeat_data->phase) {
  	case 0:
  		/*
  		 * The hyperbolic function below modifies the
  		 * heartbeat period length in dependency of the
  		 * current (1min) load. It goes through the points
  		 * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.
  		 */
  		heartbeat_data->period = 300 +
  			(6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT));
  		heartbeat_data->period =
  			msecs_to_jiffies(heartbeat_data->period);
  		delay = msecs_to_jiffies(70);
  		heartbeat_data->phase++;
1bd465e6b   Guennadi Liakhovetski   leds: allow led-d... 
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  		brightness = led_cdev->max_brightness;
891c668b9   Atsushi Nemoto   [PATCH] LED: add ... 
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  		break;
  	case 1:
  		delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
  		heartbeat_data->phase++;
  		break;
  	case 2:
  		delay = msecs_to_jiffies(70);
  		heartbeat_data->phase++;
1bd465e6b   Guennadi Liakhovetski   leds: allow led-d... 
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  		brightness = led_cdev->max_brightness;
891c668b9   Atsushi Nemoto   [PATCH] LED: add ... 
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  		break;
  	default:
  		delay = heartbeat_data->period - heartbeat_data->period / 4 -
  			msecs_to_jiffies(70);
  		heartbeat_data->phase = 0;
  		break;
  	}
  
  	led_set_brightness(led_cdev, brightness);
  	mod_timer(&heartbeat_data->timer, jiffies + delay);
  }
  
  static void heartbeat_trig_activate(struct led_classdev *led_cdev)
  {
  	struct heartbeat_trig_data *heartbeat_data;
  
  	heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
  	if (!heartbeat_data)
  		return;
  
  	led_cdev->trigger_data = heartbeat_data;
  	setup_timer(&heartbeat_data->timer,
  		    led_heartbeat_function, (unsigned long) led_cdev);
  	heartbeat_data->phase = 0;
  	led_heartbeat_function(heartbeat_data->timer.data);
  }
  
  static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
  {
  	struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
  
  	if (heartbeat_data) {
  		del_timer_sync(&heartbeat_data->timer);
  		kfree(heartbeat_data);
  	}
  }
  
  static struct led_trigger heartbeat_led_trigger = {
  	.name     = "heartbeat",
  	.activate = heartbeat_trig_activate,
  	.deactivate = heartbeat_trig_deactivate,
  };
  
  static int __init heartbeat_trig_init(void)
  {
  	return led_trigger_register(&heartbeat_led_trigger);
  }
  
  static void __exit heartbeat_trig_exit(void)
  {
  	led_trigger_unregister(&heartbeat_led_trigger);
  }
  
  module_init(heartbeat_trig_init);
  module_exit(heartbeat_trig_exit);
  
  MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
  MODULE_DESCRIPTION("Heartbeat LED trigger");
  MODULE_LICENSE("GPL");