/* * 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> #include <linux/slab.h> #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++; brightness = led_cdev->max_brightness; 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++; brightness = led_cdev->max_brightness; 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");