120 lines
3.1 KiB
C
120 lines
3.1 KiB
C
/*
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* LED Heartbeat Trigger
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*
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* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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*
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* Based on Richard Purdie's ledtrig-timer.c and some arch's
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* CONFIG_HEARTBEAT code.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/timer.h>
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#include <linux/sched.h>
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#include <linux/leds.h>
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#include "leds.h"
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struct heartbeat_trig_data {
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unsigned int phase;
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unsigned int period;
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struct timer_list timer;
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};
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static void led_heartbeat_function(unsigned long data)
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{
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struct led_classdev *led_cdev = (struct led_classdev *) data;
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struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
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unsigned long brightness = LED_OFF;
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unsigned long delay = 0;
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/* acts like an actual heart beat -- ie thump-thump-pause... */
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switch (heartbeat_data->phase) {
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case 0:
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/*
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* The hyperbolic function below modifies the
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* heartbeat period length in dependency of the
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* current (1min) load. It goes through the points
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* f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.
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*/
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heartbeat_data->period = 300 +
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(6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT));
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heartbeat_data->period =
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msecs_to_jiffies(heartbeat_data->period);
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delay = msecs_to_jiffies(70);
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heartbeat_data->phase++;
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brightness = led_cdev->max_brightness;
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break;
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case 1:
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delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
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heartbeat_data->phase++;
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break;
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case 2:
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delay = msecs_to_jiffies(70);
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heartbeat_data->phase++;
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brightness = led_cdev->max_brightness;
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break;
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default:
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delay = heartbeat_data->period - heartbeat_data->period / 4 -
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msecs_to_jiffies(70);
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heartbeat_data->phase = 0;
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break;
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}
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led_set_brightness(led_cdev, brightness);
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mod_timer(&heartbeat_data->timer, jiffies + delay);
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}
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static void heartbeat_trig_activate(struct led_classdev *led_cdev)
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{
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struct heartbeat_trig_data *heartbeat_data;
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heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
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if (!heartbeat_data)
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return;
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led_cdev->trigger_data = heartbeat_data;
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setup_timer(&heartbeat_data->timer,
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led_heartbeat_function, (unsigned long) led_cdev);
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heartbeat_data->phase = 0;
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led_heartbeat_function(heartbeat_data->timer.data);
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}
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static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
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{
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struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
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if (heartbeat_data) {
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del_timer_sync(&heartbeat_data->timer);
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kfree(heartbeat_data);
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}
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}
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static struct led_trigger heartbeat_led_trigger = {
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.name = "heartbeat",
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.activate = heartbeat_trig_activate,
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.deactivate = heartbeat_trig_deactivate,
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};
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static int __init heartbeat_trig_init(void)
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{
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return led_trigger_register(&heartbeat_led_trigger);
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}
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static void __exit heartbeat_trig_exit(void)
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{
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led_trigger_unregister(&heartbeat_led_trigger);
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}
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module_init(heartbeat_trig_init);
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module_exit(heartbeat_trig_exit);
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MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
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MODULE_DESCRIPTION("Heartbeat LED trigger");
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MODULE_LICENSE("GPL");
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