linux-imx

/*

 * 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/sched/loadavg.h>

#include <linux/leds.h>

#include <linux/reboot.h>

#include "../leds.h"

​

static int panic_heartbeats;

​

struct heartbeat_trig_data {

    struct led_classdev *led_cdev;

    unsigned int phase;

    unsigned int period;

    struct timer_list timer;

    unsigned int invert;

};

​

static void led_heartbeat_function(struct timer_list *t)

{

    struct heartbeat_trig_data *heartbeat_data =

        from_timer(heartbeat_data, t, timer);

    struct led_classdev *led_cdev;

    unsigned long brightness = LED_OFF;

    unsigned long delay = 0;

​

    led_cdev = heartbeat_data->led_cdev;

​

    if (unlikely(panic_heartbeats)) {

        led_set_brightness_nosleep(led_cdev, LED_OFF);

        return;

    }

​

    if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags))

        led_cdev->blink_brightness = led_cdev->new_blink_brightness;

​

    /* 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++;

        if (!heartbeat_data->invert)

            brightness = led_cdev->blink_brightness;

        break;

    case 1:

        delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);

        heartbeat_data->phase++;

        if (heartbeat_data->invert)

            brightness = led_cdev->blink_brightness;

        break;

    case 2:

        delay = msecs_to_jiffies(70);

        heartbeat_data->phase++;

        if (!heartbeat_data->invert)

            brightness = led_cdev->blink_brightness;

        break;

    default:

        delay = heartbeat_data->period - heartbeat_data->period / 4 -

            msecs_to_jiffies(70);

        heartbeat_data->phase = 0;

        if (heartbeat_data->invert)

            brightness = led_cdev->blink_brightness;

        break;

    }

​

    led_set_brightness_nosleep(led_cdev, brightness);