linux-imx

/*

 * Activity LED trigger

 *

 * Copyright (C) 2017 Willy Tarreau <w@1wt.eu>

 * Partially based on Atsushi Nemoto's ledtrig-heartbeat.c.

 *

 * 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/init.h>

#include <linux/kernel.h>

#include <linux/kernel_stat.h>

#include <linux/leds.h>

#include <linux/module.h>

#include <linux/reboot.h>

#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/timer.h>

#include "../leds.h"

​

static int panic_detected;

​

struct activity_data {

    struct timer_list timer;

    struct led_classdev *led_cdev;

    u64 last_used;

    u64 last_boot;

    int time_left;

    int state;

    int invert;

};

​

static void led_activity_function(struct timer_list *t)

{

    struct activity_data *activity_data = from_timer(activity_data, t,

                             timer);

    struct led_classdev *led_cdev = activity_data->led_cdev;

    unsigned int target;

    unsigned int usage;

    int delay;

    u64 curr_used;

    u64 curr_boot;

    s32 diff_used;

    s32 diff_boot;

    int cpus;

    int i;

​

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

        led_cdev->blink_brightness = led_cdev->new_blink_brightness;

​

    if (unlikely(panic_detected)) {

        /* full brightness in case of panic */

        led_set_brightness_nosleep(led_cdev, led_cdev->blink_brightness);

        return;

    }

​

    cpus = 0;

    curr_used = 0;

​

    for_each_possible_cpu(i) {

        curr_used += kcpustat_cpu(i).cpustat[CPUTIME_USER]