linux-imx

// SPDX-License-Identifier: GPL-2.0

//

// LED Kernel Transient Trigger

//

// Transient trigger allows one shot timer activation. Please refer to

// Documentation/leds/ledtrig-transient.txt for details

// Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com>

//

// Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's

// ledtrig-heartbeat.c

// Design and use-case input from Jonas Bonn <jonas@southpole.se> and

// Neil Brown <neilb@suse.de>

​

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/device.h>

#include <linux/slab.h>

#include <linux/timer.h>

#include <linux/leds.h>

#include "../leds.h"

​

struct transient_trig_data {

    int activate;

    int state;

    int restore_state;

    unsigned long duration;

    struct timer_list timer;

    struct led_classdev *led_cdev;

};

​

static void transient_timer_function(struct timer_list *t)

{

    struct transient_trig_data *transient_data =

        from_timer(transient_data, t, timer);

    struct led_classdev *led_cdev = transient_data->led_cdev;

​

    transient_data->activate = 0;

    led_set_brightness_nosleep(led_cdev, transient_data->restore_state);

}

​

static ssize_t transient_activate_show(struct device *dev,

        struct device_attribute *attr, char *buf)

{

    struct transient_trig_data *transient_data =

        led_trigger_get_drvdata(dev);

​

    return sprintf(buf, "%d\n", transient_data->activate);

}

​

static ssize_t transient_activate_store(struct device *dev,

        struct device_attribute *attr, const char *buf, size_t size)

{

    struct led_classdev *led_cdev = led_trigger_get_led(dev);

    struct transient_trig_data *transient_data =

        led_trigger_get_drvdata(dev);

    unsigned long state;

    ssize_t ret;

​

    ret = kstrtoul(buf, 10, &state);

    if (ret)

        return ret;

​