ledtrig-oneshot.c

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/*
 * One-shot LED Trigger
 *
 * Copyright 2012, Fabio Baltieri <[email protected]>
 *
 * Based on ledtrig-timer.c by Richard Purdie <[email protected]>
 *
 * 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/device.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/leds.h>
#include "leds.h"

#define DEFAULT_DELAY 100

struct oneshot_trig_data {
    unsigned int invert;
};

static ssize_t led_shot(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t size)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;

    led_blink_set_oneshot(led_cdev,
            &led_cdev->blink_delay_on, &led_cdev->blink_delay_off,
            oneshot_data->invert);

    /* content is ignored */
    return size;
}
static ssize_t led_invert_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;

    return sprintf(buf, "%u\n", oneshot_data->invert);
}

static ssize_t led_invert_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t size)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
    unsigned long state;
    int ret;

    ret = kstrtoul(buf, 0, &state);
    if (ret)
        return ret;

    oneshot_data->invert = !!state;

    if (oneshot_data->invert)
        __led_set_brightness(led_cdev, LED_FULL);
    else
        __led_set_brightness(led_cdev, LED_OFF);

    return size;
}

static ssize_t led_delay_on_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);

    return sprintf(buf, "%lu\n", led_cdev->blink_delay_on);
}

static ssize_t led_delay_on_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t size)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    unsigned long state;
    int ret;

    ret = kstrtoul(buf, 0, &state);
    if (ret)
        return ret;

    led_cdev->blink_delay_on = state;

    return size;
}
static ssize_t led_delay_off_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);

    return sprintf(buf, "%lu\n", led_cdev->blink_delay_off);
}

static ssize_t led_delay_off_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t size)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    unsigned long state;
    int ret;

    ret = kstrtoul(buf, 0, &state);
    if (ret)
        return ret;

    led_cdev->blink_delay_off = state;

    return size;
}

static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
static DEVICE_ATTR(shot, 0200, NULL, led_shot);

static void oneshot_trig_activate(struct led_classdev *led_cdev)
{
    struct oneshot_trig_data *oneshot_data;
    int rc;

    oneshot_data = kzalloc(sizeof(*oneshot_data), GFP_KERNEL);
    if (!oneshot_data)
        return;

    led_cdev->trigger_data = oneshot_data;

    rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
    if (rc)
        goto err_out_trig_data;
    rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
    if (rc)
        goto err_out_delayon;
    rc = device_create_file(led_cdev->dev, &dev_attr_invert);
    if (rc)
        goto err_out_delayoff;
    rc = device_create_file(led_cdev->dev, &dev_attr_shot);
    if (rc)
        goto err_out_invert;

    led_cdev->blink_delay_on = DEFAULT_DELAY;
    led_cdev->blink_delay_off = DEFAULT_DELAY;

    led_cdev->activated = true;

    return;

err_out_invert:
    device_remove_file(led_cdev->dev, &dev_attr_invert);
err_out_delayoff:
    device_remove_file(led_cdev->dev, &dev_attr_delay_off);
err_out_delayon:
    device_remove_file(led_cdev->dev, &dev_attr_delay_on);
err_out_trig_data:
    kfree(led_cdev->trigger_data);
}

static void oneshot_trig_deactivate(struct led_classdev *led_cdev)
{
    struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;

    if (led_cdev->activated) {
        device_remove_file(led_cdev->dev, &dev_attr_delay_on);
        device_remove_file(led_cdev->dev, &dev_attr_delay_off);
        device_remove_file(led_cdev->dev, &dev_attr_invert);
        device_remove_file(led_cdev->dev, &dev_attr_shot);
        kfree(oneshot_data);
        led_cdev->activated = false;
    }

    /* Stop blinking */
    led_set_brightness(led_cdev, LED_OFF);
}

static struct led_trigger oneshot_led_trigger = {
    .name     = "oneshot",
    .activate = oneshot_trig_activate,
    .deactivate = oneshot_trig_deactivate,
};

static int __init oneshot_trig_init(void)
{
    return led_trigger_register(&oneshot_led_trigger);
}

static void __exit oneshot_trig_exit(void)
{
    led_trigger_unregister(&oneshot_led_trigger);
}

module_init(oneshot_trig_init);
module_exit(oneshot_trig_exit);

MODULE_AUTHOR("Fabio Baltieri <[email protected]>");
MODULE_DESCRIPTION("One-shot LED trigger");
MODULE_LICENSE("GPL");