linuxdebug/drivers/leds/trigger/ledtrig-oneshot.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * One-shot LED Trigger
 *
 * Copyright 2012, Fabio Baltieri <fabio.baltieri@gmail.com>
 *
 * Based on ledtrig-timer.c by Richard Purdie <rpurdie@openedhand.com>
 */

#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 = led_trigger_get_led(dev);
	struct oneshot_trig_data *oneshot_data = led_trigger_get_drvdata(dev);

	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 oneshot_trig_data *oneshot_data = led_trigger_get_drvdata(dev);

	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 = led_trigger_get_led(dev);
	struct oneshot_trig_data *oneshot_data = led_trigger_get_drvdata(dev);
	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_nosleep(led_cdev, LED_FULL);
	else
		led_set_brightness_nosleep(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 = led_trigger_get_led(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 = led_trigger_get_led(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 = led_trigger_get_led(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 = led_trigger_get_led(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 struct attribute *oneshot_trig_attrs[] = {
	&dev_attr_delay_on.attr,
	&dev_attr_delay_off.attr,
	&dev_attr_invert.attr,
	&dev_attr_shot.attr,
	NULL
};
ATTRIBUTE_GROUPS(oneshot_trig);

static void pattern_init(struct led_classdev *led_cdev)
{
	u32 *pattern;
	unsigned int size = 0;

	pattern = led_get_default_pattern(led_cdev, &size);
	if (!pattern)
		goto out_default;

	if (size != 2) {
		dev_warn(led_cdev->dev,
			 "Expected 2 but got %u values for delays pattern\n",
			 size);
		goto out_default;
	}

	led_cdev->blink_delay_on = pattern[0];
	led_cdev->blink_delay_off = pattern[1];
	kfree(pattern);

	return;

out_default:
	kfree(pattern);
	led_cdev->blink_delay_on = DEFAULT_DELAY;
	led_cdev->blink_delay_off = DEFAULT_DELAY;
}

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

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

	led_set_trigger_data(led_cdev, oneshot_data);

	if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
		pattern_init(led_cdev);
		/*
		 * Mark as initialized even on pattern_init() error because
		 * any consecutive call to it would produce the same error.
		 */
		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
	}

	return 0;
}

static void oneshot_trig_deactivate(struct led_classdev *led_cdev)
{
	struct oneshot_trig_data *oneshot_data = led_get_trigger_data(led_cdev);

	kfree(oneshot_data);

	/* 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,
	.groups = oneshot_trig_groups,
};
module_led_trigger(oneshot_led_trigger);

MODULE_AUTHOR("Fabio Baltieri <fabio.baltieri@gmail.com>");
MODULE_DESCRIPTION("One-shot LED trigger");
MODULE_LICENSE("GPL v2");