1. 根目录:
2. drivers
3. leds
4. led-class-flash.c

/*
 * LED Flash class interface
 *
 * Copyright (C) 2015 Samsung Electronics Co., Ltd.
 * Author: Jacek Anaszewski <j.anaszewski@samsung.com>
 *
 * 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/device.h>
#include <linux/init.h>
#include <linux/led-class-flash.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "leds.h"

#define has_flash_op(fled_cdev, op)				\
	(fled_cdev && fled_cdev->ops->op)

#define call_flash_op(fled_cdev, op, args...)		\
	((has_flash_op(fled_cdev, op)) ?			\
			(fled_cdev->ops->op(fled_cdev, args)) :	\
			-EINVAL)

static const char * const led_flash_fault_names[] = {
	"led-over-voltage",
	"flash-timeout-exceeded",
	"controller-over-temperature",
	"controller-short-circuit",
	"led-power-supply-over-current",
	"indicator-led-fault",
	"led-under-voltage",
	"controller-under-voltage",
	"led-over-temperature",
};

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

	mutex_lock(&led_cdev->led_access);

	if (led_sysfs_is_disabled(led_cdev)) {
		ret = -EBUSY;
		goto unlock;
	}

	ret = kstrtoul(buf, 10, &state);
	if (ret)
		goto unlock;

	ret = led_set_flash_brightness(fled_cdev, state);
	if (ret < 0)
		goto unlock;

	ret = size;
unlock:
	mutex_unlock(&led_cdev->led_access);
	return ret;
}

static ssize_t flash_brightness_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);

	/* no lock needed for this */
	led_update_flash_brightness(fled_cdev);

	return sprintf(buf, "%u\n", fled_cdev->brightness.val);
}
static DEVICE_ATTR_RW(flash_brightness);

static ssize_t max_flash_brightness_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);

	return sprintf(buf, "%u\n", fled_cdev->brightness.max);
}
static DEVICE_ATTR_RO(max_flash_brightness);

static ssize_t flash_strobe_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
	unsigned long state;
	ssize_t ret = -EINVAL;

	mutex_lock(&led_cdev->led_access);

	if (led_sysfs_is_disabled(led_cdev)) {
		ret = -EBUSY;
		goto unlock;
	}

	ret = kstrtoul(buf, 10, &state);
	if (ret)
		goto unlock;

	if (state < 0 || state > 1) {
		ret = -EINVAL;
		goto unlock;
	}

	ret = led_set_flash_strobe(fled_cdev, state);
	if (ret < 0)
		goto unlock;
	ret = size;
unlock:
	mutex_unlock(&led_cdev->led_access);
	return ret;
}

static ssize_t flash_strobe_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
	bool state;
	int ret;

	/* no lock needed for this */
	ret = led_get_flash_strobe(fled_cdev, &state);
	if (ret < 0)
		return ret;

	return sprintf(buf, "%u\n", state);
}
static DEVICE_ATTR_RW(flash_strobe);

static ssize_t flash_timeout_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
	unsigned long flash_timeout;
	ssize_t ret;

	mutex_lock(&led_cdev->led_access);

	if (led_sysfs_is_disabled(led_cdev)) {
		ret = -EBUSY;
		goto unlock;
	}

	ret = kstrtoul(buf, 10, &flash_timeout);
	if (ret)
		goto unlock;

	ret = led_set_flash_timeout(fled_cdev, flash_timeout);
	if (ret < 0)
		goto unlock;

	ret = size;
unlock:
	mutex_unlock(&led_cdev->led_access);
	return ret;
}

static ssize_t flash_timeout_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);

	return sprintf(buf, "%u\n", fled_cdev->timeout.val);
}
static DEVICE_ATTR_RW(flash_timeout);

static ssize_t max_flash_timeout_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);

	return sprintf(buf, "%u\n", fled_cdev->timeout.max);
}
static DEVICE_ATTR_RO(max_flash_timeout);

static ssize_t flash_fault_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
	u32 fault, mask = 0x1;
	char *pbuf = buf;
	int i, ret, buf_len;

	ret = led_get_flash_fault(fled_cdev, &fault);
	if (ret < 0)
		return -EINVAL;

	*buf = '\0';

	for (i = 0; i < LED_NUM_FLASH_FAULTS; ++i) {
		if (fault & mask) {
			buf_len = sprintf(pbuf, "%s ",
					  led_flash_fault_names[i]);
			pbuf += buf_len;
		}
		mask <<= 1;
	}

	return sprintf(buf, "%s\n", buf);
}
static DEVICE_ATTR_RO(flash_fault);

static struct attribute *led_flash_strobe_attrs[] = {
	&dev_attr_flash_strobe.attr,
	NULL,
};

static struct attribute *led_flash_timeout_attrs[] = {
	&dev_attr_flash_timeout.attr,
	&dev_attr_max_flash_timeout.attr,
	NULL,
};

static struct attribute *led_flash_brightness_attrs[] = {
	&dev_attr_flash_brightness.attr,
	&dev_attr_max_flash_brightness.attr,
	NULL,
};

static struct attribute *led_flash_fault_attrs[] = {
	&dev_attr_flash_fault.attr,
	NULL,
};

static const struct attribute_group led_flash_strobe_group = {
	.attrs = led_flash_strobe_attrs,
};

static const struct attribute_group led_flash_timeout_group = {
	.attrs = led_flash_timeout_attrs,
};

static const struct attribute_group led_flash_brightness_group = {
	.attrs = led_flash_brightness_attrs,
};

static const struct attribute_group led_flash_fault_group = {
	.attrs = led_flash_fault_attrs,
};

static void led_flash_resume(struct led_classdev *led_cdev)
{
	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);

	call_flash_op(fled_cdev, flash_brightness_set,
					fled_cdev->brightness.val);
	call_flash_op(fled_cdev, timeout_set, fled_cdev->timeout.val);
}

static void led_flash_init_sysfs_groups(struct led_classdev_flash *fled_cdev)
{
	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
	const struct led_flash_ops *ops = fled_cdev->ops;
	const struct attribute_group **flash_groups = fled_cdev->sysfs_groups;

	int num_sysfs_groups = 0;

	flash_groups[num_sysfs_groups++] = &led_flash_strobe_group;

	if (ops->flash_brightness_set)
		flash_groups[num_sysfs_groups++] = &led_flash_brightness_group;

	if (ops->timeout_set)
		flash_groups[num_sysfs_groups++] = &led_flash_timeout_group;

	if (ops->fault_get)
		flash_groups[num_sysfs_groups++] = &led_flash_fault_group;

	led_cdev->groups = flash_groups;
}

int led_classdev_flash_register(struct device *parent,
				struct led_classdev_flash *fled_cdev)
{
	struct led_classdev *led_cdev;
	const struct led_flash_ops *ops;
	int ret;

	if (!fled_cdev)
		return -EINVAL;

	led_cdev = &fled_cdev->led_cdev;

	if (led_cdev->flags & LED_DEV_CAP_FLASH) {
		if (!led_cdev->brightness_set_sync)
			return -EINVAL;

		ops = fled_cdev->ops;
		if (!ops || !ops->strobe_set)
			return -EINVAL;

		led_cdev->flash_resume = led_flash_resume;

		/* Select the sysfs attributes to be created for the device */
		led_flash_init_sysfs_groups(fled_cdev);
	}

	/* Register led class device */
	ret = led_classdev_register(parent, led_cdev);
	if (ret < 0)
		return ret;

	/* Setting a torch brightness needs to have immediate effect */
	led_cdev->flags &= ~SET_BRIGHTNESS_ASYNC;
	led_cdev->flags |= SET_BRIGHTNESS_SYNC;

	return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_flash_register);

void led_classdev_flash_unregister(struct led_classdev_flash *fled_cdev)
{
	if (!fled_cdev)
		return;

	led_classdev_unregister(&fled_cdev->led_cdev);
}
EXPORT_SYMBOL_GPL(led_classdev_flash_unregister);

static void led_clamp_align(struct led_flash_setting *s)
{
	u32 v, offset;

	v = s->val + s->step / 2;
	v = clamp(v, s->min, s->max);
	offset = v - s->min;
	offset = s->step * (offset / s->step);
	s->val = s->min + offset;
}

int led_set_flash_timeout(struct led_classdev_flash *fled_cdev, u32 timeout)
{
	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
	struct led_flash_setting *s = &fled_cdev->timeout;

	s->val = timeout;
	led_clamp_align(s);

	if (!(led_cdev->flags & LED_SUSPENDED))
		return call_flash_op(fled_cdev, timeout_set, s->val);

	return 0;
}
EXPORT_SYMBOL_GPL(led_set_flash_timeout);

int led_get_flash_fault(struct led_classdev_flash *fled_cdev, u32 *fault)
{
	return call_flash_op(fled_cdev, fault_get, fault);
}
EXPORT_SYMBOL_GPL(led_get_flash_fault);

int led_set_flash_brightness(struct led_classdev_flash *fled_cdev,
				u32 brightness)
{
	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
	struct led_flash_setting *s = &fled_cdev->brightness;

	s->val = brightness;
	led_clamp_align(s);

	if (!(led_cdev->flags & LED_SUSPENDED))
		return call_flash_op(fled_cdev, flash_brightness_set, s->val);

	return 0;
}
EXPORT_SYMBOL_GPL(led_set_flash_brightness);

int led_update_flash_brightness(struct led_classdev_flash *fled_cdev)
{
	struct led_flash_setting *s = &fled_cdev->brightness;
	u32 brightness;

	if (has_flash_op(fled_cdev, flash_brightness_get)) {
		int ret = call_flash_op(fled_cdev, flash_brightness_get,
						&brightness);
		if (ret < 0)
			return ret;

		s->val = brightness;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(led_update_flash_brightness);

MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
MODULE_DESCRIPTION("LED Flash class interface");
MODULE_LICENSE("GPL v2");