/*
 * Copyright (C) 2012 Renesas Solutions Corp.
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "lights"

#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdint.h>
#include <string.h>

#include <cutils/log.h>
#include <hardware/lights.h>
#include <sys/ioctl.h>
#include <sys/types.h>

static pthread_once_t g_init = PTHREAD_ONCE_INIT;
static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER;

static char const * const BACKLIGHT_FILE =
	"/sys/class/backlight/pwm-backlight.0/brightness";

static int file_write_integer(char const *path, int value)
{
	static int already_warned = 0;
	char buffer[11];
	int bytes;
	int ret;
	int fd;

	LOGV("%s: path %s, value %d", __func__, path, value);
	fd = open(path, O_RDWR);
	if (fd < 0) {
		if (!already_warned) {
			LOGE("%s: failed to open %s\n", __func__, path);
			already_warned = 1;
		}
		return -errno;
	}

	bytes = sprintf(buffer, "%d\n", value);
	ret = write(fd, buffer, bytes);
	close(fd);

	return ret == -1 ? -errno : 0;
}

static int rgb_to_brightness(struct light_state_t const *state)
{
	int color = state->color & 0x00ffffff;

	return (77 * ((color >> 16) & 0x00ff) +
		150 * ((color >> 8) & 0x00ff) +
		29 * (color & 0x00ff)) >> 8;
}

static int light_set_backlight(struct light_device_t *dev,
			       struct light_state_t const *state)
{
	int brightness = rgb_to_brightness(state);
	int err;

	pthread_mutex_lock(&g_lock);
	err = file_write_integer(BACKLIGHT_FILE, brightness);
	pthread_mutex_unlock(&g_lock);

	return err;
}

static int light_close(struct light_device_t *dev)
{
	free(dev);
	return 0;
}

static int light_open(const struct hw_module_t *module, char const *name,
		      struct hw_device_t **device)
{
	int (*set)(struct light_device_t *dev,
		   struct light_state_t const *state);
	struct light_device_t *dev;

	LOGV("%s: open with %s", __func__, name);

	if (!strcmp(LIGHT_ID_BACKLIGHT, name))
		set = light_set_backlight;
	else
		return -EINVAL;

	pthread_mutex_init(&g_lock, NULL);

	dev = malloc(sizeof(*dev));
	memset(dev, 0, sizeof(*dev));

	dev->common.tag = HARDWARE_DEVICE_TAG;
	dev->common.version = 0;
	dev->common.module = (struct hw_module_t *)module;
	dev->common.close = (int (*)(struct hw_device_t *))light_close;
	dev->set_light = set;

	*device = (struct hw_device_t *)dev;

	return 0;
}

static struct hw_module_methods_t lights_module_methods = {
	.open =  light_open,
};

const struct hw_module_t HAL_MODULE_INFO_SYM = {
	.tag = HARDWARE_MODULE_TAG,
	.version_major = 1,
	.version_minor = 0,
	.id = LIGHTS_HARDWARE_MODULE_ID,
	.name = "Backlight Module",
	.author = "Laurent Pinchart <laurent.pinchart@ideasonboard.com>",
	.methods = &lights_module_methods,
};