Add backlight support

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 132 insertions, 0 deletions

diff --git a/liblight/lights.c b/liblight/lights.c
new file mode 100644
index 0000000..43ff00a
--- /dev/null
+++ b/liblight/lights.c
@@ -0,0 +1,132 @@
+/*
+ * 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,
+};