1 files changed, 287 insertions, 0 deletions
diff --git a/libsensors/light.c b/libsensors/light.c
new file mode 100644
index 0000000..f84691f
--- /dev/null
+++ b/libsensors/light.c
@@ -0,0 +1,287 @@
+/*
+ * Copyright (C) 2013 Paul Kocialkowski <contact@paulk.fr>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <math.h>
+#include <sys/types.h>
+#include <linux/ioctl.h>
+#include <linux/input.h>
+
+#include <hardware/sensors.h>
+#include <hardware/hardware.h>
+
+#define LOG_TAG "piranha_sensors"
+#include <utils/Log.h>
+
+#include "piranha_sensors.h"
+
+enum {
+	SENSOR_TYPE_BH1721 = 1,
+	SENSOR_TYPE_AL3201,
+	SENSOR_TYPE_GP2A,
+};
+
+struct light_data {
+	char path_enable[PATH_MAX];
+	char path_delay[PATH_MAX];
+	int sensor_type;
+};
+
+int light_init(struct piranha_sensors_handlers *handlers,
+	struct piranha_sensors_device *device)
+{
+	struct light_data *data = NULL;
+	char path[PATH_MAX] = { 0 };
+	int input_fd = -1;
+	int rc;
+
+	ALOGD("%s(%p, %p)", __func__, handlers, device);
+
+	if (handlers == NULL)
+		return -EINVAL;
+
+	data = (struct light_data *) calloc(1, sizeof(struct light_data));
+
+	input_fd = input_open("light_sensor");
+	if (input_fd < 0) {
+		ALOGE("%s: Unable to open input", __func__);
+		goto error;
+	}
+
+	rc = sysfs_path_prefix("light_sensor", (char *) &path);
+	if (rc < 0 || path[0] == '\0') {
+		ALOGE("%s: Unable to open sysfs", __func__);
+		goto error;
+	}
+
+	snprintf(data->path_enable, PATH_MAX, "%s/enable", path);
+	snprintf(data->path_delay, PATH_MAX, "%s/poll_delay", path);
+
+	handlers->poll_fd = input_fd;
+	handlers->data = (void *) data;
+
+	char device_variant[16];
+	FILE *f = fopen(DEVICE_VARIANT_SYSFS, "r");
+	if (!f || fgets(device_variant, 16, f) == NULL) {
+		ALOGE("Failed to read " DEVICE_VARIANT_SYSFS ", assuming P51xx\n");
+		strcpy(device_variant, "espresso10");
+	}
+	if (f)
+		fclose(f);
+
+	ALOGD("Device: %s", device_variant);
+
+	if (strcmp(device_variant, "espresso10") == 0) {
+		/* Device is P51xx */
+		data->sensor_type = SENSOR_TYPE_BH1721;
+	} else if (strcmp(device_variant, "espressowifi") == 0) {
+		/* Device is P3110 */
+		data->sensor_type = SENSOR_TYPE_AL3201;
+	} else {
+		/* Device is P3100 */
+		data->sensor_type = SENSOR_TYPE_GP2A;
+	}
+
+	return 0;
+
+error:
+	if (data != NULL)
+		free(data);
+
+	if (input_fd >= 0)
+		close(input_fd);
+
+	handlers->poll_fd = -1;
+	handlers->data = NULL;
+
+	return -1;
+}
+
+int light_deinit(struct piranha_sensors_handlers *handlers)
+{
+	ALOGD("%s(%p)", __func__, handlers);
+
+	if (handlers == NULL)
+		return -EINVAL;
+
+	if (handlers->poll_fd >= 0)
+		close(handlers->poll_fd);
+	handlers->poll_fd = -1;
+
+	if (handlers->data != NULL)
+		free(handlers->data);
+	handlers->data = NULL;
+
+	return 0;
+}
+
+int light_activate(struct piranha_sensors_handlers *handlers)
+{
+	struct light_data *data;
+	int rc;
+
+	ALOGD("%s(%p)", __func__, handlers);
+
+	if (handlers == NULL || handlers->data == NULL)
+		return -EINVAL;
+
+	data = (struct light_data *) handlers->data;
+
+	rc = sysfs_value_write(data->path_enable, 1);
+	if (rc < 0) {
+		ALOGE("%s: Unable to write sysfs value", __func__);
+		return -1;
+	}
+
+	handlers->activated = 1;
+
+	return 0;
+}
+
+int light_deactivate(struct piranha_sensors_handlers *handlers)
+{
+	struct light_data *data;
+	int rc;
+
+	ALOGD("%s(%p)", __func__, handlers);
+
+	if (handlers == NULL || handlers->data == NULL)
+		return -EINVAL;
+
+	data = (struct light_data *) handlers->data;
+
+	rc = sysfs_value_write(data->path_enable, 0);
+	if (rc < 0) {
+		ALOGE("%s: Unable to write sysfs value", __func__);
+		return -1;
+	}
+
+	handlers->activated = 1;
+
+	return 0;
+}
+
+int light_set_delay(struct piranha_sensors_handlers *handlers, int64_t delay)
+{
+	struct light_data *data;
+	int rc;
+
+	ALOGD("%s(%p, %" PRId64 ")", __func__, handlers, delay);
+
+	if (handlers == NULL || handlers->data == NULL)
+		return -EINVAL;
+
+	data = (struct light_data *) handlers->data;
+
+	rc = sysfs_value_write(data->path_delay, delay);
+	if (rc < 0) {
+		ALOGE("%s: Unable to write sysfs value", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+float light_convert(int value, int sensor_type)
+{
+	// Converting the AL3201 raw value to lux:
+	// I = 10 * log(light) uA
+	// U = raw * 3300 / 4095 (max ADC value is 3.3V for 4095 LSB)
+	// R = 47kOhm
+	// => light = 10 ^ (I / 10) = 10 ^ (U / R / 10)
+	// => light = 10 ^ (raw * 330 / 4095 / 47)
+	// Only 1/4 of light reaches the sensor:
+	// => light = 4 * (10 ^ (raw * 330 / 4095 / 47))
+
+	// Converting the GP2A raw value to lux:
+	// I = 10 * log(Ev) uA
+	// R = 24kOhm
+	// Max adc value 1023 = 1.25V
+	// 1/4 of light reaches sensor
+
+	switch (sensor_type) {
+		case SENSOR_TYPE_AL3201:
+			return powf(10, value * (330.0f / 4095.0f / 47.0f)) * 4;
+		case SENSOR_TYPE_BH1721:
+			return value * 0.712f;
+		case SENSOR_TYPE_GP2A:
+			return powf(10, value * (125.0f / 1023.0f / 24.0f)) * 4;
+		default:
+			ALOGE("%s: Unknown sensor type", __func__);
+	}
+
+	return 0;
+}
+
+int light_get_data(struct piranha_sensors_handlers *handlers,
+	struct sensors_event_t *event)
+{
+	struct light_data *data = (struct light_data *) handlers->data;
+	struct input_event input_event;
+	int input_fd;
+	int rc;
+
+//	ALOGD("%s(%p, %p)", __func__, handlers, event);
+
+	if (handlers == NULL || event == NULL)
+		return -EINVAL;
+
+	input_fd = handlers->poll_fd;
+	if (input_fd < 0)
+		return -EINVAL;
+
+	memset(event, 0, sizeof(struct sensors_event_t));
+	event->version = sizeof(struct sensors_event_t);
+	event->sensor = handlers->handle;
+	event->type = handlers->handle;
+
+	do {
+		rc = read(input_fd, &input_event, sizeof(input_event));
+		if (rc < (int) sizeof(input_event))
+			break;
+
+		if (input_event.type == EV_REL) {
+			if (input_event.code == REL_MISC)
+				event->light = light_convert(input_event.value, data->sensor_type);
+		} else if (input_event.type == EV_SYN) {
+			if (input_event.code == SYN_REPORT)
+				event->timestamp = input_timestamp(&input_event);
+		}
+	} while (input_event.type != EV_SYN);
+
+	return 0;
+}
+
+struct piranha_sensors_handlers light = {
+	.name = "Light",
+	.handle = SENSOR_TYPE_LIGHT,
+	.init = light_init,
+	.deinit = light_deinit,
+	.activate = light_activate,
+	.deactivate = light_deactivate,
+	.set_delay = light_set_delay,
+	.get_data = light_get_data,
+	.activated = 0,
+	.needed = 0,
+	.poll_fd = -1,
+	.data = NULL,
+};