Herring Sensorsreplicant-4.2-0002replicant-4.2-0001

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>

1 files changed, 960 insertions, 0 deletions

diff --git a/sensors/akm8973.c b/sensors/akm8973.c
new file mode 100644
index 0000000..509c365
--- /dev/null
+++ b/sensors/akm8973.c
@@ -0,0 +1,960 @@
+/*
+ * 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 <unistd.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <hardware/sensors.h>
+#include <hardware/hardware.h>
+
+#define LOG_TAG "herring_sensors"
+#include <utils/Log.h>
+
+#include "herring_sensors.h"
+#include "ak8973-reg.h"
+#include "ak8973.h"
+
+#define AKM8973_CONFIG_PATH			"/data/misc/akmd_set.txt"
+
+struct akm8973_data {
+	struct herring_sensors_handlers *orientation_sensor;
+
+	sensors_vec_t magnetic;
+	unsigned char magnetic_data[4][3];
+	int magnetic_data_count;
+	int magnetic_data_index;
+
+	unsigned char magnetic_extrema[2][3];
+	unsigned char gain_indexes[3];
+	unsigned char hdac[3];
+	int ho[3];
+
+	long int delay;
+	int device_fd;
+	int uinput_fd;
+
+	pthread_t thread;
+	pthread_mutex_t mutex;
+	int thread_continue;
+};
+
+// This AKM8973 implementation is based on intuitive understanding of how the
+// AKM8973 data is translated to SI units.
+//
+// Different parameters are used to properly configure and interpret the data:
+// * Hardware gain, which is stored in the chip's EEPROM and is a factory
+//   setting that shouldn't be changed. We don't have to deal with this value at
+//   all for our computation.
+// * Software gain, that is a factory setting we use to determine the
+//   coefficient to use at some point in the final equation.
+// * Hardware DAC offset (HDAC) that we can tune in order to be able to see
+//   variations of the raw values. This value is not a linear representation
+//   of the offset! See page 22 of the AKM8973 datasheet for further details.
+// * Software offset (HO) that we can tune in order to have the maximum final
+//   value at ~45uT and the minimal final value at ~-45uT for each axis.
+//
+// The final equation used to determine usable values from the raw input data
+// was found to be:
+// out = ((in - 128 - HO / 16) * k / 16
+//
+// * out: Final value in uT units
+// * in: Raw value as received from the sensor
+// * HO: HO software offset
+// * k: Coefficient that is determined from the software gain
+//
+// When no software calibration is used, we can translate HDAC to HO using the
+// following formulas:
+// if HDAC < 128: HO = HDAC * -1 * 16 * 16
+// if HDAC >= 128: HO = (HDAC - 128) * 16 * 16
+
+// Constant gain-specific coefficients used in the final formula
+float akm8973_gain_coefficient[] = {
+	16.33f,
+	16.28f,
+	16.24f,
+	16.18f,
+	16.14f,
+	16.10f,
+	16.04f,
+	16.00f,
+	15.96f,
+	15.90f,
+	15.86f,
+	15.82f,
+	15.76f,
+	15.72f,
+	15.69f,
+	15.65f,
+};
+
+int akm8973_gain_coefficient_count = sizeof(akm8973_gain_coefficient) /
+	sizeof(float);
+
+int akm8973_hdac(struct akm8973_data *data)
+{
+	char i2c_data[RWBUF_SIZE] = { 0 };
+	int device_fd;
+	int rc;
+
+	if (data == NULL)
+		return -EINVAL;
+
+	device_fd = data->device_fd;
+	if (device_fd < 0)
+		return -1;
+
+	i2c_data[0] = 4;
+	i2c_data[1] = AK8973_REG_HXDA;
+	i2c_data[2] = data->hdac[0];
+	i2c_data[3] = data->hdac[1];
+	i2c_data[4] = data->hdac[2];
+
+	rc = ioctl(device_fd, ECS_IOCTL_WRITE, &i2c_data);
+	if (rc < 0) {
+		ALOGE("%s: Unable to write akm8973 data", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+int akm8973_magnetic_extrema(struct akm8973_data *data, int index)
+{
+	int gain_index;
+
+	if (data == NULL || index < 0 || index >= 3)
+		return -EINVAL;
+
+	gain_index = data->gain_indexes[index];
+	if (gain_index < 0 || gain_index >= akm8973_gain_coefficient_count)
+		return -1;
+
+	// Calculate the extrema from HO (software offset)
+	data->magnetic_extrema[0][index] = (unsigned char) ((int) ((16.0f * -45.0f) / akm8973_gain_coefficient[gain_index] + 128 + data->ho[index] / 16.0f + 10.0f) & 0xff);
+	data->magnetic_extrema[1][index] = (unsigned char) ((int) ((16.0f * 45.0f) / akm8973_gain_coefficient[gain_index] + 128 + data->ho[index] / 16.0f - 10.0f) & 0xff);
+
+	return 0;
+}
+
+int akm8973_config_read(struct akm8973_data *data)
+{
+	char buffer[256] = { 0 };
+	int config_fd = -1;
+	int offset = 0;
+	int length;
+	int count;
+	int value;
+	char *p;
+	int rc;
+
+	if (data == NULL)
+		return -EINVAL;
+
+	config_fd = open(AKM8973_CONFIG_PATH, O_RDONLY);
+	if (config_fd < 0) {
+		ALOGE("%s: Unable to open akm8973 config %d %s", __func__, errno, strerror(errno));
+		goto error;
+	}
+
+	rc = 0;
+
+	do {
+		lseek(config_fd, offset, SEEK_SET);
+
+		length = read(config_fd, buffer, sizeof(buffer));
+		if (length <= 0)
+			break;
+
+		p = strchr((const char *) &buffer, '\n');
+		if (p != NULL) {
+			offset += (int) p - (int) buffer + 1;
+			*p = '\0';
+		} else if ((size_t) length < sizeof(buffer)) {
+			buffer[length] = '\0';
+		}
+
+		count = sscanf((char const *) &buffer, "HSUC_HDAC_FORM0.x = %d", &value);
+		if (count == 1) {
+			data->hdac[0] = (unsigned char) (value & 0xff);
+			rc |= 1;
+		}
+
+		count = sscanf((char const *) &buffer, "HSUC_HDAC_FORM0.y = %d", &value);
+		if (count == 1) {
+			data->hdac[1] = (unsigned char) (value & 0xff);
+			rc |= 1;
+		}
+
+		count = sscanf((char const *) &buffer, "HSUC_HDAC_FORM0.z = %d", &value);
+		if (count == 1) {
+			data->hdac[2] = (unsigned char) (value & 0xff);
+			rc |= 1;
+		}
+
+		count = sscanf((char const *) &buffer, "HSUC_HO_FORM0.x = %d", &value);
+		if (count == 1) {
+			data->ho[0] = value;
+			rc |= akm8973_magnetic_extrema(data, 0);
+		}
+
+		count = sscanf((char const *) &buffer, "HSUC_HO_FORM0.y = %d", &value);
+		if (count == 1) {
+			data->ho[1] = value;
+			rc |= akm8973_magnetic_extrema(data, 1);
+		}
+
+		count = sscanf((char const *) &buffer, "HSUC_HO_FORM0.z = %d", &value);
+		if (count == 1) {
+			data->ho[2] = value;
+			rc |= akm8973_magnetic_extrema(data, 2);
+		}
+	} while (p != NULL && length > 0);
+
+	goto complete;
+
+error:
+	rc = -1;
+
+complete:
+	if (config_fd >= 0)
+		close(config_fd);
+
+	return rc;
+}
+
+int akm8973_config_write(struct akm8973_data *data)
+{
+	char buffer[256] = { 0 };
+	int config_fd = -1;
+	int length;
+	int value;
+	int rc;
+
+	if (data == NULL)
+		return -EINVAL;
+
+	config_fd = open(AKM8973_CONFIG_PATH, O_WRONLY | O_TRUNC | O_CREAT, 0664);
+	if (config_fd < 0) {
+		ALOGE("%s: Unable to open akm8973 config", __func__);
+		goto error;
+	}
+
+	value = (int) data->hdac[0];
+	length = snprintf((char *) &buffer, sizeof(buffer), "HSUC_HDAC_FORM0.x = %d\n", value);
+
+	rc = write(config_fd, buffer, length);
+	if (rc < length) {
+		ALOGE("%s: Unable to write akm8973 config", __func__);
+		goto error;
+	}
+
+	value = (int) data->hdac[1];
+	length = snprintf((char *) &buffer, sizeof(buffer), "HSUC_HDAC_FORM0.y = %d\n", value);
+
+	rc = write(config_fd, buffer, length);
+	if (rc < length) {
+		ALOGE("%s: Unable to write akm8973 config", __func__);
+		goto error;
+	}
+
+	value = (int) data->hdac[2];
+	length = snprintf((char *) &buffer, sizeof(buffer), "HSUC_HDAC_FORM0.z = %d\n", value);
+
+	rc = write(config_fd, buffer, length);
+	if (rc < length) {
+		ALOGE("%s: Unable to write akm8973 config", __func__);
+		goto error;
+	}
+
+	value = (int) data->ho[0];
+	length = snprintf((char *) &buffer, sizeof(buffer), "HSUC_HO_FORM0.x = %d\n", value);
+
+	rc = write(config_fd, buffer, length);
+	if (rc < length) {
+		ALOGE("%s: Unable to write akm8973 config", __func__);
+		goto error;
+	}
+
+	value = (int) data->ho[1];
+	length = snprintf((char *) &buffer, sizeof(buffer), "HSUC_HO_FORM0.y = %d\n", value);
+
+	rc = write(config_fd, buffer, length);
+	if (rc < length) {
+		ALOGE("%s: Unable to write akm8973 config", __func__);
+		goto error;
+	}
+
+	value = (int) data->ho[2];
+	length = snprintf((char *) &buffer, sizeof(buffer), "HSUC_HO_FORM0.z = %d\n", value);
+
+	rc = write(config_fd, buffer, length);
+	if (rc < length) {
+		ALOGE("%s: Unable to write akm8973 config", __func__);
+		goto error;
+	}
+
+	rc = 0;
+	goto complete;
+
+error:
+	rc = -1;
+
+complete:
+	if (config_fd >= 0)
+		close(config_fd);
+
+	return rc;
+}
+
+int akm8973_hdac_calibration(struct akm8973_data *data,
+	unsigned char *magnetic_data, size_t magnetic_data_size)
+{
+	unsigned char value;
+	int update;
+	int rc;
+	int i;
+
+	if (data == NULL || magnetic_data == NULL || magnetic_data_size < 3)
+		return -EINVAL;
+
+	update = 0;
+
+	for (i = 0; i < 3; i++) {
+		// Transform non-linear HDAC to a linear value
+		if (data->hdac[i] == 0)
+			value = 0x80;
+		else if (data->hdac[i] < 0x80)
+			value = 0x80 - data->hdac[i];
+		else
+			value = data->hdac[i];
+
+		// Adjust the (linear) HDAC offset if the value is out of range.
+		// The correct range is [50;205] (in raw magnetic data).
+
+		if (magnetic_data[i] < 50 ) {
+			if (value > (0xff - 4))
+				continue;
+
+			if (magnetic_data[i] < 10)
+				value += 4;
+			else if (magnetic_data[i] < 20)
+				value += 3;
+			else if (magnetic_data[i] < 30)
+				value += 2;
+			else
+				value += 1;
+
+			update = 1;
+		}
+
+		if (magnetic_data[i] > 205) {
+			if (value < (0x00 + 4))
+				continue;
+
+			if (magnetic_data[i] > 245)
+				value -= 4;
+			else if (magnetic_data[i] > 235)
+				value -= 3;
+			else if (magnetic_data[i] > 225)
+				value -= 2;
+			else
+				value -= 1;
+
+			update = 1;
+		}
+
+		if (update) {
+			// When the HDAC (hardware offset) value is changed, the HO value and magnetic extrema become irrelevant.
+			// We can calculate HO (software offset) from HDAC but it'll need to be finely tuned later on.
+
+			data->magnetic_extrema[0][i] = 0;
+			data->magnetic_extrema[1][i] = 0;
+
+			// Transform linear value to non-linear HDAC
+			if (value == 0x80) {
+				data->hdac[i] = 0;
+				data->ho[i] = 0;
+			} else if (value < 0x80) {
+				data->hdac[i] = 0x80 - value;
+				data->ho[i] = data->hdac[i] * -1 * 16 * 16;
+			} else {
+				data->hdac[i] = value;
+				data->ho[i] = (data->hdac[i] - 128) * 16 * 16;
+			}
+		}
+	}
+
+	if (update) {
+		rc = akm8973_hdac(data);
+		if (rc < 0) {
+			ALOGE("%s: Unable to set akm8973 HDAC", __func__);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+int akm8973_ho_calibration(struct akm8973_data *data,
+	unsigned char *magnetic_data, size_t magnetic_data_size)
+{
+	float ho[2];
+	int gain_index;
+	int i;
+
+	if (data == NULL || magnetic_data == NULL || magnetic_data_size < 3)
+		return -EINVAL;
+
+	// Update the extrema from the current raw magnetic data
+	for (i = 0; i < 3; i++) {
+		if (magnetic_data[i] < data->magnetic_extrema[0][i] || data->magnetic_extrema[0][i] == 0)
+			data->magnetic_extrema[0][i] = magnetic_data[i];
+		if (magnetic_data[i] > data->magnetic_extrema[1][i] || data->magnetic_extrema[1][i] == 0)
+			data->magnetic_extrema[1][i] = magnetic_data[i];
+	}
+
+	// Calculate HO (software offset)
+	if (data->magnetic_data_count % 10 == 0) {
+		for (i = 0; i < 3; i++) {
+			gain_index = data->gain_indexes[i];
+			if (gain_index < 0 || gain_index >= akm8973_gain_coefficient_count)
+				continue;
+
+			// Calculate offset for minimum to be at -45uT
+			ho[0] = ((float) (data->magnetic_extrema[0][i] - 0x80) + (16.0f * 45.0f) / akm8973_gain_coefficient[gain_index] ) * 16.0f;
+			// Calculate offset for maximum to be at +45uT
+			ho[1] = ((float) (data->magnetic_extrema[1][i] - 0x80) - (16.0f * 45.0f) / akm8973_gain_coefficient[gain_index] ) * 16.0f;
+			// Average offset to make everyone (mostly) happy
+			data->ho[i] = (int) (ho[0] + ho[1]) / 2.0f;
+		}
+	}
+
+	return 0;
+}
+
+int akm8973_magnetic_axis(struct akm8973_data *data, int index, float *axis)
+{
+	float value;
+	int count;
+	int gain_index;
+	int i;
+
+	if (data == NULL || axis == NULL || index < 0 || index >= 3)
+		return -EINVAL;
+
+	count = data->magnetic_data_count >= 4 ? 4 : data->magnetic_data_count;
+	value = 0;
+
+	// Average the last 4 (or less) raw magnetic values
+	for (i = 0; i < count; i++)
+		value += (float) data->magnetic_data[i][index];
+	value /= count;
+
+	gain_index = data->gain_indexes[index];
+	if (gain_index < 0 || gain_index >= akm8973_gain_coefficient_count)
+		return -1;
+
+	// Formula to get the magnetic field in uT from the raw magnetic value, HO and coefficient from gain
+	*axis = ((value - 128 - ((float) data->ho[index] / 16.0f)) * akm8973_gain_coefficient[gain_index]) / 16.0f;
+
+	return 0;
+}
+
+int akm8973_magnetic(struct akm8973_data *data)
+{
+	int rc;
+
+	if (data == NULL)
+		return -EINVAL;
+
+	rc = 0;
+	rc |= akm8973_magnetic_axis(data, 0, &data->magnetic.x);
+	rc |= akm8973_magnetic_axis(data, 1, &data->magnetic.y);
+	rc |= akm8973_magnetic_axis(data, 2, &data->magnetic.z);
+
+	return rc;
+}
+
+void *akm8973_thread(void *thread_data)
+{
+	struct herring_sensors_handlers *handlers = NULL;
+	struct akm8973_data *data = NULL;
+	struct input_event event;
+	struct timeval time;
+	char i2c_data[SENSOR_DATA_SIZE] = { 0 };
+	unsigned char magnetic_data[3] = { 0 };
+	int index;
+	int value;
+	short mode;
+	long int before, after;
+	int diff;
+	int device_fd;
+	int uinput_fd;
+	int rc;
+	int i, j;
+
+	if (thread_data == NULL)
+		return NULL;
+
+	handlers = (struct herring_sensors_handlers *) thread_data;
+	if (handlers->data == NULL)
+		return NULL;
+
+	data = (struct akm8973_data *) handlers->data;
+
+	device_fd = data->device_fd;
+	if (device_fd < 0)
+		return NULL;
+
+	uinput_fd = data->uinput_fd;
+	if (uinput_fd < 0)
+		return NULL;
+
+	while (data->thread_continue) {
+		pthread_mutex_lock(&data->mutex);
+		if (!data->thread_continue)
+			break;
+
+		while (handlers->activated) {
+			gettimeofday(&time, NULL);
+			before = timestamp(&time);
+
+			mode = AK8973_MODE_MEASURE;
+			rc = ioctl(device_fd, ECS_IOCTL_SET_MODE, &mode);
+			if (rc < 0) {
+				ALOGE("%s: Unable to set akm8973 mode", __func__);
+				goto next;
+			}
+
+			memset(&i2c_data, 0, sizeof(i2c_data));
+			rc = ioctl(device_fd, ECS_IOCTL_GETDATA, &i2c_data);
+			if (rc < 0) {
+				ALOGE("%s: Unable to get akm8973 data", __func__);
+				goto next;
+			}
+
+			if (!(i2c_data[0] & 0x01)) {
+				ALOGE("%s: akm8973 data is not ready", __func__);
+				goto next;
+			}
+
+			magnetic_data[0] = (unsigned char) i2c_data[2];
+			magnetic_data[1] = (unsigned char) i2c_data[3];
+			magnetic_data[2] = (unsigned char) i2c_data[4];
+
+			rc = akm8973_hdac_calibration(data, (unsigned char *) &magnetic_data, sizeof(magnetic_data));
+			if (rc < 0) {
+				ALOGE("%s: Unable to calibrate akm8973 HDAC", __func__);
+				goto next;
+			}
+
+			index = data->magnetic_data_index;
+
+			data->magnetic_data[index][0] = magnetic_data[0];
+			data->magnetic_data[index][1] = magnetic_data[1];
+			data->magnetic_data[index][2] = magnetic_data[2];
+
+			data->magnetic_data_index = (index + 1) % 4;
+			data->magnetic_data_count++;
+
+			rc = akm8973_ho_calibration(data, (unsigned char *) &magnetic_data, sizeof(magnetic_data));
+			if (rc < 0) {
+				ALOGE("%s: Unable to calibrate akm8973 HO", __func__);
+				goto next;
+			}
+
+			rc = akm8973_magnetic(data);
+			if (rc < 0) {
+				ALOGE("%s: Unable to get akm8973 magnetic", __func__);
+				goto next;
+			}
+
+			input_event_set(&event, EV_REL, REL_X, (int) (data->magnetic.x * 1000));
+			write(uinput_fd, &event, sizeof(event));
+			input_event_set(&event, EV_REL, REL_Y, (int) (data->magnetic.y * 1000));
+			write(uinput_fd, &event, sizeof(event));
+			input_event_set(&event, EV_REL, REL_Z, (int) (data->magnetic.z * 1000));
+			write(uinput_fd, &event, sizeof(event));
+			input_event_set(&event, EV_SYN, 0, 0);
+			write(uinput_fd, &event, sizeof(event));
+
+next:
+			gettimeofday(&time, NULL);
+			after = timestamp(&time);
+
+			diff = (int) (data->delay - (after - before)) / 1000;
+			if (diff <= 0)
+				continue;
+
+			usleep(diff);
+		}
+	}
+	return NULL;
+}
+
+int akm8973_init(struct herring_sensors_handlers *handlers,
+	struct herring_sensors_device *device)
+{
+	struct akm8973_data *data = NULL;
+	pthread_attr_t thread_attr;
+	char i2c_data[RWBUF_SIZE] = { 0 };
+	char mode;
+	int device_fd = -1;
+	int uinput_fd = -1;
+	int input_fd = -1;
+	int rc;
+	int i;
+
+	ALOGD("%s(%p, %p)", __func__, handlers, device);
+
+	if (handlers == NULL || device == NULL)
+		return -EINVAL;
+
+	data = (struct akm8973_data *) calloc(1, sizeof(struct akm8973_data));
+
+	for (i = 0; i < device->handlers_count; i++) {
+		if (device->handlers[i] == NULL)
+			continue;
+
+		if (device->handlers[i]->handle == SENSOR_TYPE_ORIENTATION)
+			data->orientation_sensor = device->handlers[i];
+	}
+
+	device_fd = open("/dev/akm8973", O_RDONLY);
+	if (device_fd < 0) {
+		ALOGE("%s: Unable to open device", __func__);
+		goto error;
+	}
+
+	rc = ioctl(device_fd, ECS_IOCTL_RESET, NULL);
+	if (rc < 0) {
+		ALOGE("%s: Unable to reset akm8973", __func__);
+		goto error;
+	}
+
+	mode = AK8973_MODE_E2P_READ;
+	rc = ioctl(device_fd, ECS_IOCTL_SET_MODE, &mode);
+	if (rc < 0) {
+		ALOGE("%s: Unable to set akm8973 mode", __func__);
+		goto error;
+	}
+
+	i2c_data[0] = 3;
+	i2c_data[1] = AK8973_EEP_EHXGA;
+	rc = ioctl(device_fd, ECS_IOCTL_READ, &i2c_data);
+	if (rc < 0) {
+		ALOGE("%s: Unable to read akm8973 EEPROM data", __func__);
+		goto error;
+	}
+
+	data->gain_indexes[0] = (i2c_data[1] & 0xf0) >> 4;
+	data->gain_indexes[1] = (i2c_data[2] & 0xf0) >> 4;
+	data->gain_indexes[2] = (i2c_data[3] & 0xf0) >> 4;
+
+	ALOGD("AKM8973 gain indexes are: (%d, %d, %d)", data->gain_indexes[0],
+		data->gain_indexes[1], data->gain_indexes[2]);
+
+	mode = AK8973_MODE_POWERDOWN;
+	rc = ioctl(device_fd, ECS_IOCTL_SET_MODE, &mode);
+	if (rc < 0) {
+		ALOGE("%s: Unable to set akm8973 mode", __func__);
+		goto error;
+	}
+
+	i2c_data[5] = i2c_data[1] & 0x0f;
+	i2c_data[6] = i2c_data[2] & 0x0f;
+	i2c_data[7] = i2c_data[3] & 0x0f;
+
+	i2c_data[0] = 7;
+	i2c_data[1] = AK8973_REG_HXDA;
+
+	i2c_data[2] = 0;
+	i2c_data[3] = 0;
+	i2c_data[4] = 0;
+
+	rc = ioctl(device_fd, ECS_IOCTL_WRITE, &i2c_data);
+	if (rc < 0) {
+		ALOGE("%s: Unable to write akm8973 data", __func__);
+		goto error;
+	}
+
+	uinput_fd = uinput_rel_create("magnetic");
+	if (uinput_fd < 0) {
+		ALOGD("%s: Unable to create uinput", __func__);
+		goto error;
+	}
+
+	input_fd = input_open("magnetic");
+	if (input_fd < 0) {
+		ALOGE("%s: Unable to open magnetic input", __func__);
+		goto error;
+	}
+
+	data->thread_continue = 1;
+
+	pthread_mutex_init(&data->mutex, NULL);
+	pthread_mutex_lock(&data->mutex);
+
+	pthread_attr_init(&thread_attr);
+	pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
+
+	rc = pthread_create(&data->thread, &thread_attr, akm8973_thread, (void *) handlers);
+	if (rc < 0) {
+		ALOGE("%s: Unable to create akm8973 thread", __func__);
+		pthread_mutex_destroy(&data->mutex);
+		goto error;
+	}
+
+	data->device_fd = device_fd;
+	data->uinput_fd = uinput_fd;
+	handlers->poll_fd = input_fd;
+	handlers->data = (void *) data;
+
+	return 0;
+
+error:
+	if (data != NULL)
+		free(data);
+
+	if (uinput_fd >= 0)
+		close(uinput_fd);
+
+	if (input_fd >= 0)
+		close(input_fd);
+
+	if (device_fd >= 0)
+		close(device_fd);
+
+	handlers->poll_fd = -1;
+	handlers->data = NULL;
+
+	return -1;
+}
+
+int akm8973_deinit(struct herring_sensors_handlers *handlers)
+{
+	struct akm8973_data *data = NULL;
+	char mode;
+	int rc;
+
+	ALOGD("%s(%p)", __func__, handlers);
+
+	if (handlers == NULL || handlers->data == NULL)
+		return -EINVAL;
+
+	data = (struct akm8973_data *) handlers->data;
+
+	handlers->activated = 0;
+	data->thread_continue = 0;
+	pthread_mutex_unlock(&data->mutex);
+
+	pthread_mutex_destroy(&data->mutex);
+
+	if (data->uinput_fd >= 0) {
+		uinput_destroy(data->uinput_fd);
+		close(data->uinput_fd);
+	}
+	data->uinput_fd = -1;
+
+	if (handlers->poll_fd >= 0)
+		close(handlers->poll_fd);
+	handlers->poll_fd = -1;
+
+	mode = AK8973_MODE_POWERDOWN;
+	rc = ioctl(data->device_fd, ECS_IOCTL_SET_MODE, &mode);
+	if (rc < 0)
+		ALOGE("%s: Unable to set akm8973 mode", __func__);
+
+	if (data->device_fd >= 0)
+		close(data->device_fd);
+	data->device_fd = -1;
+
+	free(handlers->data);
+	handlers->data = NULL;
+
+	return 0;
+}
+
+int akm8973_activate(struct herring_sensors_handlers *handlers)
+{
+	struct akm8973_data *data;
+	int rc;
+
+	ALOGD("%s(%p)", __func__, handlers);
+
+	if (handlers == NULL || handlers->data == NULL)
+		return -EINVAL;
+
+	data = (struct akm8973_data *) handlers->data;
+
+	rc = akm8973_config_read(data);
+	if (rc < 0) {
+		ALOGE("%s: Unable to read akm8973 config", __func__);
+	} else if (rc > 0) {
+		rc = akm8973_hdac(data);
+		if (rc < 0) {
+			ALOGE("%s: Unable to set akm8973 HDAC", __func__);
+			return -1;
+		}
+	}
+
+	handlers->activated = 1;
+	pthread_mutex_unlock(&data->mutex);
+
+	return 0;
+}
+
+int akm8973_deactivate(struct herring_sensors_handlers *handlers)
+{
+	struct akm8973_data *data;
+	int device_fd;
+	char mode;
+	int empty;
+	int rc;
+	int i;
+
+	ALOGD("%s(%p)", __func__, handlers);
+
+	if (handlers == NULL || handlers->data == NULL)
+		return -EINVAL;
+
+	data = (struct akm8973_data *) handlers->data;
+
+	empty = 1;
+
+	for (i = 0; i < (ssize_t) sizeof(data->magnetic_extrema) / 2; i++) {
+		if (data->magnetic_extrema[0][i] != 0 || data->magnetic_extrema[1][i] != 0) {
+			empty = 0;
+			break;
+		}
+	}
+
+	if (!empty) {
+		rc = akm8973_config_write(data);
+		if (rc < 0)
+			ALOGE("%s: Unable to write akm8973 config", __func__);
+	}
+
+	device_fd = data->device_fd;
+	if (device_fd < 0)
+		return -1;
+
+	mode = AK8973_MODE_POWERDOWN;
+	rc = ioctl(data->device_fd, ECS_IOCTL_SET_MODE, &mode);
+	if (rc < 0)
+		ALOGE("%s: Unable to set akm8973 mode", __func__);
+
+	handlers->activated = 0;
+
+	return 0;
+}
+
+int akm8973_set_delay(struct herring_sensors_handlers *handlers, long int delay)
+{
+	struct akm8973_data *data;
+
+	ALOGD("%s(%p, %ld)", __func__, handlers, delay);
+
+	if (handlers == NULL || handlers->data == NULL)
+		return -EINVAL;
+
+	data = (struct akm8973_data *) handlers->data;
+
+	data->delay = delay;
+
+	return 0;
+}
+
+float akm8973_convert(int value)
+{
+	return (float) value / -1000.0f;
+}
+
+int akm8973_get_data(struct herring_sensors_handlers *handlers,
+	struct sensors_event_t *event)
+{
+	struct akm8973_data *data;
+	struct input_event input_event;
+	int input_fd;
+	int rc;
+
+//	ALOGD("%s(%p, %p)", __func__, handlers, event);
+
+	if (handlers == NULL || handlers->data == NULL || event == NULL)
+		return -EINVAL;
+
+	data = (struct akm8973_data *) handlers->data;
+
+	input_fd = handlers->poll_fd;
+	if (input_fd < 0)
+		return -1;
+
+	memset(event, 0, sizeof(struct sensors_event_t));
+	event->version = sizeof(struct sensors_event_t);
+	event->sensor = handlers->handle;
+	event->type = handlers->handle;
+
+	event->magnetic.status = SENSOR_STATUS_ACCURACY_MEDIUM;
+
+	do {
+		rc = read(input_fd, &input_event, sizeof(input_event));
+		if (rc < (int) sizeof(input_event))
+			break;
+
+		if (input_event.type == EV_REL) {
+			switch (input_event.code) {
+				case REL_X:
+					event->magnetic.y = akm8973_convert(input_event.value);
+					break;
+				case REL_Y:
+					event->magnetic.x = akm8973_convert(input_event.value);
+					break;
+				case REL_Z:
+					event->magnetic.z = akm8973_convert(input_event.value);
+					break;
+				default:
+					continue;
+			}
+		} 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);
+
+	if (data->orientation_sensor != NULL)
+		orientation_fill(data->orientation_sensor, NULL, &event->magnetic);
+
+	return 0;
+}
+
+struct herring_sensors_handlers akm8973 = {
+	.name = "AKM8973",
+	.handle = SENSOR_TYPE_MAGNETIC_FIELD,
+	.init = akm8973_init,
+	.deinit = akm8973_deinit,
+	.activate = akm8973_activate,
+	.deactivate = akm8973_deactivate,
+	.set_delay = akm8973_set_delay,
+	.get_data = akm8973_get_data,
+	.activated = 0,
+	.needed = 0,
+	.poll_fd = -1,
+	.data = NULL,
+};