drivers/sensor/sensor_lis3mdl.c

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * 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.
 */

#include <i2c.h>
#include <init.h>
#include <misc/__assert.h>
#include <misc/byteorder.h>
#include <sensor.h>
#include <string.h>

#include "sensor_lis3mdl.h"

static void lis3mdl_convert(struct sensor_value *val, int16_t raw_val,
			    uint16_t divider)
{
	/* val = raw_val / divider */
	val->type = SENSOR_VALUE_TYPE_INT_PLUS_MICRO;
	val->val1 = raw_val / divider;
	val->val2 = (((int64_t)raw_val % divider) * 1000000L) / divider;
}

static int lis3mdl_channel_get(struct device *dev,
			       enum sensor_channel chan,
			       struct sensor_value *val)
{
	struct lis3mdl_data *drv_data = dev->driver_data;

	if (chan == SENSOR_CHAN_MAGN_ANY) {
		/* magn_val = sample / mang_gain */
		lis3mdl_convert(val, drv_data->x_sample,
				lis3mdl_magn_gain[LIS3MDL_FS_IDX]);
		lis3mdl_convert(val + 1, drv_data->y_sample,
				lis3mdl_magn_gain[LIS3MDL_FS_IDX]);
		lis3mdl_convert(val + 2, drv_data->z_sample,
				lis3mdl_magn_gain[LIS3MDL_FS_IDX]);
	} else if (chan == SENSOR_CHAN_MAGN_X) {
		lis3mdl_convert(val, drv_data->x_sample,
				lis3mdl_magn_gain[LIS3MDL_FS_IDX]);
	} else if (chan == SENSOR_CHAN_MAGN_Y) {
		lis3mdl_convert(val, drv_data->y_sample,
				lis3mdl_magn_gain[LIS3MDL_FS_IDX]);
	} else if (chan == SENSOR_CHAN_MAGN_Z) {
		lis3mdl_convert(val, drv_data->z_sample,
				lis3mdl_magn_gain[LIS3MDL_FS_IDX]);
	} else { /* chan == SENSOR_CHAN_TEMP */
		/* temp_val = 25 + sample / 8 */
		lis3mdl_convert(val, drv_data->temp_sample, 8);
		val->val1 += 25;
	}

	return 0;
}

int lis3mdl_sample_fetch(struct device *dev, enum sensor_channel chan)
{
	struct lis3mdl_data *drv_data = dev->driver_data;
	int16_t buf[4];

	__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);

	/* fetch magnetometer sample */
	if (i2c_burst_read(drv_data->i2c, CONFIG_LIS3MDL_I2C_ADDR,
			   LIS3MDL_REG_SAMPLE_START, (uint8_t *)buf, 8) < 0) {
		SYS_LOG_DBG("Failed to fetch megnetometer sample.");
		return -EIO;
	}

	/*
	 * the chip doesn't allow fetching temperature data in
	 * the same read as magnetometer data, so do another
	 * burst read to fetch the temperature sample
	 */
	if (i2c_burst_read(drv_data->i2c, CONFIG_LIS3MDL_I2C_ADDR,
			   LIS3MDL_REG_SAMPLE_START + 6,
			   (uint8_t *)(buf + 3), 2) < 0) {
		SYS_LOG_DBG("Failed to fetch temperature sample.");
		return -EIO;
	};

	drv_data->x_sample = sys_le16_to_cpu(buf[0]);
	drv_data->y_sample = sys_le16_to_cpu(buf[1]);
	drv_data->z_sample = sys_le16_to_cpu(buf[2]);
	drv_data->temp_sample = sys_le16_to_cpu(buf[3]);

	return 0;
}

static struct sensor_driver_api lis3mdl_driver_api = {
#if CONFIG_LIS3MDL_TRIGGER
	.trigger_set = lis3mdl_trigger_set,
#endif
	.sample_fetch = lis3mdl_sample_fetch,
	.channel_get = lis3mdl_channel_get,
};

int lis3mdl_init(struct device *dev)
{
	struct lis3mdl_data *drv_data = dev->driver_data;
	uint8_t chip_cfg[5];
	uint8_t id, idx;

	drv_data->i2c = device_get_binding(CONFIG_LIS3MDL_I2C_MASTER_DEV_NAME);
	if (drv_data->i2c == NULL) {
		SYS_LOG_ERR("Could not get pointer to %s device.",
			    CONFIG_LIS3MDL_I2C_MASTER_DEV_NAME);
		return -EINVAL;
	}

	/* check chip ID */
	if (i2c_reg_read_byte(drv_data->i2c, CONFIG_LIS3MDL_I2C_ADDR,
			      LIS3MDL_REG_WHO_AM_I, &id) < 0) {
		SYS_LOG_ERR("Failed to read chip ID.");
		return -EIO;
	}

	if (id != LIS3MDL_CHIP_ID) {
		SYS_LOG_ERR("Invalid chip ID.");
		return -EINVAL;
	}

	/* check if CONFIG_LIS3MDL_ODR is valid */
	for (idx = 0; idx < ARRAY_SIZE(lis3mdl_odr_strings); idx++) {
		if (!strcmp(lis3mdl_odr_strings[idx], CONFIG_LIS3MDL_ODR)) {
			break;
		}
	}

	if (idx == ARRAY_SIZE(lis3mdl_odr_strings)) {
		SYS_LOG_ERR("Invalid ODR value.");
		return -EINVAL;
	}

	/* write chip configuration CTRL1-CTRL5 regs */
	chip_cfg[0] = LIS3MDL_TEMP_EN | lis3mdl_odr_bits[idx];
	chip_cfg[1] = LIS3MDL_FS_IDX << LIS3MDL_FS_SHIFT;
	chip_cfg[2] = lis3mdl_odr_bits[idx] & LIS3MDL_FAST_ODR_MASK ?
		      LIS3MDL_MD_SINGLE : LIS3MDL_MD_CONTINUOUS;
	chip_cfg[3] = ((lis3mdl_odr_bits[idx] & LIS3MDL_OM_MASK) >>
		       LIS3MDL_OM_SHIFT) << LIS3MDL_OMZ_SHIFT;
	chip_cfg[4] = LIS3MDL_BDU_EN;

	if (i2c_burst_write(drv_data->i2c, CONFIG_LIS3MDL_I2C_ADDR,
			    LIS3MDL_REG_CTRL1, chip_cfg, 5) < 0) {
		SYS_LOG_DBG("Failed to configure chip.");
		return -EIO;
	}

#ifdef CONFIG_LIS3MDL_TRIGGER
	if (lis3mdl_init_interrupt(dev) < 0) {
		SYS_LOG_DBG("Failed to initialize interrupts.");
		return -EIO;
	}
#endif

	dev->driver_api = &lis3mdl_driver_api;

	return 0;
}

struct lis3mdl_data lis3mdl_driver;

DEVICE_INIT(lis3mdl, CONFIG_LIS3MDL_NAME, lis3mdl_init, &lis3mdl_driver,
	    NULL, SECONDARY, CONFIG_LIS3MDL_INIT_PRIORITY);