fxos8700_core.c

// SPDX-License-Identifier: GPL-2.0
/*
 * FXOS8700 - NXP IMU (accelerometer plus magnetometer)
 *
 * IIO core driver for FXOS8700, with support for I2C/SPI busses
 *
 * TODO: Buffer, trigger, and IRQ support
 */
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/acpi.h>
#include <linux/bitops.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#include "fxos8700.h"

/* Register Definitions */
#define FXOS8700_STATUS             0x00
#define FXOS8700_OUT_X_MSB          0x01
#define FXOS8700_OUT_X_LSB          0x02
#define FXOS8700_OUT_Y_MSB          0x03
#define FXOS8700_OUT_Y_LSB          0x04
#define FXOS8700_OUT_Z_MSB          0x05
#define FXOS8700_OUT_Z_LSB          0x06
#define FXOS8700_F_SETUP            0x09
#define FXOS8700_TRIG_CFG           0x0a
#define FXOS8700_SYSMOD             0x0b
#define FXOS8700_INT_SOURCE         0x0c
#define FXOS8700_WHO_AM_I           0x0d
#define FXOS8700_XYZ_DATA_CFG       0x0e
#define FXOS8700_HP_FILTER_CUTOFF   0x0f
#define FXOS8700_PL_STATUS          0x10
#define FXOS8700_PL_CFG             0x11
#define FXOS8700_PL_COUNT           0x12
#define FXOS8700_PL_BF_ZCOMP        0x13
#define FXOS8700_PL_THS_REG         0x14
#define FXOS8700_A_FFMT_CFG         0x15
#define FXOS8700_A_FFMT_SRC         0x16
#define FXOS8700_A_FFMT_THS         0x17
#define FXOS8700_A_FFMT_COUNT       0x18
#define FXOS8700_TRANSIENT_CFG      0x1d
#define FXOS8700_TRANSIENT_SRC      0x1e
#define FXOS8700_TRANSIENT_THS      0x1f
#define FXOS8700_TRANSIENT_COUNT    0x20
#define FXOS8700_PULSE_CFG          0x21
#define FXOS8700_PULSE_SRC          0x22
#define FXOS8700_PULSE_THSX         0x23
#define FXOS8700_PULSE_THSY         0x24
#define FXOS8700_PULSE_THSZ         0x25
#define FXOS8700_PULSE_TMLT         0x26
#define FXOS8700_PULSE_LTCY         0x27
#define FXOS8700_PULSE_WIND         0x28
#define FXOS8700_ASLP_COUNT         0x29
#define FXOS8700_CTRL_REG1          0x2a
#define FXOS8700_CTRL_REG2          0x2b
#define FXOS8700_CTRL_REG3          0x2c
#define FXOS8700_CTRL_REG4          0x2d
#define FXOS8700_CTRL_REG5          0x2e
#define FXOS8700_OFF_X              0x2f
#define FXOS8700_OFF_Y              0x30
#define FXOS8700_OFF_Z              0x31
#define FXOS8700_M_DR_STATUS        0x32
#define FXOS8700_M_OUT_X_MSB        0x33
#define FXOS8700_M_OUT_X_LSB        0x34
#define FXOS8700_M_OUT_Y_MSB        0x35
#define FXOS8700_M_OUT_Y_LSB        0x36
#define FXOS8700_M_OUT_Z_MSB        0x37
#define FXOS8700_M_OUT_Z_LSB        0x38
#define FXOS8700_CMP_X_MSB          0x39
#define FXOS8700_CMP_X_LSB          0x3a
#define FXOS8700_CMP_Y_MSB          0x3b
#define FXOS8700_CMP_Y_LSB          0x3c
#define FXOS8700_CMP_Z_MSB          0x3d
#define FXOS8700_CMP_Z_LSB          0x3e
#define FXOS8700_M_OFF_X_MSB        0x3f
#define FXOS8700_M_OFF_X_LSB        0x40
#define FXOS8700_M_OFF_Y_MSB        0x41
#define FXOS8700_M_OFF_Y_LSB        0x42
#define FXOS8700_M_OFF_Z_MSB        0x43
#define FXOS8700_M_OFF_Z_LSB        0x44
#define FXOS8700_MAX_X_MSB          0x45
#define FXOS8700_MAX_X_LSB          0x46
#define FXOS8700_MAX_Y_MSB          0x47
#define FXOS8700_MAX_Y_LSB          0x48
#define FXOS8700_MAX_Z_MSB          0x49
#define FXOS8700_MAX_Z_LSB          0x4a
#define FXOS8700_MIN_X_MSB          0x4b
#define FXOS8700_MIN_X_LSB          0x4c
#define FXOS8700_MIN_Y_MSB          0x4d
#define FXOS8700_MIN_Y_LSB          0x4e
#define FXOS8700_MIN_Z_MSB          0x4f
#define FXOS8700_MIN_Z_LSB          0x50
#define FXOS8700_TEMP               0x51
#define FXOS8700_M_THS_CFG          0x52
#define FXOS8700_M_THS_SRC          0x53
#define FXOS8700_M_THS_X_MSB        0x54
#define FXOS8700_M_THS_X_LSB        0x55
#define FXOS8700_M_THS_Y_MSB        0x56
#define FXOS8700_M_THS_Y_LSB        0x57
#define FXOS8700_M_THS_Z_MSB        0x58
#define FXOS8700_M_THS_Z_LSB        0x59
#define FXOS8700_M_THS_COUNT        0x5a
#define FXOS8700_M_CTRL_REG1        0x5b
#define FXOS8700_M_CTRL_REG2        0x5c
#define FXOS8700_M_CTRL_REG3        0x5d
#define FXOS8700_M_INT_SRC          0x5e
#define FXOS8700_A_VECM_CFG         0x5f
#define FXOS8700_A_VECM_THS_MSB     0x60
#define FXOS8700_A_VECM_THS_LSB     0x61
#define FXOS8700_A_VECM_CNT         0x62
#define FXOS8700_A_VECM_INITX_MSB   0x63
#define FXOS8700_A_VECM_INITX_LSB   0x64
#define FXOS8700_A_VECM_INITY_MSB   0x65
#define FXOS8700_A_VECM_INITY_LSB   0x66
#define FXOS8700_A_VECM_INITZ_MSB   0x67
#define FXOS8700_A_VECM_INITZ_LSB   0x68
#define FXOS8700_M_VECM_CFG         0x69
#define FXOS8700_M_VECM_THS_MSB     0x6a
#define FXOS8700_M_VECM_THS_LSB     0x6b
#define FXOS8700_M_VECM_CNT         0x6c
#define FXOS8700_M_VECM_INITX_MSB   0x6d
#define FXOS8700_M_VECM_INITX_LSB   0x6e
#define FXOS8700_M_VECM_INITY_MSB   0x6f
#define FXOS8700_M_VECM_INITY_LSB   0x70
#define FXOS8700_M_VECM_INITZ_MSB   0x71
#define FXOS8700_M_VECM_INITZ_LSB   0x72
#define FXOS8700_A_FFMT_THS_X_MSB   0x73
#define FXOS8700_A_FFMT_THS_X_LSB   0x74
#define FXOS8700_A_FFMT_THS_Y_MSB   0x75
#define FXOS8700_A_FFMT_THS_Y_LSB   0x76
#define FXOS8700_A_FFMT_THS_Z_MSB   0x77
#define FXOS8700_A_FFMT_THS_Z_LSB   0x78
#define FXOS8700_A_TRAN_INIT_MSB    0x79
#define FXOS8700_A_TRAN_INIT_LSB_X  0x7a
#define FXOS8700_A_TRAN_INIT_LSB_Y  0x7b
#define FXOS8700_A_TRAN_INIT_LSB_Z  0x7d
#define FXOS8700_TM_NVM_LOCK        0x7e
#define FXOS8700_NVM_DATA0_35       0x80
#define FXOS8700_NVM_DATA_BNK3      0xa4
#define FXOS8700_NVM_DATA_BNK2      0xa5
#define FXOS8700_NVM_DATA_BNK1      0xa6
#define FXOS8700_NVM_DATA_BNK0      0xa7

/* Bit definitions for FXOS8700_CTRL_REG1 */
#define FXOS8700_CTRL_ODR_MSK       0x38
#define FXOS8700_CTRL_ODR_MAX       0x00
#define FXOS8700_CTRL_ODR_MIN       GENMASK(4, 3)

/* Bit definitions for FXOS8700_M_CTRL_REG1 */
#define FXOS8700_HMS_MASK           GENMASK(1, 0)
#define FXOS8700_OS_MASK            GENMASK(4, 2)

/* Bit definitions for FXOS8700_M_CTRL_REG2 */
#define FXOS8700_MAXMIN_RST         BIT(2)
#define FXOS8700_MAXMIN_DIS_THS     BIT(3)
#define FXOS8700_MAXMIN_DIS         BIT(4)

#define FXOS8700_ACTIVE             0x01
#define FXOS8700_ACTIVE_MIN_USLEEP  4000 /* from table 6 in datasheet */

#define FXOS8700_DEVICE_ID          0xC7
#define FXOS8700_PRE_DEVICE_ID      0xC4
#define FXOS8700_DATA_BUF_SIZE      3

struct fxos8700_data {
	struct regmap *regmap;
	struct iio_trigger *trig;
	__be16 buf[FXOS8700_DATA_BUF_SIZE] __aligned(IIO_DMA_MINALIGN);
};

/* Regmap info */
static const struct regmap_range read_range[] = {
	{
		.range_min = FXOS8700_STATUS,
		.range_max = FXOS8700_A_FFMT_COUNT,
	}, {
		.range_min = FXOS8700_TRANSIENT_CFG,
		.range_max = FXOS8700_A_FFMT_THS_Z_LSB,
	},
};

static const struct regmap_range write_range[] = {
	{
		.range_min = FXOS8700_F_SETUP,
		.range_max = FXOS8700_TRIG_CFG,
	}, {
		.range_min = FXOS8700_XYZ_DATA_CFG,
		.range_max = FXOS8700_HP_FILTER_CUTOFF,
	}, {
		.range_min = FXOS8700_PL_CFG,
		.range_max = FXOS8700_A_FFMT_CFG,
	}, {
		.range_min = FXOS8700_A_FFMT_THS,
		.range_max = FXOS8700_TRANSIENT_CFG,
	}, {
		.range_min = FXOS8700_TRANSIENT_THS,
		.range_max = FXOS8700_PULSE_CFG,
	}, {
		.range_min = FXOS8700_PULSE_THSX,
		.range_max = FXOS8700_OFF_Z,
	}, {
		.range_min = FXOS8700_M_OFF_X_MSB,
		.range_max = FXOS8700_M_OFF_Z_LSB,
	}, {
		.range_min = FXOS8700_M_THS_CFG,
		.range_max = FXOS8700_M_THS_CFG,
	}, {
		.range_min = FXOS8700_M_THS_X_MSB,
		.range_max = FXOS8700_M_CTRL_REG3,
	}, {
		.range_min = FXOS8700_A_VECM_CFG,
		.range_max = FXOS8700_A_FFMT_THS_Z_LSB,
	},
};

static const struct regmap_access_table driver_read_table = {
	.yes_ranges =   read_range,
	.n_yes_ranges = ARRAY_SIZE(read_range),
};

static const struct regmap_access_table driver_write_table = {
	.yes_ranges =   write_range,
	.n_yes_ranges = ARRAY_SIZE(write_range),
};

const struct regmap_config fxos8700_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = FXOS8700_NVM_DATA_BNK0,
	.rd_table = &driver_read_table,
	.wr_table = &driver_write_table,
};
EXPORT_SYMBOL(fxos8700_regmap_config);

#define FXOS8700_CHANNEL(_type, _axis) {			\
	.type = _type,						\
	.modified = 1,						\
	.channel2 = IIO_MOD_##_axis,				\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
		BIT(IIO_CHAN_INFO_SAMP_FREQ),			\
}

enum fxos8700_accel_scale_bits {
	MODE_2G = 0,
	MODE_4G,
	MODE_8G,
};

/* scan indexes follow DATA register order */
enum fxos8700_scan_axis {
	FXOS8700_SCAN_ACCEL_X = 0,
	FXOS8700_SCAN_ACCEL_Y,
	FXOS8700_SCAN_ACCEL_Z,
	FXOS8700_SCAN_MAGN_X,
	FXOS8700_SCAN_MAGN_Y,
	FXOS8700_SCAN_MAGN_Z,
	FXOS8700_SCAN_RHALL,
	FXOS8700_SCAN_TIMESTAMP,
};

enum fxos8700_sensor {
	FXOS8700_ACCEL	= 0,
	FXOS8700_MAGN,
	FXOS8700_NUM_SENSORS /* must be last */
};

enum fxos8700_int_pin {
	FXOS8700_PIN_INT1,
	FXOS8700_PIN_INT2
};

struct fxos8700_scale {
	u8 bits;
	int uscale;
};

struct fxos8700_odr {
	u8 bits;
	int odr;
	int uodr;
};

static const struct fxos8700_scale fxos8700_accel_scale[] = {
	{ MODE_2G, 244},
	{ MODE_4G, 488},
	{ MODE_8G, 976},
};

/*
 * Accellerometer and magnetometer have the same ODR options, set in the
 * CTRL_REG1 register. ODR is halved when using both sensors at once in
 * hybrid mode.
 */
static const struct fxos8700_odr fxos8700_odr[] = {
	{0x00, 800, 0},
	{0x01, 400, 0},
	{0x02, 200, 0},
	{0x03, 100, 0},
	{0x04, 50, 0},
	{0x05, 12, 500000},
	{0x06, 6, 250000},
	{0x07, 1, 562500},
};

static const struct iio_chan_spec fxos8700_channels[] = {
	FXOS8700_CHANNEL(IIO_ACCEL, X),
	FXOS8700_CHANNEL(IIO_ACCEL, Y),
	FXOS8700_CHANNEL(IIO_ACCEL, Z),
	FXOS8700_CHANNEL(IIO_MAGN, X),
	FXOS8700_CHANNEL(IIO_MAGN, Y),
	FXOS8700_CHANNEL(IIO_MAGN, Z),
	IIO_CHAN_SOFT_TIMESTAMP(FXOS8700_SCAN_TIMESTAMP),
};

static enum fxos8700_sensor fxos8700_to_sensor(enum iio_chan_type iio_type)
{
	switch (iio_type) {
	case IIO_ACCEL:
		return FXOS8700_ACCEL;
	case IIO_MAGN:
		return FXOS8700_MAGN;
	default:
		return -EINVAL;
	}
}

static int fxos8700_set_active_mode(struct fxos8700_data *data,
				    enum fxos8700_sensor t, bool mode)
{
	int ret;

	ret = regmap_write(data->regmap, FXOS8700_CTRL_REG1, mode);
	if (ret)
		return ret;

	usleep_range(FXOS8700_ACTIVE_MIN_USLEEP,
		     FXOS8700_ACTIVE_MIN_USLEEP + 1000);

	return 0;
}

static int fxos8700_set_scale(struct fxos8700_data *data,
			      enum fxos8700_sensor t, int uscale)
{
	int i, ret, val;
	bool active_mode;
	static const int scale_num = ARRAY_SIZE(fxos8700_accel_scale);
	struct device *dev = regmap_get_device(data->regmap);

	if (t == FXOS8700_MAGN) {
		dev_err(dev, "Magnetometer scale is locked at 1200uT\n");
		return -EINVAL;
	}

	/*
	 * When device is in active mode, it failed to set an ACCEL
	 * full-scale range(2g/4g/8g) in FXOS8700_XYZ_DATA_CFG.
	 * This is not align with the datasheet, but it is a fxos8700
	 * chip behavier. Set the device in standby mode before setting
	 * an ACCEL full-scale range.
	 */
	ret = regmap_read(data->regmap, FXOS8700_CTRL_REG1, &val);
	if (ret)
		return ret;

	active_mode = val & FXOS8700_ACTIVE;
	if (active_mode) {
		ret = regmap_write(data->regmap, FXOS8700_CTRL_REG1,
				   val & ~FXOS8700_ACTIVE);
		if (ret)
			return ret;
	}

	for (i = 0; i < scale_num; i++)
		if (fxos8700_accel_scale[i].uscale == uscale)
			break;

	if (i == scale_num)
		return -EINVAL;

	ret = regmap_write(data->regmap, FXOS8700_XYZ_DATA_CFG,
			    fxos8700_accel_scale[i].bits);
	if (ret)
		return ret;
	return regmap_write(data->regmap, FXOS8700_CTRL_REG1,
				  active_mode);
}

static int fxos8700_get_scale(struct fxos8700_data *data,
			      enum fxos8700_sensor t, int *uscale)
{
	int i, ret, val;
	static const int scale_num = ARRAY_SIZE(fxos8700_accel_scale);

	if (t == FXOS8700_MAGN) {
		*uscale = 1200; /* Magnetometer is locked at 1200uT */
		return 0;
	}

	ret = regmap_read(data->regmap, FXOS8700_XYZ_DATA_CFG, &val);
	if (ret)
		return ret;

	for (i = 0; i < scale_num; i++) {
		if (fxos8700_accel_scale[i].bits == (val & 0x3)) {
			*uscale = fxos8700_accel_scale[i].uscale;
			return 0;
		}
	}

	return -EINVAL;
}

static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
			     int axis, int *val)
{
	u8 base, reg;
	s16 tmp;
	int ret;

	/*
	 * Different register base addresses varies with channel types.
	 * This bug hasn't been noticed before because using an enum is
	 * really hard to read. Use an a switch statement to take over that.
	 */
	switch (chan_type) {
	case IIO_ACCEL:
		base = FXOS8700_OUT_X_MSB;
		break;
	case IIO_MAGN:
		base = FXOS8700_M_OUT_X_MSB;
		break;
	default:
		return -EINVAL;
	}

	/* Block read 6 bytes of device output registers to avoid data loss */
	ret = regmap_bulk_read(data->regmap, base, data->buf,
			       sizeof(data->buf));
	if (ret)
		return ret;

	/* Convert axis to buffer index */
	reg = axis - IIO_MOD_X;

	/*
	 * Convert to native endianness. The accel data and magn data
	 * are signed, so a forced type conversion is needed.
	 */
	tmp = be16_to_cpu(data->buf[reg]);

	/*
	 * ACCEL output data registers contain the X-axis, Y-axis, and Z-axis
	 * 14-bit left-justified sample data and MAGN output data registers
	 * contain the X-axis, Y-axis, and Z-axis 16-bit sample data. Apply
	 * a signed 2 bits right shift to the readback raw data from ACCEL
	 * output data register and keep that from MAGN sensor as the origin.
	 * Value should be extended to 32 bit.
	 */
	switch (chan_type) {
	case IIO_ACCEL:
		tmp = tmp >> 2;
		break;
	case IIO_MAGN:
		/* Nothing to do */
		break;
	default:
		return -EINVAL;
	}

	/* Convert to native endianness */
	*val = sign_extend32(tmp, 15);

	return 0;
}

static int fxos8700_set_odr(struct fxos8700_data *data, enum fxos8700_sensor t,
			    int odr, int uodr)
{
	int i, ret, val;
	bool active_mode;
	static const int odr_num = ARRAY_SIZE(fxos8700_odr);

	ret = regmap_read(data->regmap, FXOS8700_CTRL_REG1, &val);
	if (ret)
		return ret;

	active_mode = val & FXOS8700_ACTIVE;

	if (active_mode) {
		/*
		 * The device must be in standby mode to change any of the
		 * other fields within CTRL_REG1
		 */
		ret = regmap_write(data->regmap, FXOS8700_CTRL_REG1,
				   val & ~FXOS8700_ACTIVE);
		if (ret)
			return ret;
	}

	for (i = 0; i < odr_num; i++)
		if (fxos8700_odr[i].odr == odr && fxos8700_odr[i].uodr == uodr)
			break;

	if (i >= odr_num)
		return -EINVAL;

	return regmap_update_bits(data->regmap,
				  FXOS8700_CTRL_REG1,
				  FXOS8700_CTRL_ODR_MSK + FXOS8700_ACTIVE,
				  fxos8700_odr[i].bits << 3 | active_mode);
}

static int fxos8700_get_odr(struct fxos8700_data *data, enum fxos8700_sensor t,
			    int *odr, int *uodr)
{
	int i, val, ret;
	static const int odr_num = ARRAY_SIZE(fxos8700_odr);

	ret = regmap_read(data->regmap, FXOS8700_CTRL_REG1, &val);
	if (ret)
		return ret;

	val &= FXOS8700_CTRL_ODR_MSK;

	for (i = 0; i < odr_num; i++)
		if (val == fxos8700_odr[i].bits)
			break;

	if (i >= odr_num)
		return -EINVAL;

	*odr = fxos8700_odr[i].odr;
	*uodr = fxos8700_odr[i].uodr;

	return 0;
}

static int fxos8700_read_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int *val, int *val2, long mask)
{
	int ret;
	struct fxos8700_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = fxos8700_get_data(data, chan->type, chan->channel2, val);
		if (ret)
			return ret;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		*val = 0;
		ret = fxos8700_get_scale(data, fxos8700_to_sensor(chan->type),
					 val2);
		return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_SAMP_FREQ:
		ret = fxos8700_get_odr(data, fxos8700_to_sensor(chan->type),
				       val, val2);
		return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static int fxos8700_write_raw(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      int val, int val2, long mask)
{
	struct fxos8700_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_SCALE:
		return fxos8700_set_scale(data, fxos8700_to_sensor(chan->type),
					  val2);
	case IIO_CHAN_INFO_SAMP_FREQ:
		return fxos8700_set_odr(data, fxos8700_to_sensor(chan->type),
					val, val2);
	default:
		return -EINVAL;
	}
}

static IIO_CONST_ATTR(in_accel_sampling_frequency_available,
		      "1.5625 6.25 12.5 50 100 200 400 800");
static IIO_CONST_ATTR(in_magn_sampling_frequency_available,
		      "1.5625 6.25 12.5 50 100 200 400 800");
static IIO_CONST_ATTR(in_accel_scale_available, "0.000244 0.000488 0.000976");
static IIO_CONST_ATTR(in_magn_scale_available, "0.000001200");

static struct attribute *fxos8700_attrs[] = {
	&iio_const_attr_in_accel_sampling_frequency_available.dev_attr.attr,
	&iio_const_attr_in_magn_sampling_frequency_available.dev_attr.attr,
	&iio_const_attr_in_accel_scale_available.dev_attr.attr,
	&iio_const_attr_in_magn_scale_available.dev_attr.attr,
	NULL,
};

static const struct attribute_group fxos8700_attrs_group = {
	.attrs = fxos8700_attrs,
};

static const struct iio_info fxos8700_info = {
	.read_raw = fxos8700_read_raw,
	.write_raw = fxos8700_write_raw,
	.attrs = &fxos8700_attrs_group,
};

static int fxos8700_chip_init(struct fxos8700_data *data, bool use_spi)
{
	int ret;
	unsigned int val;
	struct device *dev = regmap_get_device(data->regmap);

	ret = regmap_read(data->regmap, FXOS8700_WHO_AM_I, &val);
	if (ret) {
		dev_err(dev, "Error reading chip id\n");
		return ret;
	}
	if (val != FXOS8700_DEVICE_ID && val != FXOS8700_PRE_DEVICE_ID) {
		dev_err(dev, "Wrong chip id, got %x expected %x or %x\n",
			val, FXOS8700_DEVICE_ID, FXOS8700_PRE_DEVICE_ID);
		return -ENODEV;
	}

	ret = fxos8700_set_active_mode(data, FXOS8700_ACCEL, true);
	if (ret)
		return ret;

	ret = fxos8700_set_active_mode(data, FXOS8700_MAGN, true);
	if (ret)
		return ret;

	/*
	 * The device must be in standby mode to change any of the other fields
	 * within CTRL_REG1
	 */
	ret = regmap_write(data->regmap, FXOS8700_CTRL_REG1, 0x00);
	if (ret)
		return ret;

	/* Set max oversample ratio (OSR) and both devices active */
	ret = regmap_write(data->regmap, FXOS8700_M_CTRL_REG1,
			   FXOS8700_HMS_MASK | FXOS8700_OS_MASK);
	if (ret)
		return ret;

	/* Disable and rst min/max measurements & threshold */
	ret = regmap_write(data->regmap, FXOS8700_M_CTRL_REG2,
			   FXOS8700_MAXMIN_RST | FXOS8700_MAXMIN_DIS_THS |
			   FXOS8700_MAXMIN_DIS);
	if (ret)
		return ret;

	/*
	 * Set max full-scale range (+/-8G) for ACCEL sensor in chip
	 * initialization then activate the device.
	 */
	ret = regmap_write(data->regmap, FXOS8700_XYZ_DATA_CFG, MODE_8G);
	if (ret)
		return ret;

	/* Max ODR (800Hz individual or 400Hz hybrid), active mode */
	return regmap_write(data->regmap, FXOS8700_CTRL_REG1,
			   FXOS8700_CTRL_ODR_MAX | FXOS8700_ACTIVE);
}

static void fxos8700_chip_uninit(void *data)
{
	struct fxos8700_data *fxos8700_data = data;

	fxos8700_set_active_mode(fxos8700_data, FXOS8700_ACCEL, false);
	fxos8700_set_active_mode(fxos8700_data, FXOS8700_MAGN, false);
}

int fxos8700_core_probe(struct device *dev, struct regmap *regmap,
			const char *name, bool use_spi)
{
	struct iio_dev *indio_dev;
	struct fxos8700_data *data;
	int ret;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
	if (!indio_dev)
		return -ENOMEM;

	data = iio_priv(indio_dev);
	dev_set_drvdata(dev, indio_dev);
	data->regmap = regmap;

	ret = fxos8700_chip_init(data, use_spi);
	if (ret)
		return ret;

	ret = devm_add_action_or_reset(dev, fxos8700_chip_uninit, data);
	if (ret)
		return ret;

	indio_dev->channels = fxos8700_channels;
	indio_dev->num_channels = ARRAY_SIZE(fxos8700_channels);
	indio_dev->name = name ? name : "fxos8700";
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &fxos8700_info;

	return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_GPL(fxos8700_core_probe);

MODULE_AUTHOR("Robert Jones <rjones@gateworks.com>");
MODULE_DESCRIPTION("FXOS8700 6-Axis Acc and Mag Combo Sensor driver");
MODULE_LICENSE("GPL v2");