On Mon, 16 Sep 2019 09:42:07 +0000
Jean-Baptiste Maneyrol <JManeyrol@xxxxxxxxxxxxxx> wrote:
> Add support of driving MPU9250 magnetometer connected on i2c
> auxiliary bus using the MPU i2c master.
>
> Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
Same issue of the c file not including it's own header. Fixed up.
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.
Thanks,
Jonathan
> ---
> drivers/iio/imu/inv_mpu6050/Makefile | 2 +-
> drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 144 ++++++++-
> drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 4 +
> drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c | 355 +++++++++++++++++++++
> drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h | 36 +++
> 5 files changed, 537 insertions(+), 4 deletions(-)
> create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
> create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h
>
> diff --git a/drivers/iio/imu/inv_mpu6050/Makefile b/drivers/iio/imu/inv_mpu6050/Makefile
> index 2cfbd926522f..c103441a906b 100644
> --- a/drivers/iio/imu/inv_mpu6050/Makefile
> +++ b/drivers/iio/imu/inv_mpu6050/Makefile
> @@ -5,7 +5,7 @@
>
> obj-$(CONFIG_INV_MPU6050_IIO) += inv-mpu6050.o
> inv-mpu6050-y := inv_mpu_core.o inv_mpu_ring.o inv_mpu_trigger.o \
> - inv_mpu_aux.o
> + inv_mpu_aux.o inv_mpu_magn.o
>
> obj-$(CONFIG_INV_MPU6050_I2C) += inv-mpu6050-i2c.o
> inv-mpu6050-i2c-y := inv_mpu_i2c.o inv_mpu_acpi.o
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> index 7b2e4d81bbba..f1c65e0dd1a5 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> @@ -17,6 +17,7 @@
> #include <linux/platform_device.h>
> #include <linux/regulator/consumer.h>
> #include "inv_mpu_iio.h"
> +#include "inv_mpu_magn.h"
>
> /*
> * this is the gyro scale translated from dynamic range plus/minus
> @@ -332,6 +333,11 @@ static int inv_mpu6050_init_config(struct iio_dev *indio_dev)
> */
> st->chip_period = NSEC_PER_MSEC;
>
> + /* magn chip init, noop if not present in the chip */
> + result = inv_mpu_magn_probe(st);
> + if (result)
> + goto error_power_off;
> +
> return inv_mpu6050_set_power_itg(st, false);
>
> error_power_off:
> @@ -411,6 +417,9 @@ static int inv_mpu6050_read_channel_data(struct iio_dev *indio_dev,
> ret = inv_mpu6050_sensor_show(st, st->reg->temperature,
> IIO_MOD_X, val);
> break;
> + case IIO_MAGN:
> + ret = inv_mpu_magn_read(st, chan->channel2, val);
> + break;
> default:
> ret = -EINVAL;
> break;
> @@ -469,6 +478,8 @@ inv_mpu6050_read_raw(struct iio_dev *indio_dev,
> *val2 = INV_MPU6050_TEMP_SCALE;
>
> return IIO_VAL_INT_PLUS_MICRO;
> + case IIO_MAGN:
> + return inv_mpu_magn_get_scale(st, chan, val, val2);
> default:
> return -EINVAL;
> }
> @@ -710,6 +721,11 @@ inv_mpu6050_fifo_rate_store(struct device *dev, struct device_attribute *attr,
> if (result)
> goto fifo_rate_fail_power_off;
>
> + /* update rate for magn, noop if not present in chip */
> + result = inv_mpu_magn_set_rate(st, fifo_rate);
> + if (result)
> + goto fifo_rate_fail_power_off;
> +
> fifo_rate_fail_power_off:
> result |= inv_mpu6050_set_power_itg(st, false);
> fifo_rate_fail_unlock:
> @@ -795,8 +811,14 @@ inv_get_mount_matrix(const struct iio_dev *indio_dev,
> const struct iio_chan_spec *chan)
> {
> struct inv_mpu6050_state *data = iio_priv(indio_dev);
> + const struct iio_mount_matrix *matrix;
> +
> + if (chan->type == IIO_MAGN)
> + matrix = &data->magn_orient;
> + else
> + matrix = &data->orientation;
>
> - return &data->orientation;
> + return matrix;
> }
>
> static const struct iio_chan_spec_ext_info inv_ext_info[] = {
> @@ -864,6 +886,98 @@ static const unsigned long inv_mpu_scan_masks[] = {
> 0,
> };
>
> +#define INV_MPU9X50_MAGN_CHAN(_chan2, _bits, _index) \
> + { \
> + .type = IIO_MAGN, \
> + .modified = 1, \
> + .channel2 = _chan2, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_RAW), \
> + .scan_index = _index, \
> + .scan_type = { \
> + .sign = 's', \
> + .realbits = _bits, \
> + .storagebits = 16, \
> + .shift = 0, \
This doesn't need to be set as 0 is the 'obvious' default.
> + .endianness = IIO_BE, \
> + }, \
> + .ext_info = inv_ext_info, \
> + }
> +
> +static const struct iio_chan_spec inv_mpu9250_channels[] = {
> + IIO_CHAN_SOFT_TIMESTAMP(INV_MPU9X50_SCAN_TIMESTAMP),
> + /*
> + * Note that temperature should only be via polled reading only,
> + * not the final scan elements output.
> + */
> + {
> + .type = IIO_TEMP,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW)
> + | BIT(IIO_CHAN_INFO_OFFSET)
> + | BIT(IIO_CHAN_INFO_SCALE),
> + .scan_index = -1,
> + },
> + INV_MPU6050_CHAN(IIO_ANGL_VEL, IIO_MOD_X, INV_MPU6050_SCAN_GYRO_X),
> + INV_MPU6050_CHAN(IIO_ANGL_VEL, IIO_MOD_Y, INV_MPU6050_SCAN_GYRO_Y),
> + INV_MPU6050_CHAN(IIO_ANGL_VEL, IIO_MOD_Z, INV_MPU6050_SCAN_GYRO_Z),
> +
> + INV_MPU6050_CHAN(IIO_ACCEL, IIO_MOD_X, INV_MPU6050_SCAN_ACCL_X),
> + INV_MPU6050_CHAN(IIO_ACCEL, IIO_MOD_Y, INV_MPU6050_SCAN_ACCL_Y),
> + INV_MPU6050_CHAN(IIO_ACCEL, IIO_MOD_Z, INV_MPU6050_SCAN_ACCL_Z),
> +
> + /* Magnetometer resolution is 16 bits */
> + INV_MPU9X50_MAGN_CHAN(IIO_MOD_X, 16, INV_MPU9X50_SCAN_MAGN_X),
> + INV_MPU9X50_MAGN_CHAN(IIO_MOD_Y, 16, INV_MPU9X50_SCAN_MAGN_Y),
> + INV_MPU9X50_MAGN_CHAN(IIO_MOD_Z, 16, INV_MPU9X50_SCAN_MAGN_Z),
> +};
> +
> +static const unsigned long inv_mpu9x50_scan_masks[] = {
> + /* 3-axis accel */
> + BIT(INV_MPU6050_SCAN_ACCL_X)
> + | BIT(INV_MPU6050_SCAN_ACCL_Y)
> + | BIT(INV_MPU6050_SCAN_ACCL_Z),
> + /* 3-axis gyro */
> + BIT(INV_MPU6050_SCAN_GYRO_X)
> + | BIT(INV_MPU6050_SCAN_GYRO_Y)
> + | BIT(INV_MPU6050_SCAN_GYRO_Z),
> + /* 3-axis magn */
> + BIT(INV_MPU9X50_SCAN_MAGN_X)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Y)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Z),
> + /* 6-axis accel + gyro */
> + BIT(INV_MPU6050_SCAN_ACCL_X)
> + | BIT(INV_MPU6050_SCAN_ACCL_Y)
> + | BIT(INV_MPU6050_SCAN_ACCL_Z)
> + | BIT(INV_MPU6050_SCAN_GYRO_X)
> + | BIT(INV_MPU6050_SCAN_GYRO_Y)
> + | BIT(INV_MPU6050_SCAN_GYRO_Z),
> + /* 6-axis accel + magn */
> + BIT(INV_MPU6050_SCAN_ACCL_X)
> + | BIT(INV_MPU6050_SCAN_ACCL_Y)
> + | BIT(INV_MPU6050_SCAN_ACCL_Z)
> + | BIT(INV_MPU9X50_SCAN_MAGN_X)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Y)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Z),
> + /* 6-axis gyro + magn */
> + BIT(INV_MPU6050_SCAN_GYRO_X)
> + | BIT(INV_MPU6050_SCAN_GYRO_Y)
> + | BIT(INV_MPU6050_SCAN_GYRO_Z)
> + | BIT(INV_MPU9X50_SCAN_MAGN_X)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Y)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Z),
> + /* 9-axis accel + gyro + magn */
> + BIT(INV_MPU6050_SCAN_ACCL_X)
> + | BIT(INV_MPU6050_SCAN_ACCL_Y)
> + | BIT(INV_MPU6050_SCAN_ACCL_Z)
> + | BIT(INV_MPU6050_SCAN_GYRO_X)
> + | BIT(INV_MPU6050_SCAN_GYRO_Y)
> + | BIT(INV_MPU6050_SCAN_GYRO_Z)
> + | BIT(INV_MPU9X50_SCAN_MAGN_X)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Y)
> + | BIT(INV_MPU9X50_SCAN_MAGN_Z),
> + 0,
> +};
> +
> static const struct iio_chan_spec inv_icm20602_channels[] = {
> IIO_CHAN_SOFT_TIMESTAMP(INV_ICM20602_SCAN_TIMESTAMP),
> {
> @@ -1145,6 +1259,11 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
> return result;
> }
>
> + /* fill magnetometer orientation */
> + result = inv_mpu_magn_set_orient(st);
> + if (result)
> + return result;
> +
> /* power is turned on inside check chip type*/
> result = inv_check_and_setup_chip(st);
> if (result)
> @@ -1168,14 +1287,33 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
> if (inv_mpu_bus_setup)
> inv_mpu_bus_setup(indio_dev);
>
> - if (chip_type == INV_ICM20602) {
> + switch (chip_type) {
> + case INV_MPU9250:
> + case INV_MPU9255:
> + /*
> + * Use magnetometer inside the chip only if there is no i2c
> + * auxiliary device in use.
> + */
> + if (!st->magn_disabled) {
> + indio_dev->channels = inv_mpu9250_channels;
> + indio_dev->num_channels = ARRAY_SIZE(inv_mpu9250_channels);
> + indio_dev->available_scan_masks = inv_mpu9x50_scan_masks;
> + } else {
> + indio_dev->channels = inv_mpu_channels;
> + indio_dev->num_channels = ARRAY_SIZE(inv_mpu_channels);
> + indio_dev->available_scan_masks = inv_mpu_scan_masks;
> + }
> + break;
> + case INV_ICM20602:
> indio_dev->channels = inv_icm20602_channels;
> indio_dev->num_channels = ARRAY_SIZE(inv_icm20602_channels);
> indio_dev->available_scan_masks = inv_icm20602_scan_masks;
> - } else {
> + break;
> + default:
> indio_dev->channels = inv_mpu_channels;
> indio_dev->num_channels = ARRAY_SIZE(inv_mpu_channels);
> indio_dev->available_scan_masks = inv_mpu_scan_masks;
> + break;
> }
>
> indio_dev->info = &mpu_info;
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> index 04215bc6e8ab..953f85618199 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> @@ -130,6 +130,8 @@ struct inv_mpu6050_hw {
> * @data_timestamp: timestamp for next data sample.
> * @vddio_supply voltage regulator for the chip.
> * @magn_disabled: magnetometer disabled for backward compatibility reason.
> + * @magn_raw_to_gauss: coefficient to convert mag raw value to Gauss.
> + * @magn_orient: magnetometer sensor chip orientation if available.
> */
> struct inv_mpu6050_state {
> struct mutex lock;
> @@ -152,6 +154,8 @@ struct inv_mpu6050_state {
> s64 data_timestamp;
> struct regulator *vddio_supply;
> bool magn_disabled;
> + s32 magn_raw_to_gauss[3];
> + struct iio_mount_matrix magn_orient;
> };
>
> /*register and associated bit definition*/
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
> new file mode 100644
> index 000000000000..415d8acece54
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
> @@ -0,0 +1,355 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 TDK-InvenSense, Inc.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/string.h>
> +
> +#include "inv_mpu_iio.h"
> +#include "inv_mpu_aux.h"
> +
> +/*
> + * MPU9250 magnetometer is an AKM AK8963 chip on I2C aux bus
> + */
> +#define INV_MPU_MAGN_I2C_ADDR 0x0C
> +
> +#define INV_MPU_MAGN_REG_WIA 0x00
> +#define INV_MPU_MAGN_BITS_WIA 0x48
> +
> +#define INV_MPU_MAGN_REG_ST1 0x02
> +#define INV_MPU_MAGN_BIT_DRDY 0x01
> +#define INV_MPU_MAGN_BIT_DOR 0x02
> +
> +#define INV_MPU_MAGN_REG_DATA 0x03
> +
> +#define INV_MPU_MAGN_REG_ST2 0x09
> +#define INV_MPU_MAGN_BIT_HOFL 0x08
> +#define INV_MPU_MAGN_BIT_BITM 0x10
> +
> +#define INV_MPU_MAGN_REG_CNTL1 0x0A
> +#define INV_MPU_MAGN_BITS_MODE_PWDN 0x00
> +#define INV_MPU_MAGN_BITS_MODE_SINGLE 0x01
> +#define INV_MPU_MAGN_BITS_MODE_FUSE 0x0F
> +#define INV_MPU_MAGN_BIT_OUTPUT_BIT 0x10
> +
> +#define INV_MPU_MAGN_REG_CNTL2 0x0B
> +#define INV_MPU_MAGN_BIT_SRST 0x01
> +
> +#define INV_MPU_MAGN_REG_ASAX 0x10
> +#define INV_MPU_MAGN_REG_ASAY 0x11
> +#define INV_MPU_MAGN_REG_ASAZ 0x12
> +
> +/* Magnetometer maximum frequency */
> +#define INV_MPU_MAGN_FREQ_HZ_MAX 50
> +
> +static bool inv_magn_supported(const struct inv_mpu6050_state *st)
> +{
> + switch (st->chip_type) {
> + case INV_MPU9250:
> + case INV_MPU9255:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +/* init magnetometer chip */
> +static int inv_magn_init(struct inv_mpu6050_state *st)
> +{
> + uint8_t val;
> + uint8_t asa[3];
> + int ret;
> +
> + /* check whoami */
> + ret = inv_mpu_aux_read(st, INV_MPU_MAGN_I2C_ADDR, INV_MPU_MAGN_REG_WIA,
> + &val, sizeof(val));
> + if (ret)
> + return ret;
> + if (val != INV_MPU_MAGN_BITS_WIA)
> + return -ENODEV;
> +
> + /* reset chip */
> + ret = inv_mpu_aux_write(st, INV_MPU_MAGN_I2C_ADDR,
> + INV_MPU_MAGN_REG_CNTL2,
> + INV_MPU_MAGN_BIT_SRST);
> + if (ret)
> + return ret;
> +
> + /* read fuse ROM data */
> + ret = inv_mpu_aux_write(st, INV_MPU_MAGN_I2C_ADDR,
> + INV_MPU_MAGN_REG_CNTL1,
> + INV_MPU_MAGN_BITS_MODE_FUSE);
> + if (ret)
> + return ret;
> +
> + ret = inv_mpu_aux_read(st, INV_MPU_MAGN_I2C_ADDR, INV_MPU_MAGN_REG_ASAX,
> + asa, sizeof(asa));
> + if (ret)
> + return ret;
> +
> + /* switch back to power-down */
> + ret = inv_mpu_aux_write(st, INV_MPU_MAGN_I2C_ADDR,
> + INV_MPU_MAGN_REG_CNTL1,
> + INV_MPU_MAGN_BITS_MODE_PWDN);
> + if (ret)
> + return ret;
> +
> + /*
> + * Sensitivity adjustement and scale to Gauss
> + *
> + * Hadj = H * (((ASA - 128) * 0.5 / 128) + 1)
> + * Factor simplification:
> + * Hadj = H * ((ASA + 128) / 256)
> + *
> + * Sensor sentivity
> + * 0.15 uT in 16 bits mode
> + * 1 uT = 0.01 G and value is in micron (1e6)
> + * sensitvity = 0.15 uT * 0.01 * 1e6
> + *
> + * raw_to_gauss = Hadj * 1500
> + */
> + st->magn_raw_to_gauss[0] = (((int32_t)asa[0] + 128) * 1500) / 256;
> + st->magn_raw_to_gauss[1] = (((int32_t)asa[1] + 128) * 1500) / 256;
> + st->magn_raw_to_gauss[2] = (((int32_t)asa[2] + 128) * 1500) / 256;
> +
> + return 0;
> +}
> +
> +/**
> + * inv_mpu_magn_probe() - probe and setup magnetometer chip
> + * @st: driver internal state
> + *
> + * Returns 0 on success, a negative error code otherwise
> + *
> + * It is probing the chip and setting up all needed i2c transfers.
> + * Noop if there is no magnetometer in the chip.
> + */
> +int inv_mpu_magn_probe(struct inv_mpu6050_state *st)
> +{
> + int ret;
> +
> + /* quit if chip is not supported */
> + if (!inv_magn_supported(st))
> + return 0;
> +
> + /* configure i2c master aux port */
> + ret = inv_mpu_aux_init(st);
> + if (ret)
> + return ret;
> +
> + /* check and init mag chip */
> + ret = inv_magn_init(st);
> + if (ret)
> + return ret;
> +
> + /*
> + * configure mpu i2c master accesses
> + * i2c SLV0: read sensor data, 7 bytes data(6)-ST2
> + * Byte swap data to store them in big-endian in impair address groups
> + */
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(0),
> + INV_MPU6050_BIT_I2C_SLV_RNW | INV_MPU_MAGN_I2C_ADDR);
> + if (ret)
> + return ret;
> +
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0),
> + INV_MPU_MAGN_REG_DATA);
> + if (ret)
> + return ret;
> +
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(0),
> + INV_MPU6050_BIT_SLV_EN |
> + INV_MPU6050_BIT_SLV_BYTE_SW |
> + INV_MPU6050_BIT_SLV_GRP |
> + INV_MPU9X50_BYTES_MAGN);
> + if (ret)
> + return ret;
> +
> + /* i2c SLV1: launch single measurement */
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(1),
> + INV_MPU_MAGN_I2C_ADDR);
> + if (ret)
> + return ret;
> +
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(1),
> + INV_MPU_MAGN_REG_CNTL1);
> + if (ret)
> + return ret;
> +
> + /* add 16 bits mode */
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(1),
> + INV_MPU_MAGN_BITS_MODE_SINGLE |
> + INV_MPU_MAGN_BIT_OUTPUT_BIT);
> + if (ret)
> + return ret;
> +
> + return regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(1),
> + INV_MPU6050_BIT_SLV_EN | 1);
> +}
> +
> +/**
> + * inv_mpu_magn_set_rate() - set magnetometer sampling rate
> + * @st: driver internal state
> + * @fifo_rate: mpu set fifo rate
> + *
> + * Returns 0 on success, a negative error code otherwise
> + *
> + * Limit sampling frequency to the maximum value supported by the
> + * magnetometer chip. Resulting in duplicated data for higher frequencies.
> + * Noop if there is no magnetometer in the chip.
> + */
> +int inv_mpu_magn_set_rate(const struct inv_mpu6050_state *st, int fifo_rate)
> +{
> + uint8_t d;
> +
> + /* quit if chip is not supported */
> + if (!inv_magn_supported(st))
> + return 0;
> +
> + /*
> + * update i2c master delay to limit mag sampling to max frequency
> + * compute fifo_rate divider d: rate = fifo_rate / (d + 1)
> + */
> + if (fifo_rate > INV_MPU_MAGN_FREQ_HZ_MAX)
> + d = fifo_rate / INV_MPU_MAGN_FREQ_HZ_MAX - 1;
> + else
> + d = 0;
> +
> + return regmap_write(st->map, INV_MPU6050_REG_I2C_SLV4_CTRL, d);
> +}
> +
> +/**
> + * inv_mpu_magn_set_orient() - fill magnetometer mounting matrix
> + * @st: driver internal state
> + *
> + * Returns 0 on success, a negative error code otherwise
> + *
> + * Fill magnetometer mounting matrix using the provided chip matrix.
> + */
> +int inv_mpu_magn_set_orient(struct inv_mpu6050_state *st)
> +{
> + const char *orient;
> + char *str;
> + int i;
> +
> + /* fill magnetometer orientation */
> + switch (st->chip_type) {
> + case INV_MPU9250:
> + case INV_MPU9255:
> + /* x <- y */
> + st->magn_orient.rotation[0] = st->orientation.rotation[3];
> + st->magn_orient.rotation[1] = st->orientation.rotation[4];
> + st->magn_orient.rotation[2] = st->orientation.rotation[5];
> + /* y <- x */
> + st->magn_orient.rotation[3] = st->orientation.rotation[0];
> + st->magn_orient.rotation[4] = st->orientation.rotation[1];
> + st->magn_orient.rotation[5] = st->orientation.rotation[2];
> + /* z <- -z */
> + for (i = 0; i < 3; ++i) {
> + orient = st->orientation.rotation[6 + i];
> + /* use length + 2 for adding minus sign if needed */
> + str = devm_kzalloc(regmap_get_device(st->map),
> + strlen(orient) + 2, GFP_KERNEL);
> + if (str == NULL)
> + return -ENOMEM;
> + if (strcmp(orient, "0") == 0) {
> + strcpy(str, orient);
> + } else if (orient[0] == '-') {
> + strcpy(str, &orient[1]);
> + } else {
> + str[0] = '-';
> + strcpy(&str[1], orient);
> + }
> + st->magn_orient.rotation[6 + i] = str;
> + }
> + break;
> + default:
> + st->magn_orient = st->orientation;
> + break;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * inv_mpu_magn_read() - read magnetometer data
> + * @st: driver internal state
> + * @axis: IIO modifier axis value
> + * @val: store corresponding axis value
> + *
> + * Returns 0 on success, a negative error code otherwise
> + */
> +int inv_mpu_magn_read(const struct inv_mpu6050_state *st, int axis, int *val)
> +{
> + unsigned int user_ctrl, status;
> + __be16 data[3];
> + uint8_t addr;
> + uint8_t d;
> + unsigned int period_ms;
> + int ret;
> +
> + /* quit if chip is not supported */
> + if (!inv_magn_supported(st))
> + return -ENODEV;
> +
> + /* Mag data: X - Y - Z */
> + switch (axis) {
> + case IIO_MOD_X:
> + addr = 0;
> + break;
> + case IIO_MOD_Y:
> + addr = 1;
> + break;
> + case IIO_MOD_Z:
> + addr = 2;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + /* set sample rate to max mag freq */
> + d = INV_MPU6050_FIFO_RATE_TO_DIVIDER(INV_MPU_MAGN_FREQ_HZ_MAX);
> + ret = regmap_write(st->map, st->reg->sample_rate_div, d);
> + if (ret)
> + return ret;
> +
> + /* start i2c master, wait for xfer, stop */
> + user_ctrl = st->chip_config.user_ctrl | INV_MPU6050_BIT_I2C_MST_EN;
> + ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
> + if (ret)
> + return ret;
> +
> + /* need to wait 2 periods + half-period margin */
> + period_ms = 1000 / INV_MPU_MAGN_FREQ_HZ_MAX;
> + msleep(period_ms * 2 + period_ms / 2);
> + user_ctrl = st->chip_config.user_ctrl;
> + ret = regmap_write(st->map, st->reg->user_ctrl, user_ctrl);
> + if (ret)
> + return ret;
> +
> + /* restore sample rate */
> + d = st->chip_config.divider;
> + ret = regmap_write(st->map, st->reg->sample_rate_div, d);
> + if (ret)
> + return ret;
> +
> + /* check i2c status and read raw data */
> + ret = regmap_read(st->map, INV_MPU6050_REG_I2C_MST_STATUS, &status);
> + if (ret)
> + return ret;
> +
> + if (status & INV_MPU6050_BIT_I2C_SLV0_NACK ||
> + status & INV_MPU6050_BIT_I2C_SLV1_NACK)
> + return -EIO;
> +
> + ret = regmap_bulk_read(st->map, INV_MPU6050_REG_EXT_SENS_DATA,
> + data, sizeof(data));
> + if (ret)
> + return ret;
> +
> + *val = (int16_t)be16_to_cpu(data[addr]);
> +
> + return IIO_VAL_INT;
> +}
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h
> new file mode 100644
> index 000000000000..b41bd0578478
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2019 TDK-InvenSense, Inc.
> + */
> +
> +#ifndef INV_MPU_MAGN_H_
> +#define INV_MPU_MAGN_H_
> +
> +#include <linux/kernel.h>
> +
> +#include "inv_mpu_iio.h"
> +
> +int inv_mpu_magn_probe(struct inv_mpu6050_state *st);
> +
> +/**
> + * inv_mpu_magn_get_scale() - get magnetometer scale value
> + * @st: driver internal state
> + *
> + * Returns IIO data format.
> + */
> +static inline int inv_mpu_magn_get_scale(const struct inv_mpu6050_state *st,
> + const struct iio_chan_spec *chan,
> + int *val, int *val2)
> +{
> + *val = 0;
> + *val2 = st->magn_raw_to_gauss[chan->address];
> + return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> +int inv_mpu_magn_set_rate(const struct inv_mpu6050_state *st, int fifo_rate);
> +
> +int inv_mpu_magn_set_orient(struct inv_mpu6050_state *st);
> +
> +int inv_mpu_magn_read(const struct inv_mpu6050_state *st, int axis, int *val);
> +
> +#endif /* INV_MPU_MAGN_H_ */
