On Thu, 29 Aug 2019 15:18:43 +0000
Jean-Baptiste Maneyrol <JManeyrol@xxxxxxxxxxxxxx> wrote:
> Add implementation for driving MPU9250 magnetometer connected on
> i2c auxiliary bus using the MPU i2c master. This is currently not
> wired inside the main mpu driver.
>
> Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
A few comments inline.
Thanks,
Jonathan
> ---
> drivers/iio/imu/inv_mpu6050/Makefile | 2 +-
> .../iio/imu/inv_mpu6050/inv_mpu9250_magn.c | 239 ++++++++++++++++++
> .../iio/imu/inv_mpu6050/inv_mpu9250_magn.h | 27 ++
> drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 4 +
> 4 files changed, 271 insertions(+), 1 deletion(-)
> create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu9250_magn.c
> create mode 100644 drivers/iio/imu/inv_mpu6050/inv_mpu9250_magn.h
>
> diff --git a/drivers/iio/imu/inv_mpu6050/Makefile b/drivers/iio/imu/inv_mpu6050/Makefile
> index 187f003c81f2..fee41415ebdb 100644
> --- a/drivers/iio/imu/inv_mpu6050/Makefile
> +++ b/drivers/iio/imu/inv_mpu6050/Makefile
> @@ -5,7 +5,7 @@
>
> obj-$(CONFIG_INV_MPU6050_IIO) += inv-mpu6050.o
> inv-mpu6050-y := inv_mpu_core.o inv_mpu_ring.o inv_mpu_trigger.o
> -inv-mpu6050-$(CONFIG_INV_MPU6050_MAGN) += inv_mpu_aux.o
> +inv-mpu6050-$(CONFIG_INV_MPU6050_MAGN) += inv_mpu_aux.o inv_mpu9250_magn.o
>
> obj-$(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_mpu9250_magn.c b/drivers/iio/imu/inv_mpu6050/inv_mpu9250_magn.c
> new file mode 100644
> index 000000000000..0c2230247557
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu9250_magn.c
> @@ -0,0 +1,239 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 TDK-InvenSense, Inc.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/regmap.h>
> +#include <linux/delay.h>
> +#include <linux/string.h>
> +#include <asm/unaligned.h>
> +
> +#include "inv_mpu_iio.h"
> +#include "inv_mpu_aux.h"
> +#include "inv_mpu9250_magn.h"
> +
> +/*
> + * MPU9250 magnetometer is an AKM AK8963 chip on I2C aux bus
> + */
> +#define INV_MPU9250_MAGN_I2C_ADDR 0x0C
> +
> +#define INV_MPU9250_MAGN_REG_WIA 0x00
> +#define INV_MPU9250_MAGN_BITS_WIA 0x48
> +
> +#define INV_MPU9250_MAGN_REG_ST1 0x02
> +#define INV_MPU9250_MAGN_BIT_DRDY 0x01
> +#define INV_MPU9250_MAGN_BIT_DOR 0x02
> +
> +#define INV_MPU9250_MAGN_REG_DATA 0x03
> +
> +#define INV_MPU9250_MAGN_REG_ST2 0x09
> +#define INV_MPU9250_MAGN_BIT_HOFL 0x08
> +#define INV_MPU9250_MAGN_BIT_BITM 0x10
> +
> +#define INV_MPU9250_MAGN_REG_CNTL1 0x0A
> +#define INV_MPU9250_MAGN_BITS_MODE_PWDN 0x00
> +#define INV_MPU9250_MAGN_BITS_MODE_SINGLE 0x01
> +#define INV_MPU9250_MAGN_BITS_MODE_FUSE 0x0F
> +#define INV_MPU9250_MAGN_BIT_OUTPUT_BIT 0x10
> +
> +#define INV_MPU9250_MAGN_REG_CNTL2 0x0B
> +#define INV_MPU9250_MAGN_BIT_SRST 0x01
> +
> +#define INV_MPU9250_MAGN_REG_ASAX 0x10
> +#define INV_MPU9250_MAGN_REG_ASAY 0x11
> +#define INV_MPU9250_MAGN_REG_ASAZ 0x12
> +
> +/* 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_MPU9250_MAGN_I2C_ADDR,
> + INV_MPU9250_MAGN_REG_WIA, &val, sizeof(val));
> + if (ret)
> + return ret;
> + if (val != INV_MPU9250_MAGN_BITS_WIA)
> + return -ENODEV;
> +
> + /* reset chip */
> + ret = inv_mpu_aux_write(st, INV_MPU9250_MAGN_I2C_ADDR,
> + INV_MPU9250_MAGN_REG_CNTL2,
> + INV_MPU9250_MAGN_BIT_SRST);
> + if (ret)
> + return ret;
> +
> + /* read fuse ROM data */
> + ret = inv_mpu_aux_write(st, INV_MPU9250_MAGN_I2C_ADDR,
> + INV_MPU9250_MAGN_REG_CNTL1,
> + INV_MPU9250_MAGN_BITS_MODE_FUSE);
> + if (ret)
> + return ret;
> + ret = inv_mpu_aux_read(st, INV_MPU9250_MAGN_I2C_ADDR,
> + INV_MPU9250_MAGN_REG_ASAX, asa, sizeof(asa));
> + if (ret)
> + return ret;
> +
> + /* switch back to power-down */
> + ret = inv_mpu_aux_write(st, INV_MPU9250_MAGN_I2C_ADDR,
> + INV_MPU9250_MAGN_REG_CNTL1,
> + INV_MPU9250_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 sensitivity: 0.15 uT (16 bits)
> + * 1 uT = 0.01 G and value is in micron (1e6)
> + *
> + * Hadj = H * ((ASA + 128) / 256) * 0.15 * 0.01 * 1e6
> + * Hadj = H * ((ASA + 128) / 256) * 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;
> +}
> +
> +/**
> + * Probe magnetometer chip and setup all i2c transfers.
> + * SLV0: read sensor data
> + * SLV1: launch sensor single measurement
> + *
> + * Sampling data requires 2 cycles to read after measurement.
> + * A measurement can take up to ~10ms.
> + */
> +int inv_mpu9250_magn_probe(struct inv_mpu6050_state *st)
> +{
> + int 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_MPU9250_MAGN_I2C_ADDR);
> + if (ret)
> + return ret;
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(0),
> + INV_MPU9250_MAGN_REG_DATA);
> + if (ret)
> + return ret;
blank lines in all these locations ideally. See below.
> + 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_MPU9250_MAGN_I2C_ADDR);
> + if (ret)
> + return ret;
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(1),
> + INV_MPU9250_MAGN_REG_CNTL1);
> + if (ret)
> + return ret;
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_DO(1),
> + INV_MPU9250_MAGN_BITS_MODE_SINGLE |
> + INV_MPU9250_MAGN_BIT_OUTPUT_BIT);
> + if (ret)
> + return ret;
> + ret = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(1),
> + INV_MPU6050_BIT_SLV_EN | 1);
> + if (ret)
> + return ret;
> +
return regmap_write....
Check for others of these in the rest of the patches.
> + return 0;
> +}
> +
> +/**
> + * Read magnetometer data from MPU fifo.
> + * Sampling data requires running the i2c master for 2 cycles.
> + * Use magnetometer maximal supported frequency.
> + */
> +int inv_mpu9250_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;
> +
> + /* 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_MPU9250_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;
blank line.
> + /* need to wait 2 periods + half-period margin */
> + period_ms = 1000 / INV_MPU9250_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;
Blank line.
> + if (status & INV_MPU6050_BIT_I2C_SLV0_NACK ||
> + status & INV_MPU6050_BIT_I2C_SLV1_NACK)
> + return -EIO;
Blank lines after error checks like this make the code a little
easier to read.
> + 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_mpu9250_magn.h b/drivers/iio/imu/inv_mpu6050/inv_mpu9250_magn.h
> new file mode 100644
> index 000000000000..9899dd6c560c
> --- /dev/null
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu9250_magn.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2019 TDK-InvenSense, Inc.
> + */
> +
> +#ifndef INV_MPU9250_MAGN_H_
> +#define INV_MPU9250_MAGN_H_
> +
> +#include <linux/kernel.h>
> +
> +#include "inv_mpu_iio.h"
> +
> +/* Magnetometer maximum frequency */
> +#define INV_MPU9250_MAGN_FREQ_HZ_MAX 50
> +
> +/**
> + * inv_mpu9250_magn_probe() - MPU9250 implementation
> + */
> +int inv_mpu9250_magn_probe(struct inv_mpu6050_state *st);
> +
> +/**
> + * inv_mpu9250_magn_read() - MPU9250 implementation
Documentation by implementation not in the header. Also full documentation
of all parameters needed if you are going to use kernel-doc style
> + */
> +int inv_mpu9250_magn_read(const struct inv_mpu6050_state *st, int axis,
> + int *val);
> +
> +#endif
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> index 82669ecb4735..5b462672bbcb 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
> @@ -129,6 +129,7 @@ struct inv_mpu6050_hw {
> * @it_timestamp: timestamp from previous interrupt.
> * @data_timestamp: timestamp for next data sample.
> * @vddio_supply voltage regulator for the chip.
> + * @magn_raw_to_gauss: coefficient to convert mag raw value to Gauss.
> */
> struct inv_mpu6050_state {
> struct mutex lock;
> @@ -150,6 +151,9 @@ struct inv_mpu6050_state {
> s64 it_timestamp;
> s64 data_timestamp;
> struct regulator *vddio_supply;
> +#ifdef CONFIG_INV_MPU6050_MAGN
> + s32 magn_raw_to_gauss[3];
> +#endif
> };
>
> /*register and associated bit definition*/
