diff options
Diffstat (limited to 'drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c')
| -rw-r--r-- | drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c | 356 |
1 files changed, 356 insertions, 0 deletions
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..02735af152c8 --- /dev/null +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c @@ -0,0 +1,356 @@ +// 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_aux.h" +#include "inv_mpu_iio.h" +#include "inv_mpu_magn.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; +} |