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iio: imu: inv_mpu6050: fix data polling interface 

When reading data with the polling interface, we need to wait
at 1 sampling period to have a sample.
For gyroscope and magnetometer, we need to wait for 2 periods
before having a correct sample.

Not suitable for stable or backporting.

Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Jean-Baptiste Maneyrol 2020-02-19 15:39:54 +01:00 committed by Jonathan Cameron
parent 92e7407ab1
commit ffc9648a52
3 changed files with 37 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
View File

@ -563,9 +563,14 @@ static int inv_mpu6050_read_channel_data(struct iio_dev *indio_dev,
int *val)
{
struct inv_mpu6050_state *st = iio_priv(indio_dev);
unsigned int freq_hz, period_us, min_sleep_us, max_sleep_us;
int result;
int ret;
/* compute sample period */
freq_hz = INV_MPU6050_DIVIDER_TO_FIFO_RATE(st->chip_config.divider);
period_us = 1000000 / freq_hz;
result = inv_mpu6050_set_power_itg(st, true);
if (result)
return result;
@ -576,6 +581,10 @@ static int inv_mpu6050_read_channel_data(struct iio_dev *indio_dev,
INV_MPU6050_SENSOR_GYRO);
if (result)
goto error_power_off;
/* need to wait 2 periods to have first valid sample */
min_sleep_us = 2 * period_us;
max_sleep_us = 2 * (period_us + period_us / 2);
usleep_range(min_sleep_us, max_sleep_us);
ret = inv_mpu6050_sensor_show(st, st->reg->raw_gyro,
chan->channel2, val);
result = inv_mpu6050_switch_engine(st, false,
@ -588,6 +597,10 @@ static int inv_mpu6050_read_channel_data(struct iio_dev *indio_dev,
INV_MPU6050_SENSOR_ACCL);
if (result)
goto error_power_off;
/* wait 1 period for first sample availability */
min_sleep_us = period_us;
max_sleep_us = period_us + period_us / 2;
usleep_range(min_sleep_us, max_sleep_us);
ret = inv_mpu6050_sensor_show(st, st->reg->raw_accl,
chan->channel2, val);
result = inv_mpu6050_switch_engine(st, false,
@ -600,8 +613,10 @@ static int inv_mpu6050_read_channel_data(struct iio_dev *indio_dev,
INV_MPU6050_SENSOR_TEMP);
if (result)
goto error_power_off;
/* wait for stablization */
msleep(INV_MPU6050_TEMP_UP_TIME);
/* wait 1 period for first sample availability */
min_sleep_us = period_us;
max_sleep_us = period_us + period_us / 2;
usleep_range(min_sleep_us, max_sleep_us);
ret = inv_mpu6050_sensor_show(st, st->reg->temperature,
IIO_MOD_X, val);
result = inv_mpu6050_switch_engine(st, false,
@ -610,7 +625,24 @@ static int inv_mpu6050_read_channel_data(struct iio_dev *indio_dev,
goto error_power_off;
break;
case IIO_MAGN:
result = inv_mpu6050_switch_engine(st, true,
INV_MPU6050_SENSOR_MAGN);
if (result)
goto error_power_off;
/* frequency is limited for magnetometer */
if (freq_hz > INV_MPU_MAGN_FREQ_HZ_MAX) {
freq_hz = INV_MPU_MAGN_FREQ_HZ_MAX;
period_us = 1000000 / freq_hz;
}
/* need to wait 2 periods to have first valid sample */
min_sleep_us = 2 * period_us;
max_sleep_us = 2 * (period_us + period_us / 2);
usleep_range(min_sleep_us, max_sleep_us);
ret = inv_mpu_magn_read(st, chan->channel2, val);
result = inv_mpu6050_switch_engine(st, false,
INV_MPU6050_SENSOR_MAGN);
if (result)
goto error_power_off;
break;
default:
ret = -EINVAL;

21
drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
View File

@ -44,9 +44,6 @@
#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) {
@ -321,7 +318,6 @@ int inv_mpu_magn_read(struct inv_mpu6050_state *st, int axis, int *val)
unsigned int status;
__be16 data;
uint8_t addr;
unsigned int freq_hz, period_ms;
int ret;
/* quit if chip is not supported */
@ -344,23 +340,6 @@ int inv_mpu_magn_read(struct inv_mpu6050_state *st, int axis, int *val)
}
addr += INV_MPU6050_REG_EXT_SENS_DATA;
/* compute period depending on current sampling rate */
freq_hz = INV_MPU6050_DIVIDER_TO_FIFO_RATE(st->chip_config.divider);
if (freq_hz > INV_MPU_MAGN_FREQ_HZ_MAX)
freq_hz = INV_MPU_MAGN_FREQ_HZ_MAX;
period_ms = 1000 / freq_hz;
ret = inv_mpu6050_switch_engine(st, true, INV_MPU6050_SENSOR_MAGN);
if (ret)
return ret;
/* need to wait 2 periods + half-period margin */
msleep(period_ms * 2 + period_ms / 2);
ret = inv_mpu6050_switch_engine(st, false, INV_MPU6050_SENSOR_MAGN);
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)

3
drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h
View File

@ -10,6 +10,9 @@
#include "inv_mpu_iio.h"
/* Magnetometer maximum frequency */
#define INV_MPU_MAGN_FREQ_HZ_MAX 50
int inv_mpu_magn_probe(struct inv_mpu6050_state *st);
/**