On Wed, 19 Feb 2020 15:39:54 +0100
Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx> wrote:
> 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.
>
> Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
I should have raised this before, but is this something we might want to
backport? I don't really want this whole cleanup series getting backported,
so is there a more minimal change for older kernels? (probably just sleep too
long in all cases!)
Applied,
Jonathan
> ---
> drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 36 ++++++++++++++++++++--
> drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c | 21 -------------
> drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h | 3 ++
> 3 files changed, 37 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> index a51efc4c941b..aeee39696d3a 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> @@ -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;
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
> index 3f402fa56d95..f282e9cc34c5 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.c
> @@ -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)
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h
> index f7ad50ca6c1b..185c000c697c 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_magn.h
> @@ -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);
>
> /**
