> During digital filters settling time the driver is expected to drop
> samples since they can be corrupted. Introduce the capability to drop
> a given number of samples according to the configured ODR.
> Add the sample_to_discard data for LSM6DSM sensor.
>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> ---
> drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h | 11 ++++
> .../iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 58 +++++++++++++++----
> drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 18 ++++++
> 3 files changed, 77 insertions(+), 10 deletions(-)
I forgot to say I tested this patch on my LSM6DSM and it works fine for me.
Regards,
Lorenzo
>
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> index 499fcf8875b4..8e119d78730b 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> @@ -137,6 +137,13 @@ struct st_lsm6dsx_odr_table_entry {
> int odr_len;
> };
>
> +struct st_lsm6dsx_samples_to_discard {
> + struct {
> + u32 milli_hz;
> + u16 samples;
> + } val[ST_LSM6DSX_ODR_LIST_SIZE];
> +};
> +
> struct st_lsm6dsx_fs {
> u32 gain;
> u8 val;
> @@ -291,6 +298,7 @@ struct st_lsm6dsx_ext_dev_settings {
> * @irq_config: interrupts related registers.
> * @drdy_mask: register info for data-ready mask (addr + mask).
> * @odr_table: Hw sensors odr table (Hz + val).
> + * @samples_to_discard: Number of samples to discard for filters settling time.
> * @fs_table: Hw sensors gain table (gain + val).
> * @decimator: List of decimator register info (addr + mask).
> * @batch: List of FIFO batching register info (addr + mask).
> @@ -323,6 +331,7 @@ struct st_lsm6dsx_settings {
> } irq_config;
> struct st_lsm6dsx_reg drdy_mask;
> struct st_lsm6dsx_odr_table_entry odr_table[2];
> + struct st_lsm6dsx_samples_to_discard samples_to_discard[2];
> struct st_lsm6dsx_fs_table_entry fs_table[2];
> struct st_lsm6dsx_reg decimator[ST_LSM6DSX_MAX_ID];
> struct st_lsm6dsx_reg batch[ST_LSM6DSX_MAX_ID];
> @@ -353,6 +362,7 @@ enum st_lsm6dsx_fifo_mode {
> * @hw: Pointer to instance of struct st_lsm6dsx_hw.
> * @gain: Configured sensor sensitivity.
> * @odr: Output data rate of the sensor [Hz].
> + * @samples_to_discard: Number of samples to discard for filters settling time.
> * @watermark: Sensor watermark level.
> * @decimator: Sensor decimation factor.
> * @sip: Number of samples in a given pattern.
> @@ -367,6 +377,7 @@ struct st_lsm6dsx_sensor {
> u32 gain;
> u32 odr;
>
> + u16 samples_to_discard;
> u16 watermark;
> u8 decimator;
> u8 sip;
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> index 7dd5205aea5b..c1059a79f5ff 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> @@ -457,17 +457,29 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
> }
>
> if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
> - iio_push_to_buffers_with_timestamp(
> - hw->iio_devs[ST_LSM6DSX_ID_GYRO],
> - &hw->scan[ST_LSM6DSX_ID_GYRO],
> - gyro_sensor->ts_ref + ts);
> + /* We need to discards gyro samples during
> + * filters settling time
> + */
> + if (gyro_sensor->samples_to_discard > 0)
> + gyro_sensor->samples_to_discard--;
> + else
> + iio_push_to_buffers_with_timestamp(
> + hw->iio_devs[ST_LSM6DSX_ID_GYRO],
> + &hw->scan[ST_LSM6DSX_ID_GYRO],
> + gyro_sensor->ts_ref + ts);
> gyro_sip--;
> }
> if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
> - iio_push_to_buffers_with_timestamp(
> - hw->iio_devs[ST_LSM6DSX_ID_ACC],
> - &hw->scan[ST_LSM6DSX_ID_ACC],
> - acc_sensor->ts_ref + ts);
> + /* We need to discards accel samples during
> + * filters settling time
> + */
> + if (acc_sensor->samples_to_discard > 0)
> + acc_sensor->samples_to_discard--;
> + else
> + iio_push_to_buffers_with_timestamp(
> + hw->iio_devs[ST_LSM6DSX_ID_ACC],
> + &hw->scan[ST_LSM6DSX_ID_ACC],
> + acc_sensor->ts_ref + ts);
> acc_sip--;
> }
> if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
> @@ -541,8 +553,12 @@ st_lsm6dsx_push_tagged_data(struct st_lsm6dsx_hw *hw, u8 tag,
> }
>
> sensor = iio_priv(iio_dev);
> - iio_push_to_buffers_with_timestamp(iio_dev, data,
> - ts + sensor->ts_ref);
> + /* We need to discards gyro samples during filters settling time */
> + if (sensor->samples_to_discard > 0)
> + sensor->samples_to_discard--;
> + else
> + iio_push_to_buffers_with_timestamp(iio_dev, data,
> + ts + sensor->ts_ref);
>
> return 0;
> }
> @@ -654,6 +670,25 @@ int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
> return err;
> }
>
> +static void
> +st_lsm6dsx_update_samples_to_discard(struct st_lsm6dsx_sensor *sensor)
> +{
> + const struct st_lsm6dsx_samples_to_discard *data;
> + int i;
> +
> + if (sensor->id != ST_LSM6DSX_ID_GYRO &&
> + sensor->id != ST_LSM6DSX_ID_ACC)
> + return;
> +
> + data = &sensor->hw->settings->samples_to_discard[sensor->id];
> + for (i = 0; i < ST_LSM6DSX_ODR_LIST_SIZE; i++) {
> + if (data->val[i].milli_hz == sensor->odr) {
> + sensor->samples_to_discard = data->val[i].samples;
> + return;
> + }
> + }
> +}
> +
> int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
> {
> struct st_lsm6dsx_hw *hw = sensor->hw;
> @@ -673,6 +708,9 @@ int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
> goto out;
> }
>
> + if (enable)
> + st_lsm6dsx_update_samples_to_discard(sensor);
> +
> err = st_lsm6dsx_device_set_enable(sensor, enable);
> if (err < 0)
> goto out;
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> index 3f6060c64f32..966df6ffe874 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -634,6 +634,24 @@ static const struct st_lsm6dsx_settings st_lsm6dsx_sensor_settings[] = {
> .fs_len = 4,
> },
> },
> + .samples_to_discard = {
> + [ST_LSM6DSX_ID_ACC] = {
> + .val[0] = { 12500, 1 },
> + .val[1] = { 26000, 1 },
> + .val[2] = { 52000, 1 },
> + .val[3] = { 104000, 2 },
> + .val[4] = { 208000, 2 },
> + .val[5] = { 416000, 2 },
> + },
> + [ST_LSM6DSX_ID_GYRO] = {
> + .val[0] = { 12500, 2 },
> + .val[1] = { 26000, 5 },
> + .val[2] = { 52000, 7 },
> + .val[3] = { 104000, 12 },
> + .val[4] = { 208000, 20 },
> + .val[5] = { 416000, 36 },
> + },
> + },
> .irq_config = {
> .irq1 = {
> .addr = 0x0d,
> --
> 2.39.1
>
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