> On Wed, 8 Feb 2023 15:42:31 +0100
> Lorenzo Bianconi <lorenzo@xxxxxxxxxx> wrote:
>
> > 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>
>
> Is this only necessary for the particular sensor you have provided
> values for? Or is it more general?
>
> I think the code will currently just set the number of samples to discard
> to 0 for other cases (as no value set for those sensor types).
> That's fine if 0 is definitely the right value for those other sensors.
I think all the sensors have this information in the datasheet/application
note. However, even if we add sample_to_discard just for LSM6DSM for the moment,
we do not introduce any regression for the other sensors with respect to the
previous codebase since sample_to_discard will be just set to 0 (so we do not
discard any sample). I can add sample_to_discard for LSM6DSO but at the
moment I do not have other devices for testing.
For LSM6DSO, do you prefer to add it in v2 or is it fine a follow-up patch?
Regards,
Lorenzo
>
> Thanks,
>
> Jonathan
>
>
> > ---
> > 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(-)
> >
> > 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
>
> Trivial but wrong comment syntax. If that's all that comes up I'll fix it here
> and in other instances below when applying.
>
> > + * 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,
>
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