Re: [PATCH v2] iio: adc: stm32-dfsdm: adapt sampling rate to oversampling ratio

Fabrice Gasnier
2019-11-27T16:14:00Z

On 11/27/19 2:10 PM, Olivier Moysan wrote:
> Update sampling rate when oversampling ratio is changed
> through the IIO ABI.
>
> Signed-off-by: Olivier Moysan <olivier.moysan@st.com>

Hi Olivier,

Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>

Thanks,
Fabrice
> ---
> changes in version 2:
> - correct title
> ---
> drivers/iio/adc/stm32-dfsdm-adc.c | 32 ++++++++++++++++++-------------
> 1 file changed, 19 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
> index 0339ecdd06bd..87a842507509 100644
> --- a/drivers/iio/adc/stm32-dfsdm-adc.c
> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
> @@ -1221,14 +1221,32 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
> unsigned int spi_freq;
> int ret = -EINVAL;
>
> + switch (ch->src) {
> + case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL:
> + spi_freq = adc->dfsdm->spi_master_freq;
> + break;
> + case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_FALLING:
> + case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_RISING:
> + spi_freq = adc->dfsdm->spi_master_freq / 2;
> + break;
> + default:
> + spi_freq = adc->spi_freq;
> + }
> +
> switch (mask) {
> case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> ret = iio_device_claim_direct_mode(indio_dev);
> if (ret)
> return ret;
> +
> ret = stm32_dfsdm_compute_all_osrs(indio_dev, val);
> - if (!ret)
> + if (!ret) {
> + dev_dbg(&indio_dev->dev,
> + "Sampling rate changed from (%u) to (%u)\n",
> + adc->sample_freq, spi_freq / val);
> adc->oversamp = val;
> + adc->sample_freq = spi_freq / val;
> + }
> iio_device_release_direct_mode(indio_dev);
> return ret;
>
> @@ -1240,18 +1258,6 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
> if (ret)
> return ret;
>
> - switch (ch->src) {
> - case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL:
> - spi_freq = adc->dfsdm->spi_master_freq;
> - break;
> - case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_FALLING:
> - case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_RISING:
> - spi_freq = adc->dfsdm->spi_master_freq / 2;
> - break;
> - default:
> - spi_freq = adc->spi_freq;
> - }
> -
> ret = dfsdm_adc_set_samp_freq(indio_dev, val, spi_freq);
> iio_device_release_direct_mode(indio_dev);
> return ret;
>