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

Olivier MOYSAN olivier.moysan at st.com
Fri Jan 10 02:06:13 PST 2020


Hi Jonathan, all,

Kind reminder on this patch.
Regards
Olivier

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 at st.com>
> ---
> 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;


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