| Message ID | 1560949431-22948-6-git-send-email-olivier.moysan@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: adc: stm32-dfsdm: fix and improve output data managementiio: adc: stm32-dfsdm: fix and improve output data management | expand |
On Wed, 19 Jun 2019 15:03:51 +0200 Olivier Moysan <olivier.moysan@st.com> wrote: > Add a comment on DMA configuration for 16 bits record. > > Signed-off-by: Olivier Moysan <olivier.moysan@st.com> Applied. Thanks, Jonathan > --- > drivers/iio/adc/stm32-dfsdm-adc.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c > index d855a605eab6..ee1e0569d0e1 100644 > --- a/drivers/iio/adc/stm32-dfsdm-adc.c > +++ b/drivers/iio/adc/stm32-dfsdm-adc.c > @@ -918,6 +918,11 @@ static void stm32_dfsdm_dma_buffer_done(void *data) > static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev) > { > struct stm32_dfsdm_adc *adc = iio_priv(indio_dev); > + /* > + * The DFSDM supports half-word transfers. However, for 16 bits record, > + * 4 bytes buswidth is kept, to avoid losing samples LSBs when left > + * shift is required. > + */ > struct dma_slave_config config = { > .src_addr = (dma_addr_t)adc->dfsdm->phys_base, > .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c index d855a605eab6..ee1e0569d0e1 100644 --- a/drivers/iio/adc/stm32-dfsdm-adc.c +++ b/drivers/iio/adc/stm32-dfsdm-adc.c @@ -918,6 +918,11 @@ static void stm32_dfsdm_dma_buffer_done(void *data) static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev) { struct stm32_dfsdm_adc *adc = iio_priv(indio_dev); + /* + * The DFSDM supports half-word transfers. However, for 16 bits record, + * 4 bytes buswidth is kept, to avoid losing samples LSBs when left + * shift is required. + */ struct dma_slave_config config = { .src_addr = (dma_addr_t)adc->dfsdm->phys_base, .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
Add a comment on DMA configuration for 16 bits record. Signed-off-by: Olivier Moysan <olivier.moysan@st.com> --- drivers/iio/adc/stm32-dfsdm-adc.c | 5 +++++ 1 file changed, 5 insertions(+)