Add a comment on DMA configuration for 16 bits record.
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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,