From: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
[ Upstream commit a9ab624edd9186fbad734cfe5d606a6da3ca34db ]
dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.
By using dma_request_chan() directly the driver can support deferred
probing against DMA.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
Acked-by: Olivier Moysan <olivier.moysan@xxxxxx>
Acked-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/iio/adc/stm32-dfsdm-adc.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 3ae0366a7b58..4a9337a3f9a3 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -1363,9 +1363,13 @@ static int stm32_dfsdm_dma_request(struct iio_dev *indio_dev)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
- adc->dma_chan = dma_request_slave_channel(&indio_dev->dev, "rx");
- if (!adc->dma_chan)
- return -EINVAL;
+ adc->dma_chan = dma_request_chan(&indio_dev->dev, "rx");
+ if (IS_ERR(adc->dma_chan)) {
+ int ret = PTR_ERR(adc->dma_chan);
+
+ adc->dma_chan = NULL;
+ return ret;
+ }
adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
DFSDM_DMA_BUFFER_SIZE,
@@ -1489,7 +1493,16 @@ static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev)
init_completion(&adc->completion);
/* Optionally request DMA */
- if (stm32_dfsdm_dma_request(indio_dev)) {
+ ret = stm32_dfsdm_dma_request(indio_dev);
+ if (ret) {
+ if (ret != -ENODEV) {
+ if (ret != -EPROBE_DEFER)
+ dev_err(&indio_dev->dev,
+ "DMA channel request failed with %d\n",
+ ret);
+ return ret;
+ }
+
dev_dbg(&indio_dev->dev, "No DMA support\n");
return 0;
}
--
2.25.1
