From: Peter Ujfalusi peter.ujfalusi@ti.com
[ 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@ti.com Acked-by: Olivier Moysan olivier.moysan@st.com Acked-by: Fabrice Gasnier fabrice.gasnier@st.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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; }