From: Peter Ujfalusi peter.ujfalusi@ti.com
[ Upstream commit 735404b846dffcb320264f62b76e6f70012214dd ]
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: 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-adc.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index 9f63ceb15865..a2279cccb584 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1763,9 +1763,21 @@ static int stm32_adc_dma_request(struct iio_dev *indio_dev) struct dma_slave_config config; int ret;
- adc->dma_chan = dma_request_slave_channel(&indio_dev->dev, "rx"); - if (!adc->dma_chan) + adc->dma_chan = dma_request_chan(&indio_dev->dev, "rx"); + if (IS_ERR(adc->dma_chan)) { + ret = PTR_ERR(adc->dma_chan); + if (ret != -ENODEV) { + if (ret != -EPROBE_DEFER) + dev_err(&indio_dev->dev, + "DMA channel request failed with %d\n", + ret); + return ret; + } + + /* DMA is optional: fall back to IRQ mode */ + adc->dma_chan = NULL; return 0; + }
adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev, STM32_DMA_BUFFER_SIZE,