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>
---
Hi,
Changes since v1:
- Fall back to IRQ mode only in case of ENODEV
Regards,
Peter
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 3b291d72701c..df5f5d61f9f9 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1746,9 +1746,21 @@ 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;
+ }
+
+ /* Ignore errors to 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,
--
Peter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
