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iio: adc: stm32-dfsdm: Use dma_request_chan() instead dma_request_slave_channel()

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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>
This commit is contained in:
Peter Ujfalusi 2020-01-07 13:45:32 +02:00 committed by Jonathan Cameron
parent e895bc1ebb
commit a9ab624edd
1 changed files with 17 additions and 4 deletions
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21
drivers/iio/adc/stm32-dfsdm-adc.c
View file

@ -1383,9 +1383,13 @@ 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,
@ -1509,7 +1513,16 @@ 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;
}