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

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>
This commit is contained in:
Peter Ujfalusi 2020-01-08 10:08:01 +02:00 committed by Jonathan Cameron
parent a9ab624edd
commit 735404b846
1 changed files with 14 additions and 2 deletions

View File

@ -1796,9 +1796,21 @@ 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,