Re: [PATCH v2] iio: adc: stm32-dfsdm: Use dma_request_chan() instead dma_request_slave_channel()
flat view
From: Fabrice Gasnier <hidden>
Date: 2020-01-09 09:13:24
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linux-iio, lkml
On 1/7/20 12:45 PM, Peter Ujfalusi wrote:
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 <redacted> --- Hi, Changes since v1: - Fall back to IRQ mode for ADC only in case of ENODEV
Hi Peter, Thanks for the patch, Please find a minor comment here after. Apart from that, you can add my: Acked-by: Fabrice Gasnier <redacted>
quoted hunk ↗ jump to hunk
Regards, Peter 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 e493242c266e..74a2211bdff4 100644 --- a/drivers/iio/adc/stm32-dfsdm-adc.c +++ b/drivers/iio/adc/stm32-dfsdm-adc.c@@ -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;
You may "return PTR_ERR(adc->dma_chan);" directly here. Best Regards, Fabrice
quoted hunk ↗ jump to hunk
+ } 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; }
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