* [PATCH v3] iio: adc: stm32-adc: Use dma_request_chan() instead dma_request_slave_channel()
@ 2020-01-08 8:08 Peter Ujfalusi
2020-01-11 11:00 ` Jonathan Cameron
0 siblings, 1 reply; 2+ messages in thread
From: Peter Ujfalusi @ 2020-01-08 8:08 UTC (permalink / raw)
To: jic23, mcoquelin.stm32, alexandre.torgue, fabrice.gasnier
Cc: linux-iio, vkoul, linux-kernel, linux-arm-kernel, linux-stm32
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>
---
Hi,
Changes since v2:
- Replace the comment as suggested by Fabrice
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..a8d2414ee2eb 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;
+ }
+
+ /* 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,
--
Peter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v3] iio: adc: stm32-adc: Use dma_request_chan() instead dma_request_slave_channel()
2020-01-08 8:08 [PATCH v3] iio: adc: stm32-adc: Use dma_request_chan() instead dma_request_slave_channel() Peter Ujfalusi
@ 2020-01-11 11:00 ` Jonathan Cameron
0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Cameron @ 2020-01-11 11:00 UTC (permalink / raw)
To: Peter Ujfalusi
Cc: alexandre.torgue, linux-iio, linux-kernel, vkoul,
mcoquelin.stm32, fabrice.gasnier, linux-stm32, linux-arm-kernel
On Wed, 8 Jan 2020 10:08:01 +0200
Peter Ujfalusi <peter.ujfalusi@ti.com> 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 <peter.ujfalusi@ti.com>
> Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Applied to the togreg branch of iio.git and pushed out as testing.
thanks,
Jonathan
> ---
> Hi,
>
> Changes since v2:
> - Replace the comment as suggested by Fabrice
>
> 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..a8d2414ee2eb 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;
> + }
> +
> + /* 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,
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2020-01-08 8:08 [PATCH v3] iio: adc: stm32-adc: Use dma_request_chan() instead dma_request_slave_channel() Peter Ujfalusi
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