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 <[email protected]>
---
Hi,
Changes since v1:
- Fall back to IRQ mode for ADC only in case of ENODEV
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;
+ }
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;
}
--
Peter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Acked-by: Olivier Moysan <[email protected]>
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 <[email protected]>
> ---
> Hi,
>
> Changes since v1:
> - Fall back to IRQ mode for ADC only in case of ENODEV
>
> 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;
> + }
>
> 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;
> }
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 <[email protected]>
> ---
> 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 <[email protected]>
>
> 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
> + }
>
> 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;
> }
>
On 09/01/2020 11.13, Fabrice Gasnier wrote:
> 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 <[email protected]>
>> ---
>> 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 <[email protected]>
>
>
>>
>> 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.
I don't make decision here on behalf of the adc path on to go forward w/
or w/o DMA support and if we go ahead the stm32_dfsdm_dma_release()
needs the dma_chan to be NULL in case we don't use DMA.
It is much cleaner to set dma_chan to NULL here than doing it in other
paths.
>
> Best Regards,
> Fabrice
>
>> + }
>>
>> 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;
>> }
>>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
On 1/9/20 11:32 AM, Peter Ujfalusi wrote:
>
>
> On 09/01/2020 11.13, Fabrice Gasnier wrote:
>> 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 <[email protected]>
>>> ---
>>> 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 <[email protected]>
>>
>>
>>>
>>> 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.
>
> I don't make decision here on behalf of the adc path on to go forward w/
> or w/o DMA support and if we go ahead the stm32_dfsdm_dma_release()
> needs the dma_chan to be NULL in case we don't use DMA.
>
> It is much cleaner to set dma_chan to NULL here than doing it in other
> paths.
Hi Peter,
Sorry I wasn't clear enough. I agree with you. I was suggesting only,
talking about the 'ret' variable. It may be removed to spare a few lines
:-).
if (IS_ERR(adc->dma_chan)) {
adc->dma_chan = NULL;
return PTR_ERR(adc->dma_chan);
}
I'm okay both ways.
>
>>
>> Best Regards,
>> Fabrice
>>
>>> + }
>>>
>>> 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;
>>> }
>>>
>
> - Péter
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
On 09/01/2020 13.29, Fabrice Gasnier wrote:
> On 1/9/20 11:32 AM, Peter Ujfalusi wrote:
>>
>>
>> On 09/01/2020 11.13, Fabrice Gasnier wrote:
>>> 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 <[email protected]>
>>>> ---
>>>> 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 <[email protected]>
>>>
>>>
>>>>
>>>> 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.
>>
>> I don't make decision here on behalf of the adc path on to go forward w/
>> or w/o DMA support and if we go ahead the stm32_dfsdm_dma_release()
>> needs the dma_chan to be NULL in case we don't use DMA.
>>
>> It is much cleaner to set dma_chan to NULL here than doing it in other
>> paths.
>
> Hi Peter,
Hi Fabrice,
> Sorry I wasn't clear enough. I agree with you. I was suggesting only,
> talking about the 'ret' variable. It may be removed to spare a few lines
> :-).
> if (IS_ERR(adc->dma_chan)) {
> adc->dma_chan = NULL;
> return PTR_ERR(adc->dma_chan);
> }
> I'm okay both ways.
PTR_ERR(NULL); will return 0
I need to retrieve the actual error code before NULLing dma_chan.
>
>>
>>>
>>> Best Regards,
>>> Fabrice
>>>
>>>> + }
>>>>
>>>> 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;
>>>> }
>>>>
>>
>> - Péter
>>
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
On 1/9/20 12:40 PM, Peter Ujfalusi wrote:
>
>
> On 09/01/2020 13.29, Fabrice Gasnier wrote:
>> On 1/9/20 11:32 AM, Peter Ujfalusi wrote:
>>>
>>>
>>> On 09/01/2020 11.13, Fabrice Gasnier wrote:
>>>> 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 <[email protected]>
>>>>> ---
>>>>> 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 <[email protected]>
>>>>
>>>>
>>>>>
>>>>> 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.
>>>
>>> I don't make decision here on behalf of the adc path on to go forward w/
>>> or w/o DMA support and if we go ahead the stm32_dfsdm_dma_release()
>>> needs the dma_chan to be NULL in case we don't use DMA.
>>>
>>> It is much cleaner to set dma_chan to NULL here than doing it in other
>>> paths.
>>
>> Hi Peter,
>
> Hi Fabrice,
>
>> Sorry I wasn't clear enough. I agree with you. I was suggesting only,
>> talking about the 'ret' variable. It may be removed to spare a few lines
>> :-).
>> if (IS_ERR(adc->dma_chan)) {
>> adc->dma_chan = NULL;
>> return PTR_ERR(adc->dma_chan);
>> }
>> I'm okay both ways.
>
> PTR_ERR(NULL); will return 0
> I need to retrieve the actual error code before NULLing dma_chan.
Oh yes, so please forget this.
Thanks,
Fabrice
>
>>
>>>
>>>>
>>>> Best Regards,
>>>> Fabrice
>>>>
>>>>> + }
>>>>>
>>>>> 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;
>>>>> }
>>>>>
>>>
>>> - Péter
>>>
>>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>>>
>
> - Péter
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
On Thu, 9 Jan 2020 13:56:14 +0100
Fabrice Gasnier <[email protected]> wrote:
> On 1/9/20 12:40 PM, Peter Ujfalusi wrote:
> >
> >
> > On 09/01/2020 13.29, Fabrice Gasnier wrote:
> >> On 1/9/20 11:32 AM, Peter Ujfalusi wrote:
> >>>
> >>>
> >>> On 09/01/2020 11.13, Fabrice Gasnier wrote:
> >>>> 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 <[email protected]>
> >>>>> ---
> >>>>> 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 <[email protected]>
> >>>>
> >>>>
> >>>>>
> >>>>> 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.
> >>>
> >>> I don't make decision here on behalf of the adc path on to go forward w/
> >>> or w/o DMA support and if we go ahead the stm32_dfsdm_dma_release()
> >>> needs the dma_chan to be NULL in case we don't use DMA.
> >>>
> >>> It is much cleaner to set dma_chan to NULL here than doing it in other
> >>> paths.
> >>
> >> Hi Peter,
> >
> > Hi Fabrice,
> >
> >> Sorry I wasn't clear enough. I agree with you. I was suggesting only,
> >> talking about the 'ret' variable. It may be removed to spare a few lines
> >> :-).
> >> if (IS_ERR(adc->dma_chan)) {
> >> adc->dma_chan = NULL;
> >> return PTR_ERR(adc->dma_chan);
> >> }
> >> I'm okay both ways.
> >
> > PTR_ERR(NULL); will return 0
> > I need to retrieve the actual error code before NULLing dma_chan.
>
> Oh yes, so please forget this.
> Thanks,
> Fabrice
Applied to the togreg branch of iio.git and pushed out as testing.
Note I'll need to rebase once Greg pushes out staging/staging-next
with the changes currently in staging/staging-testing. Shouldn't
have an effect on this though!
Thanks,
Jonathan
>
> >
> >>
> >>>
> >>>>
> >>>> Best Regards,
> >>>> Fabrice
> >>>>
> >>>>> + }
> >>>>>
> >>>>> 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;
> >>>>> }
> >>>>>
> >>>
> >>> - Péter
> >>>
> >>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> >>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> >>>
> >
> > - Péter
> >
> > Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> > Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> >