| Message ID | 20200107114532.6697-1-peter.ujfalusi@ti.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | a9ab624edd9186fbad734cfe5d606a6da3ca34db |
| Headers | show |
| Series | [v2] iio: adc: stm32-dfsdm: Use dma_request_chan() instead dma_request_slave_channel() | expand |
Acked-by: Olivier Moysan <olivier.moysan@st.com> 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 <peter.ujfalusi@ti.com> > --- > 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 <peter.ujfalusi@ti.com> > --- > 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 <fabrice.gasnier@st.com> > > 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 <peter.ujfalusi@ti.com> >> --- >> 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 <fabrice.gasnier@st.com> > > >> >> 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 <peter.ujfalusi@ti.com> >>> --- >>> 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 <fabrice.gasnier@st.com> >> >> >>> >>> 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 <peter.ujfalusi@ti.com> >>>> --- >>>> 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 <fabrice.gasnier@st.com> >>> >>> >>>> >>>> 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 <peter.ujfalusi@ti.com> >>>>> --- >>>>> 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 <fabrice.gasnier@st.com> >>>> >>>> >>>>> >>>>> 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 <fabrice.gasnier@st.com> 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 <peter.ujfalusi@ti.com> > >>>>> --- > >>>>> 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 <fabrice.gasnier@st.com> > >>>> > >>>> > >>>>> > >>>>> 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 > >
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; }
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> --- 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(-)