On Tue, Nov 07, 2017 at 10:49:41AM +0200, Eugen Hristev wrote: > > > On 20.10.2017 00:58, Rob Herring wrote: > > On Thu, Oct 19, 2017 at 6:14 AM, Alexandre Belloni > > <alexandre.belloni@xxxxxxxxxxxxxxxxxx> wrote: > > > On 13/10/2017 at 16:51:42 -0500, Rob Herring wrote: > > > > On Wed, Oct 11, 2017 at 09:35:28AM +0300, Eugen Hristev wrote: > > > > > Added property for DMA configuration of the device. > > > > > > > > > > Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx> > > > > > --- > > > > > Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt | 7 +++++++ > > > > > 1 file changed, 7 insertions(+) > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt b/Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt > > > > > index 552e7a8..5f94d479 100644 > > > > > --- a/Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt > > > > > +++ b/Documentation/devicetree/bindings/iio/adc/at91-sama5d2_adc.txt > > > > > @@ -17,6 +17,11 @@ Required properties: > > > > > This property uses the IRQ edge types values: IRQ_TYPE_EDGE_RISING , > > > > > IRQ_TYPE_EDGE_FALLING or IRQ_TYPE_EDGE_BOTH > > > > > > > > > > +Optional properties: > > > > > + - dmas: Phandle to dma channel for the ADC. > > > > > + See ../../dma/dma.txt for details. > > > > > + - dma-names: Must be "rx" when dmas property is being used. > > > > > > > > -names is pointless when there is only one. > > > > > > > > > > You didn't reply to the question I had previously about that: What if at > > > some point, we have multiple dmas in the same binding? > > > > Then add dma-names at that point and rx has to be first. If you know > > there's other channels, then add them now. Don't evolve the bindings > > needlessly based on what a driver supports. > > > > Would another channel make sense here? Maybe multi-channel rx in which > > case your naming wouldn't be setup for that. But "tx" on an ADC? > > > > Rob > > Hello Rob, > > I can keep only "dmas" and remove "dma-names", but then, the API used by > the drivers that request channels requires a name parameter > (dma_request_slave_channel), and it will look always inside the > "dma-names" property to match the name and find the proper channel, and > it will fail in this case. > > Looking in the general dma binding (dma.txt) I can see that both > properties are marked as required for a client driver, so that's why > I added both. > I don't understand why dma-names should be removed. For sure, if we have only one channel, it becomes useless but the helpers to get a dma channel rely on dma-names property. Ludovic > I can either keep dma-names; or try to find the channel properties by > looking directly into the OF node and create the dma_chan struct inside > my driver (maybe call some xlate function for the DMA controller), but > still need to get the DT property. A complicated option would be to > actually create an API inside the dmaengine to find a channel without > name. > > Which approach you think it's best to pursue ? > > Thanks, > Eugen > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
