Re: [PATCH 1/3] Documentation: dt: iio: at91-sama5d2_adc: add optional dma property

[Alexandre Belloni]

On 17/08/2017 at 10:10:59 -0500, Rob Herring wrote:
> On Thu, Aug 10, 2017 at 03:34:57PM +0300, Eugen Hristev wrote:
> > Added property for DMA configuration of the device.
> 
> "dt-bindings: iio: ..." is preferred for subject.
> 
> > 
> > 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..5f94d47 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's only one.
> 

Hypothetical question: what if at some point we have multiple dmas? Then
we would have the choice between breaking the backward compatibility or
handling the absence of dma-names in the driver which is less than
ideal.


-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com