Re: [PATCH 1/2] dt-bindings: iio: stm32-adc: add option to set resolution

[Fabrice Gasnier]

On 02/19/2017 01:09 PM, Jonathan Cameron wrote:
> On 15/02/17 16:55, Fabrice Gasnier wrote:
> > Add documentation for 'st,adc-res' dt optional property.
> >
> > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
> I'm happy with this, but would like to leave time for a device tree review.
>
> Ultimately we may well want to make this a generic property and call it something
> like adc-resolution but perhaps we need to wait until we have a few more devices
> supporting setting it via device tree to figure out what the best interface is.
> It would exactly be a problem to support this as a deprecated binding at that
> point.

Hi Jonathan,

I agree with you on this... It may be better to have generic property
for this, especially if you see that it will come in the near future.
May I suggest this prop to be less restrictive, e.g. like 
resolution-bits as is may also be worth for other device types, e.g. DAC 
as an example ?

> Give me a poke if we hear nothing from Rob or Mark for say another week.

No news yet, but it can wait a little longer.

Please advise,
Regards,
Fabrice

> Thanks,
>
> Jonathan
>
> > ---
> >  Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
> > index 5dfc88e..45f7ff2 100644
> > --- a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
> > +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
> > @@ -57,6 +57,9 @@ Optional properties:
> >  - dmas: Phandle to dma channel for this ADC instance.
> >    See ../../dma/dma.txt for details.
> >  - dma-names: Must be "rx" when dmas property is being used.
> > +- st,adc-res: Resolution (bits) to use for conversions. Must match device
> > +  available resolutions (e.g. can be 6, 8, 10 or 12 on stm32f4). Default
> > +  is maximum resolution if unset.
> >
> >  Example:
> >  	adc: adc@40012000 {
> > @@ -84,6 +87,7 @@ Example:
> >  			st,adc-channels = <8>;
> >  			dmas = <&dma2 0 0 0x400 0x0>;
> >  			dma-names = "rx";
> > +			st,adc-res = <8>;
> >  		};
> >  		...
> >  		other adc child nodes follow...