[alsa-devel] [PATCH 1/4] dt-bindings: Document the dmas and dma-names properties for bcm2835-analog-audio

[Michael Zoran]

On Mon, 2017-03-20 at 11:50 -0500, Rob Herring wrote:
> On Sat, Mar 11, 2017 at 10:38:17PM -0800, Michael Zoran wrote:
> > Add documentation for the DMA properties required when using the
> > PWM controller of the bcm2835 for analog audio output.
> > 
> > Signed-off-by: Michael Zoran <mzoran at crowfest.net>
> > ---
> >  Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt | 9
> > ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt
> > b/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt
> > index cf573e85b11d..08fc06fc083a 100644
> > --- a/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt
> > +++ b/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt
> > @@ -1,14 +1,21 @@
> >  BCM2835 PWM controller (Raspberry Pi controller)
> >  
> >  Required properties:
> > -- compatible: should be "brcm,bcm2835-pwm"
> > +- compatible: should be "brcm,bcm2835-pwm" or "brcm,bcm2835-
> > analog-audio"
> 
> Compatibles are not for selecting usage modes. You should describe
> the 
> connection to the pwm that makes it an audio output rather than
> change 
> the compatible.
> 

Cool, that's good to know that someone let me know after all this time.
 And please tell how if DT nodes are an exact documentation of the
hardware how are virtualized DT nodes like firmware getting into the
DTs?