Re: [PATCH 3/6] dt-bindings: Document Broadcom Cygnus SoC and clock driver

From: Arnd Bergmann
Date: Wed Oct 08 2014 - 09:36:29 EST


On Wednesday 08 October 2014 03:58:15 Scott Branden wrote:
> On 14-10-08 12:57 AM, Arnd Bergmann wrote:
> > On Tuesday 07 October 2014 22:27:02 Scott Branden wrote:
> >> diff --git a/Documentation/devicetree/bindings/arm/cygnus.txt b/Documentation/devicetree/bindings/arm/cygnus.txt
> >> new file mode 100644
> >> index 0000000..a210377
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/arm/cygnus.txt
> >> @@ -0,0 +1,12 @@
> >> +Broadcom Cygnus device tree bindings
> >> +------------------------------------
> >> +
> >> +All Cygnus boards shall have the following properties:
> >> +
> >> +Required root node property:
> >> + - compatible = "brcm,cygnus";
> >
> > Can you add a more specific model number for the soc as well?
> > I assume that cygnus refers to more than one model, so you
> > should probably list both the family and the individual
> > SoC type here.
> Add specific model numbers does not seem necessary because they are not
> needed to be specified in the device tree for compatible purposes for
> the kernel to work. Plus, the list of model numbers will continue to
> grow over time and compatible strings would need to be added to the
> kernel for no apparent reason?

It's always helpful to have them in the DT though, in case you ever
need to add a workaround for one of the SoCs.

You can change the description to just state the format of the
more specific model number so you don't need to add the particular
type to the binding, but I'd definitely recommend listing both
a generic and a more specific name here, such as

compatible = "brcm,bcm123456", "brcm,cygnus";

> >> +Boards variants shall have the following additional properties:
> >> +
> >> +Required root node property for the BCM911360_ENTPHN board:
> >> + - compatible = "brcm,bcm911360_entphn";
> >>
> >
> > We normally don't list specific boards here, since it's hard to
> > keep up.
> Thanks - removed specific boards from file and moved the cygnus.txt file
> to devicetree/bindings/arm/bcm/cygnus.txt in next version. This seems
> to be like the appropriate place to put this document. We will need to
> add back in board specific bindings when ALSA support is added. But
> that will be a later commit to deal with.

I believe most new alsa drivers can now use the binding from
Documentation/devicetree/bindings/sound/simple-card.txt
so you should no longer need a board specific driver or binding
for those.

Arnd
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