Re: [RFC 1/9] dt-bindings: display: renesas,cmm: Add R-Car CMM documentation

[Jacopo Mondi <jacopo@jmondi.org>]

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Hi Laurent,

On Sat, May 11, 2019 at 09:16:18PM +0300, Laurent Pinchart wrote:
> Hi Jacopo,
>
> Thank you for the patch.
>
> On Wed, May 08, 2019 at 07:34:20PM +0200, Jacopo Mondi wrote:
> > Add device tree bindings documentation for the Renesas R-Car Display
> > Unit Color Management Module.
> >
> > CMM is the image enhancement module available on each R-Car DU video
> > channel.
>
> Not on all of them, V3M and V3H don't include a CMM module.
>
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  .../bindings/display/renesas,cmm.txt          | 24 +++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/display/renesas,cmm.txt
> >
> > diff --git a/Documentation/devicetree/bindings/display/renesas,cmm.txt b/Documentation/devicetree/bindings/display/renesas,cmm.txt
> > new file mode 100644
> > index 000000000000..d7674417edb4
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/renesas,cmm.txt
> > @@ -0,0 +1,24 @@
> > +* Renesas R-Car Color Management Unit (CMM)
>
> It's called Color Management Module in the documentation (hence the CMM
> abbreviation)
>
> > +
> > +Renesas R-Car image enhancement module connected to R-Car DU video channels.
> > +
> > +Required properties:
> > + - compatible: shall be:
> > +   - "renesas,cmm"
>
> There's a CMM in R-Car Gen2 with a different feature set, so I think you
> need at least two compatible strings. As far as I can tell SoC-specific
> compatible strings are required.

I assume you meant "SoC-specific compatible strings are NOT required" ?

Could you otherwise specify why do you think we need a per-SoC
compatible, since there are no platform specific data (for now, at
least, but considering the CMM seems identical in all SoCs I hardly
think we will have any in the near future).

Ack on the gen2/gen3 specific strings though.

Thanks
   j


>
> > +
> > + - reg: the address base and length of the memory area where CMM control
> > +   registers are mapped to.
> > +
> > + - clocks: phandle and clock-specifier pair to the CMM functional clock
> > +   supplier.
> > +
> > +Example:
> > +--------
> > +
> > +	cmm0: cmm@fea40000 {
> > +		compatible = "renesas,cmm";
> > +		reg = <0 0xfea40000 0 0x1000>;
> > +		power-domains = <&sysc R8A7796_PD_ALWAYS_ON>;
> > +		clocks = <&cpg CPG_MOD 711>;
> > +		resets = <&cpg 711>;
> > +	};
>
> --
> Regards,
>
> Laurent Pinchart

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