Re: [PATCH v2 01/19] dt-bindings: display: renesas,cmm: Add R-Car CMM documentation

From: Jacopo Mondi <jacopo@jmondi.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Koji Matsuoka <koji.matsuoka.xm@renesas.com>,
	muroya@ksk.co.jp, VenkataRajesh.Kalakodima@in.bosch.com,
	Harsha.ManjulaMallikarjun@in.bosch.com,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 01/19] dt-bindings: display: renesas,cmm: Add R-Car CMM documentation
Date: Tue, 20 Aug 2019 09:48:26 +0200	[thread overview]
Message-ID: <20190820074826.5rdzeqyk6ylpjr7o@uno.localdomain> (raw)
In-Reply-To: <CAMuHMdWFHDGPSZt2_H_sC9rCKDYBR0XDLn0TGxzPRxZsrOTEHw@mail.gmail.com>

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Hi Geert,
   sorry for the delayed response..

On Mon, Aug 19, 2019 at 03:45:54PM +0200, Geert Uytterhoeven wrote:
> Hi Jacopo,
>
> On Mon, Jul 8, 2019 at 9:58 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Sat, Jul 6, 2019 at 4:07 PM Jacopo Mondi <jacopo+renesas@jmondi.org> 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 on R-Car Gen2 and Gen3 SoCs (V3H and V3M excluded).
> > >
> > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >
> > Thanks for your patch!
> >
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/renesas,cmm.txt
> > > @@ -0,0 +1,25 @@
> > > +* Renesas R-Car Color Management Module (CMM)
> > > +
> > > +Renesas R-Car image enhancement module connected to R-Car DU video channels.
> > > +
> > > +Required properties:
> > > + - compatible: shall be one of:
> > > +   - "renesas,rcar-gen3-cmm"
> > > +   - "renesas,rcar-gen2-cmm"
> >
> > Why do you think you do not need SoC-specific compatible values?
> > What if you discover a different across the R-Car Gen3 line tomorrow?
> > Does the IP block have a version register?
>
> Do you have an answer to these questions?

It does not seem to me that CMM has any version register, nor there
are differences between the different Gen3 SoCs..

However, even if we now define a single compatible property for
gen3/gen2 and we later find out one of the SoC needs a soc-specific
property we can safely add it and keep the generic gen3/gen2 one as
fallback.. Does it work for you?

Thanks
   j

> Thanks!
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds

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