linux-kernel - Re: [PATCH] dt-bindings: display: renesas,du: Provide bindings for r8a779a0

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Message-ID: <YNMzwtTqhfOzdJ56@pendragon.ideasonboard.com>
Date:   Wed, 23 Jun 2021 16:14:42 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Kieran Bingham <kieran.bingham@...asonboard.com>,
        Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        "open list:DRM DRIVERS FOR RENESAS" <dri-devel@...ts.freedesktop.org>,
        "open list:DRM DRIVERS FOR RENESAS" 
        <linux-renesas-soc@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dt-bindings: display: renesas,du: Provide bindings for
 r8a779a0

Hi Geert,

On Wed, Jun 23, 2021 at 03:09:06PM +0200, Geert Uytterhoeven wrote:
> On Wed, Jun 23, 2021 at 2:58 PM Laurent Pinchart wrote:
> > On Wed, Jun 23, 2021 at 02:53:33PM +0200, Geert Uytterhoeven wrote:
> > > On Wed, Jun 23, 2021 at 1:11 AM Kieran Bingham wrote:
> > > > From: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
> > > >
> > > > Extend the Renesas DU display bindings to support the r8a779a0 V3U.
> > > >
> > > > Signed-off-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
> > >
> > > Thanks for your patch!
> > >
> > > > --- a/Documentation/devicetree/bindings/display/renesas,du.yaml
> > > > +++ b/Documentation/devicetree/bindings/display/renesas,du.yaml
> > > > @@ -39,6 +39,7 @@ properties:
> > > >        - renesas,du-r8a77980 # for R-Car V3H compatible DU
> > > >        - renesas,du-r8a77990 # for R-Car E3 compatible DU
> > > >        - renesas,du-r8a77995 # for R-Car D3 compatible DU
> > > > +      - renesas,du-r8a779a0 # for R-Car V3U compatible DU
> > > >
> > > >    reg:
> > > >      maxItems: 1
> > > > @@ -774,6 +775,57 @@ allOf:
> > > >          - reset-names
> > > >          - renesas,vsps
> > > >
> > > > +  - if:
> > > > +      properties:
> > > > +        compatible:
> > > > +          contains:
> > > > +            enum:
> > > > +              - renesas,du-r8a779a0
> > > > +    then:
> > > > +      properties:
> > > > +        clocks:
> > > > +          items:
> > > > +            - description: Functional clock for DU0
> > > > +            - description: Functional clock for DU1
> > > > +
> > > > +        clock-names:
> > > > +          items:
> > > > +            - const: du.0
> > > > +            - const: du.1
> > >
> > > The hardware block has only a single function clock for both channels,
> > > like on R-Car H1.
> > >
> > > And what about DU_DOTCLKIN?
> >
> > As far as I can tell, there's no DU_DOTCLKIN in V3U.
> 
> See Table 6.13 of the Hardware User's Manual, pin IPC_CLKIN.

Maybe that's incorrect ? There's no mention of DU_DOTCLKIN anywhere
else, and the DU bits that allow selection of the input clocks list the
value documented for Gen3 SoCs as selected DU_DOTCLKIN as reserved.

> Note that the register bits to configure it are present in
> drivers/pinctrl/renesas/pfc-r8a779a0.c, but the actual pin group is
> missing.

-- 
Regards,

Laurent Pinchart