RE: [PATCH v3 03/13] dt-bindings: serial: Add compatible for Renesas RZ/T2H SoC in sci

[Thierry Bultel]

Hi Rob,
thanks for you review

> -----Original Message-----
> From: Rob Herring <robh@xxxxxxxxxx>
> Sent: lundi 3 mars 2025 14:36
> To: Thierry Bultel <thierry.bultel.yh@xxxxxxxxxxxxxx>
> Cc: thierry.bultel@xxxxxxxxxxx; linux-renesas-soc@xxxxxxxxxxxxxxx;
> geert@xxxxxxxxxxxxxx; Paul Barker <paul.barker.ct@xxxxxxxxxxxxxx>; Geert
> Uytterhoeven <geert+renesas@xxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx;
> linux-serial@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 03/13] dt-bindings: serial: Add compatible for
> Renesas RZ/T2H SoC in sci
> 
> On Wed, Feb 26, 2025 at 02:09:22PM +0100, Thierry Bultel wrote:
> > Document RZ/T2H (a.k.a r9a09g077) in SCI binding.
> >
> > Signed-off-by: Thierry Bultel <thierry.bultel.yh@xxxxxxxxxxxxxx>
> > Reviewed-by: Paul Barker <paul.barker.ct@xxxxxxxxxxxxxx>
> > ---
> >  .../bindings/serial/renesas,sci.yaml          | 64 ++++++++++++-------
> >  1 file changed, 40 insertions(+), 24 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/serial/renesas,sci.yaml
> > b/Documentation/devicetree/bindings/serial/renesas,sci.yaml
> > index 64d3db6e54e5..2c4080283963 100644
> > --- a/Documentation/devicetree/bindings/serial/renesas,sci.yaml
> > +++ b/Documentation/devicetree/bindings/serial/renesas,sci.yaml
> > @@ -9,9 +9,6 @@ title: Renesas Serial Communication Interface
> >  maintainers:
> >    - Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> >
> > -allOf:
> > -  - $ref: serial.yaml#
> > -
> >  properties:
> >    compatible:
> >      oneOf:
> > @@ -22,6 +19,8 @@ properties:
> >                - renesas,r9a07g054-sci     # RZ/V2L
> >            - const: renesas,sci            # generic SCI compatible UART
> >
> > +      - const: renesas,r9a09g077-sci      # RZ/T2H
> > +
> 
> Perhaps explain in the commit msg why the 'renesas,sci' is not applicable
> for this chip.


Would something like that be explicit enough ? 

"The SCI of RZ/T2H SoC (a.k.a r9a09g077), as a lot
of similarities with other Renesas SoCs like G2L, G3S and V2L,
but a different set of registers, that moreover are 32 bits instead
of 16 bits. 
This is why the 'renesas,sci' fallback does not apply for it".

Thanks !
Thierry