Re: [PATCH 1/3] dt-bindings: gpu: img,powervr-rogue: Document GX6250 GPU in Renesas R-Car M3-W/M3-W+

[Matt Coster <Matt.Coster@imgtec.com>]

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On 13/10/2025 20:01, Marek Vasut wrote:
> Document Imagination Technologies PowerVR Rogue GX6250 BNVC 4.45.2.58
> present in Renesas R-Car R8A77960 M3-W and R8A77961 M3-W+ SoC.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Adam Ford <aford173@gmail.com>
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Frank Binns <frank.binns@imgtec.com>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Magnus Damm <magnus.damm@gmail.com>
> Cc: Matt Coster <matt.coster@imgtec.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Simona Vetter <simona@ffwll.ch>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: devicetree@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> See https://gitlab.freedesktop.org/imagination/linux-firmware/-/issues/13
> for related userspace bits.
> ---
>  .../devicetree/bindings/gpu/img,powervr-rogue.yaml          | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml
> index c87d7bece0ecd..c9680a2560114 100644
> --- a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml
> +++ b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml
> @@ -13,6 +13,12 @@ maintainers:
>  properties:
>    compatible:
>      oneOf:
> +      - items:
> +          - enum:
> +              - renesas,r8a77960-gpu
> +              - renesas,r8a77961-gpu

I think this can just be renesas,r8a7796-gpu; most of the devices in the
dts for these SoCs appear to use the same pattern and the GPU is the
same in both.

> +          - const: img,img-gx6250
> +          - const: img,img-rogue
>        - items:
>            - enum:
>                - ti,am62-gpu

You also need to add img,img-gx6250 to the appropriate conditional
blocks below here for the number of power domains (in this case, 2) and
clocks (that's more complicated).

These older GPUs always require three clocks (core, mem and sys), but
it's not immediately clear from the Renesas TRM how these are hooked up.
I can see three "clocks" connected (fig 23.2 in my copy, clock details
from fig 8.1b):

 - Clock ZGφ: Appears to be a core clock for the GPU (3DGE). That would
   make it our "core" clock.
 - Clock S2D1φ: Appears to be a core clock used on the AXI bus, making
   it our "sys" clock.
 - MSTP ST112: Appears to be a whole module on/off control of some
   description, and definitely doesn't align with the missing "mem"
   clock.

Do you have any further insights as to how Renesas have wired things up?

Cheers,
Matt

-- 
Matt Coster
E: matt.coster@imgtec.com

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