RE: [EXT] Re: [PATCH 1/2] dt-bindings: gpu: mali-valhall-csf: Document i.MX952 support

[Guangliu Ding]

Hi Krzysztof

Thank you for the helpful guidance.
After going through the writing binding file and the corresponding
driver/dts code, I have a few updates to share:

> On 01/04/2026 13:27, Guangliu Ding wrote:
> >>>>
> >>>> We discuss only the lack of compatibility in terms of DT, how DT
> >>>> sees compatible devices.
> >>>>
> >>>> And lack of driver code is clear indication that devices are
> >>>> compatible in terms how DT understands it. Feel encouraged to bring
> >>>> actual arguments in commit msgs in the future.
> >>>>
> >>>> Best regards,
> >>>> Krzysztof
> >>>
> >>> So the best approach is only reserve "arm,mali-valhall-csf" for now,
> >>> since currently there is no need for an additional compatible entry
> >>> from a DT
> >> compatibility perspective.
> >>> We can introduce "nxp,imx952-mali" in future commits if hardware or
> >>> driver differences actually require it, and include more detailed
> >>> justification
> >> in the commit message. Right?
> >>
> >> So does that mean you decided not to read writing bindings document?
> >
> > Actually, I followed the compatible string of gpu node in imx952.dtsi
> > during code work since they share the same GPU IP.
> >          gpu: gpu@4d900000 {
> >              compatible = "nxp,imx95-mali", "arm,mali-valhall-csf"; >
> >
> > Is this line in writing bindings document that you want to mention about?
> > Could you please share more suggestions about the patch optimization?
> >               DO add new compatibles in case there are new features or
> bugs.
> 
> Please read entire file. I feel like you avoid doing this and just ask me to give
> you shortcut.
> 
> There is more than one point from that trivial writing bindings file which
> applies here.
>
> Best regards,
> Krzysztof

DO use fallback compatibles when devices are the same as or a superset of prior implementations.
Under this rule, the following compatible string is correct since the GPU on
i.MX952 is fully compatible with the GPU on i.MX95 now.
compatible = "nxp,imx95-mali", "arm,mali-valhall-csf";

DO add new compatibles in case there are new features or bugs.
Under this rule, the new compatible string is required to support new feature
and the old one must be kept if the GPU auto clock gating mechanism on i.MX952
needs additional fixes after ipa_counters are enabled in the driver.
compatible = "nxp,imx952-mali", "nxp,imx95-mali", "arm,mali-valhall-csf";