Re: [PATCH 2/6] dt-bindings: pwm: samsung: add specific compatible for Tesla FSD

[Thierry Reding <thierry.reding@gmail.com>]

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On Tue, Dec 05, 2023 at 10:22:25AM +0100, Krzysztof Kozlowski wrote:
> Tesla FSD is a derivative of Samsung Exynos SoC, thus just like the
> others it reuses several devices from older designs.  Historically we
> kept the old (block's) compatible only.  This works fine and there is no
> bug here, however guidelines expressed in
> Documentation/devicetree/bindings/writing-bindings.rst state that:
> 1. Compatibles should be specific.
> 2. We should add new compatibles in case of bugs or features.
> 
> Add Tesla FSD compatible specific to be used with an existing fallback.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> ---
> 
> I propose to take the patch through Samsung SoC (me). See cover letter
> for explanation.
> ---
>  Documentation/devicetree/bindings/pwm/pwm-samsung.yaml | 1 +
>  1 file changed, 1 insertion(+)

You point to the guidelines that say we should have specific compatible
strings, but then the string that you add seems very generic. Now, I'm
obviously not an expert on Tesla hardware, but just FSD seems to be
quite generic according to the internet. It seems like the chip derived
from Samsung used to be known as AP3/HW3, but there's now also AP4/HW4,
so I wonder if those differ in some way and if these shouldn't include
some sort of version/generation number.

Thierry

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