Re: [PATCH] ARM: dts: imx6qdl-dhcom: Move IPU iomux node from PDK2 to SoM file

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 12/08/2022 20:27, Marek Vasut wrote:
> On 8/12/22 15:25, Krzysztof Kozlowski wrote:
>> On 12/08/2022 15:03, Christoph Niedermaier wrote:
>>> To have a variant (imx6dl/imx6q) independent access to the IPU
>>> iomux node move them to the SoM file.
>>
>> There is no such variant using them, so the "possibility" is not a
>> reason for such change. The change by itself, without proper users, does
>> not make any sense.
> 
> I think it does make sense to move the IPUv3 RGB/DPI interface pinmux 
> description from PDK2 carrier board DT into the common SoM DTSI, but for 
> a different reason entirely.
> 
> The SoM specification states there is such an interface on the SoM pins:
> 
> "
> https://wiki.dh-electronics.com/images/2/2e/DOC_DHCOM-Standard-Specification_R01_2016-11-17.pdf
> 
> Page 20
> 
> 5.1.14 RGB Display
> The DHCOM standard provides a parallel 24-bit RGB interface for driving 
> displays.
> "
> 
> And from what I can tell, for a carrier board to be compatible with the 
> SoM standard above, those pins have to be used as the RGB/DPI interface 
> or not used at all.
> 
> So rather than duplicate the pinmux settings in every carrier board DT, 
> better move/deduplicate them into the SoM DTSI.
> 
> But it seems the commit message should be updated to reflect that.
> 
> btw. there are also downstream DTOs which do reference that pinmux 
> settings label, but maybe those DTOs are not really interesting with 
> regards to this specific change.

That's much better reasoning and it makes sense.

Best regards,
Krzysztof

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