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

[Christoph Niedermaier]

From: Krzysztof Kozlowski [mailto:krzysztof.kozlowski at linaro.org]
Sent: Friday, August 12, 2022 7:41 PM
> 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.

I will improve the commit message in V2.

Regards,
Christoph