Re: [PATCH 7/9] ARM: dts: stm32: add Hardware debug port (HDP) on stm32mp25

[Krzysztof Kozlowski <krzk@kernel.org>]

On 26/02/2025 17:54, Alexandre TORGUE wrote:
>>>> But, if it's not clean to do it in this way, lets define SoC compatible
>>>> for any new driver.
>>>
>>> Compatibles are for hardware.
>>>
>>>> For the HDP case it is: "st,stm32mp157" and used for STM32MP13,
>>>> STM32MP15 end STM32MP25 SoC families (if driver is the same for all
>>>> those SoCs).
>>>
>>> No, it's three compatibles, because you have three SoCs. BTW, writing
>>> bindings (and online resources and previous reviews and my talks) are
>>> saying that, so we do not ask for anything new here, anything different.
>>> At least not new when looking at last 5 years, because 10 years ago many
>>> rules were relaxed...
>>
>> So adding 3 times the same IP in 3 different SoCs implies to have 3 
>> different compatibles. So each time we use this same IP in a new SoC, we 
>> have to add a new compatible. My (wrong) understanding was: as we have 
>> the same IP (same hardware) in each SoC we have the same compatible (and 
>> IP integration differences (clocks, interrupts) are handled by DT 
>> properties.
> 
> Just to complete, reading the Linux kernel doc, as device are same we 
> will use fallbacks like this:
> 
> MP15: compatible = "st,stm32mp151-hdp";
> MP13: compatible = "st,stm32mp131-hdp", "st,stm32mp151-hdp";
> MP25: compatible = "st,stm32mp251-hdp", "st,stm32mp151-hdp";

Yes, this looks correct.

Best regards,
Krzysztof