Re: [PATCH v3 4/7] video: stm32: ltdc: support new hardware version for STM32MP25 SoC

[Patrice CHOTARD <patrice.chotard@foss.st.com>]

On 9/15/25 15:05, Raphael Gallais-Pou wrote:
> 
> 
> On 9/12/25 18:41, Patrice CHOTARD wrote:
>>
>> On 9/4/25 14:53, Raphael Gallais-Pou wrote:
>>> ...
> 
>>>  static const struct udevice_id stm32_ltdc_ids[] = {
>>>  	{ .compatible = "st,stm32-ltdc" },
>>> +	{ .compatible = "st,stm32mp251-ltdc" },
>>> +	{ .compatible = "st,stm32mp255-ltdc" },
>> in V1, only "st,stm32mp251-ltdc" compatible was introduced.
>> Why are you adding "st,stm32mp255-ltdc" compatible ? 
>>
>> For me only "st,stm32-ltdc" is needed, currently, nothing in drivers/video/stm32/stm32_ltdc.c
>> is justifying to add "st,stm32mp251-ltdc" or "st,stm32mp251-ltdc" new compatible.
>>
>> Patrice
> 
> Hi Patrice,
> 
> It has been poorly explained in the cover letter. Between the v3 and v4 versions
> of the Linux series:
> https://lore.kernel.org/all/20250822-drm-misc-next-v5-0-9c825e28f733@foss.st.com/
> 
> Since U-Boot is based on the Linux device-tree, I figured it might follow the
> added compatible.
> Now the reason why the "st,stm32mp255-ltdc" has been added is because on the
> STM32MP255 (and bigger) the LTDC needs 4 clocks, whether on the STM32MP251 and
> smaller SoCs it only needs two. Thus the two new compatibles. Furthermore there
> is features depending on the SoC version which will be added in the near future.
> Best regards, Raphaël
>>
>>>  	{ }
>>>  };
>>>  
>>>
> 

Thanks for clarification

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>

Thanks
Patrice