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

[Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>]

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
>
>>  	{ }
>>  };
>>  
>>