[Linux-stm32] [PATCH] ARM: dts: stm32: Fill GPIO line names on AV96

[Marek Vasut]

On 3/15/21 1:05 PM, Ahmad Fatoum wrote:
> On 15.03.21 12:41, Christoph Niedermaier wrote:
>>> So I'll pose another question here to the GPIO maintainers.
>>>
>>> Is it OK to define gpio-line-names in SoM DTSI even for pins which will
>>> not be used as GPIOs e.g. because they are muxed differently in the
>>> carrier board DTS ?
>>>
>>> If that is OK, then the above approach is then also OK.
>>
>> In our case, we cannot mux the GPIO pins in the carrier board DTS
>> to another functions, because then we break our SOM standard (DHCOM).
>> So in the case we relabel a GPIO in the carrier board e.g. "DHCOM-I"
>> becomes "LED1" the mux function have to be GPIO.
> 
> For standards like SMARC, where the interface is predefined, I think it makes
> much sense to have the SoM dtsi contain not only the line-names, but also
> ready-to-use, pinmuxing settings.
> 
> Base boards can then either enable peripherals with just a status = "okay"
> if they follow the standard or just override it if they choose to do
> stuff differently.

Sadly, I think I have to remind you of the discussion around pinctrl 
groups we have in stm32mp15-pinctrl.dtsi and how that does not scale. 
This is a very similar situation here, since the SoM is rather universal.

And the other thing I would like to point out here are the discussions 
around DT connector. What you described above is exactly that, except 
the implementation is still not finished. Let's CC Frank.