Re: [PATCH v3] dt-bindings: pinctrl: Convert Amlogic Meson pinctrl binding

[Heiner Kallweit <hkallweit1@gmail.com>]

On 04.02.2023 23:56, Martin Blumenstingl wrote:
> Hi Heiner,
> 
> On Wed, Feb 1, 2023 at 11:13 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
> [...]
>>>> +      - items:
>>>> +          - const: amlogic,meson8m2-aobus-pinctrl
>>>> +          - const: amlogic,meson8-aobus-pinctrl
>>>> +      - items:
>>>> +          - const: amlogic,meson8m2-cbus-pinctrl
>>>> +          - const: amlogic,meson8-cbus-pinctrl
>>>
>>> Again, can't have both with and without the fallback allowed.
>>>
>> Hi Martin,
>>
>> meson8m2 is the only chip version having a fallback for the
>> pinctrl compatible. Is this fallback really needed?
>> Looking at the driver it seems that both compatibles
>> are handled identically.
> Back in the day we decided to duplicate the Meson8 driver code just to
> add four new pin functions that are added by the Meson8m2 SoC
> generation:
> "eth_rxd2", "eth_rxd3", "eth_txd2", "eth_txd3"
> 
> The compatible string was defined with a similar approach: since
> Meson8m2 just adds a few bits to the Meson8 pin controller it's
> backwards compatible.
> 
> If the fallback has to be removed then I'm okay with that but I would
> like to understand it first.
> So far I thought that Rob basically asked to remove the following two
> compatible strings from the enum (as they're listed separately with
> their fallbacks):
> - amlogic,meson8m2-cbus-pinctrl
> - amlogic,meson8m2-aobus-pinctrl
> 
Right, this should be sufficient. There's no place where the 8m2 pinctrl
compatibles are used w/o fallback.

Then the hopefully final version of the binding is almost ready.
I'm just still checking whether there's any way in yaml to specify
a reg-names list with mandatory and optional names. Doesn't seem so.

> 
> Best regards,
> Martin

Heiner