Re: [RFC PATCH 07/16] dt-bindings: pinctrl: ralink: add new compatible strings

[Arınç ÜNAL]

On 2.03.2023 11:28, Krzysztof Kozlowski wrote:
> On 01/03/2023 09:15, Arınç ÜNAL wrote:
> > On 1.03.2023 05:44, Rob Herring wrote:
> > > On Tue, Feb 28, 2023 at 07:46:36PM +0300, Arınç ÜNAL wrote:
> > > > On 27/02/2023 20:33, Rob Herring wrote:
> > > > > On Wed, Feb 22, 2023 at 09:39:23PM +0300, arinc9.unal@xxxxxxxxx wrote:
> > > > > > From: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> > > > > >
> > > > > > Add the ralink,rt2880-pinmux compatible string. It had been removed from
> > > > > > the driver which broke the ABI.
> > > > > >
> > > > > > Add the mediatek compatible strings. Change the compatible string on the
> > > > > > examples with the mediatek compatible strings.
> > > > > >
> > > > > > Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> > > > > > ---
> > > > > >     .../devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml | 7 +++++--
> > > > > >     .../devicetree/bindings/pinctrl/ralink,mt7621-pinctrl.yaml | 7 +++++--
> > > > > >     .../devicetree/bindings/pinctrl/ralink,rt2880-pinctrl.yaml | 7 +++++--
> > > > > >     .../devicetree/bindings/pinctrl/ralink,rt305x-pinctrl.yaml | 7 +++++--
> > > > > >     .../devicetree/bindings/pinctrl/ralink,rt3883-pinctrl.yaml | 7 +++++--
> > > > > >     5 files changed, 25 insertions(+), 10 deletions(-)
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
> > > > > > index 1e63ea34146a..531b5f616c3d 100644
> > > > > > --- a/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
> > > > > > +++ b/Documentation/devicetree/bindings/pinctrl/ralink,mt7620-pinctrl.yaml
> > > > > > @@ -17,7 +17,10 @@ description:
> > > > > >     properties:
> > > > > >       compatible:
> > > > > > -    const: ralink,mt7620-pinctrl
> > > > > > +    enum:
> > > > > > +      - mediatek,mt7620-pinctrl
> > > > > > +      - ralink,mt7620-pinctrl
> > > > >
> > > > > We don't update compatible strings based on acquistions nor marketing
> > > > > whims. If you want to use 'mediatek' for new things, then fine.
> > > >
> > > > Understood. Only the SoCs with rtXXXX were rebranded, the mtXXXX SoCs share
> > > > the same architecture from Ralink, so they were incorrectly called Ralink
> > > > SoCs.
> > > >
> > > > I can remove the new strings from Ralink SoCs and add them only for MediaTek
> > > > SoCs. Or you could make an exception for this one, regarding the situation.
> > > > Whatever you think is best.
> > >
> > > I'm not in a position to make an exception as I know little about this
> > > platform. Carrying both strings is a NAK. Either you (and everyone using
> > > these platforms) care about the ABI and are stuck with the "wrong"
> > > string. In the end, they are just unique identifiers. Or you don't care
> > > and break the ABI and rename everything. If you do that, do just that in
> > > your patches and make it crystal clear in the commit msg that is your
> > > intention and why that is okay.
> >
> > Ralink had their MIPS SoCs pre-acquisition, RT2880, etc. MediaTek
> > introduced new SoCs post-acquisition, MT7620, MT7621, MT7628, and
> > MT7688, utilising the same platform from Ralink, sharing the same
> > architecture code, pinctrl core driver, etc.
> >
> > I don't intend to break the ABI at all. On the contrary, I fix it where
> > possible.
> >
> > If I understand correctly, from this conversation and what Krzysztof
> > said, all strings must be kept on the schemas so I can do what I said on
> > the composed mail. Only match the pin muxing information on the strings
> > that won't match multiple pin muxing information from other schemas.
> >
> > This way we don't break the ABI, introduce new compatible strings while
> > keeping the remaining ones, and make schemas match correctly.
> >
> > Let me know if this is acceptable to you.
>
> If by "introduce new compatible strings" you mean duplicate compatibles
> to fix the ralink->mediatek, then you ignored entire email from Rob -
> this and previous. We don't do this. Leave them as is.
>
> If you meant something else, explain more...

Let me put them in a group to better explain.

## Fix ABI

ralink,rt2880-pinmux was there before, it was removed which broke the 
ABI. I'm reintroducing it to fix it.

## New strings to be able to split bindings

New strings are needed for MT7628/MT7688 and some RT SoCs to be able to 
properly document the pin muxing information.

## Incorrect naming

MT7620, MT7621, MT7628, and MT7688 SoCs are incorrectly called Ralink, 
introduce new ralink->mediatek compatible strings to address it.

## Exception for RT SoCs to be called MediaTek

This is where I was asking an exception to be made. Rob told us here 
they know little about the platform so I explained it.

MediaTek acquired Ralink and then introduced new MediaTek SoCs utilising 
the same platform from Ralink.

Anyway, now that I look at this again, it makes sense to me as well not 
to rename the Ralink SoCs. I'll call the RT SoCs Ralink on the kconfig, 
pinctrl driver, and dt-binding schemas on my next version.

Arınç