Re: [PATCH 6/7] dt-bindings: mailbox: goog-mba: Add goog-mba mailbox bindings

[Rob Herring <robh@kernel.org>]

On Wed, Jul 15, 2026 at 09:49:14AM -0700, Doug Anderson wrote:
> Hi,
> 
> On Tue, Jul 14, 2026 at 9:51 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> > On 15/07/2026 00:21, Douglas Anderson wrote:
> > > Introduce bindings for the MailBox Array IP block present in Laguna
> > > SoCs (AKA "lga", AKA "Google Tensor G5").
> > >
> > > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > > ---
> > >
> > >  .../bindings/mailbox/google,mba.yaml          | 216 ++++++++++++++++++
> >
> > Filename must match compatible.
> 
> Whoops! Will fix in v2.
> 
> 
> > > +properties:
> > > +  compatible:
> > > +    items:
> > > +      - enum:
> > > +          - google,lga-mailbox-array
> > > +      - const: google,mailbox-array
> >
> > Don't use generic fallback. Just the SoCs.
> 
> Sure, if you insist.
> 
> In general the "mba" hardware is designed with enough identification
> registers that we should be able to autodetect which variant we're on.
> Thus, my hope is to not ever need to reference the SoC-specific
> variant in the driver itself. It's not the end of the world to use the
> "google,lga-mailbox-array" as the generic, I guess...
> 
> I don't suppose I can change your mind here? If we take
> "google,lga-mailbox-array" as the generic, then going foward a few
> generations we end up with:
> 
> properties:
>   compatible:
>     oneOf:
>       - const: google,lga-mailbox-array
>       - items:
>           - enum:
>               - google,next-mailbox-array
>               - google,nextnext-mailbox-array
>               - google,another-mailbox-array
>           - const: google,lga-mailbox-array
> 
> If we keep "google,mailbox-array" as the generic, then going forward a
> few generations we end up with this, which seems nicer / less
> confusing:
> 
> properties:
>   compatible:
>     items:
>       - enum:
>           - google,lga-mailbox-array
>           - google,next-mailbox-array
>           - google,nextnext-mailbox-array
>           - google,another-mailbox-array
>       - const: google,mailbox-array

I find 4 strings nicer than 5 strings.

> Sure, it means that if someone unexpectedly makes a new Google
> mailbox-array that's totally incompatible then the
> "google,mailbox-array" sounds too generic, but that doesn't feel like
> the end of the world. You could call the new mailbox array designed in
> the year 2037 the "google,2037-mailbox-array" and things would overall
> be less confusing than using the "google,lga-mailbox-array" as the
> generic.

What exactly do we need to do to stop having this conversation? We've 
done this scheme and version numbers and it never ends well.

The reality is the h/w folks can't help themselves from changing things, 
so nothing remains unchanged for very many generations.

Rob