Hi Rob, Sam,

On Wed, Jul 21, 2021 at 08:29:47PM -0600, Rob Herring wrote:
> On Wed, Jul 21, 2021 at 04:03:40PM +0200, Maxime Ripard wrote:
> > The binding mentions that all the drivers using that driver must use a
> > vendor-specific compatible but never enforces it, nor documents the
> > vendor-specific compatibles.
> > 
> > Let's make we document all of them, and that the binding will create an
> > error if we add one that isn't.
> > 
> > Cc: dri-devel@lists.freedesktop.org
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Cc: Sam Ravnborg <sam@ravnborg.org>
> > Cc: Thierry Reding <thierry.reding@gmail.com>
> > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> > ---
> >  .../bindings/display/panel/lvds.yaml           | 18 ++++++++++++------
> >  1 file changed, 12 insertions(+), 6 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/display/panel/lvds.yaml b/Documentation/devicetree/bindings/display/panel/lvds.yaml
> > index 49460c9dceea..d1513111eb48 100644
> > --- a/Documentation/devicetree/bindings/display/panel/lvds.yaml
> > +++ b/Documentation/devicetree/bindings/display/panel/lvds.yaml
> > @@ -31,12 +31,18 @@ allOf:
> >  
> >  properties:
> >    compatible:
> > -    contains:
> > -      const: panel-lvds
> > -    description:
> > -      Shall contain "panel-lvds" in addition to a mandatory panel-specific
> > -      compatible string defined in individual panel bindings. The "panel-lvds"
> > -      value shall never be used on its own.
> > +    items:
> > +      - enum:
> > +          - advantech,idk-1110wr
> 
> At least this one is documented elsewhere.

Indeed, I missed it.

> You can add 'minItems: 2' if you want to just enforce having 2 compatibles. Or do:
> 
> items:
>   - {}
>   - const: panel-lvds
> 
> Which also enforces the order.

It's not just about the order since a missing compatible will also raise
a warning.

Some of those panels have a binding of their own, but some probably
won't (and I can't find anything specific about the one I'm most
interested in: tbs,a711-panel)

Can we have something like:

compatible:
  oneOf:
    - items:
      - enum:
	- tbs,a711-panel
      - const: panel-lvds

    - items:
      - {}
      - const: panel-lvds

That would work for both cases I guess?

Maxime