Re: [PATCH v3 1/2] dt-bindings: rng: bcm2835: document reset support

[Rob Herring]

On Thu, Mar 4, 2021 at 6:07 AM Nicolas Saenz Julienne
<nsaenzjulienne@xxxxxxx> wrote:
>
> Hi Alvaro,
>
> On Tue, 2021-02-23 at 18:00 +0100, Álvaro Fernández Rojas wrote:
> > Some devices may need to perform a reset before using the RNG, such as the
> > BCM6368.
> >
> > Signed-off-by: Álvaro Fernández Rojas <noltari@xxxxxxxxx>
> > ---
> >  v3: make resets required if brcm,bcm6368-rng.
> >  v2: document reset support.
> >
> >  .../devicetree/bindings/rng/brcm,bcm2835.yaml   | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/rng/brcm,bcm2835.yaml b/Documentation/devicetree/bindings/rng/brcm,bcm2835.yaml
> > index c147900f9041..11c23e1f6988 100644
> > --- a/Documentation/devicetree/bindings/rng/brcm,bcm2835.yaml
> > +++ b/Documentation/devicetree/bindings/rng/brcm,bcm2835.yaml
> > @@ -37,6 +37,21 @@ required:
> >
> >
> >  additionalProperties: false
>
> I can't claim I fully understand all the meta stuff in shemas, so I generally
> just follow the patterns already available out there. That said, shoudln't this
> be at the end, just before the examples? Maybe the cause of that odd warning
> you got there?

Yes, 'resets' needs to be defined under 'properties' as
additionalProperties can't 'see' into if/then schemas. The top level
needs to define everything and then if/then schema just add additional
constraints.

>
> > +if:
> > +  properties:
> > +    compatible:
> > +      enum:
> > +        - brcm,bcm6368-rng
> > +then:
> > +  properties:
> > +    resets:
> > +      maxItems: 1
> > +  required:
> > +    - resets
>
> I belive you can't really make a property required when the bindings for
> 'brcm,bcm6368-rng' were already defined. This will break the schema for those
> otherwise correct devicetrees.

Right, unless not having the property meant the device never would have worked.

Rob