Re: [PATCH v10 4/5] dt-bindings: arm-smmu: add binding for Tegra194 SMMU

[Robin Murphy]

On 2020-07-10 21:29, Krishna Reddy wrote:
> Thanks Rob. One question on setting "minItems: ". Please see below.
>
> > > +allOf:
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            enum:
> > > +              - nvidia,tegra194-smmu
> > > +    then:
> > > +      properties:
> > > +        reg:
> > > +          minItems: 2
> > > +          maxItems: 2
>
> > This doesn't work. The main part of the schema already said there's only
> > 1 reg region. This part is ANDed with that, not an override. You need to add an else clause with 'maxItems: 1' and change the base schema to
> > {minItems: 1, maxItems: 2}.
>
> As the earlier version of base schema doesn't have "minItems: " set, should it be set to 0 for backward compatibility?  Or can it just be omitted setting in base schema as before?

We've always needed at least 1 "reg" specifier in practice, so I don't 
think being backwards-compatible with broken DTs is a concern :)

Robin.

> "else" part to set "maxItems: 1" and setting "maxItems: 2" in base schema is clear to me.
>
>
> -KR