Re: [PATCH] dt-bindings: timer: Add SiFive CLINT2

[Nick Hu <nick.hu@sifive.com>]

Hi Conor

On Fri, Mar 14, 2025 at 6:34 AM Conor Dooley <conor@kernel.org> wrote:
>
> On Thu, Mar 13, 2025 at 03:58:05PM +0800, Nick Hu wrote:
> > Hi Rob and Conor
> >
> > Thanks to all your feedback.
> >
> > On Wed, Mar 12, 2025 at 4:46 AM Conor Dooley <conor@kernel.org> wrote:
> > >
> > > On Tue, Mar 11, 2025 at 02:59:53PM -0500, Rob Herring wrote:
> > > > On Tue, Mar 11, 2025 at 01:19:03PM +0800, Nick Hu wrote:
> > > > > Add compatible string and property for the SiFive CLINT v2.
> > > > >
> > > > > Signed-off-by: Nick Hu <nick.hu@sifive.com>
> > > > > Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
> > > > > ---
> > > > >  .../bindings/timer/sifive,clint.yaml          | 19 +++++++++++++++++++
> > > > >  1 file changed, 19 insertions(+)
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> > > > > index 76d83aea4e2b..93d74c504b5f 100644
> > > > > --- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> > > > > +++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
> > > > > @@ -36,6 +36,9 @@ properties:
> > > > >                - starfive,jh7110-clint   # StarFive JH7110
> > > > >                - starfive,jh8100-clint   # StarFive JH8100
> > > > >            - const: sifive,clint0        # SiFive CLINT v0 IP block
> > > >
> > > > Notice that we don't allow clint0 by itself. We shouldn't start now.
> > > >
> > > > > +      - items:
> > > >
> > > > If you don't have a specific one yet, then add '- {}' for the first
> > > > entry.
> > > >
> > Do you suggest something like the following?
> >      - items:
> >           - {}
> >           - const: sifive,clint2        # SiFive CLINT v2 IP block
> >         description: SiFive CLINT v2 is the HRT that supports the Zicntr
> >
> > > > > +          - const: sifive,clint2        # SiFive CLINT v2 IP block
> > > > > +        description: SiFive CLINT v2 is the HRT that supports the Zicntr
> > > > >        - items:
> > > > >            - enum:
> > > > >                - allwinner,sun20i-d1-clint
> > > > > @@ -62,6 +65,22 @@ properties:
> > > > >      minItems: 1
> > > > >      maxItems: 4095
> > > > >
> > > > > +  sifive,fine-ctr-bits:
> > > > > +    description: The width in bits of the fine counter.
> > > >
> > > > maximum: 15
> > > >
> > > > Unless you know of a different maximum in which case why aren't you
> > > > documenting that too?
> > >
> > You are right. It's my bad. The maximum width should always be 15 in
> > sifive,clint2.
> > I should update to:
> >  sifive,fine-ctr-bits:
> >     maximum: 15
> >     description: The width in bits of the fine counter.
> >
> > if:
> >   not:
> >     properties:
> >       compatible:
> >         contains:
> >           const: sifive,clint2
> > then:
> >   properties:
> >     sifive,fine-ctr-bits: false
>
> I think this should be inverted, to
>
> if: properties: compatible: contains: const: sifive,clint2
> then: required: - sifive,fine-counter-bits
> else: sifive,fine-counter-bits: false
>
> since the property has no default.
>
Will update it in the next version. Thanks for the advice.

> >
> > > I'm curious why this is not something that can be discerned from the
> > > compatible. It's max 15, but are there actually versions of this with a
> > > less-than-15-bit width?
> > >
> > The width may be various on different platforms so it is possible to
> > have a less-than-15-bit width.
> >
> > > >
> > > > > +
> > > > > +if:
> > > > > +  properties:
> > > > > +    compatible:
> > > > > +      contains:
> > > > > +        const: sifive,clint2
> > > > > +then:
> > > > > +  properties:
> > > > > +    sifive,fine-ctr-bits:
> > > > > +      maximum: 15
> > > > > +else:
> > > > > +  properties:
> > > > > +    sifive,fine-ctr-bits: false
> > > > > +
> > > > >  additionalProperties: false
> > > > >
> > > > >  required:
> > > > > --
> > > > > 2.17.1
> > > > >
> >
> > Best Regards,
> > Nick

Best Regards,
Nick