Re: [PATCH] dt-bindings: power: Add SiFive Domain Management controllers

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

On Fri, May 9, 2025 at 2:40 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On Fri, May 09, 2025 at 10:16:04AM GMT, Nick Hu wrote:
> > SiFive Domain Management controller includes the following components
> > - SiFive Tile Management Controller
> > - SiFive Cluster Management Controller
> > - SiFive Core Complex Management Controller
> >
> > These controllers control the clock and power domain of the
> > corresponding domain.
> >
> > Signed-off-by: Nick Hu <nick.hu@sifive.com>
> > Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
> > ---
> >  .../devicetree/bindings/power/sifive,tmc.yaml | 89 +++++++++++++++++++
>
> Where is a patch with the driver (user of the binding)?
>
We are hoping the driver can be submitted at a later stage.
The driver that handles the MMIO is implemented in OpenSBI and depends
on some prerequisite patches [1], so it will follow afterward.

Links:
- [1] https://lore.kernel.org/opensbi/CAKddAkD00gLgpzOCXY9mXaebr2qZcU9mkUGOZ4278w0bmiLuBQ@mail.gmail.com/T/#t

> >  1 file changed, 89 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/power/sifive,tmc.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/power/sifive,tmc.yaml b/Documentation/devicetree/bindings/power/sifive,tmc.yaml
> > new file mode 100644
> > index 000000000000..7ed4f290b94b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/power/sifive,tmc.yaml
> > @@ -0,0 +1,89 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/power/sifive,tmc.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: SiFive Domain Management Controller
> > +
> > +maintainers:
> > +  - Cyan Yang <cyan.yang@sifive.com>
> > +  - Nick Hu <nick.hu@sifive.com>
> > +  - Samuel Holland <samuel.holland@sifive.com>
> > +
> > +description: |
> > +  This is the device tree binding for the following SiFive Domain Management Controllers.
>
> Explain the hardware, not that "binding is a binding for ...".
>
> Also, wrap according to Linux coding style.
>
Thanks for the advice. I'll address it in the next version =)

> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  sifive,feature-level:
> > +    description: |
> > +      Supported power features. This property is absent if the full set of features
> > +      is supported
>
> Compatible defines this. Drop.
>
The property depends on how the IP is hooked up to the rest of the SoC.
Having this property simplifies the SW and allows us to use a single
fallback compatible string, so we prefer to keep it.

Best Regards,
Nick