Re: [PATCH v7 2/7] dt-bindings: thermal: add YAML schema for sun8i-thermal driver bindings

From: Vasily Khoruzhick
Date: Wed Dec 18 2019 - 17:27:01 EST


On Wed, Dec 18, 2019 at 2:00 PM Maxime Ripard <mripard@xxxxxxxxxx> wrote:
>
> Hi,
>
> On Tue, Dec 17, 2019 at 08:21:16PM -0800, Vasily Khoruzhick wrote:
> > From: Yangtao Li <tiny.windzz@xxxxxxxxx>
> >
> > sun8i-thermal driver supports thermal sensor in wide range of Allwinner
> > SoCs. Add YAML schema for its bindings.
> >
> > Signed-off-by: Yangtao Li <tiny.windzz@xxxxxxxxx>
> > Signed-off-by: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
> > ---
> > .../thermal/allwinner,sun8i-a83t-ths.yaml | 146 ++++++++++++++++++
> > 1 file changed, 146 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/thermal/allwinner,sun8i-a83t-ths.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/thermal/allwinner,sun8i-a83t-ths.yaml b/Documentation/devicetree/bindings/thermal/allwinner,sun8i-a83t-ths.yaml
> > new file mode 100644
> > index 000000000000..8768c2450633
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/thermal/allwinner,sun8i-a83t-ths.yaml
> > @@ -0,0 +1,146 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/thermal/allwinner,sun8i-a83t-ths.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Allwinner SUN8I Thermal Controller Device Tree Bindings
> > +
> > +maintainers:
> > + - Yangtao Li <tiny.windzz@xxxxxxxxx>
> > +
> > +properties:
> > + compatible:
> > + enum:
> > + - allwinner,sun8i-a83t-ths
> > + - allwinner,sun8i-h3-ths
> > + - allwinner,sun8i-r40-ths
> > + - allwinner,sun50i-a64-ths
> > + - allwinner,sun50i-h5-ths
> > + - allwinner,sun50i-h6-ths
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + interrupts:
> > + maxItems: 1
> > +
> > + resets:
> > + maxItems: 1
> > +
> > + nvmem-cells:
> > + maxItems: 1
> > + description: Calibration data for thermal sensors
> > +
> > + nvmem-cell-names:
> > + const: calibration
> > +
> > +allOf:
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + const: allwinner,sun50i-h6-ths
> > +
> > + then:
> > + properties:
> > + clocks:
> > + minItems: 1
> > + maxItems: 1
>
> When minItems and maxItems are equal, you can only set one, the other
> will be filled automatically.

Is it documented anywhere? I have a feeling like I'm shooting in the
dark. So far I've read Documentation/devicetree/writing-schema.rst,
Documentation/devicetree/bindings/example-schema.yaml and few other
schemas for inspiration but yet I don't have solid understanding how
it's supposed to be written. Examples are pretty scarce and figuring
out why certain construction doesn't work is pretty tricky.

> > +
> > + clock-names:
> > + minItems: 1
> > + maxItems: 1
> > + items:
> > + - const: bus
>
> And this can even be just
>
> clock-names:
> const: bus

OK

> > +
> > + else:
> > + properties:
> > + clocks:
> > + minItems: 1
> > + maxItems: 2
> > +
> > + clock-names:
> > + minItems: 1
> > + maxItems: 2
> > + items:
> > + - const: bus
> > + - const: mod
>
> I'm not sure why you need the minItems set to 1 here though?
>
> it's always 2 for the !H6 case, right?
>
> if so, then we should even do something like:
>
> properties:
> ...
>
> # This is needed because we will need to check both the H6 and !H6
> # case, and it must validate. So we make sure we match against the
> # union of both cases.
> clocks:
> minItems: 1
> maxItems: 2
> items:
> - description: Bus Clock
> - description: Module Clock
>
> # Same story here
> clock-names:
> minItems: 1
> maxItems: 2
> items:
> - const: bus
> - const: mod
>
> allOf:
> - if:
> properties:
> compatible:
> contains:
> const: allwinner,sun50i-h6-ths
>
> # Here we validate in the H6 case we only have one clock
> then:
> properties:
> clocks:
> maxItems: 1
>
> clock-names:
> maxItems: 1
>
> # and here that in the other case we have two clocks, the names
> # being validated by the schema above
> else:
> properties:
> clocks:
> maxItems: 2
>
> clock-names:
> maxItems: 2
>
> # And now we can set this since all our properties will have been
> # expressed in the upper level schema
> additionalProperties: false

OK

> > +
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + const: allwinner,sun8i-h3-ths
> > +
> > + then:
> > + properties:
> > + "#thermal-sensor-cells":
> > + const: 0
> > +
> > + else:
> > + properties:
> > + "#thermal-sensor-cells":
> > + const: 1
>
> Same thing here, you should have an enum accepting both values in the
> upper schema, the condition here only making further checks. Also, in
> the case where #thermal-sensor-cells is one, then you need to document
> what that argument is.

OK

>
> Thanks!
> Maxime