Re: [RFC 5/9] dt-bindings: arm: samsung: Convert Exynos PMU bindings to json-schema

From: Rob Herring <robh+dt@kernel.org>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	"Jonathan Cameron" <jic23@kernel.org>,
	"Hartmut Knaack" <knaack.h@gmx.de>,
	"Lars-Peter Clausen" <lars@metafoo.de>,
	"Peter Meerwald-Stadler" <pmeerw@pmeerw.net>,
	"Alessandro Zummo" <a.zummo@towertech.it>,
	"Alexandre Belloni" <alexandre.belloni@bootlin.com>,
	"Paweł Chmiel" <pawel.mikolaj.chmiel@gmail.com>,
	devicetree@vger.kernel.org,
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
	<linux-arm-kernel@lists.infradead.org>,
	linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"open list:IIO SUBSYSTEM AND DRIVERS" <linux-iio@vger.kernel.org>,
	"open list:REAL TIME CLOCK (RTC) SUBSYSTEM"
	<linux-rtc@vger.kernel.org>,
	notify@kernel.org, "Arnd Bergmann" <arnd@arndb.de>,
	"Olof Johansson" <olof@lixom.net>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	"Tomasz Figa" <tomasz.figa@gmail.com>
Subject: Re: [RFC 5/9] dt-bindings: arm: samsung: Convert Exynos PMU bindings to json-schema
Date: Fri, 6 Sep 2019 16:48:53 +0100	[thread overview]
Message-ID: <CAL_JsqKyj3s-Mn3q_Lna0w38K3DJzvKN5d72WHzqt4CUVf5X4Q@mail.gmail.com> (raw)
In-Reply-To: <CAJKOXPfnvu=c5f6AcOSiQ_9E-C2fMf9qbEpy1Tr3QvH8LgAtpQ@mail.gmail.com>

On Tue, Sep 3, 2019 at 12:03 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On Tue, 3 Sep 2019 at 10:25, Rob Herring <robh+dt@kernel.org> wrote:
> >
> > On Tue, Sep 3, 2019 at 8:58 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > >
> > > On Mon, 26 Aug 2019 at 13:54, Rob Herring <robh+dt@kernel.org> wrote:
> > > >
> > > > On Fri, Aug 23, 2019 at 9:54 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > > > >
> > > > > Convert Samsung Exynos Power Management Unit (PMU) bindings to DT schema
> > > > > format using json-schema.
> > > > >
> > > > > Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> > > > > ---
> > > > >  .../devicetree/bindings/arm/samsung/pmu.txt   | 72 --------------
> > > > >  .../devicetree/bindings/arm/samsung/pmu.yaml  | 93 +++++++++++++++++++
> > > > >  2 files changed, 93 insertions(+), 72 deletions(-)
> > > > >  delete mode 100644 Documentation/devicetree/bindings/arm/samsung/pmu.txt
> > > > >  create mode 100644 Documentation/devicetree/bindings/arm/samsung/pmu.yaml
> > > >
> > > >
> > > > > diff --git a/Documentation/devicetree/bindings/arm/samsung/pmu.yaml b/Documentation/devicetree/bindings/arm/samsung/pmu.yaml
> > > > > new file mode 100644
> > > > > index 000000000000..818c6f3488ef
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/arm/samsung/pmu.yaml
> > > > > @@ -0,0 +1,93 @@
> > > > > +# SPDX-License-Identifier: GPL-2.0
> > > > > +%YAML 1.2
> > > > > +---
> > > > > +$id: http://devicetree.org/schemas/arm/samsung/pmu.yaml#
> > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > +
> > > > > +title: Samsung Exynos SoC series Power Management Unit (PMU)
> > > > > +
> > > > > +maintainers:
> > > > > +  - Krzysztof Kozlowski <krzk@kernel.org>
> > > > > +
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    items:
> > > > > +      - enum:
> > > > > +          - samsung,exynos3250-pmu
> > > > > +          - samsung,exynos4210-pmu
> > > > > +          - samsung,exynos4412-pmu
> > > > > +          - samsung,exynos5250-pmu
> > > > > +          - samsung,exynos5260-pmu
> > > > > +          - samsung,exynos5410-pmu
> > > > > +          - samsung,exynos5420-pmu
> > > > > +          - samsung,exynos5433-pmu
> > > > > +          - samsung,exynos7-pmu
> > > > > +      - const: syscon
> > > > > +
> > > > > +  reg:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +  '#clock-cells':
> > > > > +    const: 1
> > > > > +
> > > > > +  clock-names:
> > > > > +    description:
> > > > > +      list of clock names for particular CLKOUT mux inputs
> > > > > +    # TODO: what is the maximum number of elements (mux inputs)?
> > > > > +    minItems: 1
> > > > > +    maxItems: 32
> > > > > +    items:
> > > > > +      - enum:
> > > >
> > > > This isn't correct as you are only defining possible names for the
> > > > first item. Drop the '-' (making items a schema instead of a list) and
> > > > then it applies to all. However, doing that will cause a meta-schema
> > > > error which I need to fix to allow. Or if there's a small set of
> > > > possibilities of number of inputs, you can list them under a 'oneOf'
> > > > list.
> > >
> > > Mhmm, I cannot test it or I have an error in the schema. if I
> > > understand correctly, this would be:
> > >
> > >   clock-names:
> > >     description:
> > >       List of clock names for particular CLKOUT mux inputs
> > >     minItems: 1
> > >     maxItems: 16
> > >     items:
> > >       clkout0
> > >       clkout1
> > >       clkout2
> > >       clkout3
> > >       clkout4
> > >       clkout5
> > >       clkout6
> > >       clkout7
> > >       clkout8
> > >       clkout9
> > >       clkout10
> > >       clkout11
> > >       clkout12
> > >       clkout13
> > >       clkout14
> > >       clkout15
> > >       clkout16
> > >
> > > Now it produces the error "ignoring, error in schema 'items'" but
> > > maybe it is expected with current meta-schema?
> >
> > 'make dt_binding_check' will give more detailed errors.
> >
> > Are the inputs always contiguous 0-N? If so, you want:
> >
> > items:
> >   - const: clkout0
> >   - const: clkout1
> >   - const: clkout2
> >   ...
> >
> > If you want to express any number and order of strings is valid, then you need:
> >
> > items:
> >   enum:
> >     - clkout0
> >     - clkout1
> >     - clkout2
> >
> > Doing that is discouraged for bindings though. Currently, it will
> > generate an error from the meta-schema, but we could change that.
>
> It's the second case. The inputs are not contiguous. Examples:
>
> system-controller {
>     compatible = "samsung,exynos3250-pmu", "syscon";
>     clock-names = "clkout8";
>     clocks = <&cmu CLK_FIN_PLL>;
> }
>
> system-controller {
>     compatible = "samsung,exynos4412-pmu", "syscon";
>     clock-names = "clkout0", "clkout1", "clkout2", "clkout3",
>                   "clkout4", "clkout8", "clkout9";
>     clocks = <&clock CLK_OUT_DMC>, <&clock CLK_OUT_TOP>,
>              <&clock CLK_OUT_LEFTBUS>, <&clock CLK_OUT_RIGHTBUS>,
>              <&clock CLK_OUT_CPU>, <&clock CLK_XXTI>, <&clock CLK_XUSBXTI>;
> }
>
> The bindings never required any specific ordering. Also the driver
> just go through all indices and parses them.
>
> Your second syntax fails:
> Documentation/devicetree/bindings/arm/samsung/pmu.yaml:
> properties:clock-names:items: {'enum': ['clkout0', 'clkout1',
> 'clkout2', 'clkout3', 'clkout4', 'clkout5', 'clkout6', 'clkout7',
> 'clkout8', 'clkout9', 'clkout10', 'clkout11', 'clkout12', 'clkout13',
> 'clkout14', 'clkout15', 'clkout16']} is not of type 'array'

Update dt-schema and try again. It should be allowed now. You'll also
need to define minItems and maxItems though.

Rob