Re: [PATCH v2 02/20] dt-bindings: arm: Convert Marvell MMP board/soc bindings to json-schema

From: Rob Herring <robh+dt@kernel.org>
To: Lubomir Rintel <lkundrak@v3.sk>
Cc: Olof Johansson <olof@lixom.net>,
	Mark Rutland <mark.rutland@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	Marc Zyngier <maz@kernel.org>,
	Kishon Vijay Abraham I <kishon@ti.com>,
	Russell King <linux@armlinux.org.uk>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	devicetree@vger.kernel.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
	<linux-arm-kernel@lists.infradead.org>,
	linux-clk <linux-clk@vger.kernel.org>
Subject: Re: [PATCH v2 02/20] dt-bindings: arm: Convert Marvell MMP board/soc bindings to json-schema
Date: Tue, 27 Aug 2019 08:36:47 -0500	[thread overview]
Message-ID: <CAL_JsqK1pkwPZj+Us8CecNnfA7L17YVk9aTe3qPoNTAvRiHibw@mail.gmail.com> (raw)
In-Reply-To: <136a57cf3d293e3233f31d5ee660a6418726333a.camel@v3.sk>

On Tue, Aug 27, 2019 at 8:24 AM Lubomir Rintel <lkundrak@v3.sk> wrote:
>
> On Tue, 2019-08-27 at 06:59 -0500, Rob Herring wrote:
> > On Thu, Aug 22, 2019 at 4:27 AM Lubomir Rintel <lkundrak@v3.sk> wrote:
> > > Convert Marvell MMP SoC bindings to DT schema format using json-schema.
> > >
> > > Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
> > >
> > > ---
> > > Changes since v1:
> > > - Added this patch
> > >
> > >  .../devicetree/bindings/arm/mrvl/mrvl.txt     | 14 ---------
> > >  .../devicetree/bindings/arm/mrvl/mrvl.yaml    | 31 +++++++++++++++++++
> > >  2 files changed, 31 insertions(+), 14 deletions(-)
> > >  delete mode 100644 Documentation/devicetree/bindings/arm/mrvl/mrvl.txt
> > >  create mode 100644 Documentation/devicetree/bindings/arm/mrvl/mrvl.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/arm/mrvl/mrvl.txt b/Documentation/devicetree/bindings/arm/mrvl/mrvl.txt
> > > deleted file mode 100644
> > > index 951687528efb0..0000000000000
> > > --- a/Documentation/devicetree/bindings/arm/mrvl/mrvl.txt
> > > +++ /dev/null
> > > @@ -1,14 +0,0 @@
> > > -Marvell Platforms Device Tree Bindings
> > > -----------------------------------------------------
> > > -
> > > -PXA168 Aspenite Board
> > > -Required root node properties:
> > > -       - compatible = "mrvl,pxa168-aspenite", "mrvl,pxa168";
> > > -
> > > -PXA910 DKB Board
> > > -Required root node properties:
> > > -       - compatible = "mrvl,pxa910-dkb";
> > > -
> > > -MMP2 Brownstone Board
> > > -Required root node properties:
> > > -       - compatible = "mrvl,mmp2-brownstone", "mrvl,mmp2";
> > > diff --git a/Documentation/devicetree/bindings/arm/mrvl/mrvl.yaml b/Documentation/devicetree/bindings/arm/mrvl/mrvl.yaml
> > > new file mode 100644
> > > index 0000000000000..dc9de506ac6e3
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/arm/mrvl/mrvl.yaml
> > > @@ -0,0 +1,31 @@
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/arm/mrvl/mrvl.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Marvell Platforms Device Tree Bindings
> > > +
> > > +maintainers:
> > > +  - Lubomir Rintel <lkundrak@v3.sk>
> > > +
> > > +properties:
> > > +  $nodename:
> > > +    const: '/'
> > > +  compatible:
> > > +    oneOf:
> > > +      - description: PXA168 Aspenite Board
> > > +        items:
> > > +          - enum:
> > > +              - mrvl,pxa168-aspenite
> > > +          - const: mrvl,pxa168
> > > +      - description: PXA910 DKB Board
> > > +        items:
> > > +          - enum:
> > > +              - mrvl,pxa910-dkb
> >
> > Doesn't match what's in dts file:
> >
> > arch/arm/boot/dts/pxa910-dkb.dts:       compatible =
> > "mrvl,pxa910-dkb", "mrvl,pxa910";
>
> It corresponds to the .txt bindings specification this commit is
> converting. I thought it wouldn't be a good idea to do any changes to
> the contents at the time the conversion is done.

There are so many errors like this, that it's fine to do it in the
conversion. A separate patch is fine too.

> I also don't understand why does the dts file specify the board-
> specific compatible string. Surely "mrvl,pxa910" alone would be
> sufficient?

To potentially work around any board specific issue without a dtb change.

>
> > > +      - description: MMP2 Brownstone Board
> >
> > If this entry is only for this board...
> >
> > > +        items:
> > > +          - enum:
> > > +              - mrvl,mmp2-brownstone
> >
> > ...then this can be a 'const' instead. Same for the others.
>
> Sure, but is it preferable? I've actually done a "git grep -A3 enum
> Documentation/devicetree/bindings/" to see if the single-element is
> typically used and it seems like it is. Perhaps it's a good idea to
> indicate to a human reader that this is a list that's expected to
> eventually be extended with new elements.

Then the description should match and say 'MMP2 based boards'.

> In any case, there are more boards with MMP2 currently supported,
> notably the XO-1.75 laptop. I've actually sent out the dts file for
> review some time ago. I haven't added a separate compatible string for
> it because I thought it is not necessary (see above).

You should add one.

Rob