Re: [PATCH 1/2] dt-bindings: memory: convert Marvell MVEBU SDRAM controller to dtschema

["Jan Lübbe" <jlu@pengutronix.de>]

On Tue, 2021-08-17 at 13:06 +0200, Krzysztof Kozlowski wrote:
> On 17/08/2021 12:58, Jan Lübbe wrote:
> > On Tue, 2021-08-17 at 12:52 +0200, Krzysztof Kozlowski wrote:
> > > On 17/08/2021 12:46, Jan Lübbe wrote:
> > > > On Tue, 2021-08-17 at 11:38 +0200, Krzysztof Kozlowski wrote:
> > > > > Convert Marvell MVEBU SDRAM controller bindings to DT schema format
> > > > > using json-schema.
> > > > > 
> > > > > Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
> > > > > ---
> > > > >  .../marvell,mvebu-sdram-controller.yaml       | 31 +++++++++++++++++++
> > > > >  .../mvebu-sdram-controller.txt                | 21 -------------
> > > > >  2 files changed, 31 insertions(+), 21 deletions(-)
> > > > >  create mode 100644 Documentation/devicetree/bindings/memory-controllers/marvell,mvebu-sdram-controller.yaml
> > > > >  delete mode 100644 Documentation/devicetree/bindings/memory-controllers/mvebu-sdram-controller.txt
> > > > > 
> > > > > diff --git a/Documentation/devicetree/bindings/memory-controllers/marvell,mvebu-sdram-controller.yaml b/Documentation/devicetree/bindings/memory-controllers/marvell,mvebu-sdram-controller.yaml
> > > > > new file mode 100644
> > > > > index 000000000000..14a6bc8f421f
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/memory-controllers/marvell,mvebu-sdram-controller.yaml
> > > > > @@ -0,0 +1,31 @@
> > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > > +%YAML 1.2
> > > > > +---
> > > > > +$id: http://devicetree.org/schemas/memory-controllers/marvell,mvebu-sdram-controller.yaml#
> > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > +
> > > > > +title: Marvell MVEBU SDRAM controller
> > > > > +
> > > > > +maintainers:
> > > > > +  - Jan Luebbe <jlu@pengutronix.de>
> > > > > +  - Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
> > > > > +
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    const: marvell,armada-xp-sdram-controller
> > > > > +
> > > > > +  reg:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +required:
> > > > > +  - compatible
> > > > > +  - reg
> > > > > +
> > > > > +additionalProperties: false
> > > > > +
> > > > > +examples:
> > > > > +  - |
> > > > > +    memory-controller@1400 {
> > > > > +        compatible = "marvell,armada-xp-sdram-controller";
> > > > > +        reg = <0x1400 0x500>;
> > > > > +    };
> > > > > diff --git a/Documentation/devicetree/bindings/memory-controllers/mvebu-sdram-controller.txt b/Documentation/devicetree/bindings/memory-controllers/mvebu-sdram-controller.txt
> > > > > deleted file mode 100644
> > > > > index 89657d1d4cd4..000000000000
> > > > > --- a/Documentation/devicetree/bindings/memory-controllers/mvebu-sdram-controller.txt
> > > > > +++ /dev/null
> > > > > @@ -1,21 +0,0 @@
> > > > > -Device Tree bindings for MVEBU SDRAM controllers
> > > > > -
> > > > > -The Marvell EBU SoCs all have a SDRAM controller. The SDRAM controller
> > > > > -differs from one SoC variant to another, but they also share a number
> > > > > -of commonalities.
> > > > > -
> > > > > -For now, this Device Tree binding documentation only documents the
> > > > > -Armada XP SDRAM controller.
> > > > 
> > > > Please keep the description, otherwise it would be confusing why the binding is
> > > > named marvell,mvebu-sdram-controller.yaml although it (currenly) only applies to
> > > > the Armada XP.
> > > > 
> > > 
> > > The description does not explain why it only documents Armada XP, so it
> > > just duplicates what is in "compatible" part of bindings. How is the
> > > confusion removed by saying "we document currently only Armada XP"? What
> > > changes?
> > 
> > Then perhaps the binding should be named marvell,armada-xp-sdram-
> > controller.yaml? It find it unlikely that support for the other SoC's
> > controllers will be added, given their age.
> 
> Sure, could be like this but there is no confusion here and no need to
> fix anything. It is understandable and common to name bindings file as
> general (e.g. for group of devices) even though only limited amount of
> devices are currently documented/described. It's almost everywhere like
> this, when the bindings are not complete. I don't see where is the
> confusion.
> 
> Look at: arm/marvell/armada-cpu-reset.txt which mentions several SoCs
> while only three compatibles are documented.
> arm/marvell/armada-cpu-reset.txt has generic name and describes only one
> reset controller (370) while being used on multiple SoC (370, 375, 38x,
> 39x). I could go like this all over the bindings...

OK, you convinced me. Thanks for the explanation.

Jan
-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |