[PATCH 1/3] dt-bindings: mtd: rzn1: Describe Renesas RZ/N1 NAND controller

[Geert Uytterhoeven]

Hi Miquel,

On Fri, Nov 26, 2021 at 12:46 PM Miquel Raynal
<miquel.raynal at bootlin.com> wrote:
> geert at linux-m68k.org wrote on Fri, 19 Nov 2021 10:36:16 +0100:
> > On Fri, Nov 19, 2021 at 10:19 AM Miquel Raynal
> > <miquel.raynal at bootlin.com> wrote:
> > > geert at linux-m68k.org wrote on Fri, 19 Nov 2021 09:41:35 +0100:
> > > > On Thu, Nov 18, 2021 at 12:19 PM Miquel Raynal
> > > > <miquel.raynal at bootlin.com> wrote:
> > > > > Add a Yaml description for this Renesas NAND controller bindings.
> > > > >
> > > > > Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> >
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/mtd/renesas,r9a06g032-nand-controller.yaml
> > > > > @@ -0,0 +1,60 @@
> > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > > +%YAML 1.2
> > > > > +---
> > > > > +$id: http://devicetree.org/schemas/mtd/renesas,r9a06g032-nand-controller.yaml#
> > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > +
> > > > > +title: Renesas RZ/N1x NAND flash controller device tree bindings
> > > > > +
> > > > > +maintainers:
> > > > > +  - Miquel Raynal <miquel.raynal at bootlin.com>
> > > > > +
> > > > > +allOf:
> > > > > +  - $ref: "nand-controller.yaml"
> > > > > +
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    const: renesas,r9a06g032-nand-controller
> > > >
> > > > As the NAND Flash Controller is present on all of RZ/N1D, RZ/N1S,
> > > > and RZ/N1L, I think you should add a family-specific compatible value
> > > > "renesas,rzn1-nand-controller" as a fallback.
> > >
> > > I see, that's right, I should have added two compatibles.
> > >
> > > As there is currently only one 'specific' compatible (r9axxx), should I
> > > describe the two compatibles as being mandatory? Or should I set the
> > > most specific one as optional and the least specific one (rzn1)
> > > mandatory?
> >
> > Yes please.
>
> I am a little bit confused to which answered you said yes.

My apologies: yes to making both mandatory.

> >  Else you need to match on both in the driver, or we cannot
> > differentiate later if the need ever arises.
>
> I believe you meant "yes the two should be described as mandatory in the
> bindings" (at least for now) so that when the need arises, the most
> specific one can be replaced with a oneOf choice. Am I right?

Exactly.

You can already use "enum" for the most-specific one, so it's clear where
to add new lines, and to minimize future changes.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds