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

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Tudor Ambarus <Tudor.Ambarus@microchip.com>,
	Pratyush Yadav <p.yadav@ti.com>, Michael Walle <michael@walle.cc>,
	MTD Maling List <linux-mtd@lists.infradead.org>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Jimmy Lalande <jimmy.lalande@se.com>,
	Milan Stevanovic <milan.stevanovic@se.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Magnus Damm <magnus.damm@gmail.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Gareth Williams <gareth.williams.jx@renesas.com>
Subject: Re: [PATCH 1/3] dt-bindings: mtd: rzn1: Describe Renesas RZ/N1 NAND controller
Date: Fri, 26 Nov 2021 12:46:49 +0100	[thread overview]
Message-ID: <20211126124649.498366ee@xps13> (raw)
In-Reply-To: <CAMuHMdU_uJv2dUk21DKJnLSUErhvObOb1wJOZTqv_UXZ0edRBQ@mail.gmail.com>

Hi Geert,

geert@linux-m68k.org wrote on Fri, 19 Nov 2021 10:36:16 +0100:

> Hi Miquel,
> 
> On Fri, Nov 19, 2021 at 10:19 AM Miquel Raynal
> <miquel.raynal@bootlin.com> wrote:
> > geert@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@bootlin.com> wrote:  
> > > > Add a Yaml description for this Renesas NAND controller bindings.
> > > >
> > > > Signed-off-by: Miquel Raynal <miquel.raynal@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@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.

>  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?

Thanks,
Miquèl

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