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From: Keguang Zhang <keguang.zhang@gmail.com>
Date: Fri, 7 Jun 2024 10:36:12 +0800
Message-ID: <CAJhJPsU3foQ_Nr3WhH6nqJZxrK+WpjgJZAcGjGHzRp4K6pfTNw@mail.gmail.com>
Subject: Re: [PATCH v7 1/3] dt-bindings: mtd: Add Loongson-1 NAND Controller
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Keguang Zhang via B4 Relay <devnull+keguang.zhang.gmail.com@kernel.org>, 
	Richard Weinberger <richard@nod.at>, Vignesh Raghavendra <vigneshr@ti.com>, Rob Herring <robh@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, 
	linux-mips@vger.kernel.org, devicetree@vger.kernel.org
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On Fri, Jun 7, 2024 at 5:33=E2=80=AFAM Miquel Raynal <miquel.raynal@bootlin=
.com> wrote:
>
> Hi,
>
> > > > > > +properties:
> > > > > > +  compatible:
> > > > > > +    oneOf:
> > > > > > +      - const: loongson,ls1b-nfc
> > > > >
> > > > > What is the rationale behind this choice? Seems like the b varian=
t has
> > > > > two possible implementations and should always be preceded by a m=
ore
> > > > > specific compatible.
> > > > >
> > > > > As there is currently no description of this controller upstream,=
 I
> > > > > would not care too much about any out-of-tree description and dir=
ectly
> > > > > go for a clean description.
> > > > >
> > > > Excuse me, should I add a description for this property?
> > >
> > > No, description is not needed. But you are allowing the
> > > "loongson,ls1b-nfc" compatible alone, which I think is not relevant,
> > > unless you convince me it is :-)
> > >
> > "loongson,ls1b-nfc" itself is a specific implementation.
> > I was suggested to set up a fallback before.
> > https://lore.kernel.org/all/20231007-untapped-masses-01f80b7c13c7@spud/
> > Then "loongson,ls1b-nfc" became the fallback.
>
> You cannot allow 'the fallback', alone. But this is what you do above.
> Below description is fine. Just don't allow the ls1b-nfc compatible
> alone.
>
Sorry. I still don't get this.
According to https://lore.kernel.org/all/20221212163532.142533-2-krzysztof.=
kozlowski@linaro.org/,
the generic fallback should not be used alone.
In contrast, the specific fallback has to be used alone, as I understand it=
.
If not, could you please show me the right way?
Thanks very much!

> Thanks,
> Miqu=C3=A8l


--=20
Best regards,

Keguang Zhang