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Date:   Fri, 20 May 2022 16:12:22 +0200
From:   Herve Codina <herve.codina@bootlin.com>
To:     Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Claudiu Beznea <claudiu.beznea@microchip.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Horatiu Vultur <horatiu.vultur@microchip.com>,
        linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH 2/3] dt-bindings: usb: atmel: Add Microchip LAN966x
 compatible string
Message-ID: <20220520161222.71fc3a75@bootlin.com>
In-Reply-To: <YoedFkAsTdoOn/3Y@mail.local>
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Hi Alexandre,

On Fri, 20 May 2022 15:52:22 +0200
Alexandre Belloni <alexandre.belloni@bootlin.com> wrote:

> Hello,
>=20
> On 20/05/2022 15:38:36+0200, Krzysztof Kozlowski wrote:
> > On 20/05/2022 15:02, Herve Codina wrote: =20
> > > On Fri, 20 May 2022 14:50:24 +0200
> > > Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> wrote:
> > >  =20
> > >> On 20/05/2022 14:21, Herve Codina wrote: =20
> > >>>>> I think it makes sense to keep 'microchip,lan966x-udc' for the USB
> > >>>>> device controller (same controller on LAN9662 and LAN9668) and so
> > >>>>> keeping the same rules as for other common parts.     =20
> > >>>>
> > >>>> Having wildcard was rather a mistake and we already started correc=
ting
> > >>>> it, so keeping the "mistake" neither gives you consistency, nor
> > >>>> correctness...
> > >>>>   =20
> > >>>
> > >>> I think that the "family" compatible should be present.
> > >>> This one allows to define the common parts in the common
> > >>> .dtsi file (lan966x.dtsi in our case).
> > >>>
> > >>> What do you think about:
> > >>> - microchip,lan9662-udc
> > >>> - microchip,lan9668-udc
> > >>> - microchip,lan966-udc  <-- Family
> > >>>
> > >>> lan966 is defined as the family compatible string since (1) in
> > >>> bindings/arm/atmel-at91.yaml and in Documentation/arm/microchip.rst
> > >>>    =20
> > >>
> > >> You can add some family compatible, if it makes sense. I don't get w=
hy
> > >> do you mention it - we did not discuss family names, but using
> > >> wildcards... Just please do not add wildcards. =20
> > >=20
> > > Well, I mentioned it as I will only use the family compatible string
> > > and not the SOC (lan9662 or lan9668) compatible string in lan966x.dts=
i.
> > > In this case, the family compatible string can be seen as a kind of
> > > "wildcard". =20
> >=20
> > I understood as "the "family" compatible should be present" as you want
> > to add it as a fallback. It would be okay (assuming devices indeed share
> > family design). If you want to use it as the only one, then it is again
> > not a recommended approach. Please use specific compatibles.
> >=20
> > I mean, why do we have this discussion? What is the benefit for you to
> > implement something not-recommended by Devicetree spec and style?
> >  =20
>=20
> Honestly, I would just go for microchip,lan9662-udc. There is no
> difference between lan9662 and lan9668 apart from the number of switch
> ports.
>=20

Sounds good.
I will do that.

Thanks,
Herv=C3=A9

--=20
Herv=C3=A9 Codina, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com