Re: [PATCH v1 1/1] dt-bindings: net: dsa: Add DSA yaml binding

From: Rob Herring <robh@kernel.org>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Kurt Kanzenbach <kurt@linutronix.de>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>,
	devicetree@vger.kernel.org,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Jakub Kicinski <kuba@kernel.org>
Subject: Re: [PATCH v1 1/1] dt-bindings: net: dsa: Add DSA yaml binding
Date: Mon, 13 Jul 2020 14:56:43 -0600	[thread overview]
Message-ID: <CAL_JsqKe47GdjVXJ6GeRCfZ7v+WKxee6P2jAi64+M5BYaf=8SQ@mail.gmail.com> (raw)
In-Reply-To: <20200711165203.GO1014141@lunn.ch>

On Sat, Jul 11, 2020 at 10:52 AM Andrew Lunn <andrew@lunn.ch> wrote:
>
> On Sat, Jul 11, 2020 at 01:35:12PM +0200, Kurt Kanzenbach wrote:
> > On Fri Jul 10 2020, Rob Herring wrote:
> > > On Fri, 10 Jul 2020 11:06:18 +0200, Kurt Kanzenbach wrote:
> > >> For future DSA drivers it makes sense to add a generic DSA yaml binding which
> > >> can be used then. This was created using the properties from dsa.txt. It
> > >> includes the ports and the dsa,member property.
> > >>
> > >> Suggested-by: Florian Fainelli <f.fainelli@gmail.com>
> > >> Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
> > >> ---
> > >>  .../devicetree/bindings/net/dsa/dsa.yaml      | 80 +++++++++++++++++++
> > >>  1 file changed, 80 insertions(+)
> > >>  create mode 100644 Documentation/devicetree/bindings/net/dsa/dsa.yaml
> > >>
> > >
> > >
> > > My bot found errors running 'make dt_binding_check' on your patch:
> > >
> > > /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/net/ti,cpsw-switch.example.dt.yaml: switch@0: 'ports' is a required property
> > > /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/net/qcom,ipq8064-mdio.example.dt.yaml: switch@10: 'ports' is a required property
> >
> > Okay, the requirement for 'ports' has be to removed.
>
> Hummm....
>
> ti.cpsw is not a DSA switch. So this binding should not apply to
> it. It is a plain switchdev switch.

Well, the binding looks very similar with the same
ethernet-ports/port@X structure. So maybe we need a switch schema that
covers both and then a DSA schema.

> The qcom,ipq806 is just an MDIO bus master. The DSA binding might
> apply, for a specific .dts file, if that dts file has a DSA switch on
> the bus. But in general, it should not apply.
>
> So i actually think you need to work out why this binding is being
> applied when it should not be.
>
> I suspect it is the keyword 'switch'. switch does not imply it is a
> DSA switch. There are other sorts of switches as well.

Yes, by default, we match on compatible or node name if no compatible.
The simple solution here is adding 'select: false' and then dsa.yaml
will only be applied when explicitly referenced by the h/w specific
bindings.

There's also mscc-ocelot which is not yet a schema.

Rob