linux-kernel - Re: [PATCH 1/1] dt-bindings: net: mdio: Add negative patten match for child node

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Message-ID: <ZrpS7zJpa+YJZfjQ@lizhi-Precision-Tower-5810>
Date: Mon, 12 Aug 2024 14:22:39 -0400
From: Frank Li <Frank.li@....com>
To: Conor Dooley <conor@...nel.org>
Cc: Andrew Lunn <andrew@...n.ch>, Heiner Kallweit <hkallweit1@...il.com>,
	Russell King <linux@...linux.org.uk>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Florian Fainelli <f.fainelli@...il.com>,
	"open list:ETHERNET PHY LIBRARY" <netdev@...r.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>, imx@...ts.linux.dev
Subject: Re: [PATCH 1/1] dt-bindings: net: mdio: Add negative patten match
 for child node

On Mon, Aug 12, 2024 at 05:44:50PM +0100, Conor Dooley wrote:
> On Sun, Aug 11, 2024 at 11:11:14PM -0400, Frank Li wrote:
> > mdio.yaml wrong parser mdio controller's address instead phy's address when
> > mdio-mux exist.
> >
> > For example:
> > mdio-mux-emi1@54 {
> > 	compatible = "mdio-mux-mmioreg", "mdio-mux";
> >
> >         mdio@20 {
> > 		reg = <0x20>;
> > 		       ^^^ This is mdio controller register
> >
> > 		ethernet-phy@2 {
> > 			reg = <0x2>;
> >                               ^^^ This phy's address
> > 		};
> > 	};
> > };
>
> I don't understand MDIO well enough to know the answer - does this
> actually solve the problem? It seems to me that the problem is that
> mdio.yaml is applied to the mdio-mux node because it matches the pattern
> "^mdio(@.*)?" that applies the binding based on node-names. If the
> properties in mdio.yaml do not apply to mdio muxes, then the binding
> should not be applied and the patch here is only treating a symptom
> rather than the actual problem.

after I change above example 0x2 to 0x22, mdio.yaml can report exceed 31.

Only issue should be only when "ethernet-phy" use node name "mdio".

>
> From a quick check, I don't see any of the mdio-mux-mmioreg nodes using
> the properties from mdio.yaml, so should the binding be applied to them
> at all?


in mdio-mux-mmioreg.yaml line 18:
allOf:
  - $ref: /schemas/net/mdio-mux.yaml#

in mdio-mux.yaml

  patternProperties:
    '^mdio@[0-9a-f]+$':  -> A
      $ref: mdio.yaml#

In mdio.yaml

  properties:
    $nodename:
      pattern: "^mdio(@.*)?
	        ^^^^^ mdio@20 Match condition A, it should correct.

  patternProperties:
    '@[0-9a-f]+$':
                ^^^^ mdio@20 also match this one. but I suppose it should
                     search mdio@...s child node, such as ethernet-phy@2,
                     but not.


Frank

>
> Cheers,
> Conor.
>
>
> FWIW, adding a $ after the ? in the pattern I linked would stop the
> binding being applied to the mdio-mux nodes, but if something like that
> were done, all mdio nodes would need to be checked to ensure they match
> the new pattern...
>
>
> >
> > Only phy's address is limited to 31 because MDIO bus defination.
> >
> > But CHECK_DTBS report below warning:
> >
> > arch/arm64/boot/dts/freescale/fsl-ls1043a-qds.dtb: mdio-mux-emi1@54:
> > 	mdio@20:reg:0:0: 32 is greater than the maximum of 31
> >
> > The reason is that "mdio@20" match "patternProperties: '@[0-9a-f]+$'" in
> > mdio.yaml.
> >
> > Change to '^(?!mdio@).*@[0-9a-f]+$' to avoid match parent's mdio
> > controller's address.
> >
> > Signed-off-by: Frank Li <Frank.Li@....com>
> > ---
> >  Documentation/devicetree/bindings/net/mdio.yaml | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/Documentation/devicetree/bindings/net/mdio.yaml b/Documentation/devicetree/bindings/net/mdio.yaml
> > index a266ade918ca7..a7def3eb4674d 100644
> > --- a/Documentation/devicetree/bindings/net/mdio.yaml
> > +++ b/Documentation/devicetree/bindings/net/mdio.yaml
> > @@ -59,7 +59,7 @@ properties:
> >      type: boolean
> >
> >  patternProperties:
> > -  '@[0-9a-f]+$':
> > +  '^(?!mdio@).*@[0-9a-f]+$':
> >      type: object
> >
> >      properties:
> > --
> > 2.34.1
> >