RE: [PATCH v2] dt-bindings: net: xilinx_gmii2rgmii: Convert to json schema

[Somisetty, Pranavi]

> -----Original Message-----
> From: Rob Herring <robh@xxxxxxxxxx>
> Sent: Wednesday, July 19, 2023 11:52 PM
> To: Somisetty, Pranavi <pranavi.somisetty@xxxxxxx>
> Cc: davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> krzysztof.kozlowski+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx; Simek, Michal
> <michal.simek@xxxxxxx>; Katakam, Harini <harini.katakam@xxxxxxx>;
> git (AMD-Xilinx) <git@xxxxxxx>; Pandey, Radhey Shyam
> <radhey.shyam.pandey@xxxxxxx>; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2] dt-bindings: net: xilinx_gmii2rgmii: Convert to json
> schema
> 
> On Wed, Jul 19, 2023 at 12:18:08AM -0600, Pranavi Somisetty wrote:
> > Convert the Xilinx GMII to RGMII Converter device tree binding
> > documentation to json schema.
> > This converter is usually used as gem <---> gmii2rgmii <---> external
> > phy and, it's phy-handle should point to the phandle of the external phy.
> >
> > Signed-off-by: Pranavi Somisetty <pranavi.somisetty@xxxxxxx>
> > ---
> > Changes v2:
> > 1. Changed description for the property "reg".
> > 2. Added a reference to the description of "phy-handle" property.
> > ---
> >  .../bindings/net/xilinx_gmii2rgmii.txt        | 35 ------------
> >  .../bindings/net/xlnx,gmii-to-rgmii.yaml      | 54 +++++++++++++++++++
> >  2 files changed, 54 insertions(+), 35 deletions(-)  delete mode
> > 100644 Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> >  create mode 100644
> > Documentation/devicetree/bindings/net/xlnx,gmii-to-rgmii.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> > b/Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> > deleted file mode 100644
> > index 038dda48b8e6..000000000000
> > --- a/Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt
> > +++ /dev/null
> > @@ -1,35 +0,0 @@
> > -XILINX GMIITORGMII Converter Driver Device Tree Bindings
> > ---------------------------------------------------------
> > -
> > -The Gigabit Media Independent Interface (GMII) to Reduced Gigabit
> > Media -Independent Interface (RGMII) core provides the RGMII between
> > RGMII-compliant -Ethernet physical media devices (PHY) and the Gigabit
> Ethernet controller.
> > -This core can be used in all three modes of operation(10/100/1000 Mb/s).
> > -The Management Data Input/Output (MDIO) interface is used to
> > configure the -Speed of operation. This core can switch dynamically
> > between the three -Different speed modes by configuring the conveter
> register through mdio write.
> > -
> > -This converter sits between the ethernet MAC and the external phy.
> > -MAC <==> GMII2RGMII <==> RGMII_PHY
> > -
> > -For more details about mdio please refer phy.txt file in the same directory.
> > -
> > -Required properties:
> > -- compatible	: Should be "xlnx,gmii-to-rgmii-1.0"
> > -- reg		: The ID number for the phy, usually a small integer
> > -- phy-handle	: Should point to the external phy device.
> > -		  See ethernet.txt file in the same directory.
> > -
> > -Example:
> > -	mdio {
> > -		#address-cells = <1>;
> > -		#size-cells = <0>;
> > -		phy: ethernet-phy@0 {
> > -			......
> > -		};
> > -		gmiitorgmii: gmiitorgmii@8 {
> > -			compatible = "xlnx,gmii-to-rgmii-1.0";
> > -			reg = <8>;
> > -			phy-handle = <&phy>;
> > -		};
> > -	};
> > diff --git
> > a/Documentation/devicetree/bindings/net/xlnx,gmii-to-rgmii.yaml
> > b/Documentation/devicetree/bindings/net/xlnx,gmii-to-rgmii.yaml
> > new file mode 100644
> > index 000000000000..9d22382a64ba
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/net/xlnx,gmii-to-rgmii.yaml
> > @@ -0,0 +1,54 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/net/xlnx,gmii-to-rgmii.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Xilinx GMII to RGMII Converter
> > +
> > +maintainers:
> > +  - Harini Katakam <harini.katakam@xxxxxxx>
> > +
> > +description:
> > +  The Gigabit Media Independent Interface (GMII) to Reduced Gigabit
> > +Media
> > +  Independent Interface (RGMII) core provides the RGMII between
> > +RGMII-compliant
> > +  ethernet physical media devices (PHY) and the Gigabit Ethernet
> controller.
> > +  This core can be used in all three modes of operation(10/100/1000
> Mb/s).
> > +  The Management Data Input/Output (MDIO) interface is used to
> > +configure the
> > +  speed of operation. This core can switch dynamically between the
> > +three
> > +  different speed modes by configuring the converter register through
> mdio write.
> > +  The core cannot function without an external phy connected to it.
> > +
> > +properties:
> > +  compatible:
> > +    const: xlnx,gmii-to-rgmii-1.0
> > +
> > +  reg:
> > +    minimum: 0
> > +    maximum: 31
> > +    description: The ID number for the phy.
> > +
> > +  phy-handle:
> > +    $ref: ethernet-controller.yaml#/properties/phy-handle
> 
> Don't reference individual properties like this. Instead add a $ref at the top
> level to just "ethernet-controller.yaml#". Since this is the only property you
> want from there, put a 'phy-handle: true' here and use additionalProperties
> instead of unevaluatedProperties below.
>

Adding a top level $ref to ethernet-controller, implies, DT for gmii2rgmii, follows the schema in ethernet-controller.yaml. This is incorrect since gmii2rgmii IP isn't an ethernet controller.
I'm not sure how to reference ethernet-controller.yaml from this schema. Would it be okay to add a description to the phy-handle property instead of referencing the description in ethernet-controller.yaml?

Regards
Pranavi
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - phy-handle
> > +
> > +unevaluatedProperties: false
> > +
> > +examples:
> > +  - |
> > +    mdio {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +        phy: ethernet-phy@0 {
> > +            reg = <0>;
> > +        };
> > +        gmiitorgmii@8 {
> > +            compatible = "xlnx,gmii-to-rgmii-1.0";
> > +            reg = <8>;
> > +            phy-handle = <&phy>;
> > +        };
> > +    };
> > --
> > 2.36.1
> >