Re: [PATCH net-next v15 01/15] dt-bindings: net: Introduce the ethernet-connector description

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi Rob,

On 12/11/2025 13:43, Rob Herring wrote:
> On Thu, Nov 06, 2025 at 10:47:26AM +0100, Maxime Chevallier wrote:
>> The ability to describe the physical ports of Ethernet devices is useful
>> to describe multi-port devices, as well as to remove any ambiguity with
>> regard to the nature of the port.
>>
>> Moreover, describing ports allows for a better description of features
>> that are tied to connectors, such as PoE through the PSE-PD devices.
>>
>> Introduce a binding to allow describing the ports, for now with 2
>> attributes :
>>
>>  - The number of lanes, which is a quite generic property that allows
>>    differentating between multiple similar technologies such as BaseT1
>>    and "regular" BaseT (which usually means BaseT4).
>>
>>  - The media that can be used on that port, such as BaseT for Twisted
>>    Copper, BaseC for coax copper, BaseS/L for Fiber, BaseK for backplane
>>    ethernet, etc. This allows defining the nature of the port, and
>>    therefore avoids the need for vendor-specific properties such as
>>    "micrel,fiber-mode" or "ti,fiber-mode".
>>
>> The port description lives in its own file, as it is intended in the
>> future to allow describing the ports for phy-less devices.
>>
>> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
>> ---
>>  .../bindings/net/ethernet-connector.yaml      | 53 +++++++++++++++++++
>>  .../devicetree/bindings/net/ethernet-phy.yaml | 18 +++++++
>>  MAINTAINERS                                   |  1 +
>>  3 files changed, 72 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/net/ethernet-connector.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/net/ethernet-connector.yaml b/Documentation/devicetree/bindings/net/ethernet-connector.yaml
>> new file mode 100644
>> index 000000000000..2b67907582c7
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/net/ethernet-connector.yaml
>> @@ -0,0 +1,53 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/net/ethernet-connector.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Generic Ethernet Connector
>> +
>> +maintainers:
>> +  - Maxime Chevallier <maxime.chevallier@bootlin.com>
>> +
>> +description:
>> +  An Ethernet Connector represents the output of a network component such as
>> +  a PHY, an Ethernet controller with no PHY, or an SFP module.
>> +
>> +properties:
>> +
>> +  pairs:
>> +    description:
>> +      Defines the number of BaseT pairs that are used on the connector.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
> 
> Constraints? Wouldn't 4 pairs be the max?

Andrew also made that remark on the code, I'll add a constraint on
1, 2 or 4 pairs.

> 
> Is it possible you need to know which pairs are wired?

For now I don't think so, except maybe for when 2 pairs are wired
when 4 are supported on the PHY and connector, but even then I don't
think HW designers have a choice about which one to use. It's unclear
to me wether this would be useful.

> 
>> +
>> +  media:
> 
> Both of these names are a bit generic though I don't have a better 
> suggestion.
> 
>> +    description:
>> +      The mediums, as defined in 802.3, that can be used on the port.
>> +    enum:
>> +      - BaseT
>> +      - BaseK
>> +      - BaseS
>> +      - BaseC
>> +      - BaseL
>> +      - BaseD
>> +      - BaseE
>> +      - BaseF
>> +      - BaseV
>> +      - BaseMLD
>> +
>> +required:
>> +  - media
>> +
>> +allOf:
>> +  - if:
>> +      properties:
>> +        media:
>> +          contains:
>> +            const: BaseT
>> +    then:
>> +      required:
>> +        - pairs
> 
> else:
>   properties:
>     pairs: false
> 
> ??

Ah I didn't know this was necessary, I'll add that, thanks !

> 
>> +
>> +additionalProperties: true
>> +
>> +...
>> diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
>> index 2ec2d9fda7e3..f434768d6bae 100644
>> --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
>> +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
>> @@ -277,6 +277,17 @@ properties:
>>  
>>      additionalProperties: false
>>  
>> +  mdi:
>> +    type: object
>> +
>> +    patternProperties:
>> +      '^connector-[a-f0-9]+$':
> 
> Unit addresses are hex, index suffixes are decimal: connector-[0-9]+

Ah right, indeed. I'll address that.

> 
> 
>> +        $ref: /schemas/net/ethernet-connector.yaml#
>> +
>> +        unevaluatedProperties: false
>> +
>> +    additionalProperties: false
>> +
>>  required:
>>    - reg
>>  
>> @@ -313,5 +324,12 @@ examples:
>>                      default-state = "keep";
>>                  };
>>              };
>> +            /* Fast Ethernet port, with only 2 pairs wired */
>> +            mdi {
>> +                connector-0 {
>> +                    pairs = <2>;
>> +                    media = "BaseT";
>> +                };
>> +            };
>>          };
>>      };
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 1ab7e8746299..19ba82b98616 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -9276,6 +9276,7 @@ R:	Russell King <linux@armlinux.org.uk>
>>  L:	netdev@vger.kernel.org
>>  S:	Maintained
>>  F:	Documentation/ABI/testing/sysfs-class-net-phydev
>> +F:	Documentation/devicetree/bindings/net/ethernet-connector.yaml
>>  F:	Documentation/devicetree/bindings/net/ethernet-phy.yaml
>>  F:	Documentation/devicetree/bindings/net/mdio*
>>  F:	Documentation/devicetree/bindings/net/qca,ar803x.yaml
>> -- 
>> 2.49.0
>>

Thanks for reviewing !

Maxime