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

Maxime Chevallier
2025-11-12T13:37:52Z

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