Subject: Re: [PATCH v2 1/2] dt-bindings: net: micrel: Convert to DT schema

From: Rob Herring <[email-masked]>
Date: Tue, 13 Jan 2026 17:05:48 -0600

On Fri, Jan 09, 2026 at 09:21:15AM +0100, Stefan Eichenberger wrote:
> On Thu, Jan 08, 2026 at 12:48:45PM -0600, Rob Herring wrote:
> > On Thu, Jan 08, 2026 at 01:51:27PM +0100, Stefan Eichenberger wrote:
> > > From: Stefan Eichenberger <[email-masked]>
> > > 
> > > Convert the devicetree bindings for the Micrel PHYs and switches to DT
> > > schema.
> > > 
> > > Signed-off-by: Stefan Eichenberger <[email-masked]>
> > > ---
> > >  .../devicetree/bindings/net/micrel.txt        |  57 --------
> > >  .../devicetree/bindings/net/micrel.yaml       | 133 ++++++++++++++++++
> > >  2 files changed, 133 insertions(+), 57 deletions(-)
> > >  delete mode 100644 Documentation/devicetree/bindings/net/micrel.txt
> > >  create mode 100644 Documentation/devicetree/bindings/net/micrel.yaml
> > > 
> > > diff --git a/Documentation/devicetree/bindings/net/micrel.txt b/Documentation/devicetree/bindings/net/micrel.txt
> > > deleted file mode 100644
> > > index 01622ce58112..000000000000
> > > --- a/Documentation/devicetree/bindings/net/micrel.txt
> > > +++ /dev/null
> > > @@ -1,57 +0,0 @@
> > > -Micrel PHY properties.
> > > -
> > > -These properties cover the base properties Micrel PHYs.
> > > -
> > > -Optional properties:
> > > -
> > > - - micrel,led-mode : LED mode value to set for PHYs with configurable LEDs.
> > > -
> > > -	Configure the LED mode with single value. The list of PHYs and the
> > > -	bits that are currently supported:
> > > -
> > > -	KSZ8001: register 0x1e, bits 15..14
> > > -	KSZ8041: register 0x1e, bits 15..14
> > > -	KSZ8021: register 0x1f, bits 5..4
> > > -	KSZ8031: register 0x1f, bits 5..4
> > > -	KSZ8051: register 0x1f, bits 5..4
> > > -	KSZ8081: register 0x1f, bits 5..4
> > > -	KSZ8091: register 0x1f, bits 5..4
> > > -	LAN8814: register EP5.0, bit 6
> > > -
> > > -	See the respective PHY datasheet for the mode values.
> > > -
> > > - - micrel,rmii-reference-clock-select-25-mhz: RMII Reference Clock Select
> > > -						bit selects 25 MHz mode
> > > -
> > > -	Setting the RMII Reference Clock Select bit enables 25 MHz rather
> > > -	than 50 MHz clock mode.
> > > -
> > > -	Note that this option is only needed for certain PHY revisions with a
> > > -	non-standard, inverted function of this configuration bit.
> > > -	Specifically, a clock reference ("rmii-ref" below) is always needed to
> > > -	actually select a mode.
> > > -
> > > - - clocks, clock-names: contains clocks according to the common clock bindings.
> > > -
> > > -	supported clocks:
> > > -	- KSZ8021, KSZ8031, KSZ8081, KSZ8091: "rmii-ref": The RMII reference
> > > -	  input clock. Used to determine the XI input clock.
> > > -
> > > - - micrel,fiber-mode: If present the PHY is configured to operate in fiber mode
> > > -
> > > -	Some PHYs, such as the KSZ8041FTL variant, support fiber mode, enabled
> > > -	by the FXEN boot strapping pin. It can't be determined from the PHY
> > > -	registers whether the PHY is in fiber mode, so this boolean device tree
> > > -	property can be used to describe it.
> > > -
> > > -	In fiber mode, auto-negotiation is disabled and the PHY can only work in
> > > -	100base-fx (full and half duplex) modes.
> > > -
> > > - - coma-mode-gpios: If present the given gpio will be deasserted when the
> > > -		    PHY is probed.
> > > -
> > > -	Some PHYs have a COMA mode input pin which puts the PHY into
> > > -	isolate and power-down mode. On some boards this input is connected
> > > -	to a GPIO of the SoC.
> > > -
> > > -	Supported on the LAN8814.
> > > diff --git a/Documentation/devicetree/bindings/net/micrel.yaml b/Documentation/devicetree/bindings/net/micrel.yaml
> > > new file mode 100644
> > > index 000000000000..52d1b187e1d3
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/net/micrel.yaml
> > > @@ -0,0 +1,133 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/net/micrel.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Micrel KSZ series PHYs and switches
> > > +
> > > +maintainers:
> > > +  - Andrew Lunn <[email-masked]>
> > > +  - Stefan Eichenberger <[email-masked]>
> > > +
> > > +description:
> > > +  The Micrel KSZ series contains different network phys and switches.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    enum:
> > > +      - ethernet-phy-id000e.7237  # KSZ8873MLL
> > > +      - ethernet-phy-id0022.1430  # KSZ886X
> > > +      - ethernet-phy-id0022.1435  # KSZ8863
> > > +      - ethernet-phy-id0022.1510  # KSZ8041
> > > +      - ethernet-phy-id0022.1537  # KSZ8041RNLI
> > > +      - ethernet-phy-id0022.1550  # KSZ8051
> > > +      - ethernet-phy-id0022.1555  # KSZ8021
> > > +      - ethernet-phy-id0022.1556  # KSZ8031
> > > +      - ethernet-phy-id0022.1560  # KSZ8081, KSZ8091
> > > +      - ethernet-phy-id0022.1570  # KSZ8061
> > > +      - ethernet-phy-id0022.161a  # KSZ8001
> > > +      - ethernet-phy-id0022.1720  # KS8737
> > > +
> > > +  micrel,fiber-mode:
> > > +    type: boolean
> > > +    description: |
> > > +      If present the PHY is configured to operate in fiber mode.
> > > +
> > > +      The KSZ8041FTL variant supports fiber mode, enabled by the FXEN
> > > +      boot strapping pin. It can't be determined from the PHY registers
> > > +      whether the PHY is in fiber mode, so this boolean device tree
> > > +      property can be used to describe it.
> > > +
> > > +      In fiber mode, auto-negotiation is disabled and the PHY can only
> > > +      work in 100base-fx (full and half duplex) modes.
> > > +
> > > +  micrel,led-mode:
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +    description: |
> > > +      LED mode value to set for PHYs with configurable LEDs.
> > > +
> > > +      Configure the LED mode with single value. The list of PHYs and the
> > > +      bits that are currently supported:
> > > +
> > > +      KSZ8001: register 0x1e, bits 15..14
> > > +      KSZ8041: register 0x1e, bits 15..14
> > > +      KSZ8021: register 0x1f, bits 5..4
> > > +      KSZ8031: register 0x1f, bits 5..4
> > > +      KSZ8051: register 0x1f, bits 5..4
> > > +      KSZ8081: register 0x1f, bits 5..4
> > > +      KSZ8091: register 0x1f, bits 5..4
> > > +
> > > +      See the respective PHY datasheet for the mode values.
> > > +    minimum: 0
> > > +    maximum: 3
> > > +
> > > +allOf:
> > > +  - $ref: ethernet-phy.yaml#
> > > +  - if:
> > > +      not:
> > > +        properties:
> > > +          compatible:
> > > +            contains:
> > > +              const: ethernet-phy-id0022.1510
> > > +    then:
> > > +      properties:
> > > +        micrel,fiber-mode: false
> > > +  - if:
> > > +      not:
> > > +        properties:
> > > +          compatible:
> > > +            contains:
> > > +              enum:
> > > +                - ethernet-phy-id0022.1510
> > > +                - ethernet-phy-id0022.1555
> > > +                - ethernet-phy-id0022.1556
> > > +                - ethernet-phy-id0022.1550
> > > +                - ethernet-phy-id0022.1560
> > > +                - ethernet-phy-id0022.161a
> > > +    then:
> > > +      properties:
> > > +        micrel,led-mode: false
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            enum:
> > > +              - ethernet-phy-id0022.1555
> > > +              - ethernet-phy-id0022.1556
> > > +              - ethernet-phy-id0022.1560
> > > +    then:
> > > +      properties:
> > > +        clocks:
> > > +          maxItems: 1
> > 
> > This has no effect because ethernet-phy.yaml already defines this.
> 
> Thanks for the info. That means I would only set the clock-names and
> remove maxItems. I will fix that in the next version.
> 
> > > +        clock-names:
> > > +          const: rmii-ref
> > > +          description:
> > > +            The RMII reference input clock. Used to determine the XI input
> > > +            clock.
> > > +        micrel,rmii-reference-clock-select-25-mhz:
> > > +          type: boolean
> > > +          description: |
> > > +            RMII Reference Clock Select bit selects 25 MHz mode
> > > +
> > > +            Setting the RMII Reference Clock Select bit enables 25 MHz rather
> > > +            than 50 MHz clock mode.
> > 
> > These should be defined at the top-level. Then use the if/then schema to 
> > disallow the properties.
> 
> The problem with this approach is, that because it has clock in its
> name, the DT schema valdiator will complain:
> devicetree/bindings/net/micrel.yaml: properties:micrel,rmii-reference-clock-select-25-mhz: 'anyOf' conditional failed, one must be fixed:
>         'maxItems' is a required property
>                 hint: Only "maxItems" is required for a single entry if there are no constraints defined for the values.
>         'type' is not one of ['maxItems', 'description', 'deprecated']
>                 hint: Only "maxItems" is required for a single entry if there are no constraints defined for the values.
>         Additional properties are not allowed ('type' was unexpected)
>                 hint: Arrays must be described with a combination of minItems/maxItems/items
>         'type' is not one of ['description', 'deprecated', 'const', 'enum', 'minimum', 'maximum', 'multipleOf', 'default', '$ref', 'oneOf']
>         hint: cell array properties must define how many entries and what the entries are when there is more than one entry.
>         from schema $id: http://devicetree.org/meta-schemas/cell.yaml
> 
> I couldn't find another way to define that Boolean type at top level. Is
> there an option to make the validator happy?

Ah, because it collides with the standard -mhz unit suffix...

Using '$ref: /schemas/types.yaml#/definitions/flag' instead of 'type: 
boolean' might happen to work. If not, just leave it as-is.

Rob