On Tue, Mar 17, 2026 at 11:46:09AM -0700, Charles Perry wrote:
> This MDIO hardware is based on a Microsemi design supported in Linux by
> mdio-mscc-miim.c. However, The register interface is completely different
> with pic64hpsc, hence the need for separate documentation.
> 
> The hardware supports C22 and C45.
> 
> The documentation recommends an input clock of 156.25MHz and a prescaler
> of 39, which yields an MDIO clock of 1.95MHz.
> 
> The hardware supports an interrupt pin to signal transaction completion
> which is not strictly needed as the software can also poll a "TRIGGER"
> bit for this.
> 
> Signed-off-by: Charles Perry <charles.perry@microchip.com>
> ---
>  .../net/microchip,pic64hpsc-mdio.yaml         | 61 +++++++++++++++++++
>  1 file changed, 61 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml
> 
> diff --git a/Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml b/Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml
> new file mode 100644
> index 000000000000..21c76199c11b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/microchip,pic64hpsc-mdio.yaml
> @@ -0,0 +1,61 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/microchip,pic64hpsc-mdio.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip PIC64-HPSC/HX MDIO controller
> +
> +maintainers:
> +  - Charles Perry <charles.perry@microchip.com>
> +
> +description: |
> +  Microchip PIC64-HPSC/HX SoCs have two MDIO bus controller. This MDIO bus
> +  controller supports C22 and C45 register access. It is named "MDIO Initiator"
> +  in the documentation.
> +
> +allOf:
> +  - $ref: mdio.yaml#
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - const: microchip,pic64hpsc-mdio
> +      - items:
> +          - const: microchip,pic64hx-mdio
> +          - const: microchip,pic64hpsc-mdio
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-frequency: true

Does this genuinely have no constraints?

> +
> +  interrupts:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    bus {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        mdio@4000C21E000 {
> +            compatible = "microchip,pic64hpsc-mdio";
> +            reg = <0x400 0x0C21E000 0x0 0x1000>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            phy0: ethernet-phy@0 {
> +                reg = <0>;
> +            };
> +        };
> +    };
> -- 
> 2.47.3
>