Subject: Re: [PATCH net-next v3 3/4] dt-bindings: net: mdio: add phy-id-read-needs-reset property

From: Rob Herring <[email-masked]>
Date: Sun, 26 Oct 2025 16:20:26 -0500

On Fri, Oct 17, 2025 at 06:10:10PM +0200, Buday Csaba wrote:
> Some Ethernet PHYs require a hard reset before accessing their MDIO
> registers. When the ID is not provided by a compatible string,
> reading the PHY ID may fail on such devices.
> 
> This patch introduces a new device tree property called
> `phy-id-read-needs-reset`, which can be used to hard reset the
> PHY before attempting to read its ID via MDIO.

If your phy needs special handling, provide a compatible and use that.

> 
> Signed-off-by: Buday Csaba <[email-masked]>
> ---
> V2 -> V3: unchanged
> V1 -> V2: added this DT binding
> ---
>  Documentation/devicetree/bindings/net/ethernet-phy.yaml | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> index 2ec2d9fda..b570f8038 100644
> --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
> @@ -215,6 +215,14 @@ properties:
>        Delay after the reset was deasserted in microseconds. If
>        this property is missing the delay will be skipped.
>  
> +  phy-id-read-needs-reset:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      Some PHYs require a hard reset before accessing MDIO registers.
> +      This workaround allows auto-detection of the PHY ID in such cases.
> +      When the PHY ID is provided with the 'compatible' string, setting
> +      this property has no effect.
> +
>    sfp:
>      $ref: /schemas/types.yaml#/definitions/phandle
>      description:
> -- 
> 2.39.5
> 
>