Re: [PATCH v2 2/3] dt-bindings: dp83867: add binding for output-impedance

[Conor Dooley <conor@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 2288 bytes --]

On Wed, Aug 26, 2026 at 02:48:40PM +0200, Steffen Trumtrar wrote:
> Currently, the output-impedance can only be set to default, minimum or
> maximum or via a nvmem cell.
> In cases where there is no backend for a nvmem cell, a value can not be
> set.
> 
> Add a DT binding, 'ti,output-impedance-ohms', for specifying the
> output-impedance via a fixed value. The existing boolean values for
> minimum and maximum still take precedence over the new value.
> 
> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
> ---
>  Documentation/devicetree/bindings/net/ti,dp83867.yaml | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/ti,dp83867.yaml b/Documentation/devicetree/bindings/net/ti,dp83867.yaml
> index 7a6fe516bab27..49fafe3ce6f47 100644
> --- a/Documentation/devicetree/bindings/net/ti,dp83867.yaml
> +++ b/Documentation/devicetree/bindings/net/ti,dp83867.yaml
> @@ -38,6 +38,16 @@ properties:
>      items:
>        - const: io_impedance_ctrl
>  
> +  ti,output-impedance-ohms:
> +    description: |
> +      MAC Interface Impedance control to set the programmable output impedance.
> +      Valid range is 0x00 to 0x1f (32 steps).
> +      - 0x1f = 35 ohms (minimum impedance)
> +      - 0x00 = 70 ohms (maximum impedance)
> +      - Step size varies with process.
> +    minimum: 0
> +    maximum: 31

Your property is named in ohms, but not implemented in ohms.
pw-bot: changes-requested

Can't you just achieve the same result using the existing max property?
I don't get the use case where you specify a max, but then don't want to
use that max. Just set the max to what you actually want?

Thanks,
Conor.

> +
>    ti,min-output-impedance:
>      type: boolean
>      description: |
> @@ -121,6 +131,12 @@ allOf:
>        required: [nvmem-cells, "ti,min-output-impedance"]
>    - not:
>        required: [nvmem-cells, "ti,max-output-impedance"]
> +  - not:
> +      required: [nvmem-cells, "ti,output-impedance-ohms"]
> +  - not:
> +      required: ["ti,output-impedance-ohms", "ti,min-output-impedance"]
> +  - not:
> +      required: ["ti,output-impedance-ohms", "ti,max-output-impedance"]
>  
>  required:
>    - reg
> 
> -- 
> 2.54.0
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]