[PATCH 1/2] dt-bindings: phy: imx8mq-usb: improve some tuning properties

[Krzysztof Kozlowski]

On Wed, Apr 23, 2025 at 05:46:06PM GMT, Xu Yang wrote:
> Commit b2e75563dc39 ("dt-bindings: phy: imx8mq-usb: add phy tuning
> properties") add many tuning properties, but some parameter value doesn't
> match the register description. It made some changes based on the original
> value: add offset to a negative number so turn it to a non-negative number.
> However, this conversion bring many pain when some properties need to be
> improved.
> 
> Because device-tree supports negative parameter number, this will improve
> some propertie's parameter.
> 
> Mainly include below properties:
>  - fsl,phy-tx-vref-tune-percent
>  - fsl,phy-tx-rise-tune-percent
>  - fsl,phy-comp-dis-tune-percent
> 
> The parameter value of above 3 properties are USB PHY specific. i.MX8MP
> and i.MX95 USB PHY has different meanings. So this add restrictions for
> them.
> 
>  - fsl,phy-tx-vboost-level-microvolt
> 
> For this property, the parameter value is wrong in register description.
> This will correct it according to true value.
> 
> For detailed info, please refer to i.MX8MP and i.MX95 latest reference
> manual.
> 
> Signed-off-by: Xu Yang <xu.yang_2 at nxp.com>
> ---
>  .../bindings/phy/fsl,imx8mq-usb-phy.yaml      | 43 +++++++++++++++----
>  1 file changed, 35 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml
> index daee0c0fc915..b09e3dab4c59 100644
> --- a/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml
> +++ b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml
> @@ -43,15 +43,11 @@ properties:
>    fsl,phy-tx-vref-tune-percent:
>      description:
>        Tunes the HS DC level relative to the nominal level
> -    minimum: 94
> -    maximum: 124

Widest constraints should always stay here.

>  
>    fsl,phy-tx-rise-tune-percent:
>      description:
>        Adjusts the rise/fall time duration of the HS waveform relative to
>        its nominal value
> -    minimum: 97
> -    maximum: 103
>  
>    fsl,phy-tx-preemp-amp-tune-microamp:
>      description:
> @@ -63,15 +59,12 @@ properties:
>    fsl,phy-tx-vboost-level-microvolt:
>      description:
>        Adjust the boosted transmit launch pk-pk differential amplitude
> -    minimum: 880
> -    maximum: 1120
> +    enum: [844, 1008, 1156]
>  
>    fsl,phy-comp-dis-tune-percent:
>      description:
>        Adjust the voltage level used to detect a disconnect event at the host
>        relative to the nominal value
> -    minimum: 91
> -    maximum: 115
>  
>    fsl,phy-pcs-tx-deemph-3p5db-attenuation-db:
>      description:
> @@ -112,6 +105,40 @@ allOf:
>          reg:
>            maxItems: 1
>  
> +  - if:
> +      properties:
> +        compatible:
> +          enum:
> +            - fsl,imx8mq-usb-phy
> +            - fsl,imx8mp-usb-phy
> +    then:
> +      properties:
> +        fsl,phy-tx-vref-tune-percent:
> +          minimum: -6
> +          maximum: 24

That's ABI break with vague reason "some pain".

Best regards,
Krzysztof