Re: [PATCH v2 2/7] dt-bindings: phy: mediatek,tphy: add property to set pre-emphasis

[Krzysztof Kozlowski]

On 29/08/2022 11:08, Chunfeng Yun wrote:
> Add a property to set usb2 phy's pre-emphasis, which used to widen eye
> opening and boost eye swing.
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> ---
> v2: Add more description suggested by Krzysztof
> ---
>  .../devicetree/bindings/phy/mediatek,tphy.yaml         | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml b/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
> index 848edfb1f677..e0754fb44451 100644
> --- a/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
> +++ b/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
> @@ -219,6 +219,16 @@ patternProperties:
>          minimum: 1
>          maximum: 15
>  
> +      mediatek,pre-emphasis:
> +        description:
> +          The level of pre-emphasis which used to widen the eye opening and
> +          boost eye swing, the unit step is about 4.16% increment; e.g. the
> +          level 1 means amplitude increases about 4.16%, the level 2 is about
> +          8.3% etc. (U2 phy)
> +        $ref: /schemas/types.yaml#/definitions/uint32

As I proposed - use instead common units. Since only three values are
allowed - make it an enum. These bindings are expected to be
usable/applicable on several devices, so units, not register values
which can change between devices, are the proper and reliable way to
describe a feature.


Best regards,
Krzysztof