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

From: Krzysztof Kozlowski
Date: Tue Aug 23 2022 - 09:37:12 EST


On 22/08/2022 10:07, Chunfeng Yun wrote:
> On Fri, 2022-08-19 at 15:15 +0300, Krzysztof Kozlowski wrote:
>> On 19/08/2022 12:13, Chunfeng Yun wrote:
>>> Add a property to set usb2 phy's pre-emphasis.
>>>
>>> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
>>> ---
>>> Documentation/devicetree/bindings/phy/mediatek,tphy.yaml | 7
>>> +++++++
>>> 1 file changed, 7 insertions(+)
>>>
>>> diff --git
>>> a/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
>>> b/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
>>> index 848edfb1f677..aee2f3027371 100644
>>> --- a/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
>>> +++ b/Documentation/devicetree/bindings/phy/mediatek,tphy.yaml
>>> @@ -219,6 +219,13 @@ patternProperties:
>>> minimum: 1
>>> maximum: 15
>>>
>>> + mediatek,pre-emphasis:
>>> + description:
>>> + The selection of pre-emphasis (U2 phy)
>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>> + minimum: 1
>>> + maximum: 3
>>
>> Instead of hard-coding register values in bindings, you should rather
>> describe here feature/effect. If it is in units, use unit suffixes.
>> If
>> it is some choice, usually string enum is appropriate.
> How about changing description as bellow:
>
> "The level of pre-emphasis, increases one level, boosts the relative
> amplitudes of signal's higher frequencies components about 4.16% (U2
> phy)"
>

Still the question is what is the unit. 4.16%?

Best regards,
Krzysztof