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Message-ID: <bee8abe5-0299-d05e-643c-4810aa33f978@linaro.org>
Date:   Tue, 23 Aug 2022 13:24:30 +0300
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Subject: Re: [PATCH 2/7] dt-bindings: phy: mediatek,tphy: add property to set
 pre-emphasis
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To:     Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Vinod Koul <vkoul@kernel.org>, Rob Herring <robh+dt@kernel.org>
Cc:     Kishon Vijay Abraham I <kishon@ti.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-phy@lists.infradead.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Eddie Hung <eddie.hung@mediatek.com>
References: <20220819091344.2274-1-chunfeng.yun@mediatek.com>
 <20220819091344.2274-2-chunfeng.yun@mediatek.com>
 <438da392-f419-ad76-7e91-aa4aab36e12c@linaro.org>
 <816ecf6287533137b750c8bde9de5830e4229c56.camel@mediatek.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <816ecf6287533137b750c8bde9de5830e4229c56.camel@mediatek.com>
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Precedence: bulk

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@mediatek.com>
>>> ---
>>>  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