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[82.131.98.15]) by smtp.gmail.com with ESMTPSA id p16-20020ac24ed0000000b00492b1ee7489sm246608lfr.300.2022.08.25.23.36.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Aug 2022 23:36:58 -0700 (PDT) Message-ID: <000babd8-5980-3d77-f156-324b3442cbe7@linaro.org> Date: Fri, 26 Aug 2022 09:36:57 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Subject: Re: [PATCH 2/7] dt-bindings: phy: mediatek,tphy: add property to set pre-emphasis Content-Language: en-US To: Chunfeng Yun , Vinod Koul , Rob Herring Cc: Kishon Vijay Abraham I , Krzysztof Kozlowski , Matthias Brugger , 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 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> <1a16cce9fe164bafc06ae193310be71c6f645d75.camel@mediatek.com> From: Krzysztof Kozlowski In-Reply-To: <1a16cce9fe164bafc06ae193310be71c6f645d75.camel@mediatek.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/08/2022 08:36, Chunfeng Yun wrote: > On Tue, 2022-08-23 at 13:24 +0300, Krzysztof Kozlowski wrote: >> 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 >>>>> --- >>>>> 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%? > No unit, it's a level value, like an index of array. > So a value from register/device programming? Rather a regular units should be used if that's possible. If not, this should be clearly described here, not some magical number which you encode into DTS... Best regards, Krzysztof