From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DF6EECAAD3 for ; Thu, 8 Sep 2022 01:45:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229485AbiIHBpf (ORCPT ); Wed, 7 Sep 2022 21:45:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229682AbiIHBpc (ORCPT ); Wed, 7 Sep 2022 21:45:32 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75B1A93536; Wed, 7 Sep 2022 18:45:29 -0700 (PDT) X-UUID: d87fde4ea14a435aa40ce9f26ae94d7c-20220908 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:MIME-Version:Content-Type:References:In-Reply-To:Date:CC:To:From:Subject:Message-ID; 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Thu, 8 Sep 2022 09:45:23 +0800 Received: from mhfsdcap04 (10.17.3.154) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.15 via Frontend Transport; Thu, 8 Sep 2022 09:45:22 +0800 Message-ID: <291874b3c17e4456bb6fdbef68b68bdc78c11321.camel@mediatek.com> Subject: Re: [PATCH 2/7] dt-bindings: phy: mediatek,tphy: add property to set pre-emphasis From: Chunfeng Yun To: Krzysztof Kozlowski , Vinod Koul , Rob Herring CC: Kishon Vijay Abraham I , Krzysztof Kozlowski , Matthias Brugger , , , , , , Eddie Hung Date: Thu, 8 Sep 2022 09:45:22 +0800 In-Reply-To: <3c180570-ecf9-3db4-c698-39c1b4679c6e@linaro.org> 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> <000babd8-5980-3d77-f156-324b3442cbe7@linaro.org> <114c357f8d7f049d21ede789a292a8e2d45f4c61.camel@mediatek.com> <0a82842d-283c-e266-84f4-6306f29b61da@linaro.org> <8dcb4de53a52ab44d40f490099b6ed13e5ef7fe0.camel@mediatek.com> <3c180570-ecf9-3db4-c698-39c1b4679c6e@linaro.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2022-08-31 at 09:03 +0300, Krzysztof Kozlowski wrote: > On 31/08/2022 06:00, Chunfeng Yun wrote: > > On Tue, 2022-08-30 at 13:08 +0300, Krzysztof Kozlowski wrote: > > > On 29/08/2022 05:37, Chunfeng Yun wrote: > > > > On Fri, 2022-08-26 at 09:36 +0300, Krzysztof Kozlowski wrote: > > > > > 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 < > > > > > > > > > > chunfeng.yun@mediatek.com> > > > > > > > > > > --- > > > > > > > > > > Documentation/devicetree/bindings/phy/mediatek,tph > > > > > > > > > > y.ya > > > > > > > > > > ml | > > > > > > > > > > 7 > > > > > > > > > > +++++++ > > > > > > > > > > 1 file changed, 7 insertions(+) > > > > > > > > > > > > > > > > > > > > diff --git > > > > > > > > > > a/Documentation/devicetree/bindings/phy/mediatek,tp > > > > > > > > > > hy.y > > > > > > > > > > aml > > > > > > > > > > b/Documentation/devicetree/bindings/phy/mediatek,tp > > > > > > > > > > hy.y > > > > > > > > > > aml > > > > > > > > > > index 848edfb1f677..aee2f3027371 100644 > > > > > > > > > > --- > > > > > > > > > > a/Documentation/devicetree/bindings/phy/mediatek,tp > > > > > > > > > > hy.y > > > > > > > > > > aml > > > > > > > > > > +++ > > > > > > > > > > b/Documentation/devicetree/bindings/phy/mediatek,tp > > > > > > > > > > hy.y > > > > > > > > > > aml > > > > > > > > > > @@ -219,6 +219,13 @@ patternProperties: > > > > > > > > > > minimum: 1 > > > > > > > > > > maximum: 15 > > > > > > > > > > > > > > > > > > > > + mediatek,pre-emphasis: > > > > > > > > > > + description: > > > > > > > > > > + The selection of pre-emphasis (U2 phy) > > > > > > > > > > + $ref: > > > > > > > > > > /schemas/types.yaml#/definitions/uint32 > > > > > > > > > > + minimum: 1 > > > > > > > > > > + maximum: 3 > > > > > > > > > > > > > > > > > > Instead of hard-coding register values in bindings, > > > > > > > > > you > > > > > > > > > should > > > > > > > > > rather > > > > > > > > > describe here feature/effect. If it is in units, use > > > > > > > > > unit > > > > > > > > > suffixes. > > > > > > > > > If > > > > > > > > > it is some choice, usually string enum is > > > > > > > > > appropriate. > > > > > > > > > > > > > > > > How about changing description as bellow: > > > > > > > > > > > > > > > > "The level of pre-emphasis, increases one level, boosts > > > > > > > > the > > > > > > > > relative > > > > > > > > amplitudes of signal's higher frequencies components > > > > > > > > about > > > > > > > > 4.16% > > > > > > > > (U2 > > > > > > > > phy)" > > > > > > > > > > > > > > > > > > > > > > Still the question is what is the unit. 4.16%? > > > > > > > > > > > > No unit, it's a level value, like an index of array. > > > > > > > > > > > > > > > > So a value from register/device programming? > > > > > > > > Yes > > > > > Rather a regular units > > > > > should be used if that's possible. If not, this should be > > > > > clearly > > > > > described here, not some magical number which you encode into > > > > > DTS... > > > > > > > > Ok, I'll add more descriptions. > > > > > > Better use logical value, e.g. > > > > > > > https://urldefense.com/v3/__https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml*L38__;Iw!!CTRNKA9wMg0ARbw!1e-h0R_uwcaHKfKC9qYfaRWYeuWRq1sLCGy3yupNmkFyuW5s1nmRotL7Y0vFG9ETLLTA$ > > > > > > > Optional unit may be -percent or -bp, but the value 4.16% * X > > (X=1,2,3...)is not an exact value, they are variable in a range and > > dependent more factors. > > So I think use level value is simple enough. > > Then again explain exactly what are the levels. Ok, I've asked help from our DE to get more information and reply later, thanks a lot > How you wrote it last > time, -bp would do the trick. > > Best regards, > Krzysztof