From: Chunfeng Yun <chunfeng.yun@mediatek.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
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>
Subject: Re: [PATCH 2/7] dt-bindings: phy: mediatek,tphy: add property to set pre-emphasis
Date: Wed, 31 Aug 2022 11:00:57 +0800 [thread overview]
Message-ID: <8dcb4de53a52ab44d40f490099b6ed13e5ef7fe0.camel@mediatek.com> (raw)
In-Reply-To: <0a82842d-283c-e266-84f4-6306f29b61da@linaro.org>
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,tphy.ya
> > > > > > > > ml |
> > > > > > > > 7
> > > > > > > > +++++++
> > > > > > > > 1 file changed, 7 insertions(+)
> > > > > > > >
> > > > > > > > diff --git
> > > > > > > > a/Documentation/devicetree/bindings/phy/mediatek,tphy.y
> > > > > > > > aml
> > > > > > > > b/Documentation/devicetree/bindings/phy/mediatek,tphy.y
> > > > > > > > aml
> > > > > > > > index 848edfb1f677..aee2f3027371 100644
> > > > > > > > ---
> > > > > > > > a/Documentation/devicetree/bindings/phy/mediatek,tphy.y
> > > > > > > > aml
> > > > > > > > +++
> > > > > > > > b/Documentation/devicetree/bindings/phy/mediatek,tphy.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.
>
> Best regards,
> Krzysztof
next prev parent reply other threads:[~2022-08-31 3:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-19 9:13 [PATCH 1/7] dt-bindings: phy: mediatek,tphy: add support type of SGMII Chunfeng Yun
2022-08-19 9:13 ` [PATCH 2/7] dt-bindings: phy: mediatek,tphy: add property to set pre-emphasis Chunfeng Yun
2022-08-19 12:15 ` Krzysztof Kozlowski
2022-08-22 7:07 ` Chunfeng Yun
2022-08-23 10:24 ` Krzysztof Kozlowski
2022-08-26 5:36 ` Chunfeng Yun
2022-08-26 6:36 ` Krzysztof Kozlowski
2022-08-29 2:37 ` Chunfeng Yun
2022-08-30 10:08 ` Krzysztof Kozlowski
2022-08-31 3:00 ` Chunfeng Yun [this message]
2022-08-31 6:03 ` Krzysztof Kozlowski
2022-09-08 1:45 ` Chunfeng Yun
2022-09-09 3:03 ` Chunfeng Yun
2022-09-09 8:27 ` Krzysztof Kozlowski
2022-09-14 5:42 ` Chunfeng Yun
2022-08-19 9:13 ` [PATCH 3/7] phy: phy-mtk-tphy: " Chunfeng Yun
2022-08-19 9:13 ` [PATCH 4/7] phy: phy-mtk-tphy: disable hardware efuse when set INTR Chunfeng Yun
2022-08-19 9:13 ` [PATCH 5/7] phy: phy-mtk-tphy: disable gpio mode for all usb2 phys Chunfeng Yun
2022-08-19 9:13 ` [PATCH 6/7] phy: phy-mtk-tphy: set utmi 0 register in init() ops Chunfeng Yun
2022-08-19 9:13 ` [PATCH 7/7] phy: phy-mtk-tphy: fix the phy type setting issue Chunfeng Yun
2022-08-22 18:25 ` [PATCH 1/7] dt-bindings: phy: mediatek,tphy: add support type of SGMII Rob Herring
2022-08-23 20:44 ` Nícolas F. R. A. Prado
2022-08-29 6:30 ` Chunfeng Yun
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