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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Thu, 3 Mar 2022 14:23:42 -0800
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Subject: Re: [PATCH v2 1/3] dt-bindings: phy: qcom,usb-snps-femto-v2: Add phy
 override params bindings
To:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Doug Anderson <dianders@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Matthias Kaehlcke <mka@chromium.org>,
        Rob Herring <robh+dt@kernel.org>,
        Sandeep Maheswaram <quic_c_sanm@quicinc.com>,
        Vinod Koul <vkoul@kernel.org>,
        Wesley Cheng <wcheng@codeaurora.org>
Cc:     devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org,
        linux-usb@vger.kernel.org, quic_pkondeti@quicinc.com,
        quic_ppratap@quicinc.com
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Quoting Krzysztof Kozlowski (2022-03-03 07:59:22)
> On 03/03/2022 07:13, Sandeep Maheswaram wrote:
> > Add device tree bindings for SNPS phy tuning parameters.
> >
> > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> > ---
> >  .../bindings/phy/qcom,usb-snps-femto-v2.yaml       | 125 +++++++++++++++++++++
> >  1 file changed, 125 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/phy/qcom,usb-snps-femto-v2.yaml b/Documentation/devicetree/bindings/phy/qcom,usb-snps-femto-v2.yaml
> > index 0dfe691..227c097 100644
> > --- a/Documentation/devicetree/bindings/phy/qcom,usb-snps-femto-v2.yaml
> > +++ b/Documentation/devicetree/bindings/phy/qcom,usb-snps-femto-v2.yaml
> > @@ -50,6 +50,131 @@ properties:
> >    vdda33-supply:
> >      description: phandle to the regulator 3.3V supply node.
> >
> > +  qcom,hs-disconnect:
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    description:
> > +      This adjusts the voltage level for the threshold used to
> > +      detect a disconnect event at the host. Possible values are.
>
> ':', instead of full stop.
>
> > +      7 -> +21.56%
> > +      6 -> +17.43%
> > +      5 -> +13.32%
> > +      4 -> +9.73%
> > +      3 -> +6.3
> > +      2 -> +3.17%
> > +      1 -> 0, Design default%
>
> Use "default:" instead. Here and in other places.
>
> > +      0 -> -2.72%
>
> In current form this should be an enum... but actually current form is
> wrong. You should not store register values in DT. What if next version
> of hardware has a different meaning of these values?
>
> Instead, you should store here meaningful values, not register values.

+1

To emphasize one point, meaningful values typically have a unit of
measure, like Hz, ms, mV, etc. What are the percentages adjusting from?
Is it a percentage decrease from the input voltage?