Date:   Wed, 8 Jun 2022 17:37:40 +0530
From:   Krishna Kurapati PSSNV <quic_kriskura@...cinc.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        "Andy Gross" <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        "Matthias Kaehlcke" <mka@...omium.org>,
        Wesley Cheng <quic_wcheng@...cinc.com>
CC:     <devicetree@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-phy@...ts.infradead.org>, <quic_pkondeti@...cinc.com>,
        <quic_ppratap@...cinc.com>, <quic_vpulyala@...cinc.com>,
        Sandeep Maheswaram <quic_c_sanm@...cinc.com>
Subject: Re: [PATCH v8 1/3] dt-bindings: phy: qcom,usb-snps-femto-v2: Add phy
 override params bindings


On 6/8/2022 3:06 PM, Krzysztof Kozlowski wrote:
> On 01/06/2022 08:56, Krishna Kurapati wrote:
>> From: Sandeep Maheswaram <quic_c_sanm@...cinc.com>
>>
>> Add device tree bindings for SNPS phy tuning parameters.
>>
>> Signed-off-by: Sandeep Maheswaram <quic_c_sanm@...cinc.com>
>> Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.com>
>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>> ---
>>   .../bindings/phy/qcom,usb-snps-femto-v2.yaml       | 96 ++++++++++++++++++++++
>>   1 file changed, 96 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 1ce251d..daeeb04 100644
>> --- a/Documentation/devicetree/bindings/phy/qcom,usb-snps-femto-v2.yaml
>> +++ b/Documentation/devicetree/bindings/phy/qcom,usb-snps-femto-v2.yaml
>> @@ -53,6 +53,102 @@ properties:
>>     vdda33-supply:
>>       description: phandle to the regulator 3.3V supply node.
>>   
>> +  qcom,hs-disconnect-bp:
>> +    description:
>> +      This adjusts the voltage level for the threshold used to
>> +      detect a disconnect event at the host. Possible values are.
>> +      The values defined are in multiples of basis points (1bp = 0.01%).
>> +      The hardware accepts only discrete values. The value closest to the
>> +      provided input will be chosen as the override value for this param.
>> +    minimum: -272
>> +    maximum: 2156
>> +
>> +  qcom,squelch-detector-bp:
>> +    description:
>> +      This adjusts the voltage level for the threshold used to
>> +      detect valid high-speed data.
>> +      The values defined are in multiples of basis points (1bp = 0.01%).
>> +      The hardware accepts only discrete values. The value closest to the
>> +      provided input will be chosen as the override value for this param.
>> +    minimum: -2090
>> +    maximum: 1590
>> +
>> +  qcom,hs-amplitude-bp:
>> +    description:
>> +      This adjusts the high-speed DC level voltage.
>> +      The values defined are in multiples of basis points (1bp = 0.01%).
>> +      The hardware accepts only discrete values. The value closest to the
>> +      provided input will be chosen as the override value for this param.
>> +    minimum: -660
>> +    maximum: 2670
>> +
>> +  qcom,pre-emphasis-duration-bp:
>> +    description:
>> +      This signal controls the duration for which the
>> +      HS pre-emphasis current is sourced onto DP<#> or DM<#>.
>> +      The HS Transmitter pre-emphasis duration is defined in terms of
>> +      unit amounts. One unit of pre-emphasis duration is approximately
>> +      650 ps and is defined as 1X pre-emphasis duration.
>> +      The values defined are in multiples of basis points (1bp = 0.01%).
>> +      The hardware accepts only discrete values. The value closest to the
>> +      provided input will be chosen as the override value for this param.
>> +    minimum: 10000
>> +    maximum: 20000
>> +
>> +  qcom,pre-emphasis-amplitude-bp:
>> +    description:
>> +      This signal controls the amount of current sourced to
>> +      DP<#> and DM<#> after a J-to-K or K-to-J transition.
>> +      The HS Transmitter pre-emphasis current is defined in terms of unit
>> +      amounts. One unit amount is approximately 2 mA and is defined as
>> +      1X pre-emphasis current.
>> +      The values defined are in multiples of basis points (1bp = 0.01%).
>> +      The hardware accepts only discrete values. The value closest to the
>> +      provided input will be chosen as the override value for this param.
>> +    minimum: 10000
>> +    maximum: 40000
>> +
>> +  qcom,hs-rise-fall-time-bp:
>> +    description:
>> +      This adjusts the rise/fall times of the high-speed waveform.
>> +      The values defined are in multiples of basis points (1bp = 0.01%).
>> +      The hardware accepts only discrete values. The value closest to the
>> +      provided input will be chosen as the override value for this param.
>> +    minimum: -4100
>> +    maximum: 5430
>> +
>> +  qcom,hs-crossover-voltage-microvolt:
>> +    description:
>> +      This adjusts the voltage at which the DP<#> and DM<#>
>> +      signals cross while transmitting in HS mode.
>> +      The values defined are in milli volts.
> It's not accurate anymore - it's microvolt. I propose to skip this one
> sentence, because unit is obvious from the type.

Hi Krzysztof,

Sure, will omit this line in the next series.

>> +    maximum: 28000
>> +
>> +  qcom,hs-output-impedance-micro-ohms:
>> +    description:
>> +      In some applications, there can be significant series resistance
>> +      on the D+ and D- paths between the transceiver and cable. This adjusts
>> +      the driver source impedance to compensate for added series
>> +      resistance on the USB. The values defined are in milli ohms.
> The same. Other places might need similar change.
>
> Best regards,
> Krzysztof

Sure, Will make sure to remove the basis points sentence from other 
params as well as bp has been added to dtschema and is self-explanatory.


Thanks,

Krishna,

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