[v4 1/3] dt-bindings: phy: qcom,usb-snps-femto-v2: Add phy override params bindings

[Krishna Kurapati PSSNV]

On 5/11/2022 11:49 PM, Krzysztof Kozlowski wrote:
> On 11/05/2022 17:26, Krishna Kurapati wrote:
>> From: Sandeep Maheswaram <quic_c_sanm at quicinc.com>
>>
>> Add device tree bindings for SNPS phy tuning parameters.
>>
>> Signed-off-by: Sandeep Maheswaram <quic_c_sanm at quicinc.com>
>> Signed-off-by: Krishna Kurapati <quic_kriskura at quicinc.com>
>> ---
>>   .../bindings/phy/qcom,usb-snps-femto-v2.yaml       | 87 ++++++++++++++++++++++
>>   1 file changed, 87 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..70efffe 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 +53,93 @@ properties:
>>     vdda33-supply:
>>       description: phandle to the regulator 3.3V supply node.
>>   
>> +  qcom,hs-disconnect-bps:
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +    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%).
> This means there is some minimum and maximum (100%)?

Hi Krzystof,

Yes there are max and min for each parameter (not necessarily 0%/100%)

As an example if we take squelch detector threshold, the register value 
vs actual percentage changer as per data book is as follows :

% change in voltage    |     corresponding reg value

  -20.90%                        |    7
  -15.60%                        |    6
-10.30%                         |    5
-5.30%                           |    4
0%                                  |    3
5.30%                            |    2
10.60%                          |    1
15.90%                          |    0

Here the min and max are 15.9% to -20.9%

The min and max differ for each parameter and might not be necessarily 
0% and 100%
>> +      The hardware accepts only discrete values. The value closest to the
>> +      provided input will be chosen as the override value for this param.
>> +
>> +  qcom,squelch-detector-bps:
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +    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.
>> +
>> +  qcom,hs-amplitude-bps:
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +    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.
>> +
>> +  qcom,pre-emphasis-duration-bps:
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +    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.
>> +
>> +  qcom,pre-emphasis-amplitude-bps:
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +    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.
>> +
>> +  qcom,hs-rise-fall-time-bps:
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +    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.
>> +
>> +  qcom,hs-crossover-voltage-mv:
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +    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. The hardware accepts only
>> +      discrete values. The value closest to the provided input will be
>> +      chosen as the override value for this param.
>> +
>> +  qcom,hs-output-impedance-mohm:
>> +    $ref: /schemas/types.yaml#/definitions/int32
> Here and in other places, please use standard units. See
> dtschema/schemas/property-units.yaml in dtschema repo.
>
>
> Best regards,
> Krzysztof