Re: [PATCH v2 1/2] dt-bindings: net: dp83826: support TX data voltage tuning

From: Krzysztof Kozlowski
Date: Thu Feb 08 2024 - 03:55:11 EST


On 08/02/2024 09:48, POPESCU Catalin wrote:
> On 08.02.24 08:35, Krzysztof Kozlowski wrote:
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>> On 07/02/2024 18:58, Catalin Popescu wrote:
>>> Add properties ti,cfg-dac-minus-one-milli-percent and
>>> ti,cfg-dac-plus-one-milli-percent to support voltage tuning
>>> of logical levels -1/+1 of the MLT-3 encoded TX data.
>>>
>>> Signed-off-by: Catalin Popescu <catalin.popescu@xxxxxxxxxxxxxxxxxxxx>
>>> ---
>>> Changes in v2:
>>> - squash the 2 DT bindings patches in one single patch
>>> - drop redundant "binding" from the DT bindings patch title
>>> - rename DT properties and define them as percentage
>>> - add default value for each new DT property
>>> ---
>>> .../devicetree/bindings/net/ti,dp83822.yaml | 18 ++++++++++++++++++
>>> 1 file changed, 18 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/net/ti,dp83822.yaml b/Documentation/devicetree/bindings/net/ti,dp83822.yaml
>>> index db74474207ed..6bbd465e51d6 100644
>>> --- a/Documentation/devicetree/bindings/net/ti,dp83822.yaml
>>> +++ b/Documentation/devicetree/bindings/net/ti,dp83822.yaml
>>> @@ -62,6 +62,24 @@ properties:
>>> for the PHY. The internal delay for the PHY is fixed to 3.5ns relative
>>> to transmit data.
>>>
>>> + ti,cfg-dac-minus-one-milli-percent:
>>> + description: |
>>> + DP83826 PHY only.
>>> + Sets the voltage ratio (with respect to the nominal value)
>>> + of the logical level -1 for the MLT-3 encoded TX data.
>>> + enum: [50000, 56250, 62500, 68750, 75000, 81250, 87500, 93750, 100000,
>>> + 106250, 112500, 118750, 125000, 131250, 137500, 143750, 150000]
>> I see all values being multiple of basis points, so why not using -bp
>> suffix?
>
> I can read :
>
>   "-bp$":
>     $ref: types.yaml#/definitions/int32-array
>     description: basis points (1/100 of a percent)
>
> In my case it's 1/1000 of a percent. As I'm not sure exactly what the
> author meant by "basis points", would this apply to my patch as well?

So please show me the value which does not fit in -bp.

Best regards,
Krzysztof