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    SubjectRe: [PATCH 1/3] dt-bindings: net: dp83826: add ti,cfg-dac-minus binding
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    On 12/01/2024 14:41, POPESCU Catalin wrote:
    > On 11.01.24 18:21, Krzysztof Kozlowski wrote:
    >> [You don't often get email from krzysztof.kozlowski@linaro.org. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
    >>
    >> This email is not from Hexagon’s Office 365 instance. Please be careful while clicking links, opening attachments, or replying to this email.
    >>
    >>
    >> On 11/01/2024 17:59, POPESCU Catalin wrote:
    >>> On 11.01.24 17:52, Russell King (Oracle) wrote:
    >>>> This email is not from Hexagon’s Office 365 instance. Please be careful while clicking links, opening attachments, or replying to this email.
    >>>>
    >>>>
    >>>> On Thu, Jan 11, 2024 at 04:45:26PM +0000, POPESCU Catalin wrote:
    >>>>> On 11.01.24 17:35, Andrew Lunn wrote:
    >>>>>> [You don't often get email from andrew@lunn.ch. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
    >>>>>>
    >>>>>> This email is not from Hexagon’s Office 365 instance. Please be careful while clicking links, opening attachments, or replying to this email.
    >>>>>>
    >>>>>>
    >>>>>> On Thu, Jan 11, 2024 at 05:19:25PM +0100, Catalin Popescu wrote:
    >>>>>>> Add property ti,cfg-dac-minus to allow for voltage tuning
    >>>>>>> of logical level -1 of the MLT-3 encoded data.
    >>>>>>>
    >>>>>>> Signed-off-by: Catalin Popescu <catalin.popescu@leica-geosystems.com>
    >>>>>>> ---
    >>>>>>> Documentation/devicetree/bindings/net/ti,dp83822.yaml | 9 +++++++++
    >>>>>>> 1 file changed, 9 insertions(+)
    >>>>>>>
    >>>>>>> diff --git a/Documentation/devicetree/bindings/net/ti,dp83822.yaml b/Documentation/devicetree/bindings/net/ti,dp83822.yaml
    >>>>>>> index db74474207ed..2f010333be49 100644
    >>>>>>> --- a/Documentation/devicetree/bindings/net/ti,dp83822.yaml
    >>>>>>> +++ b/Documentation/devicetree/bindings/net/ti,dp83822.yaml
    >>>>>>> @@ -62,6 +62,15 @@ properties:
    >>>>>>> for the PHY. The internal delay for the PHY is fixed to 3.5ns relative
    >>>>>>> to transmit data.
    >>>>>>>
    >>>>>>> + ti,cfg-dac-minus:
    >>>>>>> + description: |
    >>>>>>> + DP83826 PHY only.
    >>>>>>> + Sets the voltage ratio of the logical level -1 for the MLT-3 encoded data.
    >>>>>>> + 0 = 50%, 1 = 56.25%, 2 = 62.50%, 3 = 68.75%, 4 = 75%, 5 = 81.25%, 6 = 87.50%,
    >>>>>>> + 7 = 93.75%, 8 = 100%, 9 = 106.25%, 10 = 112.50%, 11 = 118.75%, 12 = 125%,
    >>>>>>> + 13 = 131.25%, 14 = 137.50%, 15 = 143.75%, 16 = 150%.
    >>>>>>> + enum: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]
    >>>>>> We try to avoid register values in DT. We use real units. This is a
    >>>>>> voltage you are configuring, so can you change the unit to millivolts?
    >>>>>> Have the driver do the conversion of volts to register value.
    >>>>>>
    >>>>>> Is it possible to configure any of the other logical levels?
    >>>>> Hi Andrew,
    >>>>> These are not raw register values and these are not voltage values but
    >>>>> voltage ratios. I'm mapping the voltage ratios to enum values [0-16]
    >>>>> which are converted to register raw values by the driver. I don't see a
    >>>>> better way to do this.
    >>>> enum: [ 5000, 5625, 6250, 6875, 7500, 8125, 8750, 9375, 10000,
    >>>> 10625, 11250, 11875, 12500 13125, 13750, 14375, 15000 ]
    >>>>
    >>>> ?
    >>> I'm okay with that approach if there's no better one. I would need to
    >>> remove the register raw values tables from the driver and use a switch
    >>> statement to map those values to raw values.
    >> You can also use -bp or -percent:
    >> https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/property-units.yaml
    >
    > ti,cfg-dac-minus-percent:
    > description: |
    > DP83826 PHY only.
    > Sets the voltage ratio of the logical level -1 relative to the
    > nominal level for the MLT-3 encoded TX data.
    > enum: [50, 56, 62, 68, 75, 81, 87, 93, 100, 106, 112, 118, 125,
    > 131, 137, 143, 150]
    > default: 100

    Yes, which would also solve your problem of binding errors. But does not
    remove the need of testing it before sending to the lists.

    Best regards,
    Krzysztof


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