| Message ID | 20240209123628.2113971-1-catalin.popescu@leica-geosystems.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3,1/2] dt-bindings: net: dp83826: support TX data voltage tuning | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | success | |
| robh/patch-applied | success | |
| robh/dtbs-check | warning | build log |
| robh/dt-meta-schema | success |
On Fri, Feb 09, 2024 at 01:36:28PM +0100, Catalin Popescu wrote: > DP83826 offers the possibility to tune the voltage of logical > levels of the MLT-3 encoded TX data. This is especially interesting > when the TX data path is lossy and we want to increase the voltage > levels to compensate the loss. Maybe i'm being nit-picky.... "TX data path is lossy" should probably be "TX data path as far as the RJ46 socket is lossy". 802.3 probably defines the voltage at that point. If you tune it so the voltage is too high at that point, you are breaking the standard. So you can use this to adjust for losses in your coupling and cable run to the front panel. You should not be using this for range extension by cranking up the voltages. Yes, you might be able to, but we should not be encouraging it. Andrew
On 09.02.24 15:07, Andrew Lunn wrote: > [Some people who received this message 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 Fri, Feb 09, 2024 at 01:36:28PM +0100, Catalin Popescu wrote: >> DP83826 offers the possibility to tune the voltage of logical >> levels of the MLT-3 encoded TX data. This is especially interesting >> when the TX data path is lossy and we want to increase the voltage >> levels to compensate the loss. > Maybe i'm being nit-picky.... > > "TX data path is lossy" should probably be "TX data path as far as the > RJ46 socket is lossy". 802.3 probably defines the voltage at that > point. If you tune it so the voltage is too high at that point, you > are breaking the standard. So you can use this to adjust for losses in > your coupling and cable run to the front panel. You should not be > using this for range extension by cranking up the voltages. Yes, you > might be able to, but we should not be encouraging it. Indeed, the voltage drop (or loss) happens b/w the PHY and the connector (could be RJ45, LEMO, etc). Trying to reformulate : DP83826 offers the possibility to tune the voltage of logical levels of the MLT-3 encoded TX data. This is useful when there is a voltage drop in between the PHY and the connector and we want to increase the voltage levels to compensate for that drop. Is this more meaningful ? > > Andrew
> DP83826 offers the possibility to tune the voltage of logical levels of > the MLT-3 encoded TX data. This is useful when there is a voltage drop > in between the PHY and the connector and we want to increase the voltage > levels to compensate for that drop. > > Is this more meaningful ? Yes, that is good. Thanks Andrew
On 09/02/2024 13:36, Catalin Popescu wrote: > Add properties ti,cfg-dac-minus-one-bp/ti,cfg-dac-plus-one-bp > to support voltage tuning of logical levels -1/+1 of the MLT-3 > encoded TX data. > > Signed-off-by: Catalin Popescu <catalin.popescu@leica-geosystems.com> > --- > Changes in v2: Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Best regards, Krzysztof
diff --git a/Documentation/devicetree/bindings/net/ti,dp83822.yaml b/Documentation/devicetree/bindings/net/ti,dp83822.yaml index db74474207ed..8f4350be689c 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-bp: + 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: [5000, 5625, 6250, 6875, 7500, 8125, 8750, 9375, 10000, + 10625, 11250, 11875, 12500, 13125, 13750, 14375, 15000] + default: 10000 + + ti,cfg-dac-plus-one-bp: + 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: [5000, 5625, 6250, 6875, 7500, 8125, 8750, 9375, 10000, + 10625, 11250, 11875, 12500, 13125, 13750, 14375, 15000] + default: 10000 + required: - reg
Add properties ti,cfg-dac-minus-one-bp/ti,cfg-dac-plus-one-bp to support voltage tuning of logical levels -1/+1 of the MLT-3 encoded TX data. Signed-off-by: Catalin Popescu <catalin.popescu@leica-geosystems.com> --- 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 Changes in v3: - rename properties to "-bp" and change their admissible values accordingly --- .../devicetree/bindings/net/ti,dp83822.yaml | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) base-commit: 1f719a2f3fa67665578c759ac34fd3d3690c1a20 prerequisite-patch-id: 0000000000000000000000000000000000000000