RE: [v2 1/2] Docs/devicetree: add serdes-output-amplitude-mv to marvell.txt

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diff --git a/Documentation/devicetree/bindings/net/dsa/marvell.txt

b/Documentation/devicetree/bindings/net/dsa/marvell.txt
index 2363b412410c..9292b6f960df 100644

--- a/Documentation/devicetree/bindings/net/dsa/marvell.txt
+++ b/Documentation/devicetree/bindings/net/dsa/marvell.txt

@@ -46,6 +46,11 @@ Optional properties:
 - mdio?            : Container of PHYs and devices on the external MDIO
                      bus. The node must contains a compatible string of
                      "marvell,mv88e6xxx-mdio-external"
+- serdes-output-amplitude-mv: Configure the output amplitude of the

serdes

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+                         interface in millivolts. This option can be
+                              set in the ports node as it is a property of
+                              the port.
+    serdes-output-amplitude-mv = <210>;

The suffix should be millivolt, as can be seen in other bindings.

My bad. I recommended that. It does seem like both are used, but millivolt is
more popular.

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Also I think maybe use "tx" instead of "output"? It is more common to
refere to serdes pairs as rx/tx instead of input/output:

  serdes-tx-amplitude-millivolt

I will probably want to add this property also either to mvneta, or to
A3720 common PHY binding. Andrew, do you think it should be put
somewhere more generic?

Not sure what the common location would be. I assume for mvneta and
A3720 it is part of the generic phy comphy driver? Does generic phy have any
properties like this already?

Here we are using it in DSA. And it could also be used in a Marvell phy driver
node.

So maybe something like serdes.yaml?
bindings/phy/microchip,sparx5-serdes.yaml actually mentions

  * Tx output amplitude control

but does not define a property for it, but that looks like another use case for it.

so what is the conclusion here? Should I add it to marvell.txt for now or is there
a better place?

Best regards
Holger