On 19.01.2022 14:11:17, Marek Behún wrote:

Common PHYs and network PCSes often have the possibility to specify
peak-to-peak voltage on the differential pair - the default voltage
sometimes needs to be changed for a particular board.

Add properties `tx-p2p-microvolt` and `tx-p2p-microvolt-names` for this
purpose. The second property is needed to specify the mode for the
corresponding voltage in the `tx-p2p-microvolt` property, if the voltage
is to be used only for speficic mode. More voltage-mode pairs can be
specified.

Example usage with only one voltage (it will be used for all supported
PHY modes, the `tx-p2p-microvolt-names` property is not needed in this
case):

  tx-p2p-microvolt = <915000>;

Example usage with voltages for multiple modes:

  tx-p2p-microvolt = <915000>, <1100000>, <1200000>;
  tx-p2p-microvolt-names = "2500base-x", "usb", "pcie";

Add these properties into a separate file phy/transmit-amplitude.yaml,
which should be referenced by any binding that uses it.

If I understand your use-case correctly, you need different voltage p2p
levels in the connection between the Ethernet MAC and the Ethernet
switch or Ethernet-PHY?

Some of the two wire Ethernet standards (10base-T1S, 10base-T1L,
100base-T1, 1000base-T1) defines several p2p voltage levels on the wire,
i.e. between the PHYs. Alexandru has posed a series where you can
specify the between-PHY voltage levels:

| https://lore.kernel.org/all/20211210110509.20970-8-alexandru.tachici@analog.com/ (local)

Can we make clear that your binding specifies the voltage level on the
MII interface, in contrast Alexandru's binding?

regards,
Marc

-- 
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