u-boot/Documentation/devicetree/bindings/phy/no-op.txt

NOP PHY driver

This driver is used to stub PHY operations in a driver (USB, SATA).
This is useful when the 'client' driver (USB, SATA, ...) uses the PHY framework
and there is no actual PHY harwdare to drive.

Required properties:
- compatible     : must contain "nop-phy"
- #phy-cells     : must contain <0>

Example:

nop_phy {
	compatible = "nop-phy";
	#phy-cells = <0>;
};