.. SPDX-License-Identifier: GPL-2.0

====================================== Motorcomm yt8xxx PHY properties (_DSD)

This document describes ACPI _DSD device properties for Motorcomm yt8xxx Ethernet PHYs supported by the in-kernel driver in drivers/net/phy/motorcomm.c.

The properties are exposed on the PHY device object under the MDIO bus ACPI device (the same objects that are registered via fwnode_mdiobus_register_phy()). MAC-side connection properties such as phy-handle and phy-mode are documented in [acpi-mdio-phy]_.

Property names and semantics are intentionally aligned with the Devicetree binding [motorcomm-yt8xxx]_ so that the same driver code path (device_property_* on &phydev->mdio.dev) can consume firmware described either as Devicetree or ACPI _DSD.

UUID and placement

Per [acpi-dsd-properties-rules]_ and [acpi-mdio-phy]_, properties must be placed in an _DSD package using the standard Device Properties UUID::

ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301")

Properties

Unless noted otherwise, integer properties use the same allowed values and defaults as [motorcomm-yt8xxx]_.

rx-internal-delay-ps (u32, optional) RGMII RX internal delay in picoseconds. Only meaningful when the link is using RGMII modes with RX internal delay; see [motorcomm-yt8xxx]_.

tx-internal-delay-ps (u32, optional) RGMII TX internal delay in picoseconds. Only meaningful when the link is using RGMII modes with TX internal delay; see [motorcomm-yt8xxx]_.

motorcomm,clk-out-frequency-hz (u32, optional) Clock output frequency on the PHY clock output pin. Allowed values and default are defined in [motorcomm-yt8xxx]_.

motorcomm,keep-pll-enabled (boolean, optional) If true, keep the PLL enabled even when there is no link (useful for using the clock output without an Ethernet link). See [motorcomm-yt8xxx]_.

motorcomm,auto-sleep-disabled (boolean, optional) If true, disable the PHY auto-sleep behavior described in [motorcomm-yt8xxx]_.

motorcomm,rx-clk-drv-microamp (u32, optional) Drive strength for the rx_clk RGMII pad in microamps. Allowed values depend on the configured RGMII LDO voltage; see [motorcomm-yt8xxx]_.

motorcomm,rx-data-drv-microamp (u32, optional) Drive strength for the rx_data and rx_ctl RGMII pads in microamps. See [motorcomm-yt8xxx]_.

motorcomm,tx-clk-adj-enabled (boolean, optional) Enables adjustments related to motorcomm,tx-clk-*-inverted usage; see [motorcomm-yt8xxx]_.

motorcomm,tx-clk-10-inverted (boolean, optional) motorcomm,tx-clk-100-inverted (boolean, optional) motorcomm,tx-clk-1000-inverted (boolean, optional) Per-speed TX clock inversion options; see [motorcomm-yt8xxx]_.

ASL example (illustrative)

The example below only shows PHY-local DSD properties. A real platform still needs a MAC phy-handle and phy-mode package as in [acpi-mdio-phy].

.. code-block:: none

Scope (\_SB.MDI0)
{
	Device (PHY4)
	{
		Name (_ADR, 0x4)

		Name (_DSD, Package () {
			ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
			Package () {
				Package (2) { "rx-internal-delay-ps", 2100 },
				Package (2) { "tx-internal-delay-ps", 150 },
				Package (2) { "motorcomm,clk-out-frequency-hz", 0 },
				Package (2) { "motorcomm,keep-pll-enabled", 1 },
				Package (2) { "motorcomm,auto-sleep-disabled", 1 },
			}
		})
	}
}

References

.. [acpi-mdio-phy] Documentation/firmware-guide/acpi/dsd/phy.rst .. [acpi-dsd-properties-rules] Documentation/firmware-guide/acpi/DSD-properties-rules.rst .. [motorcomm-yt8xxx] Documentation/devicetree/bindings/net/motorcomm,yt8xxx.yaml