[net-next PATCH v2 2/3] Documentation: ACPI: DSD: Document MDIO PHY

[Calvin Johnson]

Introduce ACPI mechanism to get PHYs registered on a MDIO bus and
provide them to be connected to MAC.

An ACPI node property "mdio-handle" is introduced to reference the
MDIO bus on which PHYs are registered with autoprobing method used
by mdiobus_register().

Signed-off-by: Calvin Johnson <calvin.johnson@xxxxxxxxxxx>
---

Changes in v2: None

 Documentation/firmware-guide/acpi/dsd/phy.rst | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/firmware-guide/acpi/dsd/phy.rst

diff --git a/Documentation/firmware-guide/acpi/dsd/phy.rst b/Documentation/firmware-guide/acpi/dsd/phy.rst
new file mode 100644
index 000000000000..78dcb0cacc7e
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
@@ -0,0 +1,40 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+MDIO bus and PHYs in ACPI
+=========================
+
+The PHYs on a mdiobus are probed and registered using mdiobus_register().
+Later, for connecting these PHYs to MAC, the PHYs registered on the
+mdiobus have to be referenced.
+
+For each MAC node, a property "mdio-handle" is used to reference the
+MDIO bus on which the PHYs are registered. On getting hold of the MDIO
+bus, use find_phy_device() to get the PHY connected to the MAC.
+
+
+An example of this is show below::
+
+	Scope(\_SB.MCE0.PR17) // 1G
+	{
+	  Name (_DSD, Package () {
+	     ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		 Package () {
+		     Package (2) {"phy-channel", 1},
+		     Package (2) {"phy-mode", "rgmii-id"},
+		     Package (2) {"mdio-handle", Package (){\_SB.MDI0}}
+	      }
+	   })
+	}
+
+	Scope(\_SB.MCE0.PR18) // 1G
+	{
+	  Name (_DSD, Package () {
+	    ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package (2) {"phy-channel", 2},
+		    Package (2) {"phy-mode", "rgmii-id"},
+		    Package (2) {"mdio-handle", Package (){\_SB.MDI0}}
+	    }
+	  })
+	}
-- 
2.17.1