[net-next PATCH v3 1/5] Documentation: ACPI: DSD: Document MDIO PHY

[Calvin Johnson <calvin.johnson@oss.nxp.com>]

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().

Describe properties "phy-channel" and "phy-mode"

Signed-off-by: Calvin Johnson <calvin.johnson@oss.nxp.com>

---

Changes in v3:
- cleanup based on v2 comments
- Added description for more properties
- Added MDIO node DSDT entry

Changes in v2: None

 Documentation/firmware-guide/acpi/dsd/phy.rst | 90 +++++++++++++++++++
 1 file changed, 90 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..0132fee10b45
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
@@ -0,0 +1,90 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+MDIO bus and PHYs in ACPI
+=========================
+
+The PHYs on an 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.
+
+mdio-handle
+-----------
+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.
+
+phy-channel
+-----------
+Property "phy-channel" defines the address of the PHY on the mdiobus.
+
+phy-mode
+--------
+Property "phy-mode" defines the type of PHY interface.
+
+An example of this is shown below::
+
+DSDT entry for MAC where MDIO node is referenced
+------------------------------------------------
+	Scope(\_SB.MCE0.PR17) // 1G
+	{
+	  Name (_DSD, Package () {
+	     ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		 Package () {
+		     Package () {"phy-channel", 1},
+		     Package () {"phy-mode", "rgmii-id"},
+		     Package () {"mdio-handle", Package (){\_SB.MDI0}}
+	      }
+	   })
+	}
+
+	Scope(\_SB.MCE0.PR18) // 1G
+	{
+	  Name (_DSD, Package () {
+	    ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package () {"phy-channel", 2},
+		    Package () {"phy-mode", "rgmii-id"},
+		    Package () {"mdio-handle", Package (){\_SB.MDI0}}
+	    }
+	  })
+	}
+
+DSDT entry for MDIO node
+------------------------
+a) Silicon Component
+--------------------
+	Scope(_SB)
+	{
+	  Device(MDI0) {
+	    Name(_HID, "NXP0006")
+	    Name(_CCA, 1)
+	    Name(_UID, 0)
+	    Name(_CRS, ResourceTemplate() {
+	      Memory32Fixed(ReadWrite, MDI0_BASE, MDI_LEN)
+	      Interrupt(ResourceConsumer, Level, ActiveHigh, Shared)
+	       {
+		 MDI0_IT
+	       }
+	    }) // end of _CRS for MDI0
+	    Name (_DSD, Package () {
+	      ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+	      Package () {
+		 Package () {"little-endian", 1},
+	      }
+	    })
+	  } // end of MDI0
+	}
+
+b) Platform Component
+---------------------
+	Scope(\_SB.MDI0)
+	{
+	  Device(PHY1) {
+	    Name (_ADR, 0x1)
+	  } // end of PHY1
+
+	  Device(PHY2) {
+	    Name (_ADR, 0x2)
+	  } // end of PHY2
+	}
-- 
2.17.1