1 files changed, 59 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/net/cavium-mdio.txt b/Documentation/devicetree/bindings/net/cavium-mdio.txt
index 04cb7491d232..020df08b8a30 100644
--- a/Documentation/devicetree/bindings/net/cavium-mdio.txt
+++ b/Documentation/devicetree/bindings/net/cavium-mdio.txt
@@ -1,9 +1,12 @@
 * System Management Interface (SMI) / MDIO
 
 Properties:
-- compatible: "cavium,octeon-3860-mdio"
+- compatible: One of:
 
-  Compatibility with all cn3XXX, cn5XXX and cn6XXX SOCs.
+   "cavium,octeon-3860-mdio": Compatibility with all cn3XXX, cn5XXX
+                       and cn6XXX SOCs.
+
+   "cavium,thunder-8890-mdio": Compatibility with all cn8XXX SOCs.
 
 - reg: The base address of the MDIO bus controller register bank.
 
@@ -25,3 +28,57 @@ Example:
 			reg = <0>;
 		};
 	};
+
+
+* System Management Interface (SMI) / MDIO Nexus
+
+  Several mdio buses may be gathered as children of a single PCI
+  device, this PCI device is the nexus of the buses.
+
+Properties:
+
+- compatible: "cavium,thunder-8890-mdio-nexus";
+
+- reg: The PCI device and function numbers of the nexus device.
+
+- #address-cells: Must be <2>.
+
+- #size-cells: Must be <2>.
+
+- ranges: As needed for mapping of the MDIO bus device registers.
+
+- assigned-addresses: As needed for mapping of the MDIO bus device registers.
+
+Example:
+
+        mdio-nexus@1,3 {
+                compatible = "cavium,thunder-8890-mdio-nexus";
+                #address-cells = <2>;
+                #size-cells = <2>;
+                reg = <0x0b00 0 0 0 0>; /* DEVFN = 0x0b (1:3) */
+                assigned-addresses = <0x03000000 0x87e0 0x05000000 0x0 0x800000>;
+                ranges = <0x87e0 0x05000000 0x03000000 0x87e0 0x05000000 0x0 0x800000>;
+
+                mdio0@87e0,05003800 {
+                        compatible = "cavium,thunder-8890-mdio";
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                        reg = <0x87e0 0x05003800 0x0 0x30>;
+
+                        ethernet-phy@0 {
+                                ...
+                                reg = <0>;
+                        };
+                };
+                mdio0@87e0,05003880 {
+                        compatible = "cavium,thunder-8890-mdio";
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                        reg = <0x87e0 0x05003880 0x0 0x30>;
+
+                        ethernet-phy@0 {
+                                ...
+                                reg = <0>;
+                        };
+                };
+        };