net: mvmdio: new Marvell MDIO driver

This patch adds a separate driver for the MDIO interface of the
Marvell Ethernet controllers. There are two reasons to have a separate
driver rather than including it inside the MAC driver itself:

 *) The MDIO interface is shared by all Ethernet ports, so a driver
    must guarantee non-concurrent accesses to this MDIO interface. The
    most logical way is to have a separate driver that handles this
    single MDIO interface, used by all Ethernet ports.

 *) The MDIO interface is the same between the existing mv643xx_eth
    driver and the new mvneta driver. Even though it is for now only
    used by the mvneta driver, it will in the future be used by the
    mv643xx_eth driver as well.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: David S. Miller <davem@davemloft.net>

1 files changed, 35 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/net/marvell-orion-mdio.txt b/Documentation/devicetree/bindings/net/marvell-orion-mdio.txt
new file mode 100644
index 000000000000..34e7aafa321c
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/marvell-orion-mdio.txt
@@ -0,0 +1,35 @@
+* Marvell MDIO Ethernet Controller interface
+
+The Ethernet controllers of the Marvel Kirkwood, Dove, Orion5x,
+MV78xx0, Armada 370 and Armada XP have an identical unit that provides
+an interface with the MDIO bus. This driver handles this MDIO
+interface.
+
+Required properties:
+- compatible: "marvell,orion-mdio"
+- reg: address and length of the SMI register
+
+The child nodes of the MDIO driver are the individual PHY devices
+connected to this MDIO bus. They must have a "reg" property given the
+PHY address on the MDIO bus.
+
+Example at the SoC level:
+
+mdio {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        compatible = "marvell,orion-mdio";
+        reg = <0xd0072004 0x4>;
+};
+
+And at the board level:
+
+mdio {
+        phy0: ethernet-phy@0 {
+                reg = <0>;
+        };
+
+        phy1: ethernet-phy@1 {
+                reg = <1>;
+        };
+}