net: OpenFirmware GPIO based MDIO bitbang driver

This patch adds an MDIO bitbang driver that uses the GPIO library and its
OF bindings to access the bus I/Os.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
index 1d2a772506cf..46a9dba11f2f 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -58,6 +58,7 @@ Table of Contents
       o) Xilinx IP cores
       p) Freescale Synchronous Serial Interface
           q) USB EHCI controllers
+      r) MDIO on GPIOs
 
   VII - Marvell Discovery mv64[345]6x System Controller chips
     1) The /system-controller node
@@ -2870,6 +2871,26 @@ platforms are moved over to use the flattened-device-tree model.
                 reg = <0xe8000000 32>;
         };
 
+   r) MDIO on GPIOs
+
+   Currently defined compatibles:
+   - virtual,gpio-mdio
+
+   MDC and MDIO lines connected to GPIO controllers are listed in the
+   gpios property as described in section VIII.1 in the following order:
+
+   MDC, MDIO.
+
+   Example:
+
+        mdio {
+                compatible = "virtual,mdio-gpio";
+                #address-cells = <1>;
+                #size-cells = <0>;
+                gpios = <&qe_pio_a 11
+                         &qe_pio_c 6>;
+        };
+
 VII - Marvell Discovery mv64[345]6x System Controller chips
 ===========================================================