dt: Move device tree documentation out of powerpc directory

The device tree is used by more than just PowerPC.  Make the documentation
directory available to all.

v2: reorganized files while moving to create arch and driver specific
    directories.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/usb/usb-ehci.txt b/Documentation/devicetree/bindings/usb/usb-ehci.txt
new file mode 100644
index 000000000000..fa18612f757b
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/usb-ehci.txt
@@ -0,0 +1,25 @@
+USB EHCI controllers
+
+Required properties:
+  - compatible : should be "usb-ehci".
+  - reg : should contain at least address and length of the standard EHCI
+    register set for the device. Optional platform-dependent registers
+    (debug-port or other) can be also specified here, but only after
+    definition of standard EHCI registers.
+  - interrupts : one EHCI interrupt should be described here.
+If device registers are implemented in big endian mode, the device
+node should have "big-endian-regs" property.
+If controller implementation operates with big endian descriptors,
+"big-endian-desc" property should be specified.
+If both big endian registers and descriptors are used by the controller
+implementation, "big-endian" property can be specified instead of having
+both "big-endian-regs" and "big-endian-desc".
+
+Example (Sequoia 440EPx):
+    ehci@e0000300 {
+	   compatible = "ibm,usb-ehci-440epx", "usb-ehci";
+	   interrupt-parent = <&UIC0>;
+	   interrupts = <1a 4>;
+	   reg = <0 e0000300 90 0 e0000390 70>;
+	   big-endian;
+   };