USB: core: let USB device know device node

Although most of USB devices are hot-plug's, there are still some devices
are hard wired on the board, eg, for HSIC and SSIC interface USB devices.
If these kinds of USB devices are multiple functions, and they can supply
other interfaces like i2c, gpios for other devices, we may need to
describe these at device tree.

In this commit, it uses "reg" in dts as physical port number to match
the phyiscal port number decided by USB core, if they are the same,
then the device node is for the device we are creating for USB core.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
new file mode 100644
index 000000000000..1c35e7b665e1
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/usb-device.txt
@@ -0,0 +1,28 @@
+Generic USB Device Properties
+
+Usually, we only use device tree for hard wired USB device.
+The reference binding doc is from:
+http://www.firmware.org/1275/bindings/usb/usb-1_0.ps
+
+Required properties:
+- compatible: usbVID,PID. The textual representation of VID, PID shall
+  be in lower case hexadecimal with leading zeroes suppressed. The
+  other compatible strings from the above standard binding could also
+  be used, but a device adhering to this binding may leave out all except
+  for usbVID,PID.
+- reg: the port number which this device is connecting to, the range
+  is 1-31.
+
+Example:
+
+&usb1 {
+	status = "okay";
+
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	hub: genesys@1 {
+		compatible = "usb5e3,608";
+		reg = <1>;
+	};
+}