Documentation: ABI: Add doc for usbip-vudc attributes

As vudc provides some new attributes using sysfs infrastructure,
add a suitable documentation file for those attributes.

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/ABI/testing/sysfs-platform-usbip-vudc b/Documentation/ABI/testing/sysfs-platform-usbip-vudc
new file mode 100644 (file)
index 0000000..81fcfb4
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-platform-usbip-vudc
@@ -0,0 +1,35 @@
+What:          /sys/devices/platform/usbip-vudc.%d/dev_desc
+Date:          April 2016
+KernelVersion: 4.6
+Contact:       Krzysztof Opasiak <k.opasiak@samsung.com>
+Description:
+               This file allows to read device descriptor of
+               gadget driver which is currently bound to this
+               controller. It is possible to read this file
+               only if gadget driver is bound, otherwise error
+               is returned.
+
+What:          /sys/devices/platform/usbip-vudc.%d/usbip_status
+Date:          April 2016
+KernelVersion: 4.6
+Contact:       Krzysztof Opasiak <k.opasiak@samsung.com>
+Description:
+               Current status of the device.
+               Allowed values:
+               1 - Device is available and can be exported
+               2 - Device is currently exported
+               3 - Fatal error occurred during communication
+                 with peer
+
+What:          /sys/devices/platform/usbip-vudc.%d/usbip_sockfd
+Date:          April 2016
+KernelVersion: 4.6
+Contact:       Krzysztof Opasiak <k.opasiak@samsung.com>
+Description:
+               This file allows to export usb device to
+               connection peer. It is done by writing to this
+               file socket fd (as a string for example "8")
+               associated with a connection to remote peer who
+               would like to use this device. It is possible to
+               close the connection by writing -1 instead of
+               socked fd.