usb: gadget: configfs: OS String support

Add handling of OS String extension from the configfs interface.
A directory "os_desc" is added at the top level of a gadget's
directories hierarchy. In the "os_desc" directory there are
three attributes: "use", "b_vendor_code" and "qw_sign".
If "use" contains "0" the OS string is not reported to the host.
"b_vendor_code" contains a one-byte value which is used
for custom per-device and per-interface requests.
"qw_sign" contains an identifier to be reported as the "OS String"
proper.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/configfs-usb-gadget b/Documentation/ABI/testing/configfs-usb-gadget
index 37559a06393b..0e7b786f24ac 100644
--- a/Documentation/ABI/testing/configfs-usb-gadget
+++ b/Documentation/ABI/testing/configfs-usb-gadget
@@ -79,3 +79,14 @@ Description:
                 product         - gadget's product description
                 manufacturer    - gadget's manufacturer description
 
+What:           /config/usb-gadget/gadget/os_desc
+Date:           May 2014
+KernelVersion:  3.16
+Description:
+                This group contains "OS String" extension handling attributes.
+
+                use             - flag turning "OS Desctiptors" support on/off
+                b_vendor_code   - one-byte value used for custom per-device and
+                                per-interface requests
+                qw_sign         - an identifier to be reported as "OS String"
+                                proper