diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index a49a66f..d4f2a49 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -284,6 +284,8 @@
 extern int usb_composite_register(struct usb_composite_driver *);
 extern void usb_composite_unregister(struct usb_composite_driver *);
 
+#define OS_STRING_QW_SIGN_LEN		14
+#define OS_STRING_IDX			0xEE
 
 /**
  * struct usb_composite_device - represents one composite usb gadget
@@ -291,6 +293,9 @@
  * @req: used for control responses; buffer is pre-allocated
  * @bufsiz: size of buffer pre-allocated in @req
  * @config: the currently active configuration
+ * @qw_sign: qwSignature part of the OS string
+ * @b_vendor_code: bMS_VendorCode part of the OS string
+ * @use_os_string: false by default, interested gadgets set it
  *
  * One of these devices is allocated and initialized before the
  * associated device driver's bind() is called.
@@ -324,6 +329,11 @@
 
 	struct usb_configuration	*config;
 
+	/* OS String is a custom (yet popular) extension to the USB standard. */
+	u8				qw_sign[OS_STRING_QW_SIGN_LEN];
+	u8				b_vendor_code;
+	unsigned int			use_os_string:1;
+
 	/* private: */
 	/* internals */
 	unsigned int			suspended:1;