USB: add usb debugfs directory

Add a common usb directory in debugfs that the usb subsystem can use.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 7eee400..5f6873f 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -34,6 +34,7 @@
 #include <linux/usb.h>
 #include <linux/mutex.h>
 #include <linux/workqueue.h>
+#include <linux/debugfs.h>
 
 #include <asm/io.h>
 #include <linux/scatterlist.h>
@@ -1001,6 +1002,22 @@
 	.notifier_call = usb_bus_notify,
 };
 
+struct dentry *usb_debug_root;
+EXPORT_SYMBOL_GPL(usb_debug_root);
+
+static int usb_debugfs_init(void)
+{
+	usb_debug_root = debugfs_create_dir("usb", NULL);
+	if (!usb_debug_root)
+		return -ENOENT;
+	return 0;
+}
+
+static void usb_debugfs_cleanup(void)
+{
+	debugfs_remove(usb_debug_root);
+}
+
 /*
  * Init
  */
@@ -1012,6 +1029,10 @@
 		return 0;
 	}
 
+	retval = usb_debugfs_init();
+	if (retval)
+		goto out;
+
 	retval = ksuspend_usb_init();
 	if (retval)
 		goto out;
@@ -1083,6 +1104,7 @@
 	bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
 	bus_unregister(&usb_bus_type);
 	ksuspend_usb_cleanup();
+	usb_debugfs_cleanup();
 }
 
 subsys_initcall(usb_init);