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>

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 @@ static struct notifier_block usb_bus_nb = {
 	.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 @@ static int __init usb_init(void)
 		return 0;
 	}
 
+	retval = usb_debugfs_init();
+	if (retval)
+		goto out;
+
 	retval = ksuspend_usb_init();
 	if (retval)
 		goto out;
@@ -1083,6 +1104,7 @@ static void __exit usb_exit(void)
 	bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
 	bus_unregister(&usb_bus_type);
 	ksuspend_usb_cleanup();
+	usb_debugfs_cleanup();
 }
 
 subsys_initcall(usb_init);

include/linux/usb.h

@@ -1558,6 +1558,9 @@ extern void usb_unregister_notify(struct notifier_block *nb);
 #define err(format, arg...) printk(KERN_ERR KBUILD_MODNAME ": " \
 	format "\n" , ## arg)
 
+/* debugfs stuff */
+extern struct dentry *usb_debug_root;
+
 #endif  /* __KERNEL__ */
 
 #endif