1 files changed, 68 insertions, 0 deletions
diff --git a/drivers/usb/core/notify.c b/drivers/usb/core/notify.c
new file mode 100644
index 000000000..e61436637
--- /dev/null
+++ b/drivers/usb/core/notify.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * All the USB notify logic
+ *
+ * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
+ *
+ * notifier functions originally based on those in kernel/sys.c
+ * but fixed up to not be so broken.
+ *
+ * Released under the GPLv2 only.
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/notifier.h>
+#include <linux/usb.h>
+#include <linux/mutex.h>
+#include "usb.h"
+
+static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);
+
+/**
+ * usb_register_notify - register a notifier callback whenever a usb change happens
+ * @nb: pointer to the notifier block for the callback events.
+ *
+ * These changes are either USB devices or busses being added or removed.
+ */
+void usb_register_notify(struct notifier_block *nb)
+{
+	blocking_notifier_chain_register(&usb_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(usb_register_notify);
+
+/**
+ * usb_unregister_notify - unregister a notifier callback
+ * @nb: pointer to the notifier block for the callback events.
+ *
+ * usb_register_notify() must have been previously called for this function
+ * to work properly.
+ */
+void usb_unregister_notify(struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&usb_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(usb_unregister_notify);
+
+
+void usb_notify_add_device(struct usb_device *udev)
+{
+	blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
+}
+
+void usb_notify_remove_device(struct usb_device *udev)
+{
+	blocking_notifier_call_chain(&usb_notifier_list,
+			USB_DEVICE_REMOVE, udev);
+}
+
+void usb_notify_add_bus(struct usb_bus *ubus)
+{
+	blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
+}
+
+void usb_notify_remove_bus(struct usb_bus *ubus)
+{
+	blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
+}