1 /*
2 * All the USB notify logic
3 *
4 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
5 *
6 * notifier functions originally based on those in kernel/sys.c
7 * but fixed up to not be so broken.
8 *
9 */
10
11
12 #include <linux/kernel.h>
13 #include <linux/notifier.h>
14 #include <linux/usb.h>
15 #include <linux/mutex.h>
16 #include "usb.h"
17
18 static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);
19
20 /**
21 * usb_register_notify - register a notifier callback whenever a usb change happens
22 * @nb: pointer to the notifier block for the callback events.
23 *
24 * These changes are either USB devices or busses being added or removed.
25 */
usb_register_notify(struct notifier_block * nb)26 void usb_register_notify(struct notifier_block *nb)
27 {
28 blocking_notifier_chain_register(&usb_notifier_list, nb);
29 }
30 EXPORT_SYMBOL_GPL(usb_register_notify);
31
32 /**
33 * usb_unregister_notify - unregister a notifier callback
34 * @nb: pointer to the notifier block for the callback events.
35 *
36 * usb_register_notify() must have been previously called for this function
37 * to work properly.
38 */
usb_unregister_notify(struct notifier_block * nb)39 void usb_unregister_notify(struct notifier_block *nb)
40 {
41 blocking_notifier_chain_unregister(&usb_notifier_list, nb);
42 }
43 EXPORT_SYMBOL_GPL(usb_unregister_notify);
44
45
usb_notify_add_device(struct usb_device * udev)46 void usb_notify_add_device(struct usb_device *udev)
47 {
48 blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
49 }
50
usb_notify_remove_device(struct usb_device * udev)51 void usb_notify_remove_device(struct usb_device *udev)
52 {
53 /* Protect against simultaneous usbfs open */
54 mutex_lock(&usbfs_mutex);
55 blocking_notifier_call_chain(&usb_notifier_list,
56 USB_DEVICE_REMOVE, udev);
57 mutex_unlock(&usbfs_mutex);
58 }
59
usb_notify_add_bus(struct usb_bus * ubus)60 void usb_notify_add_bus(struct usb_bus *ubus)
61 {
62 blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
63 }
64
usb_notify_remove_bus(struct usb_bus * ubus)65 void usb_notify_remove_bus(struct usb_bus *ubus)
66 {
67 blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
68 }
69