usb: prevent registering duplicate config callbacks

Originally discussed at https://github.com/libopencm3/libopencm3/pull/722
2018-07-25 22:11:25 +00:00
parent c55ec70f49
commit f4bbe7c5bb
2 changed files with 5 additions and 1 deletions
--- a/lib/usb/usb_standard.c
+++ b/lib/usb/usb_standard.c
@@ -46,6 +46,9 @@ int usbd_register_set_config_callback(usbd_device *usbd_dev,

 	for (i = 0; i < MAX_USER_SET_CONFIG_CALLBACK; i++) {
 		if (usbd_dev->user_callback_set_config[i]) {
+			if (usbd_dev->user_callback_set_config[i] == callback) {
+				return 0;
+			}
 			continue;
 		}