+
+ /**
+ * lock_async() - Keep async schedule after a transfer
+ *
+ * It may be desired to keep the asynchronous schedule running even
+ * after a transfer finishes, usually when doing multiple transfers
+ * back-to-back. This callback allows signalling the USB controller
+ * driver to do just that.
+ */
+ int (*lock_async)(struct udevice *udev, int lock);