v4.19.13 snapshot.
diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
new file mode 100644
index 0000000..63a39d4
--- /dev/null
+++ b/sound/usb/endpoint.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_ENDPOINT_H
+#define __USBAUDIO_ENDPOINT_H
+
+#define SND_USB_ENDPOINT_TYPE_DATA 0
+#define SND_USB_ENDPOINT_TYPE_SYNC 1
+
+struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
+ struct usb_host_interface *alts,
+ int ep_num, int direction, int type);
+
+int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
+ snd_pcm_format_t pcm_format,
+ unsigned int channels,
+ unsigned int period_bytes,
+ unsigned int period_frames,
+ unsigned int buffer_periods,
+ unsigned int rate,
+ struct audioformat *fmt,
+ struct snd_usb_endpoint *sync_ep);
+
+int snd_usb_endpoint_start(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_activate(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_release(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_free(struct snd_usb_endpoint *ep);
+
+int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep);
+
+void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
+ struct snd_usb_endpoint *sender,
+ const struct urb *urb);
+
+#endif /* __USBAUDIO_ENDPOINT_H */