Index: uspace/lib/drv/include/usbhc_iface.h
===================================================================
--- uspace/lib/drv/include/usbhc_iface.h	(revision a3dfb2eaf9ecfa290c1a29eddd807f1d30db1583)
+++ uspace/lib/drv/include/usbhc_iface.h	(revision 70c852118889bcf58e9f4542b5879ca3051632d5)
@@ -166,30 +166,32 @@
     usb_transaction_outcome_t, size_t, void *);
 
+
+/** Out transfer processing function prototype. */
+typedef int (*usbhc_iface_transfer_out_t)(device_t *, usb_target_t,
+    void *, size_t,
+    usbhc_iface_transfer_out_callback_t, void *);
+
+/** Setup transfer processing function prototype. */
+typedef usbhc_iface_transfer_out_t usbhc_iface_transfer_setup_t;
+
+/** In transfer processing function prototype. */
+typedef int (*usbhc_iface_transfer_in_t)(device_t *, usb_target_t,
+    void *, size_t,
+    usbhc_iface_transfer_in_callback_t, void *);
+
 /** USB devices communication interface. */
 typedef struct {
 	int (*tell_address)(device_t *, devman_handle_t, usb_address_t *);
 
-	int (*interrupt_out)(device_t *, usb_target_t,
-	    void *, size_t,
-	    usbhc_iface_transfer_out_callback_t, void *);
-	int (*interrupt_in)(device_t *, usb_target_t,
-	    void *, size_t,
-	    usbhc_iface_transfer_in_callback_t, void *);
-
-	int (*control_write_setup)(device_t *, usb_target_t,
-	    void *, size_t,
-	    usbhc_iface_transfer_out_callback_t, void *);
-	int (*control_write_data)(device_t *, usb_target_t,
-	    void *, size_t,
-	    usbhc_iface_transfer_out_callback_t, void *);
+	usbhc_iface_transfer_out_t interrupt_out;
+	usbhc_iface_transfer_in_t interrupt_in;
+
+	usbhc_iface_transfer_setup_t control_write_setup;
+	usbhc_iface_transfer_out_t control_write_data;
 	int (*control_write_status)(device_t *, usb_target_t,
 	    usbhc_iface_transfer_in_callback_t, void *);
 
-	int (*control_read_setup)(device_t *, usb_target_t,
-	    void *, size_t,
-	    usbhc_iface_transfer_out_callback_t, void *);
-	int (*control_read_data)(device_t *, usb_target_t,
-	    void *, size_t,
-	    usbhc_iface_transfer_in_callback_t, void *);
+	usbhc_iface_transfer_setup_t control_read_setup;
+	usbhc_iface_transfer_in_t control_read_data;
 	int (*control_read_status)(device_t *, usb_target_t,
 	    usbhc_iface_transfer_out_callback_t, void *);