Document ctrl_interface_setup_dynip() function

Change-Id: Ie1d5881dda7a9b797d15e9e1eead8281a994d91e
diff --git a/src/ctrl/control_if.c b/src/ctrl/control_if.c
index b4afd55..254f9bc 100644
--- a/src/ctrl/control_if.c
+++ b/src/ctrl/control_if.c
@@ -654,6 +654,14 @@
 	return ctrl_interface_setup_dynip(data, "127.0.0.1", port, lookup);
 }
 
+/*! \brief Setup CTRL interface on a given address
+ *  \param[in] data Pointer which will be made available to each
+               set_..() get_..() verify_..() control command function
+ *  \param[in] bind_addr Address on which CTRL socket shall listen
+ *  \param[in] port Port on which CTRL socket shall listen
+ *  \param[in] lookup Lookup function pointer, can be NULL
+ *  \returns ctrl_handle pointer or NULL in case of errors
+ */
 struct ctrl_handle *ctrl_interface_setup_dynip(void *data,
 					       const char *bind_addr,
 					       uint16_t port,