diff --git a/shared/nm-glib-aux/nm-dbus-aux.c b/shared/nm-glib-aux/nm-dbus-aux.c
index 7c55b5a750..9cb0a7f091 100644
--- a/shared/nm-glib-aux/nm-dbus-aux.c
+++ b/shared/nm-glib-aux/nm-dbus-aux.c
@@ -111,8 +111,6 @@ void nm_dbus_connection_call_set (GDBusConnection *dbus_connection,
                                   NMDBusConnectionCallDefaultCb callback,
                                   gpointer user_data)
 {
-	nm_assert (callback);
-
 	g_dbus_connection_call (dbus_connection,
 	                        bus_name,
 	                        object_path,
diff --git a/src/devices/nm-device-ethernet.c b/src/devices/nm-device-ethernet.c
index a87b772e8a..bdb46844c6 100644
--- a/src/devices/nm-device-ethernet.c
+++ b/src/devices/nm-device-ethernet.c
@@ -45,18 +45,6 @@ _LOG_DECLARE_SELF(NMDeviceEthernet);
 
 /*****************************************************************************/
 
-typedef struct Supplicant {
-	NMSupplicantManager *mgr;
-	NMSupplicantInterface *iface;
-
-	/* signal handler ids */
-	gulong iface_state_id;
-	gulong auth_state_id;
-
-	/* Timeouts and idles */
-	guint con_timeout_id;
-} Supplicant;
-
 typedef enum {
 	DCB_WAIT_UNKNOWN = 0,
 	/* Ensure carrier is up before enabling DCB */
@@ -72,12 +60,6 @@ typedef enum {
 } DcbWait;
 
 typedef struct _NMDeviceEthernetPrivate {
-	guint32             speed;
-	gulong              carrier_id;
-
-	Supplicant          supplicant;
-	guint               supplicant_timeout_id;
-
 	/* s390 */
 	char *              subchan1;
 	char *              subchan2;
@@ -87,6 +69,23 @@ typedef struct _NMDeviceEthernetPrivate {
 	char *              s390_nettype;
 	GHashTable *        s390_options;
 
+	guint32             speed;
+	gulong              carrier_id;
+
+	struct {
+		NMSupplicantManager *mgr;
+		NMSupplicantInterface *iface;
+
+		/* signal handler ids */
+		gulong iface_state_id;
+		gulong auth_state_id;
+
+		/* Timeouts and idles */
+		guint con_timeout_id;
+
+		guint timeout_id;
+	} supplicant;
+
 	NMActRequestGetSecretsCallId *wired_secrets_id;
 
 	/* PPPoE */
@@ -400,7 +399,7 @@ supplicant_interface_release (NMDeviceEthernet *self)
 {
 	NMDeviceEthernetPrivate *priv = NM_DEVICE_ETHERNET_GET_PRIVATE (self);
 
-	nm_clear_g_source (&priv->supplicant_timeout_id);
+	nm_clear_g_source (&priv->supplicant.timeout_id);
 	nm_clear_g_source (&priv->supplicant.con_timeout_id);
 	nm_clear_g_signal_handler (priv->supplicant.iface, &priv->supplicant.iface_state_id);
 	nm_clear_g_signal_handler (priv->supplicant.iface, &priv->supplicant.auth_state_id);
@@ -547,7 +546,7 @@ link_timeout_cb (gpointer user_data)
 	NMConnection *applied_connection;
 	const char *setting_name;
 
-	priv->supplicant_timeout_id = 0;
+	priv->supplicant.timeout_id = 0;
 
 	req = nm_device_get_act_request (device);
 
@@ -675,7 +674,7 @@ supplicant_iface_state_cb (NMSupplicantInterface *iface,
 		}
 		break;
 	case NM_SUPPLICANT_INTERFACE_STATE_COMPLETED:
-		nm_clear_g_source (&priv->supplicant_timeout_id);
+		nm_clear_g_source (&priv->supplicant.timeout_id);
 		nm_clear_g_source (&priv->supplicant.con_timeout_id);
 
 		/* If this is the initial association during device activation,
@@ -690,8 +689,8 @@ supplicant_iface_state_cb (NMSupplicantInterface *iface,
 	case NM_SUPPLICANT_INTERFACE_STATE_DISCONNECTED:
 		if ((devstate == NM_DEVICE_STATE_ACTIVATED) || nm_device_is_activating (device)) {
 			/* Start the link timeout so we allow some time for reauthentication */
-			if (!priv->supplicant_timeout_id)
-				priv->supplicant_timeout_id = g_timeout_add_seconds (15, link_timeout_cb, device);
+			if (!priv->supplicant.timeout_id)
+				priv->supplicant.timeout_id = g_timeout_add_seconds (15, link_timeout_cb, device);
 		}
 		break;
 	case NM_SUPPLICANT_INTERFACE_STATE_DOWN:
diff --git a/src/devices/nm-device-macsec.c b/src/devices/nm-device-macsec.c
index dbb4ac8efe..b7c9e7728e 100644
--- a/src/devices/nm-device-macsec.c
+++ b/src/devices/nm-device-macsec.c
@@ -23,17 +23,6 @@ _LOG_DECLARE_SELF(NMDeviceMacsec);
 
 /*****************************************************************************/
 
-typedef struct Supplicant {
-	NMSupplicantManager *mgr;
-	NMSupplicantInterface *iface;
-
-	/* signal handler ids */
-	gulong iface_state_id;
-
-	/* Timeouts and idles */
-	guint con_timeout_id;
-} Supplicant;
-
 NM_GOBJECT_PROPERTIES_DEFINE (NMDeviceMacsec,
 	PROP_SCI,
 	PROP_CIPHER_SUITE,
@@ -53,7 +42,18 @@ typedef struct {
 	NMPlatformLnkMacsec props;
 	gulong parent_state_id;
 	gulong parent_mtu_id;
-	Supplicant supplicant;
+
+	struct {
+		NMSupplicantManager *mgr;
+		NMSupplicantInterface *iface;
+
+		/* signal handler ids */
+		gulong iface_state_id;
+
+		/* Timeouts and idles */
+		guint con_timeout_id;
+	} supplicant;
+
 	guint supplicant_timeout_id;
 	NMActRequestGetSecretsCallId *macsec_secrets_id;
 } NMDeviceMacsecPrivate;
diff --git a/src/supplicant/nm-supplicant-interface.c b/src/supplicant/nm-supplicant-interface.c
index 4b6b4f6e1e..e25928c14d 100644
--- a/src/supplicant/nm-supplicant-interface.c
+++ b/src/supplicant/nm-supplicant-interface.c
@@ -1805,19 +1805,9 @@ on_wpas_proxy_acquired (GDBusProxy *proxy, GAsyncResult *result, gpointer user_d
 	 */
 
 	if (priv->dev != NULL) {
-		const char *driver_name = NULL;
+		const char *driver_name;
 
-		switch (priv->driver) {
-		case NM_SUPPLICANT_DRIVER_WIRELESS:
-			driver_name = NM_WPAS_DEFAULT_WIFI_DRIVER;
-			break;
-		case NM_SUPPLICANT_DRIVER_WIRED:
-			driver_name = "wired";
-			break;
-		case NM_SUPPLICANT_DRIVER_MACSEC:
-			driver_name = "macsec_linux";
-			break;
-		}
+		driver_name = nm_supplicant_driver_to_string (priv->driver);
 
 		g_return_if_fail (driver_name);
 
diff --git a/src/supplicant/nm-supplicant-manager.c b/src/supplicant/nm-supplicant-manager.c
index 65b910cade..08bed98cf3 100644
--- a/src/supplicant/nm-supplicant-manager.c
+++ b/src/supplicant/nm-supplicant-manager.c
@@ -48,6 +48,16 @@ NM_CACHED_QUARK_FCN ("nm-supplicant-error-quark", nm_supplicant_error_quark)
 
 /*****************************************************************************/
 
+NM_UTILS_LOOKUP_STR_DEFINE (nm_supplicant_driver_to_string, NMSupplicantDriver,
+	NM_UTILS_LOOKUP_DEFAULT_WARN (NULL),
+	NM_UTILS_LOOKUP_ITEM    (NM_SUPPLICANT_DRIVER_UNKNOWN,  "???"),
+	NM_UTILS_LOOKUP_ITEM    (NM_SUPPLICANT_DRIVER_WIRELESS, NM_WPAS_DEFAULT_WIFI_DRIVER),
+	NM_UTILS_LOOKUP_ITEM    (NM_SUPPLICANT_DRIVER_WIRED,    "wired"),
+	NM_UTILS_LOOKUP_ITEM    (NM_SUPPLICANT_DRIVER_MACSEC,   "macsec_linux"),
+);
+
+/*****************************************************************************/
+
 static void
 _caps_set (NMSupplicantManagerPrivate *priv,
            NMSupplCapType type,
diff --git a/src/supplicant/nm-supplicant-types.h b/src/supplicant/nm-supplicant-types.h
index de0283b24a..17fbc0c009 100644
--- a/src/supplicant/nm-supplicant-types.h
+++ b/src/supplicant/nm-supplicant-types.h
@@ -127,11 +127,14 @@ typedef enum {
 } NMSupplicantError;
 
 typedef enum {
+	NM_SUPPLICANT_DRIVER_UNKNOWN,
 	NM_SUPPLICANT_DRIVER_WIRELESS,
 	NM_SUPPLICANT_DRIVER_WIRED,
 	NM_SUPPLICANT_DRIVER_MACSEC,
 } NMSupplicantDriver;
 
+const char *nm_supplicant_driver_to_string (NMSupplicantDriver driver);
+
 #define NM_SUPPLICANT_ERROR (nm_supplicant_error_quark ())
 GQuark nm_supplicant_error_quark (void);