diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index 6e8f19c71a9e..632ff86398ac 100644
--- a/drivers/net/wwan/wwan_core.c
+++ b/drivers/net/wwan/wwan_core.c
@@ -250,7 +250,7 @@ struct wwan_port *wwan_create_port(struct device *parent,
 	struct wwan_port *port;
 	int minor, err = -ENOMEM;
 
-	if (type >= WWAN_PORT_MAX || !ops)
+	if (type > WWAN_PORT_MAX || !ops)
 		return ERR_PTR(-EINVAL);
 
 	/* A port is always a child of a WWAN device, retrieve (allocate or
diff --git a/include/linux/wwan.h b/include/linux/wwan.h
index 7216c114d758..fa33cc16d931 100644
--- a/include/linux/wwan.h
+++ b/include/linux/wwan.h
@@ -15,8 +15,10 @@
  * @WWAN_PORT_QMI: Qcom modem/MSM interface for modem control
  * @WWAN_PORT_QCDM: Qcom Modem diagnostic interface
  * @WWAN_PORT_FIREHOSE: XML based command protocol
- * @WWAN_PORT_UNKNOWN: Unknown port type
- * @WWAN_PORT_MAX: Number of supported port types
+ *
+ * @WWAN_PORT_MAX: Highest supported port types
+ * @WWAN_PORT_UNKNOWN: Special value to indicate an unknown port type
+ * @__WWAN_PORT_MAX: Internal use
  */
 enum wwan_port_type {
 	WWAN_PORT_AT,
@@ -24,8 +26,12 @@ enum wwan_port_type {
 	WWAN_PORT_QMI,
 	WWAN_PORT_QCDM,
 	WWAN_PORT_FIREHOSE,
+
+	/* Add new port types above this line */
+
+	__WWAN_PORT_MAX,
+	WWAN_PORT_MAX = __WWAN_PORT_MAX - 1,
 	WWAN_PORT_UNKNOWN,
-	WWAN_PORT_MAX = WWAN_PORT_UNKNOWN,
 };
 
 struct wwan_port;