diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 3bd1888787eb..48c3b9f72722 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -93,7 +93,7 @@ v4l2_fwnode_bus_type_to_mbus(enum v4l2_fwnode_bus_type type)
 	const struct v4l2_fwnode_bus_conv *conv =
 		get_v4l2_fwnode_bus_conv_by_fwnode_bus(type);
 
-	return conv ? conv->mbus_type : V4L2_MBUS_UNKNOWN;
+	return conv ? conv->mbus_type : V4L2_MBUS_INVALID;
 }
 
 static const char *
@@ -436,6 +436,10 @@ static int __v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
 		 v4l2_fwnode_mbus_type_to_string(vep->bus_type),
 		 vep->bus_type);
 	mbus_type = v4l2_fwnode_bus_type_to_mbus(bus_type);
+	if (mbus_type == V4L2_MBUS_INVALID) {
+		pr_debug("unsupported bus type %u\n", bus_type);
+		return -EINVAL;
+	}
 
 	if (vep->bus_type != V4L2_MBUS_UNKNOWN) {
 		if (mbus_type != V4L2_MBUS_UNKNOWN &&
diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h
index 45f88f0248c4..c072ed141811 100644
--- a/include/media/v4l2-mediabus.h
+++ b/include/media/v4l2-mediabus.h
@@ -78,6 +78,7 @@
  * @V4L2_MBUS_CCP2:	CCP2 (Compact Camera Port 2)
  * @V4L2_MBUS_CSI2_DPHY: MIPI CSI-2 serial interface, with D-PHY
  * @V4L2_MBUS_CSI2_CPHY: MIPI CSI-2 serial interface, with C-PHY
+ * @V4L2_MBUS_INVALID:	invalid bus type (keep as last)
  */
 enum v4l2_mbus_type {
 	V4L2_MBUS_UNKNOWN,
@@ -87,6 +88,7 @@ enum v4l2_mbus_type {
 	V4L2_MBUS_CCP2,
 	V4L2_MBUS_CSI2_DPHY,
 	V4L2_MBUS_CSI2_CPHY,
+	V4L2_MBUS_INVALID,
 };
 
 /**