diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 6a4811f..4a36632 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -375,13 +375,13 @@
 
 	if (!np) {
 		dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
-		return ERR_PTR(-ENOSYS);
+		return ERR_PTR(-EINVAL);
 	}
 
 	if (!of_get_property(np, "mbox-names", NULL)) {
 		dev_err(cl->dev,
 			"%s() requires an \"mbox-names\" property\n", __func__);
-		return ERR_PTR(-ENOSYS);
+		return ERR_PTR(-EINVAL);
 	}
 
 	of_property_for_each_string(np, "mbox-names", prop, mbox_name) {