Index: kernel/generic/include/console/kconsole.h
===================================================================
--- kernel/generic/include/console/kconsole.h	(revision a000878c0dee83a08f032207ffd800c201fca95b)
+++ kernel/generic/include/console/kconsole.h	(revision c621f4aa64c16cb4d9c2b20dbf5be59c66c25ed3)
@@ -47,4 +47,6 @@
 	ARG_TYPE_INT,
 	ARG_TYPE_STRING,
+	/** Optional string */
+	ARG_TYPE_STRING_OPTIONAL,
 	/** Variable type - either symbol or string. */
 	ARG_TYPE_VAR