diff --git a/drivers/sm/Makefile b/drivers/sm/Makefile
index 9f4683b..af5f475 100644
--- a/drivers/sm/Makefile
+++ b/drivers/sm/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-y += sm-uclass.o
+obj-$(CONFIG_SANDBOX) += sandbox-sm.o