diff --git a/drivers/platform/x86/intel/speed_select_if/isst_if_common.h b/drivers/platform/x86/intel/speed_select_if/isst_if_common.h
index 35ff506b402e..967c338e83c5 100644
--- a/drivers/platform/x86/intel/speed_select_if/isst_if_common.h
+++ b/drivers/platform/x86/intel/speed_select_if/isst_if_common.h
@@ -30,7 +30,8 @@
 
 #define ISST_IF_DEV_MBOX	0
 #define ISST_IF_DEV_MMIO	1
-#define ISST_IF_DEV_MAX		2
+#define ISST_IF_DEV_TPMI	2
+#define ISST_IF_DEV_MAX		3
 
 /**
  * struct isst_if_cmd_cb - Used to register a IOCTL handler