diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
index 6e1ab9bead288fcbb1d97bca01dc11fb1bbd6e8e..7690f079396525232f37618d37e5a00808141724 100644
--- a/include/linux/mfd/cros_ec_commands.h
+++ b/include/linux/mfd/cros_ec_commands.h
@@ -2132,6 +2132,7 @@ struct ec_response_get_next_event_v1 {
 /* Switches */
 #define EC_MKBP_LID_OPEN	0
 #define EC_MKBP_TABLET_MODE	1
+#define EC_MKBP_BASE_ATTACHED	2
 
 /*****************************************************************************/
 /* Temperature sensor commands */