diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 42d3832f0602dc7e6f48b5ecccda13dfebc42164..657d2b09e3fee8915b642a10099bc096a39a3e07 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -644,6 +644,8 @@ struct hci_rp_set_csb {
 	__le16	interval;
 } __packed;
 
+#define HCI_OP_START_SYNC_TRAIN		0x0443
+
 #define HCI_OP_SNIFF_MODE		0x0803
 struct hci_cp_sniff_mode {
 	__le16   handle;