hci: add ENABLE_LE_ENHANCED_CONNECTION_COMPLETE_EVENT

Author: mringwal

doc/manual/docs-template/how_to.md

@@ -98,11 +98,12 @@ BTstack properties:
 | ENABLE_LE_PERIPHERAL                                      | Enable support for LE Peripheral Role in HCI and Security Manager                                                           |
 | ENABLE_LE_CENTRAL                                         | Enable support for LE Central Role in HCI and Security Manager                                                              |
 | ENABLE_LE_SECURE_CONNECTIONS                              | Enable LE Secure Connections                                                                                                |
-| ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY                    | Enable support for LE Secure Connection debug keys for testing                                                     |
+| ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY                    | Enable support for LE Secure Connection debug keys for testing                                                              |
 | ENABLE_LE_PROACTIVE_AUTHENTICATION                        | Enable automatic encryption for bonded devices on re-connect                                                                |
 | ENABLE_GATT_CLIENT_PAIRING                                | Enable GATT Client to start pairing and retry operation on security error                                                   |
 | ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS                | Use [micro-ecc library](https://github.com/kmackay/micro-ecc) for ECC operations                                            |
 | ENABLE_LE_DATA_LENGTH_EXTENSION                           | Enable LE Data Length Extension support                                                                                     |
+| ENABLE_LE_ENHANCED_CONNECTION_COMPLETE_EVENT              | Enable LE Enhanced Connection Complete Event v1 & v2                                                                        | 
 | ENABLE_LE_EXTENDED_ADVERTISING                            | Enable extended advertising and scanning                                                                                    |
 | ENABLE_LE_PERIODIC_ADVERTISING                            | Enable periodic advertising and scanning                                                                                    |
 | ENABLE_LE_SIGNED_WRITE                                    | Enable LE Signed Writes in ATT/GATT                                                                                         |

src/hci.c

@@ -2272,7 +2272,11 @@ static void hci_initializing_run(void){
         case HCI_INIT_LE_SET_EVENT_MASK:
             if (hci_le_supported()){
                 hci_stack->substate = HCI_INIT_W4_LE_SET_EVENT_MASK;
+#ifdef ENABLE_LE_ENHANCED_CONNECTION_COMPLETE_EVENT
+                hci_send_cmd(&hci_le_set_event_mask, 0xffffffff, 0x07); // all events from core v5.3
+#else
                 hci_send_cmd(&hci_le_set_event_mask, 0xfffffdff, 0x07); // all events from core v5.3 without LE Enhanced Connection Complete
+#endif
                 break;
             }
 #endif