extmod/bluetooth: Support active scanning in BLE.gap_scan().

This adds an additional optional parameter to gap_scan() to select active
scanning, where scan responses are returned as well as normal scan results.
This parameter is False by default which retains the existing behaviour.

docs/library/ubluetooth.rst

@@ -204,7 +204,7 @@ Broadcaster Role (Advertiser)
 Observer Role (Scanner)
 -----------------------
 
-.. method:: BLE.gap_scan(duration_ms, [interval_us], [window_us])
+.. method:: BLE.gap_scan(duration_ms, [interval_us], [window_us], [active])
 
     Run a scan operation lasting for the specified duration (in **milli**\ seconds).
 
@@ -228,6 +228,8 @@ Observer Role (Scanner)
         * 0x03 - ADV_NONCONN_IND - non-connectable undirected advertising
         * 0x04 - SCAN_RSP - scan response
 
+    ``active`` can be set ``True`` if you want to receive scan responses in the results.
+    
     When scanning is stopped (either due to the duration finishing or when
     explicitly stopped), the ``_IRQ_SCAN_DONE`` event will be raised.
 

extmod/btstack/modbluetooth_btstack.c

@@ -894,7 +894,7 @@ STATIC void scan_duration_timeout_handler(btstack_timer_source_t *ds) {
     mp_bluetooth_gap_scan_stop();
 }
 
-int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_t window_us) {
+int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_t window_us, bool active_scan) {
     DEBUG_EVENT_printf("mp_bluetooth_gap_scan_start\n");
 
     if (duration_ms > 0) {
@@ -903,8 +903,7 @@ int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_
         btstack_run_loop_add_timer(&scan_duration_timeout);
     }
 
-    // 0 = passive scan (we don't handle scan response).
+    gap_set_scan_parameters(active_scan ? 1 : 0, interval_us / 625, window_us / 625);
-    gap_set_scan_parameters(0, interval_us / 625, window_us / 625);
     gap_start_scan();
 
     return 0;

extmod/modbluetooth.c

@@ -609,6 +609,7 @@ STATIC mp_obj_t bluetooth_ble_gap_scan(size_t n_args, const mp_obj_t *args) {
     mp_int_t duration_ms = 0;
     mp_int_t interval_us = 1280000;
     mp_int_t window_us = 11250;
+    bool active_scan = false;
     if (n_args > 1) {
         if (args[1] == mp_const_none) {
             // scan(None) --> stop scan.
@@ -619,12 +620,15 @@ STATIC mp_obj_t bluetooth_ble_gap_scan(size_t n_args, const mp_obj_t *args) {
             interval_us = mp_obj_get_int(args[2]);
             if (n_args > 3) {
                 window_us = mp_obj_get_int(args[3]);
+                if (n_args > 4) {
+                    active_scan = mp_obj_is_true(args[4]);
                 }
             }
         }
-    return bluetooth_handle_errno(mp_bluetooth_gap_scan_start(duration_ms, interval_us, window_us));
     }
-STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gap_scan_obj, 1, 4, bluetooth_ble_gap_scan);
+    return bluetooth_handle_errno(mp_bluetooth_gap_scan_start(duration_ms, interval_us, window_us, active_scan));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gap_scan_obj, 1, 5, bluetooth_ble_gap_scan);
 #endif // MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
 
 STATIC mp_obj_t bluetooth_ble_gap_disconnect(mp_obj_t self_in, mp_obj_t conn_handle_in) {

extmod/modbluetooth.h

@@ -215,7 +215,7 @@ int mp_bluetooth_gap_disconnect(uint16_t conn_handle);
 
 #if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
 // Start a discovery (scan). Set duration to zero to run continuously.
-int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_t window_us);
+int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_t window_us, bool active_scan);
 
 // Stop discovery (if currently active).
 int mp_bluetooth_gap_scan_stop(void);

extmod/nimble/modbluetooth_nimble.c

@@ -661,7 +661,7 @@ STATIC int gap_scan_cb(struct ble_gap_event *event, void *arg) {
     return 0;
 }
 
-int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_t window_us) {
+int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_t window_us, bool active_scan) {
     if (!mp_bluetooth_is_active()) {
         return ERRNO_BLUETOOTH_NOT_ACTIVE;
     }
@@ -673,7 +673,7 @@ int mp_bluetooth_gap_scan_start(int32_t duration_ms, int32_t interval_us, int32_
         .window = MAX(BLE_HCI_SCAN_WINDOW_MIN, MIN(BLE_HCI_SCAN_WINDOW_MAX, window_us / BLE_HCI_SCAN_ITVL)),
         .filter_policy = BLE_HCI_CONN_FILT_NO_WL,
         .limited = 0,
-        .passive = 1,  // TODO: Handle BLE_HCI_ADV_RPT_EVTYPE_SCAN_RSP in gap_scan_cb above.
+        .passive = active_scan ? 0 : 1,
         .filter_duplicates = 0,
     };
     int err = ble_gap_disc(BLE_OWN_ADDR_PUBLIC, duration_ms, &discover_params, gap_scan_cb, NULL);