extmod/modbluetooth: Ensure status=0 always on success.

This commit makes sure that all discovery complete and read/write status
events set the status to zero on success.

The status value will be implementation-dependent on non-success cases.

docs/library/ubluetooth.rst

@@ -112,18 +112,21 @@ Event Handling
                 conn_handle, start_handle, end_handle, uuid = data
             elif event == _IRQ_GATTC_SERVICE_DONE:
                 # Called once service discovery is complete.
+                # Note: Status will be zero on success, implementation-specific value otherwise.
                 conn_handle, status = data
             elif event == _IRQ_GATTC_CHARACTERISTIC_RESULT:
                 # Called for each characteristic found by gattc_discover_services().
                 conn_handle, def_handle, value_handle, properties, uuid = data
             elif event == _IRQ_GATTC_CHARACTERISTIC_DONE:
                 # Called once service discovery is complete.
+                # Note: Status will be zero on success, implementation-specific value otherwise.
                 conn_handle, status = data
             elif event == _IRQ_GATTC_DESCRIPTOR_RESULT:
                 # Called for each descriptor found by gattc_discover_descriptors().
                 conn_handle, dsc_handle, uuid = data
             elif event == _IRQ_GATTC_DESCRIPTOR_DONE:
                 # Called once service discovery is complete.
+                # Note: Status will be zero on success, implementation-specific value otherwise.
                 conn_handle, status = data
             elif event == _IRQ_GATTC_READ_RESULT:
                 # A gattc_read() has completed.
@@ -131,10 +134,12 @@ Event Handling
             elif event == _IRQ_GATTC_READ_DONE:
                 # A gattc_read() has completed.
                 # Note: The value_handle will be zero on btstack (but present on NimBLE).
+                # Note: Status will be zero on success, implementation-specific value otherwise.
                 conn_handle, value_handle, status = data
             elif event == _IRQ_GATTC_WRITE_DONE:
                 # A gattc_write() has completed.
                 # Note: The value_handle will be zero on btstack (but present on NimBLE).
+                # Note: Status will be zero on success, implementation-specific value otherwise.
                 conn_handle, value_handle, status = data
             elif event == _IRQ_GATTC_NOTIFY:
                 # A peripheral has sent a notify request.

examples/bluetooth/ble_temperature_central.py

@@ -162,7 +162,7 @@ class BLETemperatureCentral:
                     self._read_callback = None
 
         elif event == _IRQ_GATTC_READ_DONE:
-            # Read completed.
+            # Read completed (no-op).
             conn_handle, value_handle, status = data
 
         elif event == _IRQ_GATTC_NOTIFY:

extmod/nimble/modbluetooth_nimble.c

@@ -764,7 +764,7 @@ STATIC int peripheral_discover_service_cb(uint16_t conn_handle, const struct ble
         mp_obj_bluetooth_uuid_t service_uuid = create_mp_uuid(&service->uuid);
         mp_bluetooth_gattc_on_primary_service_result(conn_handle, service->start_handle, service->end_handle, &service_uuid);
     } else {
-        mp_bluetooth_gattc_on_discover_complete(MP_BLUETOOTH_IRQ_GATTC_SERVICE_DONE, conn_handle, error->status);
+        mp_bluetooth_gattc_on_discover_complete(MP_BLUETOOTH_IRQ_GATTC_SERVICE_DONE, conn_handle, error->status == BLE_HS_EDONE ? 0 : error->status);
     }
     return 0;
 }
@@ -793,7 +793,7 @@ STATIC int ble_gatt_characteristic_cb(uint16_t conn_handle, const struct ble_gat
         mp_obj_bluetooth_uuid_t characteristic_uuid = create_mp_uuid(&characteristic->uuid);
         mp_bluetooth_gattc_on_characteristic_result(conn_handle, characteristic->def_handle, characteristic->val_handle, characteristic->properties, &characteristic_uuid);
     } else {
-        mp_bluetooth_gattc_on_discover_complete(MP_BLUETOOTH_IRQ_GATTC_CHARACTERISTIC_DONE, conn_handle, error->status);
+        mp_bluetooth_gattc_on_discover_complete(MP_BLUETOOTH_IRQ_GATTC_CHARACTERISTIC_DONE, conn_handle, error->status == BLE_HS_EDONE ? 0 : error->status);
     }
     return 0;
 }
@@ -822,7 +822,7 @@ STATIC int ble_gatt_descriptor_cb(uint16_t conn_handle, const struct ble_gatt_er
         mp_obj_bluetooth_uuid_t descriptor_uuid = create_mp_uuid(&descriptor->uuid);
         mp_bluetooth_gattc_on_descriptor_result(conn_handle, descriptor->handle, &descriptor_uuid);
     } else {
-        mp_bluetooth_gattc_on_discover_complete(MP_BLUETOOTH_IRQ_GATTC_DESCRIPTOR_DONE, conn_handle, error->status);
+        mp_bluetooth_gattc_on_discover_complete(MP_BLUETOOTH_IRQ_GATTC_DESCRIPTOR_DONE, conn_handle, error->status == BLE_HS_EDONE ? 0 : error->status);
     }
     return 0;
 }
@@ -840,7 +840,6 @@ STATIC int ble_gatt_attr_read_cb(uint16_t conn_handle, const struct ble_gatt_err
     if (!mp_bluetooth_is_active()) {
         return 0;
     }
-    // TODO: Maybe send NULL if error->status non-zero.
     if (error->status == 0) {
         gattc_on_data_available(MP_BLUETOOTH_IRQ_GATTC_READ_RESULT, conn_handle, attr->handle, attr->om);
     }