Bluetooth: Add configuration to control the dynamic connection callbacks

subsys/bluetooth/Kconfig

@@ -109,6 +109,16 @@ config BT_MAX_CONN
 	  Maximum number of simultaneous Bluetooth connections
 	  supported.
 
+config BT_CONN_DYNAMIC_CALLBACKS
+	bool "Dynamic connection callbacks"
+	depends on BT_CONN
+	default y
+	help
+	  Enable support for dynamic connection callbacks. This allows
+	  applications to register and unregister callbacks at runtime.
+	  If disabled, the application must register all callbacks at
+	  compile time using the BT_CONN_CB_DEFINE() macro.
+
 config BT_CONN_TX
 	bool
 	default BT_CONN || BT_ISO_TX

subsys/bluetooth/audio/bap_unicast_client.c

@@ -4467,14 +4467,13 @@ static void unicast_client_disconnected(struct bt_conn *conn, uint8_t reason)
 	unicast_client_ep_reset(conn, reason);
 }
 
-static struct bt_conn_cb conn_cbs = {
+BT_CONN_CB_DEFINE(conn_cbs) = {
 	.disconnected = unicast_client_disconnected,
 };
 
 int bt_bap_unicast_client_discover(struct bt_conn *conn, enum bt_audio_dir dir)
 {
 	struct unicast_client *client;
-	static bool conn_cb_registered;
 	uint8_t role;
 	int err;
 
@@ -4507,11 +4506,6 @@ int bt_bap_unicast_client_discover(struct bt_conn *conn, enum bt_audio_dir dir)
 	client->disc_params.start_handle = BT_ATT_FIRST_ATTRIBUTE_HANDLE;
 	client->disc_params.end_handle = BT_ATT_LAST_ATTRIBUTE_HANDLE;
 
-	if (!conn_cb_registered) {
-		bt_conn_cb_register(&conn_cbs);
-		conn_cb_registered = true;
-	}
-
 	err = bt_gatt_discover(conn, &client->disc_params);
 	if (err != 0) {
 		atomic_clear_bit(client->flags, UNICAST_CLIENT_FLAG_BUSY);

subsys/bluetooth/audio/csip_set_member.c

@@ -647,7 +647,7 @@ static void csip_bond_deleted(uint8_t id, const bt_addr_le_t *peer)
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.disconnected = csip_disconnected,
 	.security_changed = csip_security_changed,
 };
@@ -926,7 +926,6 @@ int bt_csip_set_member_register(const struct bt_csip_set_member_register_param *
 		for (size_t i = 0U; i < ARRAY_SIZE(svc_insts); i++) {
 			k_mutex_init(&svc_insts[i].mutex);
 		}
-		bt_conn_cb_register(&conn_callbacks);
 		bt_conn_auth_info_cb_register(&auth_callbacks);
 		first_register = true;
 	}