fix uart.on() failed  # 1584
@@ -202,5 +202,5 @@ int32_t aos_hal_uart_callback(aos_hal_uart_dev_t *uart, void (*cb)(int, void *,
uart->userdata = userdata;
uart_dev_table[uart->port] = uart;
uart_set_select_notif_callback(uart->port, select_notif_callback_isr);
- return -ENOTSUP;
+ return 0;
}
