static bool serial_io_dtr_signaled(struct serial_context *desc) { if (desc->config->enable_tx_irq) { #ifdef CONFIG_UART_LINE_CTRL u32_t dtr = 0; uart_line_ctrl_get(desc->port_dev, LINE_CTRL_DTR, &dtr); return dtr; #endif } return true; } which is called by a high-level ...