USR1_RTSD
usr1 &= ~USR1_RTSD;
if (usr1 & USR1_RTSD) {
imx_uart_writel(sport, USR1_RTSD | USR1_DTRD, USR1);
imx_uart_writel(sport, USR1_RTSD, USR1);
wake_active = wake_active || (usr1 & USR1_RTSD);
imx_uart_writel(sport, USR1_RTSD, USR1);