IMX_USR1_TRDY
if (usr1 & IMX_USR1_TRDY)
if (usr1 & IMX_USR1_TRDY)
if (bus_space_read_4(iot, ioh, IMX_USR1) & IMX_USR1_TRDY) {
#define IMXUART_TXINTR_USR1 (IMX_USR1_TRDY)
#define IMXUART_TXDMA_USR1 (IMX_USR1_TRDY)