Supported triggers are: IRQ_RXIDLE and IRQ_TXIDLE.
When IRQ_RXIDLE is set, the handler will be called 3 character times after
the data in burst stopped.
When IRQ_TXIDLE is set, the handler will be called immediately after the
data has been sent.
This commit requires a change to fsl_lpuart.c, because the existing code
does not support under-run appropriately.
The irq.flags() value is cleared only at an expected event. Do not change
it otherwise.
Signed-off-by: robert-hh <robert@hammelrath.com>
b7fa4e2fc8