Hello,
i am implementing niche rs485-based serial protocol as a tty line
discipline linux module. Requirement is to hit transmission window
with precision in low hundreds of microseconds (eg. +-200 uS).
Transmit window starts 500 uS after message is received.
It seems that hardware driver calls tty_receive_buf2() with sufficient
latency, so my idea was to start hrtimer using hrtimer_start() inside
of tty_receive_buf2(). And then in hrtimer handler call
for(...){tty_put_char(tty,...)} or tty->ops->write(), but it seems not
to be a good practice according to my online research. They say it's
recommended to call tty_put_char() from workqueue, but documentation
also says that calling a workqueue might introduce latency of couple
milliseconds, since it's scheduled thread context.
What would you suggest to handle such a strict timing requirements
between RX and TX data?
Thank you
Best regards
Tomas Mudrunka
