serial: 8250_mxpcie: enable enhanced mode and program FIFO trigger levels

The MUEx50 UART provides an enhanced register set and programmable FIFO
trigger levels for RX, TX, and flow control.

Enable enhanced mode during port startup and program the MUEx50 FIFO
trigger registers according to the configured port settings. Clear the
programmed state again during shutdown to restore the default UART
configuration.

The TX FIFO write pointer and read pointer are driven by different
clocks. Clear the FIFOs repeatedly during startup so both pointers are
reset before programming the trigger levels.

Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com>
Link: https://patch.msgid.link/20260731074820.735619-4-crescentcy.hsieh@moxa.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions