pcengines/apu1: Add RS485 configuration

In RS485 mode RTS line acts as a transceiver direction control.

The datasheet is not very clear about the polarity but register setting
here is tested to drive nRTS line high when transmitting.

Also note revision of B of the super-IO has errata and 8N1 setting does
not work properly, you would need revision C of the chip assembled to
fix this.

Change-Id: I705fe0c5a5f8369b0a9358a64c74500238b5c4ba
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/14998
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

0 files changed, 0 insertions, 0 deletions