system: serial via USB support

[fichtner]

via: https://forum.opnsense.org/index.php?topic=6702.0

[sjorge]

Just an FYI, the tty naming seems to be consistant for usb serial ports!

[iris :: sjorge][~]
[.]$ ls /dev | grep ttyU
ttyU0
ttyU0.init
ttyU0.lock
ttyU1
ttyU1.init
ttyU1.lock
ttyU2
ttyU2.init
ttyU2.lock
ttyU3
ttyU3.init
ttyU3.lock

This is from a FreeBSD box (not OPNsense) with a usb to 4x serial adaptor.

So you can probably target ttyU0 as the first detected serial interface over USB rather reliably.

[fichtner]

@sjorge thanks, that helps! What I wanted to investigate still is whether we need a "use USB instead of Serial TTY" or if we can get aways with loosely attaching ttyu and ttyU devices at the same time.

[sjorge]

An 'USB Serial Console' entry in the drop down for the configuration page maybe?

[fichtner]

Yes, but the real question is for /etc/ttys rewrite. Replace serial ttyu* with ttyU* or add both side by side without issues? I'll look into it when I have a bit more time.

[sjorge]

I think it is replace, I never to serial + serial over lan to work. I always just one of the too. But I am no expert on this.

[fichtner]

I've implemented a checkbox to enable USB-based serial ports.