I recently bought a cheap Arduino Board on eBay that came with a CH34x USB to Serial Chip. The eBay seller offered a link and instructions for the drivers for Linux, Mac and Windows. Installing/loading this in Crouton was not straightforward however.
Connecting the board and opening ide shows the lack of connection as expected. Note the grayed-out ‘Port’ Selector.
If you are in this spot, a few issues are against you. First, the Linux driver has to be built and loaded in Crouton. Second, the Linux Kernel (3.10.18 for me) included with Crouton lacks linux-headers and linux-image, both needed to be able to load modules. Lastly, Crouton does not allow outside modules to be loaded.
The solution proved hard to come by but easy to apply. I found this page, https://github.com/divx118/crouton-packages/blob/master/README.md which includes all goodies missing from kernel needed to load module.
After following those directions, I was able to follow the directions that came from the driver. I used this one without issues.
I was then able to pick port on Arduino IDE and make those lights blink.
Congratulations, have fun with Arduino Programming on your Crouton!