FreeBSD, BBB, and 4DCAPE-43T: touchscreen

[gonzo]

And yet another demo of 4DCAPE-43T, this time it’s touchscreen. On AM335x SoC touchscreen controller is coupled with analog-to-digital converter, for which there is a driver in FreeBSD HEAD: ti_adc. I had to implement touchscreen part and add driver userland communication protocol. For proof of concept I used significantly dumbed-down version of Linux input event protocol. tslib serves as a userland part of the demo. I believe it’s de-facto standard for touchscreen devices interface in Linux world. Only two things were changed comparing to stock one: I added bsd-raw input plugin to communicate with kernel and rewrote framebuffer-related routines.

Code is in gpiokeys branch in my work-in-progress GitHub repo and in freebsd branch of tslib fork.

[youtube http://www.youtube.com/watch?v=8aPUuMG3G9o?feature=oembed&w=500&h=281]

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