One heads up on a mistake I made that Zachary Thorson debugged for me, and explained:
https://groups.google.com/forum/#!searchin/beagleboard/Zacharary$20Thorson/beagleboard/ZLSuKKM9Im4/bKqP9-Eu0NEJ
You could possibly have conflict with Adafruits Python BBIO.ADC module with:
target = <&ocp>;
overlay {
test_helper: helper {
Thw ADC module which will put a file helper.* in /sys/devices/ocp.* For me, it is:
/sys/devices/ocp.3/helper.15
This could conflict with your driver interface file. You might consider renaming
test_helper: helper {
to something like:
test_mycape:mycape {
-Bit Pusher