GPIO modules are not enabled when a device tree overlay using bone-pinmux-helper is loaded. The module will be enabled after a single pin from it is exported through sysfs. It's a good workaround, but not an elegant solution to the problem. Before exporting only GPIO1 is enabled and every attempt to access GPIOs 0, 2, or 3 causes a bus error in the application. This is a topic on the beagleboard group discussing the issue: https://groups.google.com/forum/?fromgroups#!category-topic/beagleboard/OYFp4EXawiI
Test application: https://gist.github.com/piranha32/4fd285cc8333eeb4ec39
DT overlay used for tests: https://gist.github.com/piranha32/4abc8312339ad47d32d0
GPIO modules are not enabled when a device tree overlay using bone-pinmux-helper is loaded. The module will be enabled after a single pin from it is exported through sysfs. It's a good workaround, but not an elegant solution to the problem. Before exporting only GPIO1 is enabled and every attempt to access GPIOs 0, 2, or 3 causes a bus error in the application. This is a topic on the beagleboard group discussing the issue: https://groups.google.com/forum/?fromgroups#!category-topic/beagleboard/OYFp4EXawiI
Test application: https://gist.github.com/piranha32/4fd285cc8333eeb4ec39
DT overlay used for tests: https://gist.github.com/piranha32/4abc8312339ad47d32d0