creating attributes in sysfs

I am just trying to add a simple at开发者_如何学Pythontribute to a device in the /sys filesystem. Seemed pretty straightforward but none of the helper methods mentioned here or here are exported from the kernel so I can't use them from a module? I must be missing something, can anyone provide some insight?

none of the helper methods mentioned here or here are exported from the kernel

They certainly are, grepping two out of the tree:

fs/sysfs/file.c:EXPORT_SYMBOL_GPL(sysfs_create_file); lib/kobject.c:EXPORT_SYMBOL(kobject_add);