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?

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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);