#if defined(CONFIG_DEBUG_FS)
#include <linux/debugfs.h>

static int set_my_cool_thingie(void *data, u64 val)
{
    switch (val) {
        case 42:
	printk("WHOA\n");
        break;
	default:
	printk("FFFFUUUUUUUU\n");
    }
    return 0;
}

static int get_my_cool_thingie(void *data, u64 * val)
{
    *val = 42;
    return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(my_cool_thingie_ops, get_my_cool_thingie, set_my_cool_thingie, "%llu\n");
static int __init my_dbg_init(void) {
    struct dentry *dent;

    dent = debugfs_create_dir("my_cool_dir", 0);
    if (IS_ERR(dent))
        return PTR_ERR(dent);

    debugfs_create_file("my_cool_thingie", 0644, dent, NULL, &my_cool_thingie_ops);
    return 0;
}
device_initcall(my_dbg_init);
#endif