centos man page for debugfs_create_u64

DEBUGFS_CREATE_U64(9)					      The debugfs filesystem					     DEBUGFS_CREATE_U64(9)

NAME
       debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value

SYNOPSIS
       struct dentry * debugfs_create_u64(const char * name, umode_t mode, struct dentry * parent, u64 * value);

ARGUMENTS
       name
	   a pointer to a string containing the name of the file to create.

       mode
	   the permission that the file should have

       parent
	   a pointer to the parent dentry for this file. This should be a directory dentry if set. If this parameter is NULL, then the file will
	   be created in the root of the debugfs filesystem.

       value
	   a pointer to the variable that the file should read to and write from.

DESCRIPTION
       This function creates a file in debugfs with the given name that contains the value of the variable value. If the mode variable is so set,
       it can be read from, and written to.

       This function will return a pointer to a dentry if it succeeds. This pointer must be passed to the debugfs_remove function when the file is
       to be removed (no automatic cleanup happens if your module is unloaded, you are responsible here.) If an error occurs, NULL will be
       returned.

       If debugfs is not enabled in the kernel, the value -ENODEV will be returned. It is not wise to check for this value, but rather, check for
       NULL or !NULL instead as to eliminate the need for #ifdef in the calling code.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						     DEBUGFS_CREATE_U64(9)