ksudoku/ksudoku.h

#ifndef _KSUDOKU_H_
#define _KSUDOKU_H_
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sysfs.h>

#define to_sudoku(obj) container_of(obj, struct sudoku, kobj)
#define to_sudoku_attr(_attr) container_of(_attr, struct sudoku_attribute, attr)

struct sudoku;

static ssize_t is_valid_show(struct kobject *kobj, struct attribute *attr,
                             char *buf)
static ssize_t is_valid_store(void);

static ssize_t is_solved_show(struct kobject *kobj, struct attribute *attr,
                              char *buf);
static ssize_t is_solved_store(void);


struct matrix_attribute {
	struct attribute attr;
	ssize_t (*show)(struct kobject *kobj, struct attribute *attr,
                        char *buf);
	ssize_t (*store)(void);
        bool value;
};

/*
 * The type of sudoku, "struct sudoku" is embedded in. A class
 * or bus can only contain one sudoku type.
 * This identifies the sudoku type and carries type-specific
 * information, equivalent to the kobj_type of a kobject.
 * Since we have only one type it always will be the same button
 * we're designing a subsystem so we have to make sysfs happy.
 * If "name" is specified, the uevent will contain it in
 * the DEVTYPE variable.
 */
struct sudoku_type {
	const char *name;
        char matrix[81];

	const struct attribute_group **groups;
	int (*uevent)(struct sudoku *s, struct kobj_uevent_env *env);
	char *(*devnode)(struct sudoku *s, umode_t *mode,
			 kuid_t *uid, kgid_t *gid);
	void (*release)(struct sudoku *s);

        const struct sysfs_ops *sysfs_ops;
};

#define MATRIX_ATTR_RO(_name) \
	struct matrix_attribute matrix_##_name = __ATTR_RO(_name)

#define MATRIX_ATTR_WO(_name) \
	struct matrix_attribute matrix_##_name = __ATTR_WO(_name)

extern int sudoku_create_file(struct sudoku *s,
                              const struct matrix_attribute *attr)
#endif