include/linux/sysdev.h

/**
 * System devices follow a slightly different driver model. 
 * They don't need to do dynammic driver binding, can't be probed, 
 * and don't reside on any type of peripheral bus. 
 * So, we represent and treat them a little differently.
 * 
 * We still have a notion of a driver for a system device, because we still
 * want to perform basic operations on these devices. 
 *
 * We also support auxillary drivers binding to devices of a certain class.
 * 
 * This allows configurable drivers to register themselves for devices of
 * a certain type. And, it allows class definitions to reside in generic
 * code while arch-specific code can register specific drivers.
 *
 * Auxillary drivers registered with a NULL cls are registered as drivers
 * for all system devices, and get notification calls for each device. 
 */


#ifndef _SYSDEV_H_
#define _SYSDEV_H_

#include <linux/kobject.h>


struct sys_device;

struct sysdev_class {
	struct list_head	drivers;

	/* Default operations for these types of devices */
	int	(*shutdown)(struct sys_device *);
	int	(*suspend)(struct sys_device *, u32 state);
	int	(*resume)(struct sys_device *);
	struct kset		kset;
};


extern int sysdev_class_register(struct sysdev_class *);
extern void sysdev_class_unregister(struct sysdev_class *);


/**
 * Auxillary system device drivers.
 */

struct sysdev_driver {
	struct list_head	entry;
	int	(*add)(struct sys_device *);
	int	(*remove)(struct sys_device *);
	int	(*shutdown)(struct sys_device *);
	int	(*suspend)(struct sys_device *, u32 state);
	int	(*resume)(struct sys_device *);
};


extern int sysdev_driver_register(struct sysdev_class *, struct sysdev_driver *);
extern void sysdev_driver_unregister(struct sysdev_class *, struct sysdev_driver *);


/**
 * sys_devices can be simplified a lot from regular devices, because they're
 * simply not as versatile. 
 */

struct sys_device {
	u32		id;
	struct sysdev_class	* cls;
	struct kobject		kobj;
};

extern int sysdev_register(struct sys_device *);
extern void sysdev_unregister(struct sys_device *);


struct sysdev_attribute { 
	struct attribute	attr;
	ssize_t (*show)(struct sys_device *, char *);
	ssize_t (*store)(struct sys_device *, const char *, size_t);
};


#define SYSDEV_ATTR(_name,_mode,_show,_store) 		\
struct sysdev_attribute attr_##_name = { 			\
	.attr = {.name = __stringify(_name), .mode = _mode },	\
	.show	= _show,					\
	.store	= _store,					\
};

extern int sysdev_create_file(struct sys_device *, struct sysdev_attribute *);
extern void sysdev_remove_file(struct sys_device *, struct sysdev_attribute *);

#endif /* _SYSDEV_H_ */