[driver model] Create include/linux/sysdev.h and define sysdev_attribute.

Split out all system device definitions from device.h into their own header
sysdev.h

Define struct sysdev_attribute and define functions to export attributes 
in sysfs. 

drivers/base/sys.c

@@ -14,7 +14,7 @@
 
 #define DEBUG
 
-#include <linux/device.h>
+#include <linux/sysdev.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -25,10 +25,47 @@
 
 extern struct subsystem devices_subsys;
 
+#define to_sysdev(k) container_of(k,struct sys_device,kobj)
+#define to_sysdev_attr(a) container_of(a,struct sysdev_attribute,attr)
+
+
+static ssize_t 
+sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
+{
+	struct sys_device * sysdev = to_sysdev(kobj);
+	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
+
+	if (sysdev_attr->show)
+		return sysdev_attr->show(sysdev,buffer);
+	return 0;
+}
+
+
+static ssize_t
+sysdev_store(struct kobject * kobj, struct attribute * attr, 
+	     const char * buffer, size_t count)
+{
+	struct sys_device * sysdev = to_sysdev(kobj);
+	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
+
+	if (sysdev_attr->store)
+		return sysdev_attr->store(sysdev,buffer,count);
+	return 0;
+}
+
+static struct sysfs_ops sysfs_ops = {
+	.show	= sysdev_show,
+	.store	= sysdev_store,
+};
+
+static struct kobj_type ktype_sysdev = {
+	.sysfs_ops	= &sysfs_ops,
+};
+
 /* 
  * declare system_subsys 
  */
-decl_subsys(system,NULL,NULL);
+decl_subsys(system,&ktype_sysdev,NULL);
 
 int sysdev_class_register(struct sysdev_class * cls)
 {

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 sys_device_register(struct sys_device *);
+extern void sys_device_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_ */