driver model: convert devices to use kobjects and sysfs.

- Define a device subsystem and register it on startup. 
- Fill it in with fields converted from driverfs-style fields.
- Convert device_{create,remove}_file() to create files in sysfs. 
- Add default device attributes to device subsystem.
- Make sure devices get proper kobject familial pointers and that the kobjects
  are registered. 
 

drivers/base/core.c

@@ -23,7 +23,76 @@ DECLARE_MUTEX(device_sem);
 
 spinlock_t device_lock = SPIN_LOCK_UNLOCKED;
 
-#define to_dev(node) container_of(node,struct device,driver_list)
+struct subsystem device_subsys;
+
+#define to_dev(obj) container_of(obj,struct device,kobj)
+
+
+/*
+ * sysfs bindings for devices.
+ */
+
+#define to_dev_attr(_attr) container_of(_attr,struct device_attribute,attr)
+
+extern struct attribute * dev_default_attrs[];
+
+static ssize_t
+dev_attr_show(struct kobject * kobj, struct attribute * attr,
+	      char * buf, size_t count, loff_t off)
+{
+	struct device_attribute * dev_attr = to_dev_attr(attr);
+	struct device * dev = to_dev(kobj);
+	ssize_t ret = 0;
+
+	if (dev_attr->show)
+		ret = dev_attr->show(dev,buf,count,off);
+	return ret;
+}
+
+static ssize_t
+dev_attr_store(struct kobject * kobj, struct attribute * attr,
+	       const char * buf, size_t count, loff_t off)
+{
+	struct device_attribute * dev_attr = to_dev_attr(attr);
+	struct device * dev = to_dev(kobj);
+	ssize_t ret = 0;
+
+	if (dev_attr->store)
+		ret = dev_attr->store(dev,buf,count,off);
+	return ret;
+}
+
+static struct sysfs_ops dev_sysfs_ops = {
+	.show	= dev_attr_show,
+	.store	= dev_attr_store,
+};
+
+struct subsystem device_subsys = {
+	.kobj		= {
+		.name	= "devices",
+	},
+	.sysfs_ops	= &dev_sysfs_ops,
+	.default_attrs	= dev_default_attrs,
+};
+
+
+int device_create_file(struct device * dev, struct device_attribute * attr)
+{
+	int error = 0;
+	if (get_device(dev)) {
+		error = sysfs_create_file(&dev->kobj,&attr->attr);
+		put_device(dev);
+	}
+	return error;
+}
+
+void device_remove_file(struct device * dev, struct device_attribute * attr)
+{
+	if (get_device(dev)) {
+		sysfs_remove_file(&dev->kobj,&attr->attr);
+		put_device(dev);
+	}
+}
 
 int device_add(struct device *dev)
 {
@@ -44,6 +113,12 @@ int device_add(struct device *dev)
 	pr_debug("DEV: registering device: ID = '%s', name = %s\n",
 		 dev->bus_id, dev->name);
 
+	strncpy(dev->kobj.name,dev->bus_id,KOBJ_NAME_LEN);
+	if (dev->parent)
+		dev->kobj.parent = &dev->parent->kobj;
+	dev->kobj.subsys = &device_subsys;
+	kobject_register(&dev->kobj);
+
 	if ((error = device_make_dir(dev)))
 		goto register_done;
 
@@ -69,6 +144,7 @@ int device_add(struct device *dev)
 
 void device_initialize(struct device *dev)
 {
+	kobject_init(&dev->kobj);
 	INIT_LIST_HEAD(&dev->node);
 	INIT_LIST_HEAD(&dev->children);
 	INIT_LIST_HEAD(&dev->g_list);
@@ -184,9 +260,17 @@ void device_unregister(struct device * dev)
 
 	pr_debug("DEV: Unregistering device. ID = '%s', name = '%s'\n",
 		 dev->bus_id,dev->name);
+	kobject_unregister(&dev->kobj);
 	put_device(dev);
 }
 
+static int __init device_subsys_init(void)
+{
+	return subsystem_register(&device_subsys);
+}
+
+core_initcall(device_subsys_init);
+
 EXPORT_SYMBOL(device_register);
 EXPORT_SYMBOL(device_unregister);
 EXPORT_SYMBOL(get_device);

drivers/base/fs/device.c

@@ -21,97 +21,6 @@ static struct driver_dir_entry device_root_dir = {
 	.mode	= (S_IRWXU | S_IRUGO | S_IXUGO),
 };
 
-extern struct device_attribute * device_default_files[];
-
-#define to_dev_attr(_attr) container_of(_attr,struct device_attribute,attr)
-
-#define to_device(d) container_of(d, struct device, dir)
-
-
-/* driverfs ops for device attribute files */
-
-static int
-dev_attr_open(struct driver_dir_entry * dir)
-{
-	struct device * dev = to_device(dir);
-	get_device(dev);
-	return 0;
-}
-
-static int
-dev_attr_close(struct driver_dir_entry * dir)
-{
-	struct device * dev = to_device(dir);
-	put_device(dev);
-	return 0;
-}
-
-static ssize_t
-dev_attr_show(struct driver_dir_entry * dir, struct attribute * attr,
-	      char * buf, size_t count, loff_t off)
-{
-	struct device_attribute * dev_attr = to_dev_attr(attr);
-	struct device * dev = to_device(dir);
-	ssize_t ret = 0;
-
-	if (dev_attr->show)
-		ret = dev_attr->show(dev,buf,count,off);
-	return ret;
-}
-
-static ssize_t
-dev_attr_store(struct driver_dir_entry * dir, struct attribute * attr,
-	       const char * buf, size_t count, loff_t off)
-{
-	struct device_attribute * dev_attr = to_dev_attr(attr);
-	struct device * dev = to_device(dir);
-	ssize_t ret = 0;
-
-	if (dev_attr->store)
-		ret = dev_attr->store(dev,buf,count,off);
-	return ret;
-}
-
-static struct driverfs_ops dev_attr_ops = {
-	.open	= dev_attr_open,
-	.close	= dev_attr_close,
-	.show	= dev_attr_show,
-	.store	= dev_attr_store,
-};
-
-/**
- * device_create_file - create a driverfs file for a device
- * @dev:	device requesting file
- * @entry:	entry describing file
- *
- * Allocate space for file entry, copy descriptor, and create.
- */
-int device_create_file(struct device * dev, struct device_attribute * entry)
-{
-	int error = -EINVAL;
-
-	if (get_device(dev)) {
-		error = driverfs_create_file(&entry->attr,&dev->dir);
-		put_device(dev);
-	}
-	return error;
-}
-
-/**
- * device_remove_file - remove a device's file by name
- * @dev:	device requesting removal
- * @name:	name of the file
- *
- */
-void device_remove_file(struct device * dev, struct device_attribute * attr)
-{
-	if (dev) {
-		get_device(dev);
-		driverfs_remove_file(&dev->dir,attr->attr.name);
-		put_device(dev);
-	}
-}
-
 /**
  * device_remove_dir - remove a device's directory
  * @dev:	device in question
@@ -213,24 +122,12 @@ int device_create_dir(struct driver_dir_entry * dir, struct driver_dir_entry * p
 int device_make_dir(struct device * dev)
 {
 	struct driver_dir_entry * parent;
-	struct device_attribute * entry;
 	int error;
-	int i;
 
 	parent = dev->parent ? &dev->parent->dir : &device_root_dir;
 	dev->dir.name = dev->bus_id;
-	dev->dir.ops = &dev_attr_ops;
 
-	if ((error = device_create_dir(&dev->dir,parent)))
-		return error;
-
-	for (i = 0; (entry = *(device_default_files + i)); i++) {
-		if ((error = device_create_file(dev,entry))) {
-			device_remove_dir(dev);
-			break;
-		}
-	}
-	return error;
+	return device_create_dir(&dev->dir,parent);
 }
 
 static int device_driverfs_init(void)

drivers/base/interface.c

@@ -88,8 +88,8 @@ device_write_power(struct device * dev, const char * buf, size_t count, loff_t o
 static DEVICE_ATTR(power,S_IWUSR | S_IRUGO,
 		   device_read_power,device_write_power);
 
-struct device_attribute * device_default_files[] = {
-	&dev_attr_name,
-	&dev_attr_power,
+struct attribute * dev_default_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_power.attr,
 	NULL,
 };

include/linux/device.h

@@ -29,6 +29,7 @@
 #include <linux/list.h>
 #include <linux/sched.h>
 #include <linux/driverfs_fs.h>
+#include <linux/kobject.h>
 
 #define DEVICE_NAME_SIZE	80
 #define DEVICE_ID_SIZE		32
@@ -275,6 +276,7 @@ struct device {
 	struct list_head intf_list;
 	struct device 	* parent;
 
+	struct kobject kobj;
 	char	name[DEVICE_NAME_SIZE];	/* descriptive ascii string */
 	char	bus_id[BUS_ID_SIZE];	/* position on parent bus */
 

include/linux/driverfs_fs.h

@@ -26,6 +26,8 @@
 #ifndef _DRIVER_FS_H_
 #define _DRIVER_FS_H_
 
+#include <linux/sysfs.h>
+
 struct driver_dir_entry;
 struct attribute;
 
@@ -43,11 +45,6 @@ struct driver_dir_entry {
 	struct driverfs_ops	* ops;
 };
 
-struct attribute {
-	char			* name;
-	mode_t			mode;
-};
-
 extern int
 driverfs_create_dir(struct driver_dir_entry *, struct driver_dir_entry *);
 

include/linux/kobject.h

@@ -12,8 +12,10 @@
 #include <linux/rwsem.h>
 #include <asm/atomic.h>
 
+#define KOBJ_NAME_LEN	16
+
 struct kobject {
-	char			name[16];
+	char			name[KOBJ_NAME_LEN];
 	atomic_t		refcount;
 	struct list_head	entry;
 	struct kobject		* parent;

include/linux/sysfs.h

@@ -9,20 +9,18 @@
 #ifndef _SYSFS_H_
 #define _SYSFS_H_
 
-struct driver_dir_entry;
-struct attribute;
 struct kobject;
 
-struct sysfs_ops {
-	ssize_t	(*show)(struct kobject *, struct attribute *,char *, size_t, loff_t);
-	ssize_t	(*store)(struct kobject *,struct attribute *,const char *, size_t, loff_t);
-};
-
 struct attribute {
 	char			* name;
 	mode_t			mode;
 };
 
+struct sysfs_ops {
+	ssize_t	(*show)(struct kobject *, struct attribute *,char *, size_t, loff_t);
+	ssize_t	(*store)(struct kobject *,struct attribute *,const char *, size_t, loff_t);
+};
+
 extern int
 sysfs_create_dir(struct kobject *);