2 files changed, 91 insertions, 47 deletions

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 3cf6eb36f3d8..c3e569730afe 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -99,7 +99,8 @@ struct class * class_get(struct class * cls)
 
 void class_put(struct class * cls)
 {
-        subsys_put(&cls->subsys);
+        if (cls)
+                subsys_put(&cls->subsys);
 }
 
 
@@ -165,14 +166,25 @@ void class_unregister(struct class * cls)
 
 static void class_create_release(struct class *cls)
 {
+        pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
         kfree(cls);
 }
 
 static void class_device_create_release(struct class_device *class_dev)
 {
+        pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
         kfree(class_dev);
 }
 
+/* needed to allow these devices to have parent class devices */
+static int class_device_create_hotplug(struct class_device *class_dev,
+                                       char **envp, int num_envp,
+                                       char *buffer, int buffer_size)
+{
+        pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
+        return 0;
+}
+
 /**
  * class_create - create a struct class structure
  * @owner: pointer to the module that is to "own" this struct class
@@ -301,10 +313,12 @@ static void class_dev_release(struct kobject * kobj)
         kfree(cd->devt_attr);
         cd->devt_attr = NULL;
 
-        if (cls->release)
+        if (cd->release)
+                cd->release(cd);
+        else if (cls->release)
                 cls->release(cd);
         else {
-                printk(KERN_ERR "Device class '%s' does not have a release() function, "
+                printk(KERN_ERR "Class Device '%s' does not have a release() function, "
                         "it is broken and must be fixed.\n",
                         cd->class_id);
                 WARN_ON(1);
@@ -382,14 +396,18 @@ static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
         buffer = &buffer[length];
         buffer_size -= length;
 
-        if (class_dev->class->hotplug) {
-                /* have the bus specific function add its stuff */
-                retval = class_dev->class->hotplug (class_dev, envp, num_envp,
-                                                    buffer, buffer_size);
-                        if (retval) {
-                        pr_debug ("%s - hotplug() returned %d\n",
-                                  __FUNCTION__, retval);
-                }
+        if (class_dev->hotplug) {
+                /* have the class device specific function add its stuff */
+                retval = class_dev->hotplug(class_dev, envp, num_envp,
+                                            buffer, buffer_size);
+                if (retval)
+                        pr_debug("class_dev->hotplug() returned %d\n", retval);
+        } else if (class_dev->class->hotplug) {
+                /* have the class specific function add its stuff */
+                retval = class_dev->class->hotplug(class_dev, envp, num_envp,
+                                                   buffer, buffer_size);
+                if (retval)
+                        pr_debug("class->hotplug() returned %d\n", retval);
         }
 
         return retval;
@@ -476,37 +494,42 @@ static char *make_class_name(struct class_device *class_dev)
 
 int class_device_add(struct class_device *class_dev)
 {
-        struct class * parent = NULL;
-        struct class_interface * class_intf;
+        struct class *parent_class = NULL;
+        struct class_device *parent_class_dev = NULL;
+        struct class_interface *class_intf;
         char *class_name = NULL;
-        int error;
+        int error = -EINVAL;
 
         class_dev = class_device_get(class_dev);
         if (!class_dev)
                 return -EINVAL;
 
-        if (!strlen(class_dev->class_id)) {
-                error = -EINVAL;
+        if (!strlen(class_dev->class_id))
                 goto register_done;
-        }
 
-        parent = class_get(class_dev->class);
+        parent_class = class_get(class_dev->class);
+        if (!parent_class)
+                goto register_done;
+        parent_class_dev = class_device_get(class_dev->parent);
 
         pr_debug("CLASS: registering class device: ID = '%s'\n",
                  class_dev->class_id);
 
         /* first, register with generic layer. */
         kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
-        if (parent)
-                class_dev->kobj.parent = &parent->subsys.kset.kobj;
+        if (parent_class_dev)
+                class_dev->kobj.parent = &parent_class_dev->kobj;
+        else
+                class_dev->kobj.parent = &parent_class->subsys.kset.kobj;
 
-        if ((error = kobject_add(&class_dev->kobj)))
+        error = kobject_add(&class_dev->kobj);
+        if (error)
                 goto register_done;
 
         /* add the needed attributes to this device */
         class_dev->uevent_attr.attr.name = "uevent";
         class_dev->uevent_attr.attr.mode = S_IWUSR;
-        class_dev->uevent_attr.attr.owner = parent->owner;
+        class_dev->uevent_attr.attr.owner = parent_class->owner;
         class_dev->uevent_attr.store = store_uevent;
         class_device_create_file(class_dev, &class_dev->uevent_attr);
 
@@ -520,7 +543,7 @@ int class_device_add(struct class_device *class_dev)
                 }
                 attr->attr.name = "dev";
                 attr->attr.mode = S_IRUGO;
-                attr->attr.owner = parent->owner;
+                attr->attr.owner = parent_class->owner;
                 attr->show = show_dev;
                 class_device_create_file(class_dev, attr);
                 class_dev->devt_attr = attr;
@@ -538,18 +561,20 @@ int class_device_add(struct class_device *class_dev)
         kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
 
         /* notify any interfaces this device is now here */
-        if (parent) {
-                down(&parent->sem);
-                list_add_tail(&class_dev->node, &parent->children);
-                list_for_each_entry(class_intf, &parent->interfaces, node)
+        if (parent_class) {
+                down(&parent_class->sem);
+                list_add_tail(&class_dev->node, &parent_class->children);
+                list_for_each_entry(class_intf, &parent_class->interfaces, node)
                         if (class_intf->add)
                                 class_intf->add(class_dev, class_intf);
-                up(&parent->sem);
+                up(&parent_class->sem);
         }
 
  register_done:
-        if (error && parent)
-                class_put(parent);
+        if (error) {
+                class_put(parent_class);
+                class_device_put(parent_class_dev);
+        }
         class_device_put(class_dev);
         kfree(class_name);
         return error;
@@ -564,21 +589,28 @@ int class_device_register(struct class_device *class_dev)
 /**
  * class_device_create - creates a class device and registers it with sysfs
  * @cs: pointer to the struct class that this device should be registered to.
+ * @parent: pointer to the parent struct class_device of this new device, if any.
  * @dev: the dev_t for the char device to be added.
  * @device: a pointer to a struct device that is assiociated with this class device.
  * @fmt: string for the class device's name
  *
  * This function can be used by char device classes.  A struct
  * class_device will be created in sysfs, registered to the specified
- * class.  A "dev" file will be created, showing the dev_t for the
- * device.  The pointer to the struct class_device will be returned from
- * the call.  Any further sysfs files that might be required can be
- * created using this pointer.
+ * class.
+ * A "dev" file will be created, showing the dev_t for the device, if
+ * the dev_t is not 0,0.
+ * If a pointer to a parent struct class_device is passed in, the newly
+ * created struct class_device will be a child of that device in sysfs.
+ * The pointer to the struct class_device will be returned from the
+ * call.  Any further sysfs files that might be required can be created
+ * using this pointer.
  *
  * Note: the struct class passed to this function must have previously
  * been created with a call to class_create().
  */
-struct class_device *class_device_create(struct class *cls, dev_t devt,
+struct class_device *class_device_create(struct class *cls,
+                                         struct class_device *parent,
+                                         dev_t devt,
                                          struct device *device, char *fmt, ...)
 {
         va_list args;
@@ -597,6 +629,9 @@ struct class_device *class_device_create(struct class *cls, dev_t devt,
         class_dev->devt = devt;
         class_dev->dev = device;
         class_dev->class = cls;
+        class_dev->parent = parent;
+        class_dev->release = class_device_create_release;
+        class_dev->hotplug = class_device_create_hotplug;
 
         va_start(args, fmt);
         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
@@ -614,17 +649,18 @@ error:
 
 void class_device_del(struct class_device *class_dev)
 {
-        struct class * parent = class_dev->class;
-        struct class_interface * class_intf;
+        struct class *parent_class = class_dev->class;
+        struct class_device *parent_device = class_dev->parent;
+        struct class_interface *class_intf;
         char *class_name = NULL;
 
-        if (parent) {
-                down(&parent->sem);
+        if (parent_class) {
+                down(&parent_class->sem);
                 list_del_init(&class_dev->node);
-                list_for_each_entry(class_intf, &parent->interfaces, node)
+                list_for_each_entry(class_intf, &parent_class->interfaces, node)
                         if (class_intf->remove)
                                 class_intf->remove(class_dev, class_intf);
-                up(&parent->sem);
+                up(&parent_class->sem);
         }
 
         if (class_dev->dev) {
@@ -640,8 +676,8 @@ void class_device_del(struct class_device *class_dev)
         kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);
         kobject_del(&class_dev->kobj);
 
-        if (parent)
-                class_put(parent);
+        class_device_put(parent_device);
+        class_put(parent_class);
         kfree(class_name);
 }
 
@@ -721,7 +757,8 @@ struct class_device * class_device_get(struct class_device *class_dev)
 
 void class_device_put(struct class_device *class_dev)
 {
-        kobject_put(&class_dev->kobj);
+        if (class_dev)
+                kobject_put(&class_dev->kobj);
 }
 
 
diff --git a/include/linux/device.h b/include/linux/device.h
index e86a580b72e1..226e550ae2ea 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -213,7 +213,11 @@ struct class_device {
         struct class_device_attribute uevent_attr;
         struct device           * dev;          /* not necessary, but nice to have */
         void                    * class_data;   /* class-specific data */
+        struct class_device     *parent;        /* parent of this child device, if there is one */
 
+        void    (*release)(struct class_device *dev);
+        int     (*hotplug)(struct class_device *dev, char **envp,
+                           int num_envp, char *buffer, int buffer_size);
         char    class_id[BUS_ID_SIZE];  /* unique to this class */
 };
 
@@ -261,9 +265,12 @@ extern void class_interface_unregister(struct class_interface *);
 
 extern struct class *class_create(struct module *owner, char *name);
 extern void class_destroy(struct class *cls);
-extern struct class_device *class_device_create(struct class *cls, dev_t devt,
-                                                struct device *device, char *fmt, ...)
-                                        __attribute__((format(printf,4,5)));
+extern struct class_device *class_device_create(struct class *cls,
+                                                struct class_device *parent,
+                                                dev_t devt,
+                                                struct device *device,
+                                                char *fmt, ...)
+                                        __attribute__((format(printf,5,6)));
 extern void class_device_destroy(struct class *cls, dev_t devt);