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-rw-r--r--drivers/base/class.c87
1 files changed, 87 insertions, 0 deletions
diff --git a/drivers/base/class.c b/drivers/base/class.c
index eb85e4312301..161746deab4b 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -488,6 +488,93 @@ void class_interface_unregister(struct class_interface *class_intf)
class_put(parent);
}
+struct class_compat {
+ struct kobject *kobj;
+};
+
+/**
+ * class_compat_register - register a compatibility class
+ * @name: the name of the class
+ *
+ * Compatibility class are meant as a temporary user-space compatibility
+ * workaround when converting a family of class devices to a bus devices.
+ */
+struct class_compat *class_compat_register(const char *name)
+{
+ struct class_compat *cls;
+
+ cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
+ if (!cls)
+ return NULL;
+ cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
+ if (!cls->kobj) {
+ kfree(cls);
+ return NULL;
+ }
+ return cls;
+}
+EXPORT_SYMBOL_GPL(class_compat_register);
+
+/**
+ * class_compat_unregister - unregister a compatibility class
+ * @cls: the class to unregister
+ */
+void class_compat_unregister(struct class_compat *cls)
+{
+ kobject_put(cls->kobj);
+ kfree(cls);
+}
+EXPORT_SYMBOL_GPL(class_compat_unregister);
+
+/**
+ * class_compat_create_link - create a compatibility class device link to
+ * a bus device
+ * @cls: the compatibility class
+ * @dev: the target bus device
+ * @device_link: an optional device to which a "device" link should be created
+ */
+int class_compat_create_link(struct class_compat *cls, struct device *dev,
+ struct device *device_link)
+{
+ int error;
+
+ error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
+ if (error)
+ return error;
+
+ /*
+ * Optionally add a "device" link (typically to the parent), as a
+ * class device would have one and we want to provide as much
+ * backwards compatibility as possible.
+ */
+ if (device_link) {
+ error = sysfs_create_link(&dev->kobj, &device_link->kobj,
+ "device");
+ if (error)
+ sysfs_remove_link(cls->kobj, dev_name(dev));
+ }
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(class_compat_create_link);
+
+/**
+ * class_compat_remove_link - remove a compatibility class device link to
+ * a bus device
+ * @cls: the compatibility class
+ * @dev: the target bus device
+ * @device_link: an optional device to which a "device" link was previously
+ * created
+ */
+void class_compat_remove_link(struct class_compat *cls, struct device *dev,
+ struct device *device_link)
+{
+ if (device_link)
+ sysfs_remove_link(&dev->kobj, "device");
+ sysfs_remove_link(cls->kobj, dev_name(dev));
+}
+EXPORT_SYMBOL_GPL(class_compat_remove_link);
+
int __init classes_init(void)
{
class_kset = kset_create_and_add("class", NULL, NULL);