diff options
| -rw-r--r-- | drivers/base/class.c | 87 | ||||
| -rw-r--r-- | include/linux/device.h | 8 |
2 files changed, 95 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); diff --git a/include/linux/device.h b/include/linux/device.h index e19e40a3dcbe..62ff53a67931 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -225,6 +225,14 @@ extern void class_unregister(struct class *class); __class_register(class, &__key); \ }) +struct class_compat; +struct class_compat *class_compat_register(const char *name); +void class_compat_unregister(struct class_compat *cls); +int class_compat_create_link(struct class_compat *cls, struct device *dev, + struct device *device_link); +void class_compat_remove_link(struct class_compat *cls, struct device *dev, + struct device *device_link); + extern void class_dev_iter_init(struct class_dev_iter *iter, struct class *class, struct device *start, |