Linux Kernel设备驱动模型之 总线注册

设备驱动模型之总线注册

/**
 * bus_register - register a driver-core subsystem
 * @bus: bus to register
 *
 * Once we have that, we register the bus with the kobject
 * infrastructure, then register the children subsystems it has:
 * the devices and drivers that belong to the subsystem.
 */
int bus_register(struct bus_type *bus)
{
 int retval;
 struct subsys_private *priv;
 struct lock_class_key *key = &bus->lock_key;
 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
 if (!priv)
  return -ENOMEM;
 priv->bus = bus;
 bus->p = priv;
 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
 if (retval)
  goto out;
 priv->subsys.kobj.kset = bus_kset;
 priv->subsys.kobj.ktype = &bus_ktype;
 priv->drivers_autoprobe = 1;
 retval = kset_register(&priv->subsys);
 if (retval)
  goto out;
 retval = bus_create_file(bus, &bus_attr_uevent);
 if (retval)
  goto bus_uevent_fail;
 priv->devices_kset = kset_create_and_add("devices", NULL,
       &priv->subsys.kobj);
 if (!priv->devices_kset) {
  retval = -ENOMEM;
  goto bus_devices_fail;
 }
 priv->drivers_kset = kset_create_and_add("drivers", NULL,
       &priv->subsys.kobj);
 if (!priv->drivers_kset) {
  retval = -ENOMEM;
  goto bus_drivers_fail;
 }
 INIT_LIST_HEAD(&priv->interfaces);
 __mutex_init(&priv->mutex, "subsys mutex", key);
 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
 klist_init(&priv->klist_drivers, NULL, NULL);
 retval = add_probe_files(bus);
 if (retval)
  goto bus_probe_files_fail;
 retval = bus_add_groups(bus, bus->bus_groups);
 if (retval)
  goto bus_groups_fail;
 pr_debug("bus: '%s': registered\n", bus->name);
 return 0;
bus_groups_fail:
 remove_probe_files(bus);
bus_probe_files_fail:
 kset_unregister(bus->p->drivers_kset);
bus_drivers_fail:
 kset_unregister(bus->p->devices_kset);
bus_devices_fail:
 bus_remove_file(bus, &bus_attr_uevent);
bus_uevent_fail:
 kset_unregister(&bus->p->subsys);
out:
 kfree(bus->p);
 bus->p = NULL;
 return retval;
}