bus_add_driver() -- 将驱动添加到总线上

driver_register() --> bus_add_driver()

/usr/src/linux-2.6.21.5/drivers/base/bus.c
bus_add_driver - Add a driver to the bus.
bus_add_driver() -- 将驱动添加到总线上，并与总线上的设备匹配

int bus_add_driver(struct device_driver *drv)
{
查找与驱动程序相关的总线
|-------------------------------------------------|
|   struct bus_type * bus = get_bus(drv->bus);    |
|-------------------------------------------------|
    int error = 0;
    if (!bus)
        return 0;

根据驱动程序的名字以及相关的总线，创建驱动程序的sysfs目录
|--------------------------------------------------------------|
|   pr_debug("bus %s: add driver %s\n", bus->name, drv->name); |
|   error = kobject_set_name(&drv->kobj, "%s", drv->name);     |
|   if (error)                                                 |
|       goto out_put_bus;                                      |
|   drv->kobj.kset = &bus->drivers;                            |
|   if ((error = kobject_register(&drv->kobj)))                |
|       goto out_put_bus;                                      |
|--------------------------------------------------------------|

遍历总线上的所有设备，搜寻与驱动匹配的设备
|----------------------------------|
|   error = driver_attach(drv);    |
|   if (error)                     |
|       goto out_unregister;       |
|----------------------------------|

    klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
    module_add_driver(drv->owner, drv);

|-------------------------------------------------------------|
|   error = driver_add_attrs(bus, drv);                       |
|   if (error) {                                              |
|       printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n", -|
|           __FUNCTION__, drv->name);                         |
|   }                                                         |
|   error = add_bind_files(drv);                              |
|   if (error) {                                              |
|       printk(KERN_ERR "%s: add_bind_files(%s) failed\n",    |
|           __FUNCTION__, drv->name);                         |
|   }                                                         |
|-------------------------------------------------------------|

    return error;
out_unregister:
    kobject_unregister(&drv->kobj);
out_put_bus:
    put_bus(bus);
    return error;
}