linux设备驱动模型代码分析

struct i2c_client *i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
	struct i2c_client	*client;
	client->adapter = adap;

	client->dev.platform_data = info->platform_data;
	
	client->dev.parent = &client->adapter->dev;
	client->dev.bus = &i2c_bus_type;
	client->dev.type = &i2c_client_type;
	
	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), client->addr);
	status = device_register(&client->dev);
	=>int device_register(struct device *dev)
		device_initialize(dev);
		=>void device_initialize(struct device *dev)
			dev->kobj.kset = devices_kset;
			kobject_init(&dev->kobj, &device_ktype);
		
		return device_add(dev);
		=>int device_add(struct device *dev)
			parent = get_device(dev->parent);
			setup_parent(dev, parent);
			
			error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
			
			error = device_create_file(dev, &uevent_attr);
			
			if (MAJOR(dev->devt))
				error = device_create_file(dev, &devt_attr);
				
				error = device_create_sys_dev_entry(dev);
				=>int device_create_sys_dev_entry(struct device *dev)
					struct kobject *kobj = device_to_dev_kobj(dev);
					if (kobj) 
						format_dev_t(devt_str, dev->devt);
						error = sysfs_create_link(kobj, &dev->kobj, devt_str);
						
			error = device_add_class_symlinks(dev);
			=>int device_add_class_symlinks(struct device *dev)
				error = sysfs_create_link(&dev->kobj, &dev->class->p->class_subsys.kobj, "subsystem");
				//举例，实设备下定义subsystem反指虚设备
					/sys/devices/e f000 0000.soc/f f011 9100.i2c/i2c-3/3-0055/rtc/rtc0 ]# ls -l
					subsystem->../../../../../../../class/rtc
					
				error = sysfs_create_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev));			
				error = sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
				//举例，
					/sys/class/rtc ]# ls -l
					rtc0->../../devices/e f000 0000.soc/f f011 9100.i2c/i2c-3/3-0055/rtc/rtc0
					device->../../../3-0055
				
			error = device_add_attrs(dev);
			
			error = bus_add_device(dev);
			=>int bus_add_device(struct device *dev)
				struct bus_type *bus = bus_get(dev->bus);
				if (bus)
					error = device_add_attrs(bus, dev);
					
					error = sysfs_create_link(&bus->p->devices_kset->kobj, &dev->kobj, dev_name(dev));
					//举例，bus是虚设备，所以链接指向实际设备
						/sys/bus/i2c/devices ]# ls -l
						3-0055->../../../devices/e f000 0000.soc/f f011 9100.i2c/i2c-3/3-0055
										
					error = sysfs_create_link(&dev->kobj, &dev->bus->p->subsys.kobj, "subsystem");
					//举例，实设备下定义subsystem反指虚设备
						/sys/devices/e f000 0000.soc/f f011 9100.i2c/i2c-3/3-0055 ]# ls -l
						subsystem->../../../../../bus/i2c
					
					klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
					
				if (dev->bus)
					blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_ADD_DEVICE, dev);
					
				kobject_uevent(&dev->kobj, KOBJ_ADD);
				
				bus_probe_device(dev);
				
				if (parent)
					klist_add_tail(&dev->p->knode_parent, &parent->p->klist_children);
					
				if (dev->class)
					klist_add_tail(&dev->knode_class, &dev->class->p->class_devices);
					
					list_for_each_entry(class_intf, &dev->class->p->class_interfaces, node)
					
					if (class_intf->add_dev)
						class_intf->add_dev(dev, class_intf);

参考文章
五、2sysfs API总结   博客好好学习一下
https://blog.youkuaiyun.com/qq_20678703/article/details/52670871

六 设备驱动模型-总线
https://blog.youkuaiyun.com/qq_20678703/article/details/52688958