3.4_class_create和device_create

1、驱动和其他的数据传输

驱动和应用联系：通过两个函数“copy_to_user”和“copy_from_user”

驱动和硬件联系：虚拟地址等

2、驱动程序辅助信息（自动创建类和节点）

major = register_chrdev(0, "hello_drv", &hello_fops);

class_for_hello = class_create(THIS_MODULE, "hello_class"); /* /sys/class/hello_class/ */

device_create(class_for_hello, NULL, MKDEV(major, 0), NULL, "myhello");

device_destroy(class_for_hello, MKDEV(major, 0)); /* /dev/myhello */

class_destroy(class_for_hello);

unregister_chrdev(major, "hello_drv");