tty_class = class_simple_create(THIS_MODULE, "tty");
tty_class = class_create(THIS_MODULE, "tty");
static int __init tty_class_init(void){	tty_class = class_simple_create(THIS_MODULE, "tty");	if (IS_ERR(tty_class))		return PTR_ERR(tty_class);	return 0;}