不需要手工mknod的例子

 

Makefile

obj-m += mymodule.o

all:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

mymodule.c

#include 
#include 
#include 
#include 
#include 
#include 

struct class *mymodule_class;
EXPORT_SYMBOL(mymodule_class);

MODULE_DESCRIPTION("mymodule module");
MODULE_AUTHOR("Chris Malley");
MODULE_LICENSE("GPL");

#define MYMODULE_MAJOR    248

static const struct file_operations mymodule_fops = {
	.owner = THIS_MODULE,
};

static void __exit cleanup_mymodule(void)
{
	device_destroy(mymodule_class, MKDEV(MYMODULE_MAJOR, 0)); 
        class_destroy(mymodule_class);
	unregister_chrdev(MYMODULE_MAJOR, "mymodule");
}

static int __init init_mymodule(void)
{
	int err = 0;

	if (register_chrdev(MYMODULE_MAJOR, "mymodule", &mymodule_fops)) {
		printk(KERN_ERR "mymodule: unable to get major %d\n", MYMODULE_MAJOR);
		err = -EIO;
		goto out;
	}

        mymodule_class = class_create(THIS_MODULE, "mymodule");
        if (IS_ERR(mymodule_class)) {
                err = PTR_ERR(mymodule_class);
		goto out_chrdev;
	}

	device_create(mymodule_class, NULL, MKDEV(MYMODULE_MAJOR, 0), "mymod0"); 

	err = 0;
	goto out;

out_chrdev:
	unregister_chrdev(MYMODULE_MAJOR, "mymodule");
out:
        return err;
}

module_init(init_mymodule);
module_exit(cleanup_mymodule);