linux驱动入门

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>

#define DEVICE_NAME "my_char_device"
#define MAJOR_NUM 240

static int device_open(struct inode *inode, struct file *file) {
    printk(KERN_INFO "Device opened
");
    return 0;
}

static int device_release(struct inode *inode, struct file *file) {
    printk(KERN_INFO "Device released
");
    return 0;
}

static struct file_operations fops = {
   .open = device_open,
   .release = device_release,
};

static int __init my_driver_init(void) {
    int ret;
    ret = register_chrdev(MAJOR_NUM, DEVICE_NAME, &fops);
    if (ret < 0) {
        printk(KERN_ALERT "Failed to register device, error code: %d
", ret);
        return ret;
    }
    printk(KERN_INFO "Driver registered successfully
");
    return 0;
}

static void __exit my_driver_exit(void) {
    unregister_chrdev(MAJOR_NUM, DEVICE_NAME);
    printk(KERN_INFO "Driver unregistered successfully
");
}

module_init(my_driver_init);
module_exit(my_driver_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("A simple character device driver");