linux 编写字符驱动

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

#define DEVICE_NAME "my_char_device"
#define CLASS_NAME "my_char_class"

static int major_number;
static struct class* my_char_class;
static struct device* my_char_device;

static int device_open(struct inode* inode, struct file* file) {
    // 设备打开时的操作
    return 0;
}

static int device_release(struct inode* inode, struct file* file) {
    // 设备关闭时的操作
    return 0;
}

static ssize_t device_read(struct file* file, char* buffer, size_t length, loff_t* offset) {
    // 读取设备数据的操作
    return 0;
}

static ssize_t device_write(struct file* file, const char* buffer, size_t length, loff_t* offset) {
    // 写入设备数据的操作
    return 0;
}

static struct file_operations fops = {
    .open = device_open,
    .release = device_release,
    .read = device_read,
    .write = device_write,
};

static int __init my_char_driver_init(void) {
    major_number = register_chrdev(0, DEVICE_NAME, &fops);
    if (major_number < 0) {
        printk(KERN_ALERT "Failed to register device\n");
        return major_number;
    }
    my_char_class = class_create(THIS_MODULE, CLASS_NAME);
    if (IS_ERR(my_char_class)) {
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to create device class\n");
        return PTR_ERR(my_char_class);
    }
    my_char_device = device_create(my_char_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
    if (IS_ERR(my_char_device)) {
        class_destroy(my_char_class);
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to create device\n");
        return PTR_ERR(my_char_device);
    }
    printk(KERN_INFO "Character driver initialized\n");
    return 0;
}

static void __exit my_char_driver_exit(void) {
    device_destroy(my_char_class, MKDEV(major_number, 0));
    class_destroy(my_char_class);
    unregister_chrdev(major_number, DEVICE_NAME);
    printk(KERN_INFO "Character driver exited\n");
}

module_init(my_char_driver_init);
module_exit(my_char_driver_exit);

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