写一个字符设备的驱动模板

好的，以下是一个简单的字符设备驱动模板，可以作为参考：

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

MODULE_LICENSE("GPL");

#define DEVICE_NAME "mydevice"
#define CLASS_NAME "myclass"

static int major_number;
static struct class* device_class = NULL;
static struct device* device = NULL;

static int device_open(struct inode* inode, struct file* filp)
{
    // 打开设备的处理逻辑
    return 0;
}

static int device_release(struct inode* inode, struct file* filp)
{
    // 关闭设备的处理逻辑
    return 0;
}

static ssize_t device_read(struct file* filp, char* buffer, size_t length, loff_t* offset)
{
    // 读取设备数据的处理逻辑
    return 0;
}

static ssize_t device_write(struct file* filp, const char* buffer, size_t length, loff_t* offset)
{
    // 写入设备数据的处理逻辑
    return length;
}

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

static int __init mydevice_init(void)
{
    // 注册字符设备驱动
    major_number = register_chrdev(0, DEVICE_NAME, &fops);
    if (major_number < 0) {
        printk(KERN_ALERT "Failed to register a major number\n");
        return major_number;
    }
    
    // 创建设备类
    device_class = class_create(THIS_MODULE, CLASS_NAME);
    if (IS_ERR(device_class)) {
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to register device class\n");
        return PTR_ERR(device_class);
    }
    
    // 创建设备节点
    device = device_create(device_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
    if (IS_ERR(device)) {
        class_destroy(device_class);
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to create device\n");
        return PTR_ERR(device);
    }
    
    printk(KERN_INFO "Device driver loaded successfully\n");
    return 0;
}

static void __exit mydevice_exit(void)
{
    // 注销设备节点
    device_destroy(device_class, MKDEV(major_number, 0));
    
    // 注销设备类
    class_unregister(device_class);
    class_destroy(device_class);
    
    // 注销字符设备驱动
    unregister_chrdev(major_number, DEVICE_NAME);
    
    printk(KERN_INFO "Device driver unloaded successfully\n");
}

module_init(mydevice_init);
module_exit(mydevice_exit);

这是一个简单的字符设备驱动模板，包含了设备的打开、关闭、读取和写入等操作，以及设备节点的创建和注销逻辑。你可以根据自己的需求修改和扩展这个模板。