linux 驱动编译成模块

// chardev_example.c
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/uaccess.h>

#define DEVICE_NAME "chardev_example"
#define CLASS_NAME "chardev_example_class"

static int major_number;
static struct class *chardev_class;
static struct device *chardev_device;

static int chardev_open(struct inode *inode, struct file *file) {
    printk(KERN_INFO "Chardev opened\n");
    return 0;
}

static int chardev_release(struct inode *inode, struct file *file) {
    printk(KERN_INFO "Chardev released\n");
    return 0;
}

static ssize_t chardev_read(struct file *file, char __user *buffer, size_t length, loff_t *offset) {
    printk(KERN_INFO "Chardev read\n");
    return 0;
}

static ssize_t chardev_write(struct file *file, const char __user *buffer, size_t length, loff_t *offset) {
    printk(KERN_INFO "Chardev write\n");
    return length;
}

static struct file_operations fops = {
    .open = chardev_open,
    .release = chardev_release,
    .read = chardev_read,
    .write = chardev_write,
};

static int __init chardev_init(void) {
    major_number = register_chrdev(0, DEVICE_NAME, &fops);
    if (major_number < 0) {
        printk(KERN_ALERT "Chardev registration failed\n");
        return major_number;
    }

    chardev_class = class_create(THIS_MODULE, CLASS_NAME);
    if (IS_ERR(chardev_class)) {
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Chardev class creation failed\n");
        return PTR_ERR(chardev_class);
    }

    chardev_device = device_create(chardev_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
    if (IS_ERR(chardev_device)) {
        class_destroy(chardev_class);
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Chardev device creation failed\n");
        return PTR_ERR(chardev_device);
    }

    printk(KERN_INFO "Chardev registered successfully\n");
    return 0;
}

static void __exit chardev_exit(void) {
    device_destroy(chardev_class, MKDEV(major_number, 0));
    class_unregister(chardev_class);
    class_destroy(chardev_class);
    unregister_chrdev(major_number, DEVICE_NAME);
    printk(KERN_INFO "Chardev unregistered successfully\n");
}

module_init(chardev_init);
module_exit(chardev_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("A simple character device driver example");
MODULE_VERSION("0.1");

obj-m += chardev_example.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