linux驱动详解

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

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

static int major_number;
static struct class* my_class = NULL;
static struct device* my_device = NULL;

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) {
    major_number = register_chrdev(0, DEVICE_NAME, &fops);
    if (major_number < 0) {
        printk(KERN_ALERT "Failed to register a major number
");
        return major_number;
    }
    my_class = class_create(THIS_MODULE, CLASS_NAME);
    if (IS_ERR(my_class)) {
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to register device class
");
        return PTR_ERR(my_class);
    }
    my_device = device_create(my_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
    if (IS_ERR(my_device)) {
        class_destroy(my_class);
        unregister_chrdev(major_number, DEVICE_NAME);
        printk(KERN_ALERT "Failed to create the device
");
        return PTR_ERR(my_device);
    }
    printk(KERN_INFO "Driver loaded successfully
");
    return 0;
}

static void __exit my_driver_exit(void) {
    device_destroy(my_class, MKDEV(major_number, 0));
    class_unregister(my_class);
    class_destroy(my_class);
    unregister_chrdev(major_number, DEVICE_NAME);
    printk(KERN_INFO "Driver unloaded 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");