Linux下的第一个驱动程序

makefile文件：

 KERN_DIR = /home/youshan/linux-2.6.32.2

 all:
         make -C $(KERN_DIR) M=`pwd` modules

 clean:
         make -C $(KERN_DIR) M=`pwd` modules clean
         rm -rf modules.order

 obj-m   += first_drv.o

驱动程序：

 /*************************************************
 * File name   : first_drv.c(可当做模板使用)
 * Description : 参考韦东山视频，改写了部分代码
 * Author      : [email protected]
 * Version     : V1.0
 * Date        :
 * Compiler    : arm-linux-gcc-4.4.3
 * Target      : mini2440(Linux-2.6.32)
 * History     :
 *   <author>  <time>   <version >   <desc>
 *************************************************/
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/fs.h>
 #include <linux/errno.h>
 #include <linux/mm.h>
 #include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/cdev.h>
 #include <asm/io.h>
 #include <asm/system.h>
 #include <asm/uaccess.h>
 #include <linux/device.h>       /* device_create() */

 static struct class *firstdrv_class;
 static struct class_device *firstdrv_class_dev;
 static int major;

 static int first_drv_open(struct inode *inode, struct file *file)
 {
     printk("First_drv_open\n");
     return 0;
 }

 static ssize_t first_drv_read(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
 {
     printk("First_drv_read\n");
     return 0;
 }

 static ssize_t first_drv_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
 {
     printk("First_drv_write\n");
     return 0;
 }

 static int first_drv_release(struct inode *inode, struct file *file)
 {
     printk("First_drv_release\n");
     return 0;
 }

 static struct file_operations first_drv_fops = {
     .owner = THIS_MODULE,
     .open = first_drv_open,
     .read = first_drv_read,
     .write = first_drv_write,
     .release = first_drv_release,
 };

 static int __init first_drv_init(void)
 {
     /* cat /proc/devices  */
     major = register_chrdev(0, "first_drv_proc", &first_drv_fops);

     /* ls /sys/class/first_drv */
     firstdrv_class = class_create(THIS_MODULE, "first_drv_sys");
     if (IS_ERR(firstdrv_class))
         return PTR_ERR(firstdrv_class);

     /* ls /dev/first_drv */
     firstdrv_class_dev = device_create(firstdrv_class, NULL, MKDEV(major, 0), NULL, "first_drv_dev");
     if (unlikely(IS_ERR(firstdrv_class_dev)))
         return PTR_ERR(firstdrv_class_dev);

     return 0;
 }

 static void __exit first_drv_exit(void)
 {
     unregister_chrdev(major, "first_drv_proc");
     device_unregister(firstdrv_class_dev);
     class_destroy(firstdrv_class);
 }

 module_init(first_drv_init);
 module_exit(first_drv_exit);

 MODULE_AUTHOR("WHUT-ShiGuang");
 MODULE_DESCRIPTION("Mini2440 Test Driver");
 MODULE_VERSION("1.0");
 MODULE_LICENSE("GPL");

测试程序：

 /*************************************************
 * File name   :
 * Description :
 * Author      : [email protected]
 * Version     : V1.0
 * Date        :
 * Compiler    : arm-linux-gcc-4.4.3
 * Target      : mini2440(Linux-2.6.32)
 * History     :
 *   <author>  <time>   <version >   <desc>
 *************************************************/
 #include<stdio.h>
 #include<stdlib.h>
 #include<fcntl.h>
 #include<sys/types.h>
 #include<sys/stat.h>

 int main()
 {
     int fd;
     int val = 1;
     fd = open("/dev/first_drv_dev", O_RDWR);
     printf("fd = %d\n", fd);
     write(fd, &val, 4);
     read(fd, &val, 4);
     close(fd);
     return 0;
 }

测试结果：

[root@FriendlyARM /home]# 
[root@FriendlyARM /home]# ls /dev/first_drv_dev -l
crw-rw----    1 root     root     253,   0 Jan  1 08:31 /dev/first_drv_dev
[root@FriendlyARM /home]# 
[root@FriendlyARM /home]# cat /proc/devices | grep first_drv    
253 first_drv_proc
[root@FriendlyARM /home]# 
[root@FriendlyARM /home]# ls /sys/class/first_drv_sys/
first_drv_dev
[root@FriendlyARM /home]# 
[root@FriendlyARM /home]# 
[root@FriendlyARM /home]# ./app 
First_drv_open
fd = 3
First_drv_write
First_drv_read
First_drv_release
[root@FriendlyARM /home]# 
[root@FriendlyARM /home]# 

 OVER! THANK YOU !