字符驱动的格式以及应用程序如何调用

作者：李浩

 

硬件平台：OMAP-L138

软件平台：linux2.6.32

 

自己编写的一个简单的字符驱动，具体的功能实现没有写出:

fpga driver：

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/device.h>

//******************************************************************************************
MODULE_AUTHOR("LiHao <[email protected]>");

MODULE_DESCRIPTION("FPGA Driver");

MODULE_LICENSE("GPL");

#define DEVICE_NAME "FPGA"

#define FPGA_MAJOR 231

static struct cdev cdev_fpga;

struct class *fpga_class;

//******************************************************************************************
static int FPGA_open(struct inode *inode,struct file *filp);
static ssize_t FPGA_read(struct file *filp,char __user *buf,size_t count,loff_t *f_pos);
static ssize_t FPGA_write(struct file *filp,char __user *buf,size_t count,loff_t *f_pos);
static int FPGA_ioctl(struct inode *inode,struct file *filp,unsigned int cmd,unsigned long arg);
static int FPGA_release(struct inode *inode,struct file *filp);
//******************************************************************************************
static struct file_operations FPGA_fops = {
 .owner = THIS_MODULE,
 .open = FPGA_open,
 .read = FPGA_read,
 .write = FPGA_write,
 .ioctl = FPGA_ioctl,
 .release = FPGA_release,
};

static int __init fpga_init(void)
{
 int ret;
 dev_t devno;
 
 printk("fpga_init start.../n");
 
 devno = MKDEV(FPGA_MAJOR,0);

 ret = register_chrdev_region(devno,1,DEVICE_NAME);
 if(ret < 0)
 {
  printk("<>fpga_init::register_chrdev_region error!/n");
  return ret;
 }
 
 cdev_init(&cdev_fpga,&FPGA_fops);
 
 cdev_fpga.owner = THIS_MODULE;
 
 ret = cdev_add(&cdev_fpga,devno,1);
 if(ret)
 {
  printk("<>fpga_init::can not add fpga device!/n");
  return ret;
 }

 fpga_class = class_create(THIS_MODULE,"fpga_class");
 if(IS_ERR(fpga_class))
 {
  printk("<>fpga_init::class_create error!/n");
  return -1;
 }

 device_create(fpga_class,NULL,MKDEV(FPGA_MAJOR,0),NULL,DEVICE_NAME);
 
 printk("fpga_init end.../n");
 return 0;
}

static void __exit fpga_exit(void)
{
 printk("fpga_exit start..../n");

 cdev_del(&cdev_fpga);

 unregister_chrdev_region(MKDEV(FPGA_MAJOR,0),1);

 device_destroy(fpga_class,MKDEV(FPGA_MAJOR,0));

 class_destroy(fpga_class);

 printk("fpga_exit..../n");
}

static int FPGA_open(struct inode *inode,struct file *filp)
{
 printk("FPGA_open start../n");
 
 printk("FPGA_open end../n");

 return 0;
}

static ssize_t FPGA_read(struct file *filp,char __user *buf,size_t count,loff_t *f_pos)
{
 printk("FPGA_read start../n");
 
 printk("FPGA_read end../n");

 return 0;
}

static ssize_t FPGA_write(struct file *filp,char __user *buf,size_t count,loff_t *f_pos)
{
 printk("FPGA_write start../n");

 printk("FPGA_write end../n");

 return 0;
}

static int FPGA_ioctl(struct inode *inode,struct file *filp,unsigned int cmd,unsigned long arg)
{
 printk("FPGA_ioctl start../n");
 
 switch(cmd)
 {
 case 0:
 break;

 case 1:
 break;
 }
 
 printk("FPGA_ioctl end../n");

 return 0;
}

static int FPGA_release(struct inode *inode,struct file *filp)
{
 printk("FPGA_release start../n");
 
 printk("FPGA_release end../n"); 

 return 0;
}

module_init(fpga_init);

module_exit(fpga_exit);

 

**********************************************************************************************

**********************************************************************************************
应用程序调用：

#include <stdio.h>
#include <pthread.h>
#include <sys/time.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <termios.h>
#include <time.h>

 

int main(int argc,char **argv)
{
 int fpga;
 int file_len=10;
 unsigned char read_buf[512]={0};
 unsigned char recv_buf[512]={0};
 
 fpga = open("/dev/FPGA",O_RDWR,S_IRUSR | S_IWUSR);
 
 if(fpga > 0)
 {
  read(fpga,read_buf,file_len);
  
  write(fpga,recv_buf,file_len);
  
  close(fpga);
  
  return 0;
 }

 printf("open fpga error!/n");
 return 1;
}