步骤：

1、框架

2、完好硬件的操作：

a.看原理图、引脚

b.看2440手冊

c.写代码： IO口须要用ioremap映射

我的板子电路例如以下所看到的

1、配置GPBCON 寄存器，配置输出   在open函数中去配置

2、配置GPBDAT 寄存器                        在write函数中去配置

#########################################################################

手冊资料：

GPBCON 寄存器的物理地址为：0x56000010

GPBDAT  寄存器的物理地址为：0x56000014

#########################################################################

1、首先声明全局变量：

volatile unsigned long *gpbcon = NULL;

volatile unsigned long *gpbdat = NULL;

2、在入口函数中对引脚进行映射

/*映射物理地址*/

	gpbcon = (volatile unsigned long *) ioremap(0x56000010,16);

	gpbdat = gpbcon + 1;

3、在出口函数中取消映射

iounmap(gpbcon);

4、在open函数中将引脚设置为输出

	/*配置 GPB 5 6 7 8为输出*/

	*gpbcon &=~((0x3<<(5*2))|(0x3<<(6*2))|(0x3<<(7*2))|(0x3<<(8*2)));//先清零

	*gpbcon |=((0x1<<(5*2))|(0x1<<(6*2))|(0x1<<(7*2))|(0x1<<(8*2)));// 配置为1 （输出）

5、在写函数中对用户空间数据进行简单处理

	int val;

	copy_from_user(&val,buf,count);//从用户空间向内核空间拷贝数据

	if(val == 1)

	{

		//点灯

		*gpbdat &=~((1<<5)|(1<<6)|(1<<7)|(1<<8));

	}

	else

	{

		//灭灯

		*gpbdat|=(1<<5)|(1<<6)|(1<<7)|(1<<8);

	}

完整的驱动代码例如以下：

#include <linux/init.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <asm/io.h>

#include <linux/cdev.h>

#include <linux/device.h>

#include <asm/uaccess.h>

static struct class *firstdrv_class;

static struct class_devices *firstdrv_class_dev;

volatile unsigned long *gpbcon = NULL;

volatile unsigned long *gpbdat = NULL;

MODULE_LICENSE("Dual BSD/GPL");

static int first_dev_open(struct inode *inode,struct file *file)

{

	/*配置 GPB 5 6 7 8为输出*/

	*gpbcon &=~((0x3<<(5*2))|(0x3<<(6*2))|(0x3<<(7*2))|(0x3<<(8*2)));//先清零

	*gpbcon |=((0x1<<(5*2))|(0x1<<(6*2))|(0x1<<(7*2))|(0x1<<(8*2)));// 配置为1 （输出）

	//printk("first dev open\n");

	return 0;

}

static ssize_t first_dev_write(struct file *file,const char __user *buf,size_t count,loff_t *ppos)

{

	int val;

	copy_from_user(&val,buf,count);//从用户空间向内核空间拷贝数据

	if(val == 1)

	{

		//点灯

		*gpbdat &=~((1<<5)|(1<<6)|(1<<7)|(1<<8));

	}

	else

	{

		//灭灯

		*gpbdat|=(1<<5)|(1<<6)|(1<<7)|(1<<8);

	}

	//printk("first dev write\n");

	return 0;

}

static struct file_operations first_sdv_fops =

{

		.owner = THIS_MODULE,

		.open  = first_dev_open,

		.write = first_dev_write,

};

int major;

int first_drv_init(void)

{

	major = register_chrdev(0,"first_drv",&first_sdv_fops);//注冊

	firstdrv_class = class_create(THIS_MODULE,"first_drv");

	if(IS_ERR(firstdrv_class))

		return PTR_ERR(firstdrv_class);

	firstdrv_class_dev = device_create(firstdrv_class,NULL,MKDEV(major,0),NULL,"wq_device");

	if(unlikely(IS_ERR(firstdrv_class_dev)))

		return PTR_ERR(firstdrv_class_dev);

	/*映射物理地址*/

	gpbcon = (volatile unsigned long *) ioremap(0x56000010,16);

	gpbdat = gpbcon + 1;

	//printk("init   major= %d\n",major);

	return 0;

}

void first_dev_exit(void)

{

	//printk("exit\n");

	unregister_chrdev(major,"first_drv");//卸载

	device_unregister(firstdrv_class_dev);

	class_destroy(firstdrv_class);

	iounmap(gpbcon);

}

module_init(first_drv_init);

module_exit(first_dev_exit);

完整的測试代码例如以下：

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <stdio.h>

/*wq_device on  打开

 *wq_device off 关闭

 */

int main(int argc, char **argv)

{

	int fd;

	int val = 1;

	fd = open("/dev/wq_device",	O_RDWR);

	if(fd < 0)

	{

		printf("can't open \n");

	}

	if(argc != 2)

	{

		printf("Usage :\n");

		printf("%s <on|off>\n",argv[0]);

		return 0;

	}

	if(strcmp(argv[1],"on") == 0)

	{

		val =1;

	}

	else

	{

		val =0;

	}

	write(fd,&val,4);

	return 0;

}