首先贴上代码：
字符设备驱动代码：
/**
*file name: led.c
*/
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/random.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/wait.h>
#include <linux/mutex.h>
#include <linux/io.h> #include <linux/fs.h> static struct class *led_class; //创建类
static struct class_device *led_class_devs[]; //创建类对应的设备 1个总设备文件 3个单个灯的设备文件 volatile unsigned long *gpfcon = NULL;
volatile unsigned long *gpfdat = NULL; int led_open(struct inode *inode, struct file *fp)
{
int minor = MINOR(inode->i_rdev); //获取打开设备文件的次设备号
switch(minor)
{
case :
*gpfcon &= ~((0x3<<(*))|(0x3<<(*))|(0x3<<(*)));
*gpfcon |= (0x1<<(*))|(0x1<<(*))|(0x1<<(*));
break;
case :
*gpfcon &= ~(0x3<<(*));
*gpfcon |= (0x1<<(*));
break;
case :
*gpfcon &= ~(0x3<<(*));
*gpfcon |= (0x1<<(*));
break;
case :
*gpfcon &= ~(0x3<<(*));
*gpfcon |= (0x1<<(*));
break;
}
return ;
} ssize_t led_read(struct file *fp, char __user *c, size_t *t){
int minor = MINOR(fp->f_dentry->d_inode->i_rdev);
char leds_status;
switch(minor)
{
case 0:
leds_status = (~((*gpfdat & ((1<<4)|(1<<5)|(1<<6)))>>4))&0x7;
copy_to_user(buff,(const void *)&leds_status,1); //将数据从用户拷贝到内核空间
break;
case 1:
leds_status = (~(*gpfdat>>4))&0x1;
copy_to_user(buff,(const void *)&leds_status,1);
break;
case 2:
leds_status = (~(*gpfdat>>5))&0x1;
copy_to_user(buff,(const void *)&leds_status,1);
break;
case 3:
leds_status = (~(*gpfdat>>6))&0x1;
copy_to_user(buff,(const void *)&leds_status,1);
break;
}
} ssize_t led_write(struct file *fp, const char __user *buf, size_t count, loff_t *ppos){
int minor = MINOR(fp->f_dentry->d_inode->i_rdev);
int val;
copy_from_user(&val, buf, );
switch(minor)
{
case :
val &= 0x1;
*gpfdat &= ~((<<)|(<<)|(<<));
*gpfdat |= (val<<)|(val<<)|(val<<);
break;
case :
*gpfdat &= ~(<<);
*gpfdat |= (val&0x1)<<;
break; case :
*gpfdat &= ~(<<);
*gpfdat |= (val&0x1)<<;
break;
case :
*gpfdat &= ~(<<);
*gpfdat |= (val&0x1)<<;
break;
}
} struct file_operations led_fops={
.owner = THIS_MODULE,
.open = led_open,
.write = led_write, }; int major;
static int led_init(void)
{
int minor;
major = register_chrdev( ,"led_drv", &led_fops ); //当指定的设备号为0时，系统会自动生成一个设备号
led_class = class_create(THIS_MODULE, "my_leds");
if(IS_ERR(led_class))
return PTR_ERR(led_class); led_class_devs[] = class_device_create(led_class,NULL,MKDEV(major,),NULL,"my_leds"); //创建设备文件
if(unlikely(IS_ERR(led_class_devs)))
return PTR_ERR(led_class_devs);
for( minor=; minor<; minor++ )
{
led_class_devs[minor] = class_device_create(led_class,NULL,MKDEV(major,minor),NULL,"my_led%d",minor);
if(unlikely(IS_ERR(led_class_devs)))
return PTR_ERR(led_class_devs);
}
gpfcon = (volatile unsigned long *)ioremap(0x56000050,); //物理地址映射为虚拟地址
gpfdat = gpfcon + ; printk("led install Module\n"); return ;
} static void led_exit(void)
{
unregister_chrdev( major, "led_drv" );
class_device_unregister(led_class_devs[]); //注销设备文件
class_device_unregister(led_class_devs[]);
class_device_unregister(led_class_devs[]);
class_device_unregister(led_class_devs[]);
class_destroy(led_class); //销毁类
iounmap(gpfcon); //取消物理地址映射
printk("led Module exit\n");
} module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
模块的Makefile：
obj-m:=led.o
KERNELDIR:=/home/jz2440/linux-2.6.22.6
PWD:=$(shell pwd)
default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
clean:
rm -rf *.o *.mod.c *.mod.o *.ko *.symvers
测试文件：
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h> int main( int argc, char **argv )
{
int fd;
int val = ;
if(argc != )
{
printf("please input righ data\n");
printf("eg:/dev/my_leds <on\"off>\n");
return ;
}
fd = open(argv[], O_RDWR);
if(fd<)
{
printf("open failed\n");
return ;
} if(strcmp(argv[],"on")==)
{
val = ;
}
else
{
val = ;
}
write(fd, &val, );
read(fd, &val,1);
printf("led status =%d\n",val);
return ; }
完