button_drv.c驱动文件:
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/io.h> //包含iomap函数IoUnmap函数
#include <asm/uaccess.h> //包含copy_from_user函数
#include <linux/device.h> //包含class类相关的处理函数
#include <linux/fs.h> //包含file_operations结构体
#define DRIVER_name "button_drv"
#define DEVICE_name "button_dev"
int major;
static struct class *buttondrv_class;
static struct class_device *buttondrv_class_dev;
volatile unsigned long *gpfcon = NulL;
volatile unsigned long *gpfdat = NulL;
volatile unsigned long *gpgcon = NulL;
volatile unsigned long *gpgdat = NulL;
static int button_drv_open(struct inode *inode,struct file *file)
{
*gpfcon &= ~((0x3<<(0*2)) | (0x3<<(2*2)));
*gpgcon &= ~((0x3<<(3*2)) | (0x3<<(11*2)));
return 0;
}
static int button_drv_read(struct file * file,char __user * userbuf,size_t count,loff_t * off)
int ret;
unsigned char keyval[4];
unsigned long keyvals;
if(count!=sizeof(keyval))
{
printk("button_drv_read error 1 \n");
}
keyvals = *gpfdat;
keyval[0] = ((keyvals>>0) & 1);
keyval[1] = ((keyvals>>2) & 1);
keyvals = *gpgdat;
keyval[2] = ((keyvals>>3) & 1);
keyval[3] = ((keyvals>>11) & 1);
ret = copy_to_user(userbuf,keyval,sizeof(keyval));
if(ret<0)
printk("button_drv_read error 2 \n");
return sizeof(keyval);
static struct file_operations button_drv_fops = {
.owner = THIS_MODulE,
.open = button_drv_open,courIEr; Font-size: 18px;"> .read = button_drv_read,courIEr; Font-size: 18px;">};
static int button_drv_init(voID)
major = register_chrdev(0,DRIVER_name,&button_drv_fops);
buttondrv_class = class_create(THIS_MODulE,DEVICE_name);
buttondrv_class_dev = class_device_create(buttondrv_class,NulL,MKDEV(major,0),DEVICE_name);
gpfcon = (volatile unsigned long *)ioremap(0x56000050,16);
gpfdat = gpfcon + 1;
gpgcon = (volatile unsigned long *)ioremap(0x56000060,courIEr; Font-size: 18px;"> gpgdat = gpgcon + 1;
static voID button_drv_exit(voID)
unregister_chrdev(major,DRIVER_name);
class_device_unregister(buttondrv_class_dev);
class_destroy(buttondrv_class);
IoUnmap(gpfcon);
IoUnmap(gpgcon);
module_init(button_drv_init);
module_exit(button_drv_exit);
MODulE_liCENSE("GPL");
Makefile文件:
obj-m += button_drv.o
KERN_DIR = /work/system/linux-2.6.22.6
all:
make -C $(KERN_DIR) M=`pwd` modules
clean:
rm -rf *.o *.ko *.order *.symvers *.mod.c
button_app.c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;
char *filename;
unsigned char keyval[4];
filename = argv[1];
fd = open(filename,O_RDWR);
if(fd<0)
printf("can not open \n");
while(1)
read(fd,courIEr; Font-size: 18px;"> if(!keyval[0] || !keyval[1] || !keyval[2] || !keyval[3])
{
printf("key pressed %d %d %d %d \n",keyval[0],keyval[1],keyval[2],keyval[3]);
}
}
}
编译生成button_drv.ko文件和button_app文件,运行:./button_app /dev/button_dev
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