button_drv.c驱动文件：
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <asm/io.h> //含有iomap函数iounmap函数
#include <asm/uaccess.h> //含有copy_from_user函数
#include <linux/device.h> //含有类相关的处理函数
#include <asm/arch/regs-gpio.h> //含有S3C2410_GPF0等相关的
#include <linux/irq.h> //含有IRQ_HANDLED\IRQ_TYPE_EDGE_RISING
#include <asm-arm/irq.h> //含有IRQT_BOTHEDGE触发类型
#include <linux/interrupt.h> //含有request_irq、free_irq函数
#include <linux/delay.h>
#include <asm/hardware.h>
#include <linux/poll.h>
#define DRVIER_NAME "button_drv"
#define DEVICE_NAME "button_dev"
int major;
int keyVal;
struct class *button_class;
struct class_device *button_class_device;
volatile unsigned long *gpfcon = NULL;
volatile unsigned long *gpfdat = NULL;
volatile unsigned long *gpgcon = NULL;
volatile unsigned long *gpgdat = NULL;
int ev_press = 0;
DECLARE_WAIT_QUEUE_HEAD(button_waitq); //注册等待队列
DECLARE_MUTEX(button_lock); //定义互斥锁
struct fasync_struct *button_fasync; //定义fasync_struct结构体
struct timer_list timer_button; //定义一个定时器
struct pin_desc {
unsigned int pin;
unsigned int key_val;
};
struct pin_desc pins_desc[4] = {
{S3C2410_GPF0, 0x01},
{S3C2410_GPF2, 0x02},
{S3C2410_GPG3, 0x03},
{S3C2410_GPG11, 0x04},
};
struct pin_desc *pinss_desc = NULL;
irqreturn_t button_irq(int irq, void *dev_id)
{
pinss_desc = (struct pin_desc *)dev_id;
mod_timer(&timer_button, jiffies+HZ/100); //10ms之后调用定时器处理函数
return IRQ_HANDLED;
}
int button_drv_open(struct inode *inode, struct file *file)
{
int ret;
if(file->f_flags&O_NONBLOCK) //非阻塞方式
{
if(down_trylock(&button_lock)) //获取信号量, 若失败则立即返回
{
return -EBUSY;
}
}
else //阻塞模式
{
down(&button_lock); //获取信号量, 若失败则该进程立刻进入睡眠状态
}
ret = request_irq(IRQ_EINT0, button_irq, IRQT_BOTHEDGE, "S1", &pins_desc[0]);
if(ret)
{
printk("failed 1 button_drv_open \n");
}
ret = request_irq(IRQ_EINT2, button_irq, IRQT_BOTHEDGE, "S2", &pins_desc[1]);
if(ret)
{
printk("failed 2 button_drv_open \n");
}
ret = request_irq(IRQ_EINT11, button_irq, IRQT_BOTHEDGE, "S3", &pins_desc[2]);
if(ret)
{
printk("failed 3 button_drv_open \n");
}
ret = request_irq(IRQ_EINT19, button_irq, IRQT_BOTHEDGE, "S4", &pins_desc[3]);
if(ret)
{
printk("failed 4 button_drv_open \n");
}
return 0;
}
int button_drv_close(struct inode *inode, struct file *file)
{
up(&button_lock); //释放信号量
free_irq(IRQ_EINT0, &pins_desc[0]);
free_irq(IRQ_EINT2, &pins_desc[1]);
free_irq(IRQ_EINT11, &pins_desc[2]);
free_irq(IRQ_EINT19, &pins_desc[3]);
return 0;
}
int button_drv_read(struct file *file, char __user *userbuf, size_t count, loff_t *off)
{
int ret;
if(file->f_flags&O_NONBLOCK) //若文件是以非阻塞方式读取
{
if(!ev_press) //判断案件是否按下, 没有则直接返回
{
keyVal = 0;
ret = copy_to_user(userbuf, &keyVal, 1);
if(ret)
{
printk("failed 1 button_drv_read \n");
return -1;
}
return -EBUSY;
}
}
else //若文件是以阻塞方式读取
{
wait_event_interruptible(button_waitq, ev_press); //若ev_press为0, 则将进程放入button_waitq等到队列中
}
ret = copy_to_user(userbuf, &keyVal, 1);
ev_press = 0; //按键已处理, 可以继续休眠
if(ret)
{
printk("failed 2 button_drv_read \n");
return -1;
}
return 1;
}
int button_drv_fasync(int fd, struct file *file, int on)
{
int ret;
ret = fasync_helper(fd, file, on, &button_fasync);
if(ret<0)
{
printk("failed 1 button_drv_fasync \n");
return ret;
}
return 0;
}
void timer_button_timeout(unsigned long data)
{
unsigned int pin_val;
if(pinss_desc==NULL)
{
return;
}
else
{
pin_val = s3c2410_gpio_getpin(pinss_desc->pin);
if(pin_val)
{
keyVal = 0x80 | pinss_desc->key_val;
}
else
{
keyVal = pinss_desc->key_val;
}
wake_up_interruptible(&button_waitq); //唤醒休眠进程
ev_press = 1;
kill_fasync(&button_fasync, SIGIO, POLL_IN); //发送信号给进程
}
}
struct file_operations button_fops = {
.owner = THIS_MODULE,
.open = button_drv_open,
.release = button_drv_close,
.read = button_drv_read,
.fasync = button_drv_fasync,
};
int __init button_drv_init(void)
{
init_timer(&timer_button); //初始化一个定时器用于处理按键抖动
timer_button.expires = 0; //定时器的定时时间
timer_button.function = timer_button_timeout; //定是时间到后的处理函数
add_timer(&timer_button); //将定义的定时器放入定时器链表
major = register_chrdev(0, DRVIER_NAME, &button_fops); //注册驱动
if(major<0)
{
printk("failed 1 button_drv_init \n");
}
button_class = class_create(THIS_MODULE, DEVICE_NAME); //创建设备类
if(button_class<0)
{
printk("failed 2 button_drv_init \n");
}
button_class_device = class_device_create(button_class, NULL, MKDEV(major, 0), NULL, DEVICE_NAME); //创建设备文件(设备节点)
if(button_class_device<0)
{
printk("failed 3 button_drv_init \n");
}
gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16); //虚拟地址重映射
gpfdat = gpfcon + 1;
gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);
gpgdat = gpgcon + 1;
return 0;
}
void __exit button_drv_exit(void)
{
unregister_chrdev(major, DEVICE_NAME);
class_device_unregister(button_class_device);
class_destroy(button_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>
#include <poll.h>
#include <signal.h>
static int fd;
void button_signal(int signum)
{
unsigned char keyVal;
printf("signal = %d \n", signum);
read(fd, &keyVal, 1);
printf("keyVal = 0x%x \n", keyVal);
}
int main(int argc, char **argv)
{
int oflags;
char *filename;
filename = argv[1];
fd = open(filename, O_RDWR|O_NONBLOCK); //非阻塞
if(fd<0)
{
printf("can not open \n");
}
signal(SIGIO, button_signal); //注册一个信号, 启动信号驱动机制
fcntl(fd, F_SETOWN, getpid()); //将本应用程序的进程号告诉给内核，最终使得驱动程序可以成功发送信号给应用程序
oflags = fcntl(fd, F_GETFL); //取得当前的状态
fcntl(fd, F_SETFL, oflags|FASYNC); //改变fasync标记, 最终会调用到驱动的fasync->fasync_helper
while(1)
{
sleep(1000);
}
return 0;
}
编译生成button_drv.ko和button_app文件，运行./button_app /dev/button_dev