驱动代码:
/*
*目的:我们将按键按下或弹起的事件记录
*到一个全局数组中,通过应用层read函数,将数组
*的数据传到上层,静儿上层进一步的判断,从而
*实现更进一步的应用
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/ioctl.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#define DEVICE_NAME "buttons"
int major;//主设备号
int ev_press;//标志是否按下
DECLARE_WAIT_QUEUE_HEAD(buttons_queue);
static volatile char keys_value[] = {'0','0','0','0','0','0','0'};
struct class * buttons_class;
struct buttons_irq_desc
{
int irq;//中断号
int pin;//中断引脚
int num;
char *name;
};
static struct buttons_irq_desc key_desc[] =
{
{IRQ_EINT8, S3C2410_GPG(0),0,"key1"},
{IRQ_EINT11,S3C2410_GPG(3),1,"key2"},
{IRQ_EINT13,S3C2410_GPG(5),2,"key3"},
{IRQ_EINT14,S3C2410_GPG(6),3,"key4"},
{IRQ_EINT15,S3C2410_GPG(7),4,"key5"},
{IRQ_EINT19,S3C2410_GPG(11),5,"key6"},
};
static irqreturn_t buttons_interrupt(int irq,void * dev_id)
{
int down;//标志是否按下
struct buttons_irq_desc *now_desc = (struct buttons_irq_desc *)dev_id;
//当按键按下寄存器的值为0,反之为0
down = !s3c2410_gpio_getpin(now_desc->pin);
if(down != (keys_value[now_desc->num]&1))
{
keys_value[now_desc->num] = '0'+1;
ev_press = 1;
wake_up_interruptible(&buttons_queue);
}
return IRQ_RETVAL(IRQ_HANDLED);
}
int buttons_open(struct inode* inode,struct file *filp)
{ int i;
printk("buttons open success\n");
for(i=0; i<6;i++)
{
request_irq(key_desc[i].irq,buttons_interrupt,IRQ_TYPE_EDGE_BOTH,
key_desc[i].name,(void *)&key_desc[i]);
}
return 0;
}
int buttons_release(struct inode *inode,struct file *filp)
{
int i;
printk("buttons release ok \n");
for(i=0;i < 6;i++)
{
free_irq(key_desc[i].irq,(void *)&key_desc[i]);
}
return 0;
}
int buttons_read(struct file *filp,char __user *buff,
size_t count,loff_t *offp)
{
int error;
printk("read is ok\n");
if(!ev_press)//有没有按下的标志,按下为1,否则为0
{
if(filp->f_flags &O_NONBLOCK)//看看是否非阻塞
return -EAGAIN;
else
{
wait_event_interruptible(buttons_queue,ev_press);
}
}
ev_press = 0;
error = copy_to_user(buff,(const void*)keys_value,count) ;
memset((void *)keys_value, 0, sizeof(keys_value));
return error?-EFAULT:count;
}
//file_operations结构体
static const struct file_operations buttons_fops=
{
.owner = THIS_MODULE,
.open = buttons_open,
.release = buttons_release,
.read = buttons_read,
};
static int __init buttons_init(void)
{
major = register_chrdev(0,DEVICE_NAME,&buttons_fops);
if( major < 0)
{
printk("can't register major\n");
return major;
}
printk("register major success\n");
buttons_class = class_create(THIS_MODULE,"buttons");//创建类
device_create(buttons_class,NULL,MKDEV(major,0),NULL,"buttons");
return 0;
}
static void __exit buttons_exit(void)
{
unregister_chrdev(major,DEVICE_NAME);
device_destroy(buttons_class,MKDEV(major,0));
class_destroy(buttons_class);
}
module_init(buttons_init);
module_exit(buttons_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("suyonggang");
测试代码:
/*
*目的实现,读取key的值
*/
#include <stdio.h>//printf基本函数
#include <stdlib.h>
#include <fcntl.h>//包含open函数等
#include <signal.h>
#include <sys/ioctl.h>
int main(int argc,char **argv)
{
int fd;
int i;
char buffer[6]= {'0','0','0','0','0','0'};
fd = open("/dev/buttons",O_RDWR);
if(fd < 0)
{
printf("can't open /dev/buttons");
}
while(1)
{
read(fd,buffer,6);
for(i=0;i<6;i++)
{
if(buffer[i] == '1')
{
printf("the key %d was %c\n",i+1,buffer[i]);
}
}
}
close(fd);
return 0;
}
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