S3C6410按键驱动

S3C6410按键驱动——查询方式实现

OK6410总共有6个按键，按键分别接在GPN0~GPN5,原理图上根本没有这么说，原理图上说的是KEYINT!~KEYINT6,很明显这里是接在中断引脚上的，直接查询S3C6410的中断引脚就可以知道这个6个按键的接法，一下是用查询方法实现的按键驱动：

 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include //新版内核

 static struct class *key_drv_class;
 static struct class_device  *key_class_dev;
 volatile unsigned long  *gpncon=NULL;
 volatile unsigned long  *gpndat=NULL;


 static int key_drv_open(struct inode  * inode, struct file * file)
 {
     *gpncon &=~((0x3<<0)|(0x3<<2)|(0x3<<4)|(0x3<<6));
     return 0;
 }
 static ssize_t key_drv_write(struct inode * file, const char __user *buf, size_t count, loff_t *ppos)
 {

     return 0;
 }
 ssize_t key_drv_read (struct file *file, char __user *buf, size_t size, loff_t *ppos)
 {
     //返回四个引脚的电平
     unsigned char key_val[4];
     int regval;

     if(size != sizeof(key_val))
         return -EINVAL;
     regval=*gpndat;
     key_val[0]  = (regval & (1<<0))?1:0;
     key_val[1]  = (regval & (1<<1))?1:0;
     key_val[2]  = (regval & (1<<2))?1:0;
     key_val[3]  = (regval & (1<<3))?1:0;
     copy_to_user(buf,key_val,sizeof(key_val));

     return sizeof(key_val);
 }

 static struct file_operations key_drv_openration ={
     .owner = THIS_MODULE,
     .open = key_drv_open,
     .write =key_drv_write,
     .read=key_drv_read,
 };
 int major;
 static int key_drv_init(void)
 {
     major=register_chrdev(0,"key_drv",&key_drv_openration);

     key_drv_class = class_create(THIS_MODULE, "key_drv");
         //自动创建设备节点
     /* 新版的内核不能用class_device_create 要用device_create*/
     key_class_dev = device_create(key_drv_class, NULL, MKDEV(major, 0), NULL, "key"); /* /dev/xyz */

     gpncon = (volatile unsigned long*)ioremap(0x7F008830,16);
     gpndat=gpncon+1;//指针的操作是按照指针指向的长度为单位?
                         /*本例中使用的是unsigned long类型刚好是4个字节*/

     return 0;
 }
 static void key_drv_exit(void)
 {
     unregister_chrdev(major,"key_drv");
     device_unregister(key_class_dev);
     class_destroy(key_drv_class);

     iounmap(gpncon);
     return 0;
 }

 module_init(key_drv_init);
 module_exit(key_drv_exit);
 MODULE_LICENSE("GPL");

一下是测试程序：

 #include
 #include
 #include
 #include

 int main(int argc,char **argv)
 {
     int fd;
     unsigned char key_val[4];
     int cnt;
     fd=open("/dev/key",O_RDWR);
     if(fd < 0)
         printf("can not open!!!\n");
     while(1)
         {
             read(fd,key_val,sizeof(key_val));
             if(!key_val[0]||!key_val[1]||!key_val[2]||!key_val[3])
                 {
                     printf("%04d key pressed :%d %d %d %d\n\n",cnt++,key_val[0],key_val[1],key_val[2],key_val[3]);
                 }
         }
     return 0;
 }

一下是测试运行结果：

1452 key pressed :1 0 1 1


1453 key pressed :1 0 1 1


1454 key pressed :1 0 1 1


1455 key pressed :1 0 1 1


1456 key pressed :1 0 1 1


1457 key pressed :1 0 1 1


1458 key pressed :1 0 1 1


1459 key pressed :1 0 1 1


1460 key pressed :1 0 1 1


1461 key pressed :1 0 1 1

让测试程序后台运行，查看CPU的运行状态：

Mem: 7968K used, 246548K free, 0K shrd, 0K buff, 2096K cached
CPU:  9.1% usr 90.8% sys  0.0% nic  0.0% idle  0.0% io  0.0% irq  0.0% sirq
Load average: 0.34 0.13 0.07 2/25 984
  PID  PPID USER     STAT   VSZ %VSZ CPU %CPU COMMAND
  983   969 root     R      792  0.3   0 99.6 ./main
  984   969 root     R     2268  0.8   0  0.2 top
  969     1 root     S     2268  0.8   0  0.0 -/bin/sh
    1     0 root     S     2264  0.8   0  0.0 init
    4     2 root     SW       0  0.0   0  0.0 [kworker/0:0]
    5     2 root     SW       0  0.0   0  0.0 [kworker/u:0]

可以看出按键 程序的CPU占用率很大，这种驱动方式很不好。

S3C6410按键驱动--中断方式

 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include //新版内核

 #include
 #include


 static struct class *key_irq_class;
 static struct class_device  *key_class_irq;
 volatile unsigned long  *gpncon=NULL;
 volatile unsigned long  *gpndat=NULL;

 static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

 /* 中断事件标志, 中断服务程序将它置1，third_drv_read将它清0 */
 static volatile int ev_press = 0;
 struct key_desc{
     unsigned int pin;
     unsigned int key_val;
     };
 /*键值:按下时，0x01,0x02,0x03,0x04,0x05,0x06*/
 /*键值:松开时，0x81,0x82,0x83,0x84,0x85,0x86*/
 static unsigned char key_num;
 struct key_desc keys_desc[6]={
     {1,0x01},
     {2,0x02},
     {3,0x03},
     {4,0x04},
     {5,0x05},
     {6,0x06},
 };

 static irqreturn_t key_irq(int irq, void *dev_id)
 {
     struct key_desc *pin=(struct key_desc*)dev_id;
     unsigned int pinval;
     pinval=gpio_get_value(S3C64XX_GPN(pin->pin));
     if(pinval)
         {
             key_num=0x80|pin->key_val;
         }
     else
         {
             key_num=pin->key_val;
         }
     //printk("*********************");
     //printk("key_num= %x\n",key_num);
     //printk("*********************");
     //ev_press=1;/*表示中断发生了*/
     wake_up_interruptible(&button_waitq);/*唤醒休眠的进程*/
     return IRQ_HANDLED;
 }

 static int key_drv_open(struct inode  * inode, struct file * file)
 {
     request_irq(IRQ_EINT(1),key_irq,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,"S1",&keys_desc[0]);
     request_irq(IRQ_EINT(2),key_irq,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,"S2",&keys_desc[1]);
     request_irq(IRQ_EINT(3),key_irq,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,"S3",&keys_desc[2]);
     request_irq(IRQ_EINT(4),key_irq,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,"S4",&keys_desc[3]);
     request_irq(IRQ_EINT(5),key_irq,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,"S5",&keys_desc[4]);
     request_irq(IRQ_EINT(6),key_irq,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,"S6",&keys_desc[5]);
     return 0;
 }
 static ssize_t key_drv_write(struct inode * file, const char __user *buf, size_t count, loff_t *ppos)
 {

     return 0;
 }
 ssize_t key_drv_read (struct file *file, char __user *buf, size_t size, loff_t *ppos)
 {
     //返回四个引脚的电平
     if(size != 1)
         return -EINVAL;
     /*如果没有按键动作发生就休眠*/
     wait_event_interruptible(button_waitq, ev_press);
     /*如果有按键动作，返回键值*/
     copy_to_user(buf,&key_num,1);
     ev_press=0;
     return 1;
 }
 int key_drv_release(struct inode * inode, struct file * file)
 {
     free_irq(IRQ_EINT(1),&keys_desc[0]);
     free_irq(IRQ_EINT(2),&keys_desc[1]);
     free_irq(IRQ_EINT(3),&keys_desc[2]);
     free_irq(IRQ_EINT(4),&keys_desc[3]);
     free_irq(IRQ_EINT(5),&keys_desc[4]);
     free_irq(IRQ_EINT(6),&keys_desc[5]);

     return 0;
 }
 static struct file_operations key_drv_openration ={
     .owner = THIS_MODULE,
     .open = key_drv_open,
     .write =key_drv_write,
     .read=key_drv_read,
     .release=key_drv_release,
 };
 int major;
 static int key_drv_init(void)
 {
     major=register_chrdev(0,"key_irq",&key_drv_openration);

     key_irq_class = class_create(THIS_MODULE, "key_irq");
         //自动创建设备节点
     /* 新版的内核不能用class_device_create 要用device_create*/
     key_class_irq = device_create(key_irq_class, NULL, MKDEV(major, 0), NULL, "key"); /* /dev/xyz */

     gpncon = (volatile unsigned long*)ioremap(0x7F008830,16);
     gpndat=gpncon+1;//指针的操作是按照指针指向的长度为单位?
                         /*本例中使用的是unsigned long类型刚好是4个字节*/

     return 0;
 }
 static void key_drv_exit(void)
 {
     unregister_chrdev(major,"key_irq");
     device_unregister(key_class_irq);
     class_destroy(key_irq_class);

     iounmap(gpncon);
     return 0;
 }

 module_init(key_drv_init);
 module_exit(key_drv_exit);
 MODULE_LICENSE("GPL");

测试程序：

 #include
 #include
 #include
 #include

 int main(int argc,char **argv)
 {
     int fd;
     unsigned char key_val;
     int cnt;
     fd=open("/dev/key",O_RDWR);
     if(fd < 0)
         {
             printf("can not open!!!\n");
             return 0;
         }
     while(1)
         {
             read(fd,&key_val,1);
             printf("key_val = 0x%x\n", key_val);
         }
     return 0;
 }

测试结果：

[root@Pillar /driver/key/key_IRQ]#./main &
[root@Pillar /driver/key/key_IRQ]#*********************key_num= 81
*********************key_val = 0x81
*********************key_num= 82
*********************key_val = 0x82
*********************key_num= 3
******************************************key_num= 3
******************************************key_num= 83
*********************key_val = 0x3