poll机制按键驱动.doc

Poll机制按键驱动实验器材: ok6410开发板RedHat5.0 实验目的: 利用poll机制来测试按键驱动实验原理: 从上图可以得出: 当按键没有按下时,为高电平; 当按下时,为低电平 S2-7按键分别对应的是外部中断XEINT0-5驱动程序:#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define GPNCON 0x7F008830#define GPNDAT 0x7F008834volatile unsigned long *s3c6410_GPNCON;volatile unsigned long *s3c6410_GPNDAT;static struct class *mythird_key_class;static struct device *mythird_key_class_dev;static DECLARE_WAIT_QUEUE_HEAD(key_waitq); /定义一个等待队列头/* 中断事件标志，中断服务程序将它置，函数将它置 */static volatile int ev_press = 0; /* 键值: 按下时, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06 */* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 ,0x85, 0x86 */static unsigned int keyvals;struct mythird_keyunsigned int irq_no;unsigned int key_val;unsigned int num;char *name;static struct mythird_key third_keys6 = IRQ_EINT(0), 0x01, 0, KEY1 ,IRQ_EINT(1), 0x02, 1, KEY2 ,IRQ_EINT(2), 0x03, 2, KEY3 ,IRQ_EINT(3), 0x04, 3, KEY4 ,IRQ_EINT(4), 0x05, 4, KEY5 ,IRQ_EINT(5), 0x06, 5, KEY6 ,;static irqreturn_t mykey_handle(int irq, void *dev_id)int num;unsigned int tmp;unsigned int pinval;struct mythird_key *pindesc = (struct mythird_key *)dev_id;num = pindesc-num;tmp = readl(S3C64XX_GPNDAT);pinval = (tmp & (1key_val | 0x80;else /按下keyvals = pindesc-key_val;ev_press = 1;wake_up_interruptible(&key_waitq);return IRQ_RETVAL(IRQ_HANDLED);static int mythird_key_open(struct inode *inode, struct file *file)/* 配置 GPN0-5 为中断引脚*/int i = 0;int err;for(i = 0; i sizeof(third_keys)/sizeof(third_keys0); i+)err = request_irq(third_keysi.irq_no, mykey_handle, IRQ_TYPE_EDGE_BOTH, third_, (void*)&third_keysi);return 0;static int mythird_key_close(struct inode *inode, struct file *file)int i= 0;for(i = 0; i sizeof(third_keys)/sizeof(third_keys0); i+ )free_irq(third_keysi.irq_no, (void*)&third_keysi);return 0;static int mythird_key_read(struct file *file, char _user *buf, size_t size, loff_t *offp)if(size != 1)return -EINVAL;/*如果没有按键按下, 就休眠*/wait_event_interruptible(key_waitq, ev_press);/*如果有按键按下, 就唤醒*/ev_press = 0;copy_to_user(buf, &keyvals, 1);return 1;static unsigned mythird_key_poll(struct file *file, poll_table *wait)unsigned int mask = 0;poll_wait(file, &key_waitq, wait); /只是将进程挂到key_waitq队列, 并不会休眠if(ev_press)mask |= POLLIN | POLLRDNORM;return mask;static struct file_operations mythird_key = .owner = THIS_MODULE, .open = mythird_key_open,.read = mythird_key_read,.release = mythird_key_close,.poll = mythird_key_poll,;static int major;static int _init mythird_key_init(void)major = register_chrdev(0, mythird_key, &mythird_key);mythird_key_class = class_create(THIS_MODULE, mythird_key);mythird_key_class_dev = device_create(mythird_key_class, NULL, MKDEV(major, 0), NULL, key);s3c6410_GPNCON = (volatile unsigned long *)ioremap(GPNCON, 16);s3c6410_GPNDAT = s3c6410_GPNCON + 1;return 0;static void _exit mythird_key_exit(void)unregister_chrdev(major,mythird_key);device_destroy(mythird_key_class, MKDEV(major, 0);class_destroy(mythird_key_class);iounmap(s3c6410_GPNCON);module_init(mythird_key_init);module_exit(mythird_key_exit);MODULE_LICENSE(GPL);测试程序:#include #include #include #include int main()int fd;int ret;unsigned int keyvals;struct pollfd fds1;/我们只需要监控一个fd = open(/dev/key, O_RDWR);if(fd 0)printf(open key error!n);return -1;fds0.fd = fd; /需要监控是那个fds0.events = POLLIN; / 等待数据去读while(1)ret = poll(fds, 1, 5000);if(ret = 0)/超时printf(time outn);elseread(fd, &keyvals, 1 );printf(keyvals = 0x%xn,keyvals);return 0;Makefile:KERN_DIR = /root/linux2.6.28(前提是linux2.6.28要编译好)all:make -C $(KERN_DIR) M=pwd modu