定时器去抖动
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前面程序按键速度较快时出现按下打印几个相同值的情况，这个和机械的抖动有关,现在使用定时器去抖动
#include <linux/module.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/init.h>#include <linux/delay.h>#include <linux/irq.h>#include <asm/uaccess.h>#include <asm/irq.h>#include <asm/io.h>#include <asm/arch/regs-gpio.h>#include <asm/hardware.h>#include <linux/poll.h>static struct class *sevendrv_class;static struct class_device*sevendrv_class_dev;volatile unsigned long *gpfcon;volatile unsigned long *gpfdat;volatile unsigned long *gpgcon;volatile unsigned long *gpgdat;static struct timer_list buttons_timer;/*第一步:定义一个定时器结构体buttons_timer*/static DECLARE_WAIT_QUEUE_HEAD(button_waitq);/* 中断事件标志, 中断服务程序将它置1，seven_drv_read将它清0 */static volatile int ev_press = 0;static struct fasync_struct *button_async;struct pin_desc{unsigned int pin;unsigned int key_val;};/* 键值: 按下时, 0x01, 0x02, 0x03, 0x04 *//* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 */static unsigned char key_val;struct pin_desc pins_desc[4] = {{S3C2410_GPF0, 0x01},{S3C2410_GPF2, 0x02},{S3C2410_GPG3, 0x03},{S3C2410_GPG11, 0x04},};//static atomic_t canopen = ATOMIC_INIT(1); //定义原子变量并初始化为1static DECLARE_MUTEX(button_lock); //定义互斥锁static struct pin_desc *irq_pd =NULL;static irqreturn_t buttons_irq(int irq, void *dev_id){/*保存键值*/irq_pd = (struct pin_desc *)dev_id;/*第三步:修改定时器，消抖动，最后一次时调用超时函数 *buttons_timer_function *修改定时器10ms,按键有抖动，而抖动时间肯定小于10ms,所以 *第一次抖动修改定时器，定时器延后抖动发生 的10ms *第N-1次抖动修改定时器，定时器延后抖动发生 的10ms *最后一次(第N次)抖动发生，定时器修改到抖动发生后10ms *N次抖动后10ms，即N次的定时器超时时间10ms到后，调用定时器 *处理函数buttons_timer_function */mod_timer(&buttons_timer, jiffies+HZ/100);return IRQ_RETVAL(IRQ_HANDLED);}static int seven_drv_open(struct inode *inode, struct file *file){#if 0if (!atomic_dec_and_test(&canopen)){atomic_inc(&canopen);return -EBUSY;}#endifif (file->f_flags & O_NONBLOCK){if (down_trylock(&button_lock))return -EBUSY;}else{/* 获取信号量 */down(&button_lock);}/* 配置GPF0,2为输入引脚 *//* 配置GPG3,11为输入引脚 */request_irq(IRQ_EINT0, buttons_irq, IRQT_BOTHEDGE, "S2", &pins_desc[0]);request_irq(IRQ_EINT2, buttons_irq, IRQT_BOTHEDGE, "S3", &pins_desc[1]);request_irq(IRQ_EINT11, buttons_irq, IRQT_BOTHEDGE, "S4", &pins_desc[2]);request_irq(IRQ_EINT19, buttons_irq, IRQT_BOTHEDGE, "S5", &pins_desc[3]);return 0;}ssize_t seven_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos){if (size != 1)return -EINVAL;if (file->f_flags & O_NONBLOCK){if (!ev_press)return -EAGAIN;}else{/* 如果没有按键动作, 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_val, 1);ev_press = 0;return 1;}int seven_drv_close(struct inode *inode, struct file *file){//atomic_inc(&canopen);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]);up(&button_lock);return 0;}static unsigned seven_drv_poll(struct file *file, poll_table *wait){unsigned int mask = 0;poll_wait(file, &button_waitq, wait); // 不会立即休眠if (ev_press)mask |= POLLIN | POLLRDNORM;return mask;}static int seven_drv_fasync (int fd, struct file *filp, int on){printk("driver: seven_drv_fasync\n");return fasync_helper (fd, filp, on, &button_async);}static struct file_operations sencod_drv_fops = { .owner = THIS_MODULE, /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */ .open = seven_drv_open, .read =seven_drv_read, .release = seven_drv_close,.poll = seven_drv_poll,.fasync = seven_drv_fasync,};/*第四步:最后一次抖动的上升沿或下降沿10ms后调用buttons_timer_function*/static void buttons_timer_function(unsigned date){struct pin_desc * pindesc = irq_pd;unsigned int pinval;/*add_timer添加时就产生了定时器超时，所以需要判断*/if(!pindesc) return;pinval = s3c2410_gpio_getpin(pindesc->pin);if (pinval){/* 松开 */key_val = 0x80 | pindesc->key_val;}else{/* 按下 */key_val = pindesc->key_val;} ev_press = 1; /* 表示中断发生了 */ wake_up_interruptible(&button_waitq); /* 唤醒休眠的进程 */kill_fasync (&button_async, SIGIO, POLL_IN);}int major;static int seven_drv_init(void){/*第二步:初始化buttons_timer, 并启用定时器*//*buttons_timer为结构体双向链表，我只需要填充一个项，第一次将定时器加入链表，需要初始化整个链表*/init_timer(&buttons_timer);/*初始化定时器结构体成员function,function为定时器超时后调用的函数buttons_timer_function*/buttons_timer.function = buttons_timer_function;/*注册定时器并运行*/add_timer(&buttons_timer);major = register_chrdev(0, "seven_drv", &sencod_drv_fops);sevendrv_class = class_create(THIS_MODULE, "seven_drv");sevendrv_class_dev = class_device_create(sevendrv_class, NULL, MKDEV(major, 0), NULL, "buttons"); /* /dev/buttons */gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);gpfdat = gpfcon + 1;gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);gpgdat = gpgcon + 1;return 0;}static void seven_drv_exit(void){unregister_chrdev(major, "seven_drv");class_device_unregister(sevendrv_class_dev);class_destroy(sevendrv_class);iounmap(gpfcon);iounmap(gpgcon);return 0;}module_init(seven_drv_init);module_exit(seven_drv_exit);MODULE_LICENSE("GPL");mod_timer(&buttons_timer, jiffies+HZ/100);jiffies表示系统启动到现在的tick数，比如jiffies=50,过了一段时间jiffies=55则产生了55-50个系统定时器中断,现在HZ=100，即产生一个定时器中断,1个tick的时间产生了一个定时器中断，而tick为HZ的倒数，即1秒产生100个定时器中断，一个定时器中断为10ms
测试代码:
#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <stdio.h>#include <poll.h>#include <signal.h>#include <sys/types.h>#include <unistd.h>#include <fcntl.h>/* sevendrvtest */int main(int argc, char **argv){unsigned char key_val;int ret,fd;int Oflags;//signal(SIGIO, my_signal_fun);fd = open("/dev/buttons", O_RDWR );if (fd < 0){printf("can't open!\n");return -1;}//fcntl(fd, F_SETOWN, getpid());//Oflags = fcntl(fd, F_GETFL); //fcntl(fd, F_SETFL, Oflags | FASYNC);while (1){ret = read(fd, &key_val, 1);printf("key_val: 0x%x, ret = %d\n", key_val, ret);//sleep(5);}测试结果:
# insmod seven_drv.ko # lsmodModule Size Used by Not taintedseven_drv 4740 0 # ./sevendrvtest &# ./sevendrvtest &# ./sevendrvtest &# ./sevendrvtest &# ps PID Uid VSZ Stat Command 1 0 3092 S init 2 0 SW< [kthreadd] 3 0 SWN [ksoftirqd/0] 4 0 SW< [watchdog/0] 5 0 SW< [events/0] 6 0 SW< [khelper] 55 0 SW< [kblockd/0] 56 0 SW< [ksuspend_usbd] 59 0 SW< [khubd] 61 0 SW< [kseriod] 73 0 SW [pdflush] 74 0 SW [pdflush] 75 0 SW< [kswapd0] 76 0 SW< [aio/0] 710 0 SW< [mtdblockd] 745 0 SW< [kmmcd] 762 0 SW< [rpciod/0] 770 0 3096 S -sh 776 0 1308 S ./sevendrvtest 777 0 1308 D ./sevendrvtest 778 0 1308 D ./sevendrvtest 779 0 1308 D ./sevendrvtest 780 0 3096 R ps # key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1key_val: 0x1, ret = 1key_val: 0x81, ret = 1
也可以用异步通知，驱动程序不变，测试源码改为:
#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <stdio.h>#include <unistd.h>#include <signal.h>/*sevendrvtest */int fd;void my_signal_func(int signum){unsigned char key_val;//printf("signum = %d\n", signum);read(fd, &key_val, 1);printf("key_val = 0x%x\n", key_val);}int main(int argc, char **argv){int O_FLAGS,ret=0;unsigned char key_val=0;signal( SIGIO, my_signal_func); /*安装信号处理函数*/fd = open("/dev/buttons", O_RDWR);if (fd < 0){printf("can't open!, fd = %d\n", fd);return -1;}fcntl( fd, F_SETOWN, getpid());O_FLAGS = fcntl(fd, F_GETFL);fcntl(fd, F_SETFL, O_FLAGS|O_ASYNC);while (1){sleep(5); //屏蔽掉，因为read没有按键产生，six_drv_read会休眠}return 0;}测试结果:
# ps PID Uid VSZ Stat Command 1 0 3092 S init 2 0 SW< [kthreadd] 3 0 SWN [ksoftirqd/0] 4 0 SW< [watchdog/0] 5 0 SW< [events/0] 6 0 SW< [khelper] 55 0 SW< [kblockd/0] 56 0 SW< [ksuspend_usbd] 59 0 SW< [khubd] 61 0 SW< [kseriod] 73 0 SW [pdflush] 74 0 SW [pdflush] 75 0 SW< [kswapd0] 76 0 SW< [aio/0] 710 0 SW< [mtdblockd] 745 0 SW< [kmmcd] 762 0 SW< [rpciod/0] 770 0 3096 S -sh 776 0 1312 S ./sevendrvtest 777 0 1308 D ./sevendrvtest 778 0 1308 D ./sevendrvtest 779 0 1308 D ./sevendrvtest 781 0 3096 R ps # kill -9 776 777 778 779# [4] + Killed ./sevendrvtest[3] + Killed ./sevendrvtest[2] + Killed ./sevendrvtest[1] + Killed ./sevendrvtest# # ./sevendrvtest &# driver: sixth_drv_fasync# ./sevendrvtest &# ./sevendrvtest &# ./sevendrvtest &# ps PID Uid VSZ Stat Command 1 0 3092 S init 2 0 SW< [kthreadd] 3 0 SWN [ksoftirqd/0] 4 0 SW< [watchdog/0] 5 0 SW< [events/0] 6 0 SW< [khelper] 55 0 SW< [kblockd/0] 56 0 SW< [ksuspend_usbd] 59 0 SW< [khubd] 61 0 SW< [kseriod] 73 0 SW [pdflush] 74 0 SW [pdflush] 75 0 SW< [kswapd0] 76 0 SW< [aio/0] 710 0 SW< [mtdblockd] 745 0 SW< [kmmcd] 762 0 SW< [rpciod/0] 770 0 3096 S -sh 782 0 1308 S ./sevendrvtest 783 0 1308 D ./sevendrvtest 784 0 1308 D ./sevendrvtest 785 0 1308 D ./sevendrvtest 786 0 3096 R ps # key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x2key_val = 0x82key_val = 0x2key_val = 0x82key_val = 0x2key_val = 0x82key_val = 0x2key_val = 0x82key_val = 0x2key_val = 0x82key_val = 0x2key_val = 0x82key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1key_val = 0x81key_val = 0x1
计时5sS3C2410 Timer Tick由965663变为966585,966585-965663=922,可知大约5s ,1000此定时器中断，即HZ=200，而在本实验中在HZ上ctrl+鼠标左键,HZ=100,和内核的并不相同
# cat proc/interrupts CPU0 16: 179 s3c-ext0 S2 18: 194 s3c-ext0 S3 30: 965663 s3c S3C2410 Timer Tick 32: 0 s3c s3c2410-lcd 33: 0 s3c s3c-mci 34: 0 s3c I2SSDI 35: 0 s3c I2SSDO 37: 12 s3c s3c-mci 42: 0 s3c ohci_hcd:usb1 43: 0 s3c s3c2440-i2c 51: 1613 s3c-ext eth0 55: 0 s3c-ext S4 60: 0 s3c-ext s3c-mci 63: 0 s3c-ext S5 70: 176 s3c-uart0 s3c2440-uart 71: 1067 s3c-uart0 s3c2440-uart 79: 20 s3c-adc s3c2410_action 80: 20332 s3c-adc s3c2410_action 83: 0 - s3c2410-wdtErr: 0# cat proc/interrupts CPU0 16: 179 s3c-ext0 S2 18: 194 s3c-ext0 S3 30: 966585 s3c S3C2410 Timer Tick 32: 0 s3c s3c2410-lcd 33: 0 s3c s3c-mci 34: 0 s3c I2SSDI 35: 0 s3c I2SSDO 37: 12 s3c s3c-mci 42: 0 s3c ohci_hcd:usb1 43: 0 s3c s3c2440-i2c 51: 1623 s3c-ext eth0 55: 0 s3c-ext S4 60: 0 s3c-ext s3c-mci 63: 0 s3c-ext S5 70: 178 s3c-uart0 s3c2440-uart 71: 1104 s3c-uart0 s3c2440-uart 79: 20 s3c-adc s3c2410_action
0 0
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