Linux_arm驱动之按键模拟脉冲实现定时器的精确计时
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- /*****************************************************************
- 内核驱动部分button_ker.c
- *****************************************************************/
- /*
- *应用内核定时器简单实现计时的功能
- *但是内核定时器精确度最小就为50ms
- *较4_button_timer完善功能:利用硬件的定时器计时
- *精确度提高
- *应用linux-2.6.32.2内核里arch/arm/plat_s3/timer.c
- *实现对定时器的精确提高问题
- */
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/fs.h>
- #include <linux/init.h>
- #include <linux/delay.h>
- #include <asm/irq.h>
- #include <linux/irq.h>
- #include <linux/interrupt.h>
- #include <asm/uaccess.h>
- #include <linux/timer.h>
- #include <linux/sched.h>
- //*****///
- #include <linux/clk.h>
- #include <plat/regs-timer.h>
- #include <asm/io.h>
- ///****///
- #include <linux/miscdevice.h>
- #include <mach/regs-irq.h>
- //#include <linux/platform_device.h>
- //#include <linux/miscdevice.h>
- //#include <mach/regs-gpio.h>
- #include <linux/wait.h>
- #define DEVICE_NAME "timer_test"
- #define BUTTON_MAJOR 240
- #define TIMER_IOCTL_SET_FREQ 1
- #define TIMER_IOCTL_STOP 0
- static struct semaphore lock;
- struct button_irq_desc{
- int irq;
- unsigned long flags;
- int num;
- char *name;
- };
- //用来指定按键所有的外部中断引脚以及中断出发方式和名字
- static struct button_irq_desc button_irqs[] = {
- {IRQ_EINT0,IRQF_TRIGGER_FALLING,1,"KEY1"},
- {IRQ_EINT1,IRQF_TRIGGER_FALLING,2,"KEY2"},
- {IRQ_EINT2,IRQF_TRIGGER_FALLING,3,"KEY3"},
- {IRQ_EINT4,IRQF_TRIGGER_FALLING,4,"KEY4"},
- };
- static volatile char key_values[4]={‘0‘,‘0‘,‘0‘,‘0‘};
- static DECLARE_WAIT_QUEUE_HEAD(button_waitq);
- static volatile int ev_press =0;
- static void timer_open(void);
- static void timer_stop(void);
- static inline int timer_interrupt_pending(void);
- static unsigned long get_timer_offset(void);
- ///********************************////
- static volatile bool value=false;
- static volatile unsigned long count = 0;
- static volatile unsigned long freq_value = 500;
- static volatile unsigned long tcnt_value = 50625;
- //定时器中断函数
- static irqreturn_t timer_interrupt_function(int irq,void *dev_id)
- {
- count++;
- //printk("timer_interrupt occur!\n");
- return IRQ_HANDLED;
- }
- //时间处理函数
- static void timer_second_manage(unsigned long second_value)
- {
- static volatile unsigned long ss_value1 = 0;
- static volatile unsigned long ms_value2 = 0;
- static volatile unsigned long us_value3 = 0;
- us_value3 = //(second_value*10000/tcnt_value)*1000/freq_value/10;
- (second_value*1000/freq_value)*10000/tcnt_value/10;
- ms_value2 = (count%freq_value)*1000/freq_value + us_value3/1000;
- ss_value1 = count/freq_value + ms_value2/1000;
- printk("++++++++++++++++++++++++\n");
- printk("used time:%lu n\n",count);
- printk("the second_value :%lu n\n",second_value);
- printk("used time:%lu.%03lu %03lu s\n",ss_value1,
- ms_value2%1000,us_value3%1000);
- printk("++++++++++++++++++++++++\n");
- }
- //外部中断函数
- static irqreturn_t button_interrupt(int irq,void *dev_id){
- unsigned long second_value = 0;
- int num= ((struct button_irq_desc *)dev_id)->num;
- switch(num){
- case 2://17
- value=false;
- timer_stop();
- printk("key1 press\n");
- break;
- case 4://48
- if(!value) {
- value=true; count=0;
- timer_open();
- }else {
- timer_stop();
- second_value=get_timer_offset();
- timer_second_manage(second_value);
- value=false;
- }
- printk("key2 press\n");
- break;
- case 3://18
- value=false;
- timer_stop();
- printk("key3 press\n");
- break;
- case 1://16
- value=false;
- timer_stop();
- printk("key4 press\n");
- break;
- default:
- printk("num error,nothing to do!\n");
- }
- //ev_press=1;
- //wake_up_interruptible(&button_waitq);
- return IRQ_HANDLED;
- }
- //频率设置函数
- //freq: pclk/50/16/65536~pclk/50/16
- //if : pclk=50mhz freq is 1Hz~62500Hz
- //human ear : 20Hz~20000Hz
- //
- static void timer_set_freq(unsigned long freq)
- {
- unsigned long tcon;
- unsigned long tcnt;
- unsigned long tcfg0;
- unsigned long tcfg1;
- struct clk *clk_p;
- unsigned long pclk;
- tcon = __raw_readl(S3C2410_TCON);
- tcfg0 = __raw_readl(S3C2410_TCFG0);
- tcfg1 = __raw_readl(S3C2410_TCFG1);
- tcfg0 &= ~(255<<0);
- //tcfg0 |= (50-1);
- tcfg0 |= 0;
- tcfg1 &= ~(15<<0);
- tcfg1 |= (0<<0);
- __raw_writel(tcfg0,S3C2410_TCFG0);
- __raw_writel(tcfg1,S3C2410_TCFG1);
- clk_p = clk_get(NULL,"pclk");
- pclk = clk_get_rate(clk_p);
- printk("the pclk is : %ld\n",pclk);
- //tcnt = (pclk/50/16)/freq;
- tcnt = (pclk/2)/freq;
- tcnt_value = tcnt;
- printk("the tcnt is %ld\n",tcnt);
- __raw_writel(tcnt,S3C2410_TCNTB(0));
- __raw_writel(0,S3C2410_TCMPB(0));
- //tcon &= ~0x1f;
- tcon &= ~0x1e;
- tcon |=0xb;
- __raw_writel(tcon,S3C2410_TCON);
- tcon &= ~2;
- __raw_writel(tcon,S3C2410_TCON);
- }
- static void timer_open(void)
- {
- unsigned long tcon = 0;
- //printk("***1>tcnto is :%u\n",__raw_readl(S3C2410_TCNTO(0)));
- tcon = __raw_readl(S3C2410_TCON);
- tcon |= 1;
- __raw_writel(tcon,S3C2410_TCON);
- //printk("***2>tcnto is :%u\n",__raw_readl(S3C2410_TCNTO(0)));
- }
- static void timer_stop(void)
- {
- unsigned long tcon;
- tcon = __raw_readl(S3C2410_TCON);
- tcon &= ~1;
- __raw_writel(tcon,S3C2410_TCON);
- }
- #define SRCPND_TIMER0 (1<<(IRQ_TIMER0 - IRQ_TIMER0))
- //中断识别函数 查看在按键产生中断时,定时器是否也在中断中
- static inline int timer_interrupt_pending(void)
- {
- return __raw_readl(S3C2410_SRCPND) & SRCPND_TIMER0;
- }
- //计算中断寄存器中TCNTO0中的偏移量
- static unsigned long get_timer_offset (void)
- {
- unsigned long tdone;
- unsigned long tval;
- tdone = (tcnt_value -__raw_readl(S3C2410_TCNTO(0)));
- if(timer_interrupt_pending()) {
- tval = __raw_readl(S3C2410_TCNTO(0));
- tdone = tcnt_value - tval;
- if(!tval)
- tdone += tcnt_value;
- }
- return tdone;
- }
- static struct irqaction timer_irq = {
- .name = "S3C2410 Timer Tick",
- .flags = IRQF_DISABLED |IRQF_TIMER|IRQF_IRQPOLL,
- .handler = timer_interrupt_function,
- .dev_id = NULL
- };
- static int button_open(struct inode *inode,struct file *file)
- {
- int i,err;
- if(down_trylock(&lock)){
- printk("down_trylock failed!\n");
- return -EBUSY;
- }
- if(setup_irq(IRQ_TIMER0,&timer_irq)){
- printk("setup_irq failed!\n");
- return -EBUSY;
- }
- for(i=0;i<sizeof(button_irqs)/sizeof(button_irqs[0]);i++) {
- err=request_irq(button_irqs[i].irq,button_interrupt,button_irqs[i].flags,
- button_irqs[i].name,(void*)&(button_irqs[i]));
- if(err)
- break;
- }
- if(err) {
- for(--i;i>=0;i--)
- free_irq(button_irqs[i].irq,(void *)&button_irqs[i].num);
- printk("request_irq error!\n");
- return -1;
- }
- disable_irq(IRQ_EINT0);
- disable_irq(IRQ_EINT1);
- disable_irq(IRQ_EINT2);
- disable_irq(IRQ_EINT4);
- set_irq_type(IRQ_EINT0,IRQ_TYPE_LEVEL_LOW);//key4
- set_irq_type(IRQ_EINT1,IRQ_TYPE_EDGE_RISING);//key1
- set_irq_type(IRQ_EINT2,IRQ_TYPE_EDGE_FALLING);//key3
- //set_irq_type(IRQ_EINT4,IRQ_TYPE_EDGE_BOTH);//key2
- set_irq_type(IRQ_EINT4,IRQ_TYPE_EDGE_FALLING);//key2
- enable_irq(IRQ_EINT0);
- enable_irq(IRQ_EINT1);
- enable_irq(IRQ_EINT2);
- enable_irq(IRQ_EINT4);
- return 0;
- }
- static int button_close(struct inode *inode,struct file *file)
- {
- int i;
- for(i=0;i<sizeof(button_irqs)/sizeof(button_irqs[0]);i++) {
- free_irq(button_irqs[i].irq,(void *)&button_irqs[i]);
- }
- remove_irq(IRQ_TIMER0,&timer_irq);
- up(&lock);
- return 0;
- }
- static int button_read(struct file *filp,char __user *buff,
- size_t count,loff_t *offp)
- {
- unsigned long err;
- if(filp->f_flags & O_NONBLOCK)
- return -EAGAIN;
- else {
- wait_event_interruptible(button_waitq,ev_press);
- }
- ev_press=0;
- err=copy_to_user(buff,(const void*)key_values,
- min(sizeof(key_values),count));
- return err ? -EFAULT : min(sizeof(key_values),count);
- }
- static int timer_ioctl(struct inode *inode,struct file *file,
- unsigned int cmd,unsigned long arg)
- {
- switch (cmd) {
- case TIMER_IOCTL_SET_FREQ:
- printk("timer_ioctl_set_freq\n");
- if(arg==0)
- return -EINVAL;
- timer_set_freq(arg);
- freq_value = arg;
- break;
- case TIMER_IOCTL_STOP:
- printk("timer_ioctl_stop\n");
- timer_stop();
- break;
- }
- return 0;
- }
- static struct file_operations button_fops = {
- .owner = THIS_MODULE,
- .open = button_open,
- .read = button_read,
- .release = button_close,
- .ioctl = timer_ioctl,
- };
- static struct miscdevice misc = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = DEVICE_NAME,
- .fops = &button_fops,
- };
- //初始化函数
- static int __init button_init(void)
- {
- init_MUTEX(&lock);
- /*
- if(register_chrdev(BUTTON_MAJOR,DEVICE_NAME,&button_fops)<0) {
- printk(DEVICE_NAME"can‘t register major number!\n");
- return -1;
- }
- printk(DEVICE_NAME"register sucess!\n");
- */
- if(misc_register(&misc)<0) {
- printk(DEVICE_NAME"can‘t register major number!\n");
- return -1;
- }
- printk(DEVICE_NAME"register sucess!\n");
- return 0;
- }
- static void __exit button_exit(void)
- {
- timer_stop();
- //unregister_chrdev(BUTTON_MAJOR,DEVICE_NAME);
- misc_deregister(&misc);
- }
- module_init(button_init);
- module_exit(button_exit);
- MODULE_LICENSE("GPL");
- /**********************************************************************
- 应用程序部分button_app.c
- **********************************************************************/
- #include <stdio.h>
- #include <stdlib.h>
- #include <unistd.h>
- #include <sys/ioctl.h>
- #define msleep(x) usleep(x*1000);
- #define TIMER_IOCTL_SET_FREQ 1
- #define TIMER_IOCTL_STOP 0
- int main(int argc,char **argv)
- {
- int fd;
- int ioarg=500;
- int press_cnt[4]={0};
- if((fd=open("/dev/timer_test",0))<0){
- printf("Can‘t open /dev/timer_test~!");
- return -1;
- }
- printf("sleep begin...\n");
- ioctl(fd,TIMER_IOCTL_SET_FREQ,ioarg);
- //msleep(70000);
- while(1)
- usleep(11111);
- ioctl(fd,TIMER_IOCTL_STOP);
- printf("sleep end...\n");
- close(fd);
- return 0;
- }
- /***************************************************************
- makefile部分
- ****************************************************************/
- ifneq ($(KERNELRELEASE),)
- obj-m := button_ker.o
- else
- KDIR :=/home/kernel/linux-2.6.32.2
- all:
- make -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-linux-
- arm-linux-gcc button_app.c -o button_app
- clean:
- rm -f *.ko *.o *.mod.o *.mod.c *.symvers modul*
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