热度 22
2012-4-8 11:02
4501 次阅读|
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这里本人使用中断形式实现按键的驱动,首先还是先呈上源程序: #include linux/kernel.h #include linux/module.h #include linux/init.h #include linux/fs.h #include linux/gpio.h #include linux/types.h #include linux/cdev.h #include linux/interrupt.h #include linux/sched.h #include linux/device.h #include linux/poll.h #include linux/semaphore.h #include linux/timer.h #include asm/irq.h #include asm/uaccess.h //#include mach/hardware.h #include mach/irqs.h #define DEVICE_NAME "keyint" #define KEYNUM 6 dev_t devid; static DEFINE_SEMAPHORE(key_lock); //declare a mutex lock for keyint static struct fasync_struct *key_async; static struct timer_list key_timer; struct key_irq_desc { int irq; //irq num unsigned long flags; //irq flags,identified the way of irq here,eq.edge,level char *name; //irq name }; static struct key_irq_desc key_irqs = {0,0,0,0,0,0}; static irqreturn_t keys_interrupt(int irq, void *dev_id) { volatile int *press_cnt = (volatile int *) dev_id; /*set the pressed key flag(must do here due to not be static value)*/ *press_cnt = *press_cnt + 1; mod_timer(key_timer,jiffies+HZ/100); //start timer after 10ms return IRQ_RETVAL(IRQ_HANDLED); } static void key_timer_func(unsigned long data) { ev_press = 1; wake_up_interruptible(key_waitq); kill_fasync(key_async, SIGIO, POLL_IN); } static int key_fasync(int fd, struct file *filp, int on) { printk("Function key_fasync\n"); return fasync_helper(fd,filp,on,key_async); } static unsigned key_poll(struct file *file, poll_table *wait) { unsigned int mask=0; poll_wait(file,key_waitq,wait); if(ev_press) mask |= POLL_IN | POLLRDNORM; printk("poll wait\n"); return mask; } static int key_open(struct inode *inode, struct file *file) { int num; if(file-f_flags O_NONBLOCK) { if(down_trylock(key_lock)) return -EBUSY; } else { down(key_lock); } for(num=0;numKEYNUM;num++) { request_irq(key_irqs .irq, keys_interrupt, key_irqs .flags, key_irqs .name, (void *)press_cnt ); } return 0; } static int key_close(struct inode *inode, struct file *file) { int num; for(num=0;num6;num++) { free_irq(key_irqs .irq, (void *)press_cnt ); } up(key_lock); printk("key_close free irqs\n"); return 0; } static int key_read(struct file *filp, char __user *buff, size_t count, loff_t *offp) { // unsigned int err; if(filp-f_flags O_NONBLOCK) { if(!ev_press) return -EAGAIN; } else { /*if ev_press==0,then sleep*/ wait_event_interruptible(key_waitq,ev_press); } ev_press = 0; copy_to_user(buff,(const void *)press_cnt,min(sizeof(press_cnt),count)); memset((void *)press_cnt,0,sizeof(press_cnt)); // printk("read and clean press_cnt\n"); return 1; } static struct file_operations key_ops = { .owner = THIS_MODULE, .open = key_open, .release = key_close, .read = key_read, .poll = key_poll, .fasync = key_fasync, }; static struct cdev *cdev_keyint; static struct class *keyint_class; static int __init s3c6410_keyint_init(void) { int val; /*timer initial */ init_timer(key_timer); key_timer.function = key_timer_func; add_timer(key_timer); /*register device*/ val = alloc_chrdev_region(devid,0,1,DEVICE_NAME); if(val) { return -1; printk("register keyint error\n"); } cdev_keyint = cdev_alloc(); cdev_init(cdev_keyint, key_ops); cdev_keyint-owner = THIS_MODULE; cdev_keyint-ops = key_ops; val = cdev_add(cdev_keyint,devid,1); if(val) { return -1; printk("add device error\n"); } keyint_class = class_create(THIS_MODULE,DEVICE_NAME); device_create(keyint_class,NULL,devid,NULL,"%s",DEVICE_NAME); printk("KEY initialezed ^_^\n"); return 0; } static void __exit s3c6410_keyint_exit(void) { cdev_del(cdev_keyint); device_destroy(keyint_class,devid); class_destroy(keyint_class); unregister_chrdev_region(devid,1); } module_init(s3c6410_keyint_init); module_exit(s3c6410_keyint_exit); MODULE_LICENSE("GPL"); 下面贴上测试程序^_^: #include stdio.h #include stdlib.h #include unistd.h #include sys/ioctl.h int main(int argc, char **argv) { int fd; int val; int i; int press_cnt ; fd = open("/dev/keyint",0); if(fd0) { printf("open devie error\n"); return -1; } while(1) { val = read(fd,press_cnt, sizeof(press_cnt)); if(val0) { printf("read error\n"); continue; } for(i=0;i6;i++) { if(press_cnt ) printf("KEY%d pressed\n",(i+1),press_cnt ); } } close(fd); return 0; } 将测试程序编译后放到目标板上执行,可以看到哪个键按下时候会显示到终端。 本着互利互惠,共同分享的原则,依然奉献到底,贴上makefile: 执行程序makefile: CROSS_COMPILE=/usr/local/arm/4.2.2-eabi/usr/bin/arm-unknown-linux-gnueabi- keyint_test : keyint_test.c $(CROSS_COMPILE)gcc $^ -o $@ clean: rm -rf *~ 模块编译makefile: KDIR = /home/xu/Documents/linux-3.0.24 PWD = $(shell pwd) obj-m += keyint.o default: $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules clean: rm -rf *.o *~ *.mod.o *.mod.c 以上就是简单的按键驱动了,在记录自己的点滴的同时也希望能给比我更为初学的人(no offense/并无恶意 )以帮助。