多按键驱动程序优化
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发表于 2017/8/1 8:42:56
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多按键驱动优化
多按键支持
按键访问应用程序设计
相关代码
#include <linux/module.h> #include <linux/init.h> #include <linux/miscdevice.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/fs.h> #include <linux/uaccess.h> #define GPFCON 0x56000050 #define GPFDAT 0x56000054 struct work_struct *work1; struct timer_list key_timer ; unsigned int * gpio_data; unsigned int key_num; void work1_func(struct work_struct *work) { //printk("key down \n"); //启动定时器 //jiffies 是linux是全局变量,表示现在的时间(滴答数) mod_timer(&key_timer,jiffies + HZ/10);//HZ是1s,这里超时是100ms } void key_timer_func(unsigned long delta) { unsigned short data ; data = readw(gpio_data)&0x01 ; if( data == 0 ){ printk("key4 down \n"); key_num = 4; } data = readw(gpio_data)&0x04 ; if( data == 0 ){ printk("key3 down \n"); key_num = 3; } } irqreturn_t key_int(int irq , void * dev_id) { //提交下半部 schedule_work(work1); return 0; } void key_hw_init() { unsigned int * gpio_config; unsigned short data; gpio_config = ioremap(GPFCON,4); data = readw(gpio_config); data &= ~0b110011; data |= 0b100010; writew(data,gpio_config); gpio_data = ioremap(GPFDAT,4); } void key_open(struct inode *node, struct file *filp) { return 0 ; } ssize_t key_read(struct file *filp,char __user *buf,size_t size,loff_t *pos) { copy_to_user(buf,key_num,4); } struct file_operations key_fops={ .open = key_open, .read = key_read, }; struct miscdevice key_miscdev = { .minor = 200, .name = "key", .fops = &key_fops, }; static int button_init() { misc_register(&key_miscdev); //注册中断处理程序 request_irq(IRQ_EINT0,key_init,IRQF_TRIGGER_FALLING,"key",0); //K4 request_irq(IRQ_EINT2,key_init,IRQF_TRIGGER_FALLING,"key",0); //K3 //按键初始化 key_hw_init(); //创建工作 work1 = kmalloc(sizeof(struct work_struct),GFP_KERNEL); INIT_WORK(work1,work1_func); //初始化定时器 init_timer(&key_timer); //key_timer.expires = 10 ; key_timer.function = key_timer_func ; //注册定时器 add_timer(&key_timer); return 0 ; } static void button_exit() { misc_deregister(&key_miscdev); } module_init(button_init); module_exit(button_exit);
三、按键访问应用程序
#include <stdio.h> #include <stdlib.h> int main() { int fd,key_num; //1.打开设备 fd = open("/dev/2440key",0); if(fd < 0){ printf("open device fail!\n"); } //2.读取设备 read(fd,&key_num,4); printf("key is %d\n",key_num); //3.关闭设备 close(fd); }
四、创建设备文件
mknod /dev/2440key c 10 200 // 主设备号10(混杂设备),次设备号200, c是字符设备。