4412驱动-key 按键驱动

//key_driver.c

#include <linux/module.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/init.h>#include <linux/delay.h>#include <asm/uaccess.h>#include <asm/irq.h>#include <asm/io.h>#include <linux/of.h>#include <linux/of_device.h>#include <linux/of_platform.h>static struct class *keydrv_class;static struct class_device*keydrv_class_dev;#define DEV_NAME"key-dev"//定义按键配置寄存器的地址 #define GPX3CON     0x11000C60volatile unsigned long *button_config = NULL ; volatile unsigned long *button_dat = NULL ; //open方法 int key_open(struct inode *inode, struct file *filp){printk("key_open\n");//配置4个按键为输入状态，因为按键是从GPXCON[2]开始的，所以要左移8位到对应的位置，将8位以后的16位清0//这样的话就将按键配置的寄存器设置为输入状态了，因为输入是0x0 //*button_config &= ~(0xffff << 8);*button_config  &= ~((0xf<<(2*4)) | (0xf<<(3*4)) | (0xf<<(4*4)) | (0xf<<(5*4)));return 0;}//read方法 ssize_t key_read(struct file *file , char __user *buf ,size_t size ,loff_t *offset){//如果传进来的size小于4，那么就返回-1 if(size < 4){return -1 ; }unsigned char key_val  ;//获取按键的键值，因为按键是从该寄存器的第二位开始的，所以需要左移2位，接着与上0xf---1111//这样，如果用户按下按键，就会返回一个键值保存在key_val这个变量里 key_val = (*button_dat >> 2) & 0xf ;//将获取到的值拷贝到用户空间 copy_to_user(buf , &key_val , sizeof(key_val));//返回键值 return  key_val ;}//close方法 int key_close(struct inode *inode, struct file *filp){printk("key_close\n");return 0;}struct file_operations fops = {.owner = THIS_MODULE ,.open = key_open,.read = key_read,.release = key_close,};int major ;int test_init(void){printk("key_init\n");//注册设备 major = register_chrdev(0, DEV_NAME, &fops);keydrv_class = class_create(THIS_MODULE, DEV_NAME);keydrv_class_dev = device_create(keydrv_class, NULL, MKDEV(major, 0), NULL, DEV_NAME); /* /dev/xyz *///映射端口 button_config = (volatile unsigned long *)ioremap(GPX3CON , 16);button_dat = button_config + 1 ;return 0;}void test_exit(void){printk("key_exit\n");//注销设备 unregister_chrdev(major, DEV_NAME);device_destroy(keydrv_class,  MKDEV(major, 0));class_destroy(keydrv_class);//取消映射 iounmap(button_config);}module_init(test_init);module_exit(test_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("hai");MODULE_VERSION("2017.4.30");

// key_test.c

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#define DEV_NAME"/dev/key-dev"void delay(void);int main(int argc, char **argv){int fd;unsigned int val = 0 ;char key_buf[4] = {0};fd = open(DEV_NAME,O_RDWR) ;if(-1 == fd){printf("open fair!\n");return -1 ;}while(1){//在这里，我已经提前做了一个程序将按键的值读出来了，那么直接看就行了。 val = read(fd , key_buf , 4);switch(val){case 7 :printf("the first_key press! key_val=%u\n",val);delay();break;case 11:printf("the second_key press! key_val=%u\n",val);delay();break ;case 13:printf("the third_key press! key_val=%u\n",val);delay();break ;case 14:printf("the fourth_key press! key_val=%u\n",val);delay();break ;default :   printf("no key is press!\n");  delay();}}return 0;}void delay(void){unsigned int i = 0xffffff ; while(i--);}

//Makefile

KERN_DIR = /home/tools/linux-3.5all:make -C $(KERN_DIR) M=`pwd` modules clean:make -C $(KERN_DIR) M=`pwd` cleanrm -rf modules.orderobj-m+= key_driver.o