Linux驱动开发之基于输入子系统按键驱动程序

1、驱动源代码

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <asm/irq.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <asm/arch/regs-gpio.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>
#include <linux/input.h>

struct input_dev *button_dev;
struct button_irq_desc {
int irq; //中断号
int pin; //对应的管脚
int pin_setting; //GPIO控制寄存器的配置
int number; //按键的编号
char *name; //按键的名称
};

static struct button_irq_desc button_irqs [] = {
{IRQ_EINT0 , S3C2410_GPF0 , S3C2410_GPF0_EINT0 , 0, "KEY0"},
{IRQ_EINT2, S3C2410_GPF2 , S3C2410_GPF2_EINT2 , 1, "KEY1"},
{IRQ_EINT11, S3C2410_GPG3 , S3C2410_GPG3_EINT11 , 2, "KEY2"},
{IRQ_EINT19, S3C2410_GPG11 , S3C2410_GPG11_EINT19 , 3, "KEY3"},
};

static int key_values = 0;

static irqreturn_t buttons_interrupt(int irq, void *dev_id)
{
struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;//获得设备信息
int down;
udelay(0);
down = !s3c2410_gpio_getpin(button_irqs->pin); //读取GPIO端口的信息，down: 1(按下)，0（弹起）
if (!down) { //按键弹起

   /*报告事件*/
   key_values = button_irqs->number;
   //printk("====>rising key_values=%d\n",key_values);
if(key_values==0)
   input_report_key(button_dev, KEY_1, 0);
if(key_values==1)
   input_report_key(button_dev, KEY_2, 0);
if(key_values==2)
   input_report_key(button_dev, KEY_3, 0);
if(key_values==3)
   input_report_key(button_dev, KEY_4, 0);

input_sync(button_dev);
    }

else { //按键按下

key_values = button_irqs->number; //获得是哪一个按键按下的
//printk("====>falling key_values=%d\n",key_values);
if(key_values==0) //0号按键按下
input_report_key(button_dev, KEY_1, 1); //提交按键按下事件
if(key_values==1)//1号按键按下
input_report_key(button_dev, KEY_2, 1);
if(key_values==2)//2号按键按下
input_report_key(button_dev, KEY_3, 1);
if(key_values==3)//3号按键按下
input_report_key(button_dev, KEY_4, 1);
input_sync(button_dev); //发送同步事件

}

return IRQ_RETVAL(IRQ_HANDLED);//中断返回
}

static int s3c24xx_request_irq(void)
{
int i;
int err = 0;

for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {

               if (button_irqs[i].irq < 0) { //中断号检查
                               continue;
                   }
    /* IRQ_TYPE_EDGE_FALLING,IRQ_TYPE_EDGE_RISING,IRQ_TYPE_EDGE_BOTH */
err = request_irq(button_irqs[i].irq, buttons_interrupt, IRQ_TYPE_EDGE_BOTH, //中断为双边沿触发
button_irqs[i].name, (void *)&button_irqs[i]); //注册中断
if (err)
break;
}

if (err) { //中断注册出错处理
i--;
for (; i >= 0; i--) {
   if (button_irqs[i].irq < 0) {
       continue;
   }
   disable_irq(button_irqs[i].irq);
free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);//注销中断
}
return -EBUSY;
}

return 0;
}

static int __init dev_init(void)
{

/*request irq*/
s3c24xx_request_irq(); //中断初始化函数
   /* Initialise input stuff */
   button_dev = input_allocate_device(); //分配输入设备
   if (!button_dev) {
       printk(KERN_ERR "Unable to allocate the input device !!\n");
       return -ENOMEM;
   }
   button_dev->name = "s3c2440_button"; //设置输入设备的名称
   button_dev->id.bustype = BUS_RS232; //设置输入设备的ID信息
button_dev->id.vendor = 0xDEAD;
button_dev->id.product = 0xBEEF;
button_dev->id.version = 0x0100;

   button_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_SYN);//设置设备支持的事件
   //set_bit(EV_KEY, button_dev->evbit)//支持EV_KEY事件
   set_bit(KEY_1, button_dev->keybit); //设置键盘的键值
   set_bit(KEY_2, button_dev->keybit);
   set_bit(KEY_3, button_dev->keybit);
   set_bit(KEY_4, button_dev->keybit);
   //printk("KEY_RESERVED=%d ,KEY_1=%d",KEY_RESERVED,KEY_1);
   input_register_device(button_dev); //注册input设备

printk ("initialized\n");

return 0;
}

static void __exit dev_exit(void)
{
   int i;

for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {
       if (button_irqs[i].irq < 0) {
       continue;
           }
       free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);//注销中断
}

input_unregister_device(button_dev);//注销输入设备
}

module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");

2、Makefile

ifeq ($(KERNELRELEASE),)
KDIR := /home/source/linux-2.6.22.6/
PWD := $(shell pwd)
all:
$(MAKE) -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-linux-
clean:
$(MAKE) -C $(KDIR) M=$(PWD) clean
else
obj-m := input_button.o
endif

3、应用程序

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/select.h>
#include <sys/time.h>
#include <errno.h>
#include <linux/input.h>
int main(void)
{
int buttons_fd;
int key_value,i=0,count;

   struct input_event ev_key;
   buttons_fd = open("/dev/event1", O_RDWR); //阻塞方式打开设备
   if (buttons_fd < 0) {
       perror("open device buttons");
       exit(1);
   }

   for (;;) {
       count = read(buttons_fd,&ev_key,sizeof(struct input_event));
       for(i=0; i<(int)count/sizeof(struct input_event); i++)
           if(EV_KEY==ev_key.type)
               printf("type:%d,code:%d,value:%d\n", ev_key.type,ev_key.code-1,ev_key.value);
           if(EV_SYN==ev_key.type)
               printf("syn event\n\n");

}

close(buttons_fd);
return 0;
}

Linux驱动开发之基于输入子系统按键驱动程序

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