GPIO中断（一）GPIO简单驱动

要写pxa270上的GPIO中断，迟迟没有进展，无奈，从基础开始，先连个按键做简单的中断，但是因为中断号方面的问题，始终看不出效果，没办法，先做个简单的GPIO驱动吧，就让GPIO9号引脚隔两秒变成低电平，再隔两秒变成高电平，很快实现。

没什么难度，就是终于有一点可视的效果了（示波器），记录结果，做个基础的滚回点吧。代码如下：

 

 

（1）驱动程序irq_driver.c

 

#include<linux/config.h>

#include<linux/module.h>

#include<linux/devfs_fs_kernel.h>

#include<linux/interrupt.h>

#include<linux/kernel.h>

#include<linux/fs.h>

#include<linux/init.h>

#include<linux/unistd.h>

#include<linux/signal.h>

#include<linux/jiffies.h>

#include<asm/param.h>

 

#include<linux/miscdevice.h>

#include<linux/sched.h>

#include<linux/delay.h>

#include<linux/poll.h>

#include<linux/spinlock.h>

#include<linux/delay.h>

#include<asm/system.h>

#include<asm/hardware.h>

 

#include<asm/arch/pxa-regs.h>

#include<asm/arch/irqs.h>

 

 

#define DEVICE_NAME "irq_270"

#define IRQ_MAJOR 0

 

staticint irq_major=IRQ_MAJOR;

 

staticvoid GPIO_init()

   {

      GPDR0|=(0x1<<9);         //GPIO第9位置，表输出

      GPSR0|=(0x1<<9);         //置高

      printk("GPIO_init ok!\n");    

   }

 

   staticvoid GPIO_low()

   {

      GPCR0|=(0x1<<9);

   }

 

   staticvoid GPIO_heigh()

   {

      GPSR0|=(0x1<<9);

   }

 

   staticint irq_open(struct inode *inode ,struct file *file)

   {

      printk(DEVICE_NAME"open success!\n");

      return 0;

   }

  

   staticint irq_release(struct inode *inode ,struct file *filp)

   {

      printk(DEVICE_NAME "release!\n");

      return 0;

   }

 

   static ssize_t irq_read(struct file *filp, char *buff, size_t count, loff_t *ppos)

   {

      printk("user read data from driver\n");

      return count;

   }

   staticint gpio_ioctl(struct inode *inode,struct file *file,unsignedint cmd,unsignedlong arg)

   {

      switch(cmd){

         case 0:

            {

            GPIO_low();

            printk("GPIO to low level!\n");

            }break;

         case 1:

            {

            GPIO_heigh();

            printk("GPIO to high level!\n");

            }break;

         default:

            printk("error cmd number\n");break;

         }

      return 0;

   }

 

   staticstruct file_operations irq_fops={

      owner: THIS_MODULE,

      read: irq_read,

      ioctl: gpio_ioctl,

      open: irq_open,

      release: irq_release,

   };

 

   staticint __init irq_init(void)

   {

      int ret=-1;

      int flags;

      ret=register_chrdev(irq_major,DEVICE_NAME,&irq_fops);

      if(ret<0)

      {

         printk("pxa270:init_irq failed with %d.\n[--kernel--]",ret);

         return ret;

      }

      GPIO_init();

      printk(DEVICE_NAME "initialized\n");

      return 0;

   }

 

   staticvoid __exit irq_exi(void)

   {

      unregister_chrdev(irq_major,"GPIO9");

      printk(DEVICE_NAME "unload!\n");

   }

 

   module_init(irq_init);

   module_exit(irq_exi);

   MODULE_DESCRIPTION("IRQ module");

   MODULE_LICENSE("GPL");

 

（2）测试程序irq_test.c

#include<stdio.h>

#include<stdlib.h>

#include<fcntl.h>

#include<unistd.h>

#include<sys/ioctl.h>

 

int main()

{

   int fd;

   int r_buf[1024];

   fd=open("/dev/irq",O_RDONLY);

   if(fd !=-1);

   else

      printf("Device open failure!\n");

   while(1)

      {

         ioctl(fd,0,NULL);

         sleep(2);

         ioctl(fd,1,NULL);

         sleep(2);

      } 

   close(fd);

   return 0;

}

 

（3）Makefile文件

 

PWD=$(shell pwd)

KERNEL:= /up-techpxa270/kernel/linux-2.6.9

obj-m := irq_driver.o

module-objs:=irq_driver.o

all:

    $(MAKE) -C$(KERNEL) M=$(PWD) modules

clean:

    rm *.mod.c

    rm *.ko

    rm *.o

 

运行：

insmod irq_driver.ko

mknod /dev/irq c 253 0

./test

卸载：

rmmod irq_driver.ko

rm /dev/irq

转载于:https://www.cnblogs.com/icelemon/archive/2012/06/13/2547954.html