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Linux 驅動——Button驅動1

static 驅動 val makefile mod not turn fops button

button_drv.c驅動文件:

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/io.h>           //包含iomap函數iounmap函數
#include <asm/uaccess.h>       //包含copy_from_user函數
#include <linux/device.h>       //包含class類相關的處理函數
#include <linux/fs.h>         //包含

file_operations結構體

#define DRIVER_NAME "button_drv"
#define DEVICE_NAME "button_dev"

int major;

static struct class *buttondrv_class;
static struct class_device *buttondrv_class_dev;

volatile unsigned long *gpfcon = NULL;
volatile unsigned long *gpfdat = NULL;
volatile unsigned long *gpgcon = NULL;


volatile unsigned long *gpgdat = NULL;

static int button_drv_open(struct inode *inode, struct file *file)
{
  *gpfcon &= ~((0x3<<(0*2)) | (0x3<<(2*2)));
  *gpgcon &= ~((0x3<<(3*2)) | (0x3<<(11*2)));
  return 0;
}

static int button_drv_read(struct file * file, char __user * userbuf, size_t count, loff_t * off)


{
  int ret;
  unsigned char keyVal[4];
  unsigned long keyVals;

  if(count!=sizeof(keyVal))
  {
    printk("button_drv_read error 1 \n");
  }

  keyVals = *gpfdat;
  keyVal[0] = ((keyVals>>0) & 1);
  keyVal[1] = ((keyVals>>2) & 1);
  keyVals = *gpgdat;
  keyVal[2] = ((keyVals>>3) & 1);
  keyVal[3] = ((keyVals>>11) & 1);
  
  ret = copy_to_user(userbuf, keyVal, sizeof(keyVal));
  if(ret<0)
  {
    printk("button_drv_read error 2 \n");
  }

  return sizeof(keyVal);
}

static struct file_operations button_drv_fops = {
  .owner = THIS_MODULE,
  .open = button_drv_open,
  .read = button_drv_read,
};

static int button_drv_init(void)
{
  major = register_chrdev(0, DRIVER_NAME, &button_drv_fops);

  buttondrv_class = class_create(THIS_MODULE, DEVICE_NAME);
  buttondrv_class_dev = class_device_create(buttondrv_class, NULL, MKDEV(major, 0), NULL, DEVICE_NAME);

  gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);
  gpfdat = gpfcon + 1;
  gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);
  gpgdat = gpgcon + 1;
  return 0;
}

static void button_drv_exit(void)
{
  unregister_chrdev(major, DRIVER_NAME);
  class_device_unregister(buttondrv_class_dev);
  class_destroy(buttondrv_class);
  iounmap(gpfcon);
  iounmap(gpgcon);
}

module_init(button_drv_init);
module_exit(button_drv_exit);

MODULE_LICENSE("GPL");

Makefile文件:

obj-m += button_drv.o

KERN_DIR = /work/system/linux-2.6.22.6

all:
make -C $(KERN_DIR) M=`pwd` modules
clean:
rm -rf *.o *.ko *.order *.symvers *.mod.c

button_app.c文件:

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>

int main(int argc, char **argv)
{
  int fd;
  int val;
  char *filename;
  unsigned char keyVal[4];

  filename = argv[1];
  fd = open(filename, O_RDWR);
  if(fd<0)
  {
    printf("can not open \n");
  }

  while(1)
  {
    read(fd, keyVal, sizeof(keyVal));
    if(!keyVal[0] || !keyVal[1] || !keyVal[2] || !keyVal[3])
    {
      printf("key pressed %d %d %d %d \n", keyVal[0], keyVal[1], keyVal[2], keyVal[3]);
    }
  }

  return 0;
}

編譯生成button_drv.ko文件和button_app文件,運行:./button_app /dev/button_dev

Linux 驅動——Button驅動1