我的第一个驱动程序_第一个驱动源码-优快云博客

本文详细介绍了如何使用C语言和Linux内核开发一个LED驱动程序，并提供了完整的代码实现及测试程序，包括初始化、注册字符设备、GPIO配置、驱动操作等关键步骤。

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arm编译器版本:3.32

内核版本:2.6.28.7

arm号:s3c2440

驱动源码:

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/types.h>
#include <linux/device.h>

#include <asm/hardware.h>
#include <asm/regs-gpio.h>

#define DEVICE_NAME "leds"
#define LED_MAJOR   237
dev_t devnm=MKDEV(LED_MAJOR,0);
static struct cdev *leds_cdev;
static struct class *my_class;

MODULE_LICENSE("Dual BSD/GPL");

static int leds_ioctl(struct inode *inode,struct file *file,unsigned int cmd,unsigned long arg)
{
   switch(cmd)
   {
       case 0:   s3c2410_gpio_setpin(S3C2410_GPF5,cmd);return 0;break;
       case 1: s3c2410_gpio_setpin(S3C2410_GPF5,cmd);return 0;break;
       default: return -EINVAL;
   }
}

static struct file_operations leds_fops={
   .owner=THIS_MODULE,
   .ioctl=leds_ioctl,
};

static int leds_cdev_init(struct cdev *dev,int index)
{
   int err;
   dev->owner=THIS_MODULE;
   dev->ops=&leds_fops;
   cdev_init(dev,&leds_fops);

   err=cdev_add(dev,devnm,1);
   if(err)
   {
       printk("cdev err!\n");
       return err;
   }
   my_class=class_create(THIS_MODULE,DEVICE_NAME);
   if(IS_ERR(my_class))
   {
       printk("err class!\n");
       return -1;
   }
   device_create(my_class,NULL,devnm,NULL,"leds");
   return 0;
}


static int   leds_init(void)
{
   int ret=0;

   leds_cdev=cdev_alloc();
   if(leds_cdev==NULL)
   {
       printk(" cdev_alloc err!\n");
       return -1;
   }
   ret=register_chrdev(LED_MAJOR,DEVICE_NAME,&leds_fops);
   if(ret<0)
   {
       printk("DEVICE_NAME cat't register number!\n");
       return ret;
   }
   ret=leds_cdev_init(leds_cdev,0);
   s3c2410_gpio_cfgpin(S3C2410_GPF5,S3C2410_GPF5_OUTP);
   s3c2410_gpio_setpin(S3C2410_GPF5,1);

   printk(KERN_ALERT "Hello ,world\n");
   return 0;
}

static void leds_exit(void)
{
   cdev_del(leds_cdev);
   unregister_chrdev(LED_MAJOR,DEVICE_NAME);
   device_destroy(my_class,devnm);
   class_destroy(my_class);
   printk(KERN_ALERT "Goodbye ,cruel world\n");
}

module_init(leds_init);
module_exit(leds_exit);

编译Makefile :

obj-m:=leds.o
KDIR:=/home/share/linux
PWD:=$(shell pwd)

all:
   $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
   @rm -rf *.mod.*
   @rm -rf .*.cmd
   @rm -rf *.o
   @rm -rf Module.*

clean:
   @rm -rf *.ko

测试程序:

#include <stdio.h>
#include <sys/ioctl.h>
#include <fcntl.h>

int main(void)
{
   int on=0;
   int fp;
   fp=open("/dev/leds",0);
   if(fp<0)
   {
       printf("open led err!\n");
       return -1;
   }
   printf("start...................\n");
   while(1)
   {

       printf("helo %d\n",on);
       ioctl(fp,on,0);
       on=!on;
       usleep(400000);

   }
   close(fp);
   return 0;
}