蜂鸣器驱动代码

驱动程序：beep_drv.c

 #include
 #include
 #include
 #include

 static int beep_major = 0;
 static struct class *pClass = NULL;
 module_param(beep_major, int, 0);
 MODULE_AUTHOR("woshishui");
 MODULE_LICENSE("GPL");

 #define BEEP_MAGIC 'k'
 #define BEEP_START_CMD _IO (BEEP_MAGIC, 1)
 #define BEEP_STOP_CMD _IO (BEEP_MAGIC, 2)

 /*
  * Open the device; in fact, there's nothing to do here.
  */
 int beep_open (struct inode *inode, struct file *filp)
 {
     return 0;
 }

 ssize_t beep_read(struct file *file, char __user *buff, size_t count, loff_t *offp)
 {

     *buff = gpio_get_value(S5PV210_GPD0(0));//获取引脚的电平值

     return 0;
 }

 ssize_t beep_write(struct file *file, const char __user *buff, size_t count, loff_t *offp)
 {
     return 0;
 }

 void beep_stop( void )
 {
     s3c_gpio_cfgpin(S5PV210_GPD0(0), S3C_GPIO_OUTPUT);//设置引进为输出状态
     s3c_gpio_setpull(S5PV210_GPD0(0), S3C_GPIO_PULL_NONE);//不设置上拉
     gpio_set_value(S5PV210_GPD0(0), 0);//设置引脚为低电平，即不要蜂鸣器响
 }

 void beep_start( void )
 {
     s3c_gpio_cfgpin(S5PV210_GPD0(0), S3C_GPIO_OUTPUT);
     s3c_gpio_setpull(S5PV210_GPD0(0), S3C_GPIO_PULL_NONE);
     gpio_set_value(S5PV210_GPD0(0), 1);//设置引脚为高电平，即要蜂鸣器响
 }

 static int beep_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 {
     switch ( cmd ) {
         case BEEP_START_CMD: {
             beep_start();   break;
         }
         case BEEP_STOP_CMD: {
             beep_stop();    break;
         }
         default: {
             break;
         }
     }
     return 0;
 }

 static int beep_release(struct inode *node, struct file *file)
 {
     return 0;
 }

 /*
  * Our various sub-devices.
  */
 /* Device 0 uses remap_pfn_range */
 static struct file_operations beep_remap_ops = {
     .owner   = THIS_MODULE,
     .open    = beep_open,
     .release = beep_release,
     .read    = beep_read,
     .write   = beep_write,
     .ioctl   = beep_ioctl,
 };

 /*
  * There's no need for us to maintain any
  * special housekeeping info, so we just deal with raw cdevs.
  */
 static struct cdev BeepDevs;

 /*
  * Module housekeeping.
  */
 static int beep_init(void)
 {
     int result;
     dev_t dev = MKDEV(beep_major, 0);

     s3c_gpio_cfgpin(S5PV210_GPD0(0), S3C_GPIO_OUTPUT);
     s3c_gpio_setpull(S5PV210_GPD0(0), S3C_GPIO_PULL_NONE);
     gpio_set_value(S5PV210_GPD0(0), 0);

     /* Figure out our device number. */
     if (beep_major)
         result = register_chrdev_region(dev, 1, "beep");
     else {
         result = alloc_chrdev_region(&dev, 0, 1, "beep");
         beep_major = MAJOR(dev);
     }
     if (result < 0) {
         printk(KERN_WARNING "beep: unable to get major %d\n", beep_major);
         return result;
     }
     if (beep_major == 0)
         beep_major = result;

     /* Register a class_device in the sysfs. */
     pClass = class_create(THIS_MODULE, "beep");//注册一个类，使mdev可以在"/dev/"目录下面建立设备节点,在设备中动态创建节点
     if(NULL == pClass)
     {
         unregister_chrdev_region(dev, 1);
         return -1;
     }
     device_create(pClass, NULL, dev, NULL, "beep");
     /* Now set up cdev. */
     cdev_init(&BeepDevs, &beep_remap_ops);
     BeepDevs.owner = THIS_MODULE;
     result = cdev_add (&BeepDevs, dev, 1);
     if(result != 0)
     {
         device_destroy(pClass, dev);
         class_destroy(pClass);
         unregister_chrdev_region(dev, 1);
         return -1;
     }

     printk("beep device installed, with major %d\n", beep_major);
     return 0;
 }

 static void beep_cleanup(void)
 {
     cdev_del(&BeepDevs);
     unregister_chrdev_region(MKDEV(beep_major, 0), 1);
     printk("beep device uninstalled\n");
 }

 module_init(beep_init);
 module_exit(beep_cleanup);
 EXPORT_SYMBOL(beep_major);

 //1.自动获取主设备号、次设备号
 //2.动态生成设备节点（dev/  目录下）
 //  动态卸载

驱动程序的Makefile：

 ifeq ($(KERNELRELEASE),)

 KERNELDIR ?=/home/fs/linux-3.14 //内核编码

 #当前Makefile目录
 PWD := $(shell pwd)

 #   -C $(KERNELDIR)指明跳转到内核源码目录下读取那里的Makefile
 #   M=$(PWD) 表明然后返回到当前目录继续读入、执行当前的Makefile
 modules:
     $(MAKE) -C $(KERNELDIR) M=$(PWD) modules

 modules_install:
     $(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install

 clean:
     rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions

 .PHONY: modules modules_install clean

 else
     obj-m := beep_drv.o
 endif

应用程序：beep_test.c

 #include
 #include
 #include
 #include

 #define BEEP_MAGIC 'k'
 #define BEEP_START_CMD _IO (BEEP_MAGIC, 1)
 #define BEEP_STOP_CMD _IO (BEEP_MAGIC, 2)

 int main()
 {
     int i = 0;
     char buf;
     int dev_fd;
     dev_fd = open("/dev/beep",O_RDWR | O_NONBLOCK);
     if ( dev_fd == -1 ) {
         printf("Cann't open file /dev/beep\n");
         exit(1);
     }
     while(1)
     {
         getchar();
         ioctl (dev_fd, BEEP_START_CMD,0);
         read(dev_fd,&buf,sizeof(buf));
         printf("The value of the buzzer:%d\n",buf);

         getchar();
         ioctl (dev_fd, BEEP_STOP_CMD,0);
         read(dev_fd,&buf,sizeof(buf));
         printf("The value of the buzzer:%d\n",buf);
     }
     return 0;
 }
   应用程序要arm-none-linux-gnuebi-gcc 编译器编译，把编译好的可执行程序放到NFS下，在开发板下运行该程序。