linux2.4和2.6在註冊設備驅動函數…

2.4內核註冊驅動要用：
int register_chrdev (unsigned int major, const char *name, struct file_operations *fops);
2.4內核註銷驅動要用：
int unregister_chrdev( unsigned int major, const char *name );
2.4內核驅動註冊完後，要用以下代碼創建設備文件
static devfs_handle_t devfs_handle;
devfs_handle = devfs_register( NULL, DEVICE_NAME, DEVFS_FL_DEFAULT,
         BUTTON_MAJOR,&sbc2410_buttons_fops, NULL);
2.4內核驅動要用以下代碼移除設備文件：
devfs_unregister( devfs_handle);
------------------------------------------------------------------------------------------- 

2.6驅動i註冊設備號要用：
（1）如果主設備號事先知道，要用：
int register_chrdev_region( dev_t first, unsigned int count, char *name );
（2）如果主設備號爲0，則要用動態分配：
int alloc_chrdev_region( dev_t *dev, unsigned int firstminor,unsigned int count, char *name );
2.6釋放設備號要用：
void unregister_chrdev_region( dev_t first, unsigned int count );
2.6內核字符設備驅動註冊要用：
struct cdev *my_cdev = cdev_alloc();
my_cdev->ops = &chr_fops;
void cdev_init( struct cdev *cdev, struct file_operations *fops);
int cdev_add( struct cdev *dev, dev_t num, unsigned int count);
2.6內核字符設備驅動移除要用：
void cdev_del( struct cdev *dev );
2.6內核驅動註冊完後，要用以下代碼創建設備文件

從linux內核2.6的某個版本之後，devfs不復存在，udev成爲devfs的替代。相比devfs，udev有很多優勢，在此就不羅嗦了，提醒一點，udev是應用層的東東，不要試圖在內核的配置選項裏找到它;加入對udev的支持很簡單，以作者所寫的一個字符設備驅動爲例，在驅動初始化的代碼裏調用class_create爲該設備創建一個class，再爲每個設備調用 class_device_create創建對應的設備。大致用法如下：
struct class *myclass = class_create(THIS_MODULE, “my_device_driver”);
class_device_create(myclass, NULL, MKDEV(major_num, 0), NULL, “my_device”);
這樣的module被加載時，udev daemon就會自動在/dev下創建my_device設備文件。
class_create()
-------------------------------------------------
linux-2.6.22/include/linux/device.h
struct class *class_create(struct module *owner, const char *name)
    class_create - create a struct class structure
    @owner: pointer to the module that is to "own" this struct class
    @name: pointer to a string for the name of this class.
在/sys/class/下創建類目錄
class_device_create()
-------------------------------------------------
linux-2.6.22/include/linux/device.h
struct class_device *class_device_create(struct class        *cls,
                                         struct class_device *parent,
                                         dev_t               devt,
                                         struct device       *device,
                                         const char          *fmt, ...)

    class_device_create - creates a class device and registers it with sysfs
    @cls: pointer to the struct class that this device should be registered to.
    @parent: pointer to the parent struct class_device of this new device, if any.
    @devt: the dev_t for the char device to be added.
    @device: a pointer to a struct device that is assiociated with this class device.
    @fmt: string for the class device's name 



以上也可以用命令創建設備文件：
mknod /dev/設備文件名字符設備(c是字符設備，b是塊設備)   主設備號次設備號
例如：mknod /dev/testChar c  100 0
刪除設備入口：
rm /dev/testChar
-------------------------------------------------------------------------------------------------- 2.4驅動總體編寫框架：
static int __init my_init(void)
{
 ／／註冊設備驅動
  register_chrdev (unsigned int major, const char *name, struct file_operations *fops);
 ／／創建設備文件
  static devfs_handle_t devfs_handle;
 devfs_handle = devfs_register( NULL, DEVICE_NAME, DEVFS_FL_DEFAULT,
  BUTTON_MAJOR,&sbc2410_buttons_fops, NULL);
}
static int __exit my_exit(void)
{
 ／／移除設備文件
  devfs_unregister( devfs_handle);
 ／／註銷設備驅動
  unregister_chrdev( unsigned int major, const char *name );
}
module_init( my_init );
module_exit( my_exit );
--------------------------------------------------------------------------------------------------
2.6驅動總體編寫框架：
static int __init my_init(void)
{
 static struct class *sbc2440_leds_class = NULL；
 if(主設備號)  //分配設備編號
 {
  sbc2440_leds_dev = MKDEV (LED_MAJOR, LED_MINOR);
  result = register_chrdev_region (sbc2440_leds_dev, count, DEVICE_NAME);
 }
 else
 {
  result = alloc_chrdev_region (&sbc2440_leds_dev, LED_MINOR, count, DEVICE_NAME);
  LED_MAJOR = MAJOR (sbc2440_leds_dev);
 }
 //註冊字符設備驅動
 sbc2440_leds_cdev = cdev_alloc();
 if (sbc2440_leds_cdev != NULL)
 {
  cdev_init (sbc2440_leds_cdev, &sbc2440_leds_fops);
  sbc2440_leds_cdev->ops = &sbc2440_leds_fops;
  sbc2440_leds_cdev->owner = THIS_MODULE;
  if (cdev_add (sbc2440_leds_cdev, sbc2440_leds_dev, count) )
   printk (KERN_NOTICE "Someting wrong when adding sbc2440_leds_cdev!/n");
  else
   printk ("Success adding sbc2440_leds_cdev!/n");
 }
 
 //創建設備文件

sbc2440_leds_class = class_create(THIS_MODULE, “ sbc2440_leds_class”);
class_device_create(sbc2440_leds_class ,NULL,MKDEV(LED_MAJOR,0),NULL,"DEVICE_NAME");

 
}
static int __exit my_exit(void)
{
 class_destroy(sbc2440_leds_class );

 class_device_destroy(sbc2440_leds_class,MKDEV(LED_MAJOR,0));
 //註銷字符設備
 cdev_del (sbc2440_leds_cdev);
 //釋放設備編號：
 unregister_chrdev_region (sbc2440_leds_dev, count);
}
module_init( my_init );
module_exit( my_exit );

 

紅色部分改了有一些改動，可能也存在以下問題，如果網友發現，歡迎指正。謝謝大家!