device_create ()詳解
阿新 • • 發佈：2018-12-30
……
//建立一個裝置節點，節點名為DEVICE_NAME
device_create(mydriver_class, NULL, MKDEV(MYDRIVER_Major, 0), NULL, DEVICE_NAME);
……
}
從linux核心2.6的某個版本之後，devfs不復存在，udev成為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，不要試圖在核心的配置選項裡找到它;加入對udev的支 持很簡單，以作者所寫的一個字元裝置驅動為例，在驅動初始化的程式碼裡呼叫class_create為該裝置建立一個class，再為每個裝置呼叫 class_device_create建立對應的裝置。
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被載入時，udev daemon就會自動在/dev下建立my_device裝置檔案。
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/下建立類目錄
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
//建立一個裝置節點，節點名為DEVICE_NAME
device_create(mydriver_class, NULL, MKDEV(MYDRIVER_Major, 0), NULL, DEVICE_NAME);
……
}
從linux核心2.6的某個版本之後，devfs不復存在，udev成為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，不要試圖在核心的配置選項裡找到它;加入對udev的支 持很簡單，以作者所寫的一個字元裝置驅動為例，在驅動初始化的程式碼裡呼叫class_create為該裝置建立一個class，再為每個裝置呼叫 class_device_create建立對應的裝置。
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被載入時，udev daemon就會自動在/dev下建立my_device裝置檔案。
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/下建立類目錄
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