10  * 2012-10-20     Bernard      add device check in register function,
12  * 2012-12-25     Bernard      return RT_EOK if the device interface not exist.
41  * This function registers a device driver with specified name.
43  * @param dev the pointer of device driver structure
44  * @param name the device driver's name
45  * @param flags the capabilities flag of device
74  * This function removes a previously registered device driver
76  * @param dev the pointer of device driver structure
93  * This function initializes all registered device driver
98  *             of a device is performed when applicaiton opens it.
106  * This function finds a device driver by specified name.
108  * @param name the device driver's name
110  * @return the registered device driver on successful, or RT_NULL on failure.
122     /* try to find device object */  in rt_device_find()
151  * This function creates a device object with user data size.
153  * @param type, the kind type of this device object.
156  * @return the allocated device object, or RT_NULL when failed.
161     rt_device_t device;  in rt_device_create()  local
168     device = (rt_device_t)rt_malloc(size);  in rt_device_create()
169     if (device)  in rt_device_create()
171         rt_memset(device, 0x0, sizeof(struct rt_device));  in rt_device_create()
172         device->type = (enum rt_device_class_type)type;  in rt_device_create()
175     return device;  in rt_device_create()
180  * This function destroy the specific device object.
182  * @param dev, the specific device object.
192     /* release this device object */  in rt_device_destroy()
199  * This function will initialize the specified device
201  * @param dev the pointer of device driver structure
211     /* get device init handler */  in rt_device_init()
219                 rt_kprintf("To initialize device:%s failed. The error code is %d\n",  in rt_device_init()
233  * This function will open a device
235  * @param dev the pointer of device driver structure
236  * @param oflag the flags for device open
247     /* if device is not initialized, initialize it. */  in rt_device_open()
255                 rt_kprintf("To initialize device:%s failed. The error code is %d\n",  in rt_device_open()
265     /* device is a stand alone device and opened */  in rt_device_open()
272     /* call device open interface */  in rt_device_open()
299  * This function will close a device
301  * @param dev the pointer of device driver structure
320     /* call device close interface */  in rt_device_close()
335  * This function will read some data from a device.
337  * @param dev the pointer of device driver structure
344  * @note since 0.4.0, the unit of size/pos is a block for block device.
360     /* call device read interface */  in rt_device_read()
374  * This function will write some data to a device.
376  * @param dev the pointer of device driver structure
378  * @param buffer the data buffer to be written to device
383  * @note since 0.4.0, the unit of size/pos is a block for block device.
399     /* call device write interface */  in rt_device_write()
415  * @param dev the pointer of device driver structure
416  * @param cmd the command sent to device
426     /* call device write interface */  in rt_device_control()
438  * is invoked when this device receives data.
440  * @param dev the pointer of device driver structure
459  * This function will set the indication callback function when device has
462  * @param dev the pointer of device driver structure