diff --git a/src/device.c b/src/device.c
index 1ba471446e..58eda6140b 100644
--- a/src/device.c
+++ b/src/device.c
@@ -28,18 +28,20 @@
  *
  * @return the error code, RT_EOK on initialization successfully.
  */
-rt_err_t rt_device_register(rt_device_t dev, const char *name, rt_uint16_t flags)
+rt_err_t rt_device_register(rt_device_t dev,
+                            const char *name,
+                            rt_uint16_t flags)
 {
-	if (dev == RT_NULL)
-		return -RT_ERROR;
+    if (dev == RT_NULL)
+        return -RT_ERROR;
 
-	if (rt_device_find(name) != RT_NULL) 
-		return -RT_ERROR;
+    if (rt_device_find(name) != RT_NULL)
+        return -RT_ERROR;
 
-	rt_object_init(&(dev->parent), RT_Object_Class_Device, name);
-	dev->flag = flags;
+    rt_object_init(&(dev->parent), RT_Object_Class_Device, name);
+    dev->flag = flags;
 
-	return RT_EOK;
+    return RT_EOK;
 }
 RTM_EXPORT(rt_device_register);
 
@@ -52,11 +54,11 @@ RTM_EXPORT(rt_device_register);
  */
 rt_err_t rt_device_unregister(rt_device_t dev)
 {
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	rt_object_detach(&(dev->parent));
+    rt_object_detach(&(dev->parent));
 
-	return RT_EOK;
+    return RT_EOK;
 }
 RTM_EXPORT(rt_device_unregister);
 
@@ -67,39 +69,39 @@ RTM_EXPORT(rt_device_unregister);
  */
 rt_err_t rt_device_init_all(void)
 {
-	struct rt_device *device;
-	struct rt_list_node *node;
-	struct rt_object_information *information;
-	register rt_err_t result;
+    struct rt_device *device;
+    struct rt_list_node *node;
+    struct rt_object_information *information;
+    register rt_err_t result;
 
-	extern struct rt_object_information rt_object_container[];
+    extern struct rt_object_information rt_object_container[];
 
-	information = &rt_object_container[RT_Object_Class_Device];
+    information = &rt_object_container[RT_Object_Class_Device];
 
-	/* for each device */
-	for (node = information->object_list.next; node != &(information->object_list); node = node->next)
-	{
-		rt_err_t (*init)(rt_device_t dev);
-		device = (struct rt_device *)rt_list_entry(node, struct rt_object, list);
+    /* for each device */
+    for (node = information->object_list.next; node != &(information->object_list); node = node->next)
+    {
+        rt_err_t (*init)(rt_device_t dev);
+        device = (struct rt_device *)rt_list_entry(node, struct rt_object, list);
 
-		/* get device init handler */
-		init = device->init;
-		if (init != RT_NULL && !(device->flag & RT_DEVICE_FLAG_ACTIVATED))
-		{
-			result = init(device);
-			if (result != RT_EOK)
-			{
-				rt_kprintf("To initialize device:%s failed. The error code is %d\n",
-					device->parent.name, result);
-			}
-			else
-			{
-				device->flag |= RT_DEVICE_FLAG_ACTIVATED;
-			}
-		}
-	}
+        /* get device init handler */
+        init = device->init;
+        if (init != RT_NULL && !(device->flag & RT_DEVICE_FLAG_ACTIVATED))
+        {
+            result = init(device);
+            if (result != RT_EOK)
+            {
+                rt_kprintf("To initialize device:%s failed. The error code is %d\n",
+                           device->parent.name, result);
+            }
+            else
+            {
+                device->flag |= RT_DEVICE_FLAG_ACTIVATED;
+            }
+        }
+    }
 
-	return RT_EOK;
+    return RT_EOK;
 }
 
 /**
@@ -111,37 +113,37 @@ rt_err_t rt_device_init_all(void)
  */
 rt_device_t rt_device_find(const char *name)
 {
-	struct rt_object *object;
-	struct rt_list_node *node;
-	struct rt_object_information *information;
+    struct rt_object *object;
+    struct rt_list_node *node;
+    struct rt_object_information *information;
 
-	extern struct rt_object_information rt_object_container[];
+    extern struct rt_object_information rt_object_container[];
 
-	/* enter critical */
-	if (rt_thread_self() != RT_NULL)
-		rt_enter_critical();
+    /* enter critical */
+    if (rt_thread_self() != RT_NULL)
+        rt_enter_critical();
 
-	/* try to find device object */
-	information = &rt_object_container[RT_Object_Class_Device];
-	for (node = information->object_list.next; node != &(information->object_list); node = node->next)
-	{
-		object = rt_list_entry(node, struct rt_object, list);
-		if (rt_strncmp(object->name, name, RT_NAME_MAX) == 0)
-		{
-			/* leave critical */
-			if (rt_thread_self() != RT_NULL)
-				rt_exit_critical();
+    /* try to find device object */
+    information = &rt_object_container[RT_Object_Class_Device];
+    for (node = information->object_list.next; node != &(information->object_list); node = node->next)
+    {
+        object = rt_list_entry(node, struct rt_object, list);
+        if (rt_strncmp(object->name, name, RT_NAME_MAX) == 0)
+        {
+            /* leave critical */
+            if (rt_thread_self() != RT_NULL)
+                rt_exit_critical();
 
-			return (rt_device_t)object;
-		}
-	}
+            return (rt_device_t)object;
+        }
+    }
 
-	/* leave critical */
-	if (rt_thread_self() != RT_NULL)
-		rt_exit_critical();
+    /* leave critical */
+    if (rt_thread_self() != RT_NULL)
+        rt_exit_critical();
 
-	/* not found */
-	return RT_NULL;
+    /* not found */
+    return RT_NULL;
 }
 RTM_EXPORT(rt_device_find);
 
@@ -154,33 +156,33 @@ RTM_EXPORT(rt_device_find);
  */
 rt_err_t rt_device_init(rt_device_t dev)
 {
-	rt_err_t result = RT_EOK;
-	rt_err_t (*init)(rt_device_t dev);
-	
-	RT_ASSERT(dev != RT_NULL);
+    rt_err_t result = RT_EOK;
+    rt_err_t (*init)(rt_device_t dev);
+    
+    RT_ASSERT(dev != RT_NULL);
 
-	/* get device init handler */
-	init = dev->init;
-	if (init != RT_NULL)
-	{
-		if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
-		{
-			result = init(dev);
-			if (result != RT_EOK)
-			{
-				rt_kprintf("To initialize device:%s failed. The error code is %d\n",
-					dev->parent.name, result);
-			}
-			else
-			{
-				dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
-			}
-		}
-	}
-	else
-		result = -RT_ENOSYS;
+    /* get device init handler */
+    init = dev->init;
+    if (init != RT_NULL)
+    {
+        if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
+        {
+            result = init(dev);
+            if (result != RT_EOK)
+            {
+                rt_kprintf("To initialize device:%s failed. The error code is %d\n",
+                           dev->parent.name, result);
+            }
+            else
+            {
+                dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
+            }
+        }
+    }
+    else
+        result = -RT_ENOSYS;
 
-	return result;
+    return result;
 }
 
 /**
@@ -193,52 +195,52 @@ rt_err_t rt_device_init(rt_device_t dev)
  */
 rt_err_t rt_device_open(rt_device_t dev, rt_uint16_t oflag)
 {
-	rt_err_t result;
-	rt_err_t (*open)(rt_device_t dev, rt_uint16_t oflag);
+    rt_err_t result;
+    rt_err_t (*open)(rt_device_t dev, rt_uint16_t oflag);
 
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	result = RT_EOK;
+    result = RT_EOK;
 
-	/* if device is not initialized, initialize it. */
-	if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
-	{
-		if (dev->init != RT_NULL )
-		{
-			result = dev->init(dev);
-			if (result != RT_EOK)
-			{
-				rt_kprintf("To initialize device:%s failed. The error code is %d\n",
-					dev->parent.name, result);
+    /* if device is not initialized, initialize it. */
+    if (!(dev->flag & RT_DEVICE_FLAG_ACTIVATED))
+    {
+        if (dev->init != RT_NULL)
+        {
+            result = dev->init(dev);
+            if (result != RT_EOK)
+            {
+                rt_kprintf("To initialize device:%s failed. The error code is %d\n",
+                           dev->parent.name, result);
 
-				return result;
-			}
-		}
+                return result;
+            }
+        }
 
-		dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
-	}
+        dev->flag |= RT_DEVICE_FLAG_ACTIVATED;
+    }
 
-	/* device is a stand alone device and opened */
-	if ((dev->flag & RT_DEVICE_FLAG_STANDALONE) && (dev->open_flag & RT_DEVICE_OFLAG_OPEN))
-		return -RT_EBUSY;
+    /* device is a stand alone device and opened */
+    if ((dev->flag & RT_DEVICE_FLAG_STANDALONE) && (dev->open_flag & RT_DEVICE_OFLAG_OPEN))
+        return -RT_EBUSY;
 
-	/* call device open interface */
-	open = dev->open;
-	if (open != RT_NULL)
-	{
-		result = open(dev, oflag);
-	}
-	else
-	{
-		/* no this interface in device driver */
-		/* result = -RT_ENOSYS; not set errno */
-	}
+    /* call device open interface */
+    open = dev->open;
+    if (open != RT_NULL)
+    {
+        result = open(dev, oflag);
+    }
+    else
+    {
+        /* no this interface in device driver */
+        /* result = -RT_ENOSYS; not set errno */
+    }
 
-	/* set open flag */
-	if (result == RT_EOK || result == -RT_ENOSYS)
-		dev->open_flag = oflag | RT_DEVICE_OFLAG_OPEN;
+    /* set open flag */
+    if (result == RT_EOK || result == -RT_ENOSYS)
+        dev->open_flag = oflag | RT_DEVICE_OFLAG_OPEN;
 
-	return result;
+    return result;
 }
 RTM_EXPORT(rt_device_open);
 
@@ -251,28 +253,28 @@ RTM_EXPORT(rt_device_open);
  */
 rt_err_t rt_device_close(rt_device_t dev)
 {
-	rt_err_t result;
-	rt_err_t (*close)(rt_device_t dev);
+    rt_err_t result;
+    rt_err_t (*close)(rt_device_t dev);
 
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	/* call device close interface */
-	close = dev->close;
-	if (close != RT_NULL)
-	{
-		result = close(dev);
-	}
-	else
-	{
-		/* no this interface in device driver */
-		/* result = -RT_ENOSYS; not set errno */
-	}
+    /* call device close interface */
+    close = dev->close;
+    if (close != RT_NULL)
+    {
+        result = close(dev);
+    }
+    else
+    {
+        /* no this interface in device driver */
+        /* result = -RT_ENOSYS; not set errno */
+    }
 
-	/* set open flag */
-	if (result == RT_EOK || result == -RT_ENOSYS)
-		dev->open_flag = RT_DEVICE_OFLAG_CLOSE;
+    /* set open flag */
+    if (result == RT_EOK || result == -RT_ENOSYS)
+        dev->open_flag = RT_DEVICE_OFLAG_CLOSE;
 
-	return result;
+    return result;
 }
 RTM_EXPORT(rt_device_close);
 
@@ -288,23 +290,26 @@ RTM_EXPORT(rt_device_close);
  *
  * @note since 0.4.0, the unit of size/pos is a block for block device.
  */
-rt_size_t rt_device_read(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
+rt_size_t rt_device_read(rt_device_t dev,
+                         rt_off_t    pos,
+                         void       *buffer,
+                         rt_size_t   size)
 {
-	rt_size_t (*read)(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
+    rt_size_t (*read)(rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);
 
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	/* call device read interface */
-	read = dev->read;
-	if (read != RT_NULL)
-	{
-		return read(dev, pos, buffer, size);
-	}
+    /* call device read interface */
+    read = dev->read;
+    if (read != RT_NULL)
+    {
+        return read(dev, pos, buffer, size);
+    }
 
-	/* set error code */
-	rt_set_errno(-RT_ENOSYS);
+    /* set error code */
+    rt_set_errno(-RT_ENOSYS);
 
-	return 0;
+    return 0;
 }
 RTM_EXPORT(rt_device_read);
 
@@ -320,23 +325,26 @@ RTM_EXPORT(rt_device_read);
  *
  * @note since 0.4.0, the unit of size/pos is a block for block device.
  */
-rt_size_t rt_device_write(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
+rt_size_t rt_device_write(rt_device_t dev,
+                          rt_off_t    pos,
+                          const void *buffer,
+                          rt_size_t   size)
 {
-	rt_size_t (*write)(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
+    rt_size_t (*write)(rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);
 
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	/* call device write interface */
-	write = dev->write;
-	if (write != RT_NULL)
-	{
-		return write(dev, pos, buffer, size);
-	}
+    /* call device write interface */
+    write = dev->write;
+    if (write != RT_NULL)
+    {
+        return write(dev, pos, buffer, size);
+    }
 
-	/* set error code */
-	rt_set_errno(-RT_ENOSYS);
+    /* set error code */
+    rt_set_errno(-RT_ENOSYS);
 
-	return 0;
+    return 0;
 }
 RTM_EXPORT(rt_device_write);
 
@@ -351,18 +359,18 @@ RTM_EXPORT(rt_device_write);
  */
 rt_err_t rt_device_control(rt_device_t dev, rt_uint8_t cmd, void *arg)
 {
-	rt_err_t (*control)(rt_device_t dev, rt_uint8_t cmd, void *arg);
+    rt_err_t (*control)(rt_device_t dev, rt_uint8_t cmd, void *arg);
 
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	/* call device write interface */
-	control = dev->control;
-	if (control != RT_NULL)
-	{
-		return control(dev, cmd, arg);
-	}
+    /* call device write interface */
+    control = dev->control;
+    if (control != RT_NULL)
+    {
+        return control(dev, cmd, arg);
+    }
 
-	return -RT_ENOSYS;
+    return -RT_ENOSYS;
 }
 RTM_EXPORT(rt_device_control);
 
@@ -375,32 +383,36 @@ RTM_EXPORT(rt_device_control);
  *
  * @return RT_EOK
  */
-rt_err_t rt_device_set_rx_indicate(rt_device_t dev, rt_err_t (*rx_ind)(rt_device_t dev, rt_size_t size))
+rt_err_t
+rt_device_set_rx_indicate(rt_device_t dev,
+                          rt_err_t (*rx_ind)(rt_device_t dev, rt_size_t size))
 {
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	dev->rx_indicate = rx_ind;
+    dev->rx_indicate = rx_ind;
 
-	return RT_EOK;
+    return RT_EOK;
 }
 RTM_EXPORT(rt_device_set_rx_indicate);
 
 /**
- * This function will set the indication callback function when device has written
- * data to physical hardware.
+ * This function will set the indication callback function when device has 
+ * written data to physical hardware.
  *
  * @param dev the pointer of device driver structure
  * @param tx_done the indication callback function
  *
  * @return RT_EOK
  */
-rt_err_t rt_device_set_tx_complete(rt_device_t dev, rt_err_t (*tx_done)(rt_device_t dev, void *buffer))
+rt_err_t
+rt_device_set_tx_complete(rt_device_t dev,
+                          rt_err_t (*tx_done)(rt_device_t dev, void *buffer))
 {
-	RT_ASSERT(dev != RT_NULL);
+    RT_ASSERT(dev != RT_NULL);
 
-	dev->tx_complete = tx_done;
+    dev->tx_complete = tx_done;
 
-	return RT_EOK;
+    return RT_EOK;
 }
 RTM_EXPORT(rt_device_set_tx_complete);