diff --git a/components/drivers/ipc/pipe.c b/components/drivers/ipc/pipe.c
index e86ac3576f8..64540eade17 100644
--- a/components/drivers/ipc/pipe.c
+++ b/components/drivers/ipc/pipe.c
@@ -190,7 +190,7 @@ static int pipe_fops_ioctl(struct dfs_file *fd, int cmd, void *args)
 
     pipe = (rt_pipe_t *)fd->vnode->data;
 
-    switch (cmd)
+    switch ((rt_ubase_t)cmd)
     {
     case FIONREAD:
         *((int*)args) = rt_ringbuffer_data_len(pipe->fifo);
diff --git a/components/drivers/serial/dev_serial.c b/components/drivers/serial/dev_serial.c
index eb7c5275ec0..3ebe3063ace 100644
--- a/components/drivers/serial/dev_serial.c
+++ b/components/drivers/serial/dev_serial.c
@@ -125,7 +125,7 @@ static int serial_fops_ioctl(struct dfs_file *fd, int cmd, void *args)
     int mask  = O_NONBLOCK | O_APPEND;
 
     device = (rt_device_t)fd->vnode->data;
-    switch (cmd)
+    switch ((rt_ubase_t)cmd)
     {
     case FIONREAD:
         break;
@@ -1074,7 +1074,7 @@ static rt_err_t rt_serial_control(struct rt_device *dev,
     RT_ASSERT(dev != RT_NULL);
     serial = (struct rt_serial_device *)dev;
 
-    switch (cmd)
+    switch ((rt_ubase_t)cmd)
     {
         case RT_DEVICE_CTRL_SUSPEND:
             /* suspend device */
diff --git a/components/drivers/serial/dev_serial_v2.c b/components/drivers/serial/dev_serial_v2.c
index 2a526c809a0..d2b9fde8289 100644
--- a/components/drivers/serial/dev_serial_v2.c
+++ b/components/drivers/serial/dev_serial_v2.c
@@ -121,7 +121,7 @@ static int serial_fops_ioctl(struct dfs_file *fd, int cmd, void *args)
     int         mask  = O_NONBLOCK | O_APPEND;
 
     device = (rt_device_t)fd->vnode->data;
-    switch (cmd)
+    switch ((rt_ubase_t)cmd)
     {
     case FIONREAD:
         break;
@@ -1385,7 +1385,7 @@ static rt_err_t rt_serial_control(struct rt_device *dev,
     RT_ASSERT(dev != RT_NULL);
     serial = (struct rt_serial_device *)dev;
 
-    switch (cmd)
+    switch ((rt_ubase_t)cmd)
     {
     case RT_DEVICE_CTRL_SUSPEND:
         /* suspend device */