diff --git a/drivers/dev_null.c b/drivers/dev_null.c
index c058afb8de497b2f83ef886cbb41426060808d9f..5c495451b16b5d2c7cd65903c908900b484bd0cc 100644
--- a/drivers/dev_null.c
+++ b/drivers/dev_null.c
@@ -73,11 +73,19 @@ static struct file_operations devnull_fops =
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: devnull_read
+ ****************************************************************************/
+
 static ssize_t devnull_read(FAR struct file *filp, FAR char *buffer, size_t len)
 {
   return 0; /* Return EOF */
 }
 
+/****************************************************************************
+ * Name: devnull_write
+ ****************************************************************************/
+
 static ssize_t devnull_write(FAR struct file *filp, FAR const char *buffer, size_t len)
 {
   return len; /* Say that everything was written */
@@ -87,6 +95,14 @@ static ssize_t devnull_write(FAR struct file *filp, FAR const char *buffer, size
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: devnull_register
+ *
+ * Description:
+ *   Register /dev/null
+ *
+ ****************************************************************************/
+
 void devnull_register(void)
 {
   (void)register_driver("/dev/null", &devnull_fops, 0666, NULL);