diff --git a/src/clock.c b/src/clock.c
index 86d15f146..53c32aeb8 100644
--- a/src/clock.c
+++ b/src/clock.c
@@ -21,7 +21,7 @@
 #include <rthw.h>
 #include <rtthread.h>
 
-static rt_tick_t rt_tick;
+static rt_tick_t rt_tick = 0;
 
 extern void rt_timer_check(void);
 
@@ -29,10 +29,11 @@ extern void rt_timer_check(void);
  * This function will init system tick and set it to zero.
  * @ingroup SystemInit
  *
+ * @deprecated since 1.1.0, this function does not need to be invoked
+ * in the system initialization.
  */
 void rt_system_tick_init(void)
 {
-	rt_tick = 0;
 }
 
 /**
diff --git a/src/thread.c b/src/thread.c
index c99cf6070..8cc7e95fb 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -598,7 +598,7 @@ rt_err_t rt_thread_resume(rt_thread_t thread)
 
 /**
  * This function is the timeout function for thread, normally which is invoked
- * when thread is timeout to wait some resourse.
+ * when thread is timeout to wait some resource.
  *
  * @param parameter the parameter of thread timeout function
  *