[drivers][rtc]Add comments

components/drivers/include/drivers/rtc.h

@@ -8,6 +8,7 @@
  * 2012-10-10     aozima       first version.
  * 2021-06-11     iysheng      implement RTC framework V2.0
  * 2021-07-30     Meco Man     move rtc_core.h to rtc.h
+ * 2022-04-05     tyx          add timestamp function
  */
 
 #ifndef __RTC_H__

components/drivers/rtc/rtc.c

@@ -229,7 +229,7 @@ rt_err_t set_time(rt_uint32_t hour, rt_uint32_t minute, rt_uint32_t second)
 }
 
 /**
- * Set timestamp(utc).
+ * Set timestamp(UTC).
  *
  * @param time_t timestamp
  *
@@ -251,7 +251,7 @@ rt_err_t set_timestamp(time_t timestamp)
 }
 
 /**
- * Get timestamp(utc).
+ * Get timestamp(UTC).
  *
  * @param time_t* timestamp
  *