From e2addab7f0328ef144219f665555445579b21f2d Mon Sep 17 00:00:00 2001
From: Benjamin Valentin <benpicco@googlemail.com>
Date: Thu, 27 Aug 2020 23:11:19 +0200
Subject: [PATCH] cpu/kinetis: RTC use rtc_mktime()

Use RTC helper functions instead of libc functions.
This gives us y2038 safety by the extended epoch
and saves a good chunk of memory:

mktime():

   text	   data	    bss	    dec	    hex	filename
  24756	    232	   2736	  27724	   6c4c	testssperiph_rtc/bin/openlabs-kw41z-mini/tests_periph_rtc.elf

rtc_mktime():

   text	   data	    bss	    dec	    hex	filename
  16348	    132	   2696	  19176	   4ae8	tests/periph_rtc/bin/openlabs-kw41z-mini/tests_periph_rtc.elf
---
 cpu/kinetis/periph/rtc.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/cpu/kinetis/periph/rtc.c b/cpu/kinetis/periph/rtc.c
index cf89681a5b..6e022b8809 100644
--- a/cpu/kinetis/periph/rtc.c
+++ b/cpu/kinetis/periph/rtc.c
@@ -20,8 +20,6 @@
  * @}
  */
 
-#include <stdint.h>
-#include <time.h>
 #include "cpu.h"
 #include "periph/rtc.h"
 #include "periph/rtt.h"
@@ -41,7 +39,7 @@ static rtc_state_t rtc_callback;
  *
  * @param[inout] arg    argument passed from the RTT interrupt
  */
-static void rtc_cb(void* arg);
+static void rtc_cb(void *arg);
 
 void rtc_init(void)
 {
@@ -50,38 +48,38 @@ void rtc_init(void)
 
 int rtc_set_time(struct tm *time)
 {
-    time_t t = mktime(time);
+    uint32_t t = rtc_mktime(time);
 
-    rtt_set_counter((uint32_t)t);
+    rtt_set_counter(t);
 
     return 0;
 }
 
 int rtc_get_time(struct tm *time)
 {
-    time_t t = (time_t)rtt_get_counter();
+    uint32_t t = rtt_get_counter();
 
-    gmtime_r(&t, time);
+    rtc_localtime(t, time);
 
     return 0;
 }
 
 int rtc_set_alarm(struct tm *time, rtc_alarm_cb_t cb, void *arg)
 {
-    time_t t = mktime(time);
+    uint32_t t = rtc_mktime(time);
 
     rtc_callback.cb = cb;
 
-    rtt_set_alarm((uint32_t)t, rtc_cb, arg);
+    rtt_set_alarm(t, rtc_cb, arg);
 
     return 0;
 }
 
 int rtc_get_alarm(struct tm *time)
 {
-    time_t t = (time_t)rtt_get_alarm();
+    uint32_t t = rtt_get_alarm();
 
-    gmtime_r(&t, time);
+    rtc_localtime(t, time);
 
     return 0;
 }
@@ -102,7 +100,7 @@ void rtc_poweroff(void)
     rtt_poweroff();
 }
 
-static void rtc_cb(void* arg)
+static void rtc_cb(void *arg)
 {
     if (rtc_callback.cb != NULL) {
         rtc_callback.cb(arg);