diff --git a/drivers/rtc/at91sam9_rtt.c b/drivers/rtc/at91sam9_rtt.c
index d3cdee0..a684ad6 100644
--- a/drivers/rtc/at91sam9_rtt.c
+++ b/drivers/rtc/at91sam9_rtt.c
@@ -54,8 +54,7 @@
 	at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
 	ulong tim;
 
-	tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
-		      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+	tim = rtc_mktime(tmp);
 
 	/* clear alarm, set prescaler to 32768, clear counter */
 	writel(32768+AT91_RTT_RTTRST, &rtt->mr);
diff --git a/drivers/rtc/bfin_rtc.c b/drivers/rtc/bfin_rtc.c
index 6cb1eba..a079a1d 100644
--- a/drivers/rtc/bfin_rtc.c
+++ b/drivers/rtc/bfin_rtc.c
@@ -67,8 +67,7 @@
 	wait_for_complete();
 
 	/* Calculate number of seconds this incoming time represents */
-	remain = mktime(tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
-			tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+	remain = rtc_mktime(tmp);
 
 	/* Figure out how many days since epoch */
 	days = remain / NUM_SECS_IN_DAY;
diff --git a/drivers/rtc/date.c b/drivers/rtc/date.c
index 79beb94..8c643a0 100644
--- a/drivers/rtc/date.c
+++ b/drivers/rtc/date.c
@@ -128,22 +128,23 @@
  * machines were long is 32-bit! (However, as time_t is signed, we
  * will already get problems at other places on 2038-01-19 03:14:08)
  */
-unsigned long
-mktime (unsigned int year, unsigned int mon,
-	unsigned int day, unsigned int hour,
-	unsigned int min, unsigned int sec)
+unsigned long rtc_mktime(const struct rtc_time *tm)
 {
-	if (0 >= (int) (mon -= 2)) {	/* 1..12 -> 11,12,1..10 */
+	int mon = tm->tm_mon;
+	int year = tm->tm_year;
+	int days, hours;
+
+	mon -= 2;
+	if (0 >= (int)mon) {	/* 1..12 -> 11,12,1..10 */
 		mon += 12;		/* Puts Feb last since it has leap day */
 		year -= 1;
 	}
 
-	return (((
-		(unsigned long) (year/4 - year/100 + year/400 + 367*mon/12 + day) +
-			year*365 - 719499
-	    )*24 + hour /* now have hours */
-	  )*60 + min /* now have minutes */
-	)*60 + sec; /* finally seconds */
+	days = (unsigned long)(year / 4 - year / 100 + year / 400 +
+			367 * mon / 12 + tm->tm_mday) +
+			year * 365 - 719499;
+	hours = days * 24 + tm->tm_hour;
+	return (hours * 60 + tm->tm_min) * 60 + tm->tm_sec;
 }
 
 #endif
diff --git a/drivers/rtc/ds1306.c b/drivers/rtc/ds1306.c
index 3fe6721..7dd3e19 100644
--- a/drivers/rtc/ds1306.c
+++ b/drivers/rtc/ds1306.c
@@ -180,8 +180,7 @@
 	{
 		ulong tim;
 
-		tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
-			      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+		tim = rtc_mktime(tmp);
 
 		immap->im_sitk.sitk_rtck = KAPWR_KEY;
 		immap->im_sit.sit_rtc = tim;
diff --git a/drivers/rtc/ds1374.c b/drivers/rtc/ds1374.c
index 04793b5..7847357 100644
--- a/drivers/rtc/ds1374.c
+++ b/drivers/rtc/ds1374.c
@@ -147,9 +147,7 @@
 	if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
 		printf("WARNING: year should be between 1970 and 2069!\n");
 
-	time = mktime(tmp->tm_year, tmp->tm_mon,
-			tmp->tm_mday, tmp->tm_hour,
-			tmp->tm_min, tmp->tm_sec);
+	time = rtc_mktime(tmp);
 
 	DEBUGR ("Set RTC s since 1.1.1970: %ld (0x%02lx)\n", time, time);
 
diff --git a/drivers/rtc/ftrtc010.c b/drivers/rtc/ftrtc010.c
index 3c5d955..7d0cfb3 100644
--- a/drivers/rtc/ftrtc010.c
+++ b/drivers/rtc/ftrtc010.c
@@ -104,8 +104,7 @@
 	      tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 	      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 
-	new = mktime(tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_hour,
-		     tmp->tm_min, tmp->tm_sec);
+	new = rtc_mktime(tmp);
 
 	now = ftrtc010_time();
 
diff --git a/drivers/rtc/imxdi.c b/drivers/rtc/imxdi.c
index e89034d..17519ce 100644
--- a/drivers/rtc/imxdi.c
+++ b/drivers/rtc/imxdi.c
@@ -209,8 +209,7 @@
 			goto err;
 	}
 
-	now = mktime(tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
-		     tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+	now = rtc_mktime(tmp);
 	/* zero the fractional part first */
 	rc = DI_WRITE_WAIT(0, dtclr);
 	if (rc == 0)
diff --git a/drivers/rtc/mc13xxx-rtc.c b/drivers/rtc/mc13xxx-rtc.c
index 30c4e66..3e46336 100644
--- a/drivers/rtc/mc13xxx-rtc.c
+++ b/drivers/rtc/mc13xxx-rtc.c
@@ -51,8 +51,7 @@
 	if (!p)
 		return -1;
 
-	time = mktime(rtc->tm_year, rtc->tm_mon, rtc->tm_mday,
-		      rtc->tm_hour, rtc->tm_min, rtc->tm_sec);
+	time = rtc_mktime(rtc);
 	day = time / 86400;
 	time %= 86400;
 
diff --git a/drivers/rtc/mpc8xx.c b/drivers/rtc/mpc8xx.c
index 796295d..147a225 100644
--- a/drivers/rtc/mpc8xx.c
+++ b/drivers/rtc/mpc8xx.c
@@ -44,8 +44,7 @@
 		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 
-	tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
-		      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+	tim = rtc_mktime(tmp);
 
 	immr->im_sitk.sitk_rtck = KAPWR_KEY;
 	immr->im_sit.sit_rtc = tim;
diff --git a/drivers/rtc/mx27rtc.c b/drivers/rtc/mx27rtc.c
index 7ba74d3..29ccdf1 100644
--- a/drivers/rtc/mx27rtc.c
+++ b/drivers/rtc/mx27rtc.c
@@ -40,8 +40,7 @@
 	struct rtc_regs *rtc_regs = (struct rtc_regs *)IMX_RTC_BASE;
 	uint32_t day, hour, min, sec;
 
-	sec = mktime(time->tm_year, time->tm_mon, time->tm_mday,
-		time->tm_hour, time->tm_min, time->tm_sec);
+	sec = rtc_mktime(time);
 
 	day  = sec / (24 * 3600);
 	sec  = sec % (24 * 3600);
diff --git a/drivers/rtc/mxsrtc.c b/drivers/rtc/mxsrtc.c
index 82c2fbf..6e32154 100644
--- a/drivers/rtc/mxsrtc.c
+++ b/drivers/rtc/mxsrtc.c
@@ -52,8 +52,7 @@
 {
 	uint32_t secs;
 
-	secs = mktime(time->tm_year, time->tm_mon, time->tm_mday,
-		time->tm_hour, time->tm_min, time->tm_sec);
+	secs = rtc_mktime(time);
 
 	return mxs_rtc_set_time(secs);
 }
diff --git a/drivers/rtc/pl031.c b/drivers/rtc/pl031.c
index e6c1a6c..fc83049 100644
--- a/drivers/rtc/pl031.c
+++ b/drivers/rtc/pl031.c
@@ -72,8 +72,7 @@
 	}
 
 	/* Calculate number of seconds this incoming time represents */
-	tim = mktime(tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
-			tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+	tim = rtc_mktime(tmp);
 
 	RTC_WRITE_REG(RTC_LR, tim);