diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index d4cba0d415b6..f3268655fd37 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -268,7 +268,7 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 	struct rtc_time *tm = &alrm->time, tm_now;
-	unsigned long alarm, farest;
+	time64_t alarm, farest;
 	int ret;
 
 	ret = rzn1_rtc_read_time(dev, &tm_now);
@@ -278,7 +278,7 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	/* We cannot set alarms more than one week ahead */
 	farest = rtc_tm_to_time64(&tm_now) + rtc->rtcdev->alarm_offset_max;
 	alarm = rtc_tm_to_time64(tm);
-	if (time_after(alarm, farest))
+	if (alarm > farest)
 		return -ERANGE;
 
 	writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);