rtc: test: Emit the seconds-since-1970 value instead of days-since-1970

This is easier to handle because you can just consult date(1) to convert
between a seconds-since-1970 value and a date string:

	$ date --utc -d @3661
	Thu Jan  1 01:01:01 AM UTC 1970

	$ date -d "Jan 1 12:00:00 AM UTC 1900" +%s
	-2208988800

The intended side effect is that this prepares the test for dates before
1970. The division of a negative value by 86400 doesn't result in the
desired days-since-1970 value as e.g. secs=-82739 should map to days=-1.

Signed-off-by: Uwe Kleine-König <[email protected]>
Signed-off-by: Alexandre Mergnat <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

Author: ukleinek

drivers/rtc/lib_test.c

@@ -46,16 +46,13 @@ static void rtc_time64_to_tm_test_date_range(struct kunit *test, int years)
 
 	struct rtc_time result;
 	time64_t secs;
-	s64 days;
 
 	for (secs = 0; secs <= total_secs; secs += 86400) {
 
 		rtc_time64_to_tm(secs, &result);
 
-		days = div_s64(secs, 86400);
-
 		#define FAIL_MSG "%d/%02d/%02d (%2d) : %lld", \
-			year, month, mday, yday, days
+			year, month, mday, yday, secs
 
 		KUNIT_ASSERT_EQ_MSG(test, year - 1900, result.tm_year, FAIL_MSG);
 		KUNIT_ASSERT_EQ_MSG(test, month - 1, result.tm_mon, FAIL_MSG);