Linux-libre 4.5-gnu

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index e7ebcc0b7..988566caa 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -219,6 +219,17 @@ static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	u8 regs[8];
 	int err;
 
+	/*
+	 * The hardware can only store values between 0 and 99 in it's YEAR
+	 * register (with 99 overflowing to 0 on increment).
+	 * After 2100-02-28 we could start interpreting the year to be in the
+	 * interval [2100, 2199], but there is no path to switch in a smooth way
+	 * because the chip handles YEAR=0x00 (and the out-of-spec
+	 * YEAR=0xa0) as a leap year, but 2100 isn't.
+	 */
+	if (tm->tm_year < 100 || tm->tm_year >= 200)
+		return -EINVAL;
+
 	err = pcf8523_stop_rtc(client);
 	if (err < 0)
 		return err;