Since tm->tm_year is the offset relative to 1900, it needs to check for
positive value to avoid overflow in YEARS_REG register.

The system will hang at the following stage on the next boot when overflow
has occurred.

[    2.221192] systemd[1]: Time has been changed

This patch fixes the above hanging issue by adding bounds checking.

Signed-off-by: Taiyi Wu <taiyity...@moxa.com>
Signed-off-by: SZ Lin (林上智) <sz....@moxa.com>
---
 drivers/rtc/rtc-tps65910.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/rtc/rtc-tps65910.c b/drivers/rtc/rtc-tps65910.c
index d0244d7979fc..6be9f7bb0f1b 100644
--- a/drivers/rtc/rtc-tps65910.c
+++ b/drivers/rtc/rtc-tps65910.c
@@ -105,6 +105,12 @@ static int tps65910_rtc_set_time(struct device *dev, 
struct rtc_time *tm)
        struct tps65910 *tps = dev_get_drvdata(dev->parent);
        int ret;
 
+       if ((tm->tm_year - 100) < 0) {
+               dev_err(dev, "the requested year %d is unsupported\n",
+                       1900 + tm->tm_year);
+               return -EINVAL;
+       }
+
        rtc_data[0] = bin2bcd(tm->tm_sec);
        rtc_data[1] = bin2bcd(tm->tm_min);
        rtc_data[2] = bin2bcd(tm->tm_hour);
-- 
2.15.1

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