drivers/rtc/rtc-mxc.c: fix setting time for MX1 SoC

There is no way to track year in the i.MX1 RTC: Days Counter register is
9-bit wide only.  Attempt to save date after 1970-01-01 plus 512 days
causes endless loop in mxc_rtc_set_mmss().  Fix this by resetting year to
1970.

[[email protected]: use conventional comment layout]
Signed-off-by: Yauhen Kharuzhy <[email protected]>
Cc: Daniel Mack <[email protected]>
Cc: Alessandro Zummo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/drivers/rtc/rtc-mxc.c b/drivers/rtc/rtc-mxc.c
index 39e41fbdf08ba6de6259347feb0cc5dee76803d7..11b7b614fc8d6ecde83222dd95d0649fa723b688 100644 (file)
--- a/drivers/rtc/rtc-mxc.c
+++ b/drivers/rtc/rtc-mxc.c
@@ -290,6 +290,17 @@ static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
  */
 static int mxc_rtc_set_mmss(struct device *dev, unsigned long time)
 {
+       /*
+        * TTC_DAYR register is 9-bit in MX1 SoC, save time and day of year only
+        */
+       if (cpu_is_mx1()) {
+               struct rtc_time tm;
+
+               rtc_time_to_tm(time, &tm);
+               tm.tm_year = 70;
+               rtc_tm_to_time(&tm, &time);
+       }
+
        /* Avoid roll-over from reading the different registers */
        do {
                set_alarm_or_time(dev, MXC_RTC_TIME, time);