drivers/rtc/rtc-mxc.c: fix setting time for MX1 SoC
Yauhen Kharuzhy [Tue, 10 Jan 2012 23:10:32 +0000 (15:10 -0800)]
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.

[akpm@linux-foundation.org: use conventional comment layout]
Signed-off-by: Yauhen Kharuzhy <jekhor@gmail.com>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-mxc.c

index 39e41fb..11b7b61 100644 (file)
@@ -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);