drivers/rtc/interface.c: check the validation of rtc_time in __rtc_read_time

Some rtc devices always return '0' when rtc_class_ops.read_time is
called.  So if rtc_time isn't verified in callback, rtc interface cannot
know whether rtc_time is valid.

Check rtc_time by using 'rtc_valid_tm' in '__rtc_read_time'.  And add
the message for debugging.

Signed-off-by: Hyogi Gim <hyogi.gim@lge.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 5b2717f..818ea97 100644 (file)
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -30,6 +30,14 @@ static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
        else {
                memset(tm, 0, sizeof(struct rtc_time));
                err = rtc->ops->read_time(rtc->dev.parent, tm);
+               if (err < 0) {
+                       dev_err(&rtc->dev, "read_time: fail to read\n");
+                       return err;
+               }
+
+               err = rtc_valid_tm(tm);
+               if (err < 0)
+                       dev_err(&rtc->dev, "read_time: rtc_time isn't valid\n");
        }
        return err;
 }