A better approach to avoid reading the RTC during updates, as sugested in the S3C2416 User's Manual.
Signed-off-by: José Miguel Gonçalves jose.goncalves@inov.pt --- Changes for v2: - New patch
Changes for v3: - Removed unneeded parenthesis
Changes for v4: - None
Changes for v5: - None --- drivers/rtc/s3c24x0_rtc.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/rtc/s3c24x0_rtc.c b/drivers/rtc/s3c24x0_rtc.c index c16ff2e..b31dc53 100644 --- a/drivers/rtc/s3c24x0_rtc.c +++ b/drivers/rtc/s3c24x0_rtc.c @@ -65,20 +65,26 @@ int rtc_get(struct rtc_time *tmp) uchar sec, min, hour, mday, wday, mon, year; __maybe_unused uchar a_sec, a_min, a_hour, a_date, a_mon, a_year, a_armed; + int have_retried = 0;
/* enable access to RTC registers */ SetRTC_Access(RTC_ENABLE);
/* read RTC registers */ do { - sec = readb(&rtc->bcdsec); min = readb(&rtc->bcdmin); hour = readb(&rtc->bcdhour); mday = readb(&rtc->bcddate); wday = readb(&rtc->bcdday); mon = readb(&rtc->bcdmon); year = readb(&rtc->bcdyear); - } while (sec != readb(&rtc->bcdsec)); + sec = readb(&rtc->bcdsec); + /* + * The only way to work out whether the RTC was mid-update + * when we read it is to check the seconds counter. + * If it's zero, then we re-try the entire read. + */ + } while (sec == 0 && !have_retried++);
/* read ALARM registers */ a_sec = readb(&rtc->almsec);