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authorJohannes Weiner <jw@emlix.com>2009-12-01 13:17:48 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-01 16:32:20 -0800
commit48a7f7746875425797aea31ed2910088635c1c7a (patch)
treea73c35a8b24550ca9d120eab98b45d71bb06eafe /drivers
parent0a1f127a0594d62cb23c26732686d0e2b097b264 (diff)
downloadlinux-48a7f7746875425797aea31ed2910088635c1c7a.tar.gz
rtc-x1205: fix rtc_time to y2k register value conversion
The possible CCR_Y2K register values are 19 or 20 and struct rtc_time's
tm_year is in years since 1900.

The function translating rtc_time to register values assumes tm_year to be
years since first christmas, though, and we end up storing 0 or 1 in the
CCR_Y2K register, which the hardware does not refuse to do.

A subsequent probing of the clock fails due to the invalid value range in
the register, though.

[ And if it didn't, reading the clock would yield a bogus year because
  the function translating registers to tm_year is assuming a register
  value of 19 or 20. ]

This fixes the conversion from years since 1900 in tm_year to the
corresponding CCR_Y2K value of 19 or 20.

Signed-off-by: Johannes Weiner <jw@emlix.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/rtc/rtc-x1205.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-x1205.c b/drivers/rtc/rtc-x1205.c
index 310c10795e9a..cc9ba47b2154 100644
--- a/drivers/rtc/rtc-x1205.c
+++ b/drivers/rtc/rtc-x1205.c
@@ -195,7 +195,7 @@ static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
 		/* year, since the rtc epoch*/
 		buf[CCR_YEAR] = bin2bcd(tm->tm_year % 100);
 		buf[CCR_WDAY] = tm->tm_wday & 0x07;
-		buf[CCR_Y2K] = bin2bcd(tm->tm_year / 100);
+		buf[CCR_Y2K] = bin2bcd((tm->tm_year + 1900) / 100);
 	}
 
 	/* If writing alarm registers, set compare bits on registers 0-4 */