[PATCH linux] rtc: aspeed month is off-by-one

[OpenBMC Patches]

From: "Milton D. Miller II" <miltonm at us.ibm.com>

Norm reported hwclock set the date one hour different from what it
read back.

The mktime64 call takes the month as the 1-based counted month not
the 0-based months since January like struct rtc_tm and struct tm.
No adjustment from the harware is needed.  Also mask off a few 0 bits.

Reported-by: Norman James <nkskjames at gmail.com>
Signed-off-by: Milton Miller <miltonm at us.ibm.com>
---
 drivers/rtc/rtc-aspeed.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-aspeed.c b/drivers/rtc/rtc-aspeed.c
index cfb5ee0..1a5bbd1 100644
--- a/drivers/rtc/rtc-aspeed.c
+++ b/drivers/rtc/rtc-aspeed.c
@@ -48,8 +48,7 @@ static int aspeed_rtc_read_time(struct device *dev, struct rtc_time *tm)
 	sec  = (reg1 >>  0) & 0x3f;
 	cent = (reg2 >> 16) & 0x1f;
 	year = (reg2 >>  8) & 0x7f;
-	/* struct rtc_time counts from 0 to 11, but hardware is 1 to 12 */
-	mon  = ((reg2 >>  0) & 0x3f) - 1;
+	mon  = (reg2 >>  0) & 0xf;	/* mktime64 and hardware use 1 = Jan */
 
 	rtc_time64_to_tm(mktime64(cent*100 + year, mon, day, hour, min, sec),
 			 tm);
-- 
2.6.4