Commit 96fc3a45 authored Jun 29, 2010 by Joakim Tjernlund Committed by Linus Torvalds Jun 29, 2010

rtc: fix ds1388 time corruption



The ds1307 driver misreads the ds1388 registers when checking for 12 or 24
hour mode.  Instead of checking the hour register it reads the minute
register.  Therefore the driver thinks minutes >= 40 has the 12HR bit set
and resets the minute register by zeroing the high bits.  This results in
minutes are reset to 0-9, jumping back in time 40 or 50 minutes.  The time
jump is also written back to the RTC.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a02875a6

drivers/rtc/rtc-ds1307.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -777,7 +777,7 @@ static int __devinit ds1307_probe(struct i2c_client *client,

		read_rtc:
		/* read RTC registers */
		tmp = ds1307->read_block_data(ds1307->client, 0, 8, buf);
		tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
		if (tmp != 8) {
		pr_debug("read error %d\n", tmp);
		err = -EIO;
		@@ -862,7 +862,7 @@ read_rtc:
		if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
		tmp += 12;
		i2c_smbus_write_byte_data(client,
		DS1307_REG_HOUR,
		ds1307->offset + DS1307_REG_HOUR,
		bin2bcd(tmp));
		}

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