[3.11.y.z extended stable] Patch "rtc: max8907: weekday encoding fixes" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    rtc: max8907: weekday encoding fixes

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 81b750f3cab032d17ee9c527d497b0afb724d37c Mon Sep 17 00:00:00 2001
From: Stephen Warren <swarren at nvidia.com>
Date: Thu, 23 Jan 2014 15:55:19 -0800
Subject: rtc: max8907: weekday encoding fixes

commit 75ea799df4cb07e505c91b4abaa87bc28aad3e66 upstream.

The current MAX8907 driver has two issues related to weekday value
handling:

1)

The HW WEEKDAY register has range 0..6 rather than 1..7 as documented.
Note that I validated the actual HW range by observing the HW register
roll from 6->0 rather than 6->7->1 as would otherwise be expected.

This matches Linux's tm_wday range of 0..6.

When the CMOS RAM content is lost, the date returned from the device is
2007-01-01 00:00:00, which is a Monday.  The WEEKDAY register reads 1 in
this case.  This matches the numbering in Linux's tm_wday field.

Hence we should write Linux's tm_wday value to the register without
modifying it.  Hence, remove the +1/-1 calculations for WEEKDAY/tm_wday.

2)

There's no need to make alarms match on the WEEKDAY register, since the
other fields together uniquely define the alarm date/time.  Ignoring the
WEEKDAY value in the match isolates the driver from any incorrect value in
the current time copy of the WEEKDAY register.

Each change individually, or both together, solves an issue that I
observed; "hwclock -r" would time out waiting for its alarm to fire if the
CMOS RAM content had been lost, and hence the WEEKDAY register value
mismatched what the driver expected it to be.  "hwclock -w" would solve
this by over-writing the HW default WEEKDAY register value with what the
driver expected.

Signed-off-by: Stephen Warren <swarren at nvidia.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/rtc/rtc-max8907.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-max8907.c b/drivers/rtc/rtc-max8907.c
index 8e45b3c..3032178 100644
--- a/drivers/rtc/rtc-max8907.c
+++ b/drivers/rtc/rtc-max8907.c
@@ -51,7 +51,7 @@ static irqreturn_t max8907_irq_handler(int irq, void *data)
 {
 	struct max8907_rtc *rtc = data;

-	regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 0);
+	regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);

 	rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);

@@ -64,7 +64,7 @@ static void regs_to_tm(u8 *regs, struct rtc_time *tm)
 		bcd2bin(regs[RTC_YEAR1]) - 1900;
 	tm->tm_mon = bcd2bin(regs[RTC_MONTH] & 0x1f) - 1;
 	tm->tm_mday = bcd2bin(regs[RTC_DATE] & 0x3f);
-	tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07) - 1;
+	tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07);
 	if (regs[RTC_HOUR] & HOUR_12) {
 		tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x01f);
 		if (tm->tm_hour == 12)
@@ -88,7 +88,7 @@ static void tm_to_regs(struct rtc_time *tm, u8 *regs)
 	regs[RTC_YEAR1] = bin2bcd(low);
 	regs[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
 	regs[RTC_DATE] = bin2bcd(tm->tm_mday);
-	regs[RTC_WEEKDAY] = tm->tm_wday + 1;
+	regs[RTC_WEEKDAY] = tm->tm_wday;
 	regs[RTC_HOUR] = bin2bcd(tm->tm_hour);
 	regs[RTC_MIN] = bin2bcd(tm->tm_min);
 	regs[RTC_SEC] = bin2bcd(tm->tm_sec);
@@ -153,7 +153,7 @@ static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	tm_to_regs(&alrm->time, regs);

 	/* Disable alarm while we update the target time */
-	ret = regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 0);
+	ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
 	if (ret < 0)
 		return ret;

@@ -163,8 +163,7 @@ static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 		return ret;

 	if (alrm->enabled)
-		ret = regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL,
-					 0x7f, 0x7f);
+		ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x77);

 	return ret;
 }
--
1.8.3.2