Patch "rtc: s5m: fix to update ctrl register" has been added to the 4.2-stable tree

Patch "rtc: s5m: fix to update ctrl register" has been added to the 4.2-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    rtc: s5m: fix to update ctrl register

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     rtc-s5m-fix-to-update-ctrl-register.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ff02c0444b83201ff76cc49deccac8cf2bffc7bc Mon Sep 17 00:00:00 2001
From: Joonyoung Shim <jy0922.shim@samsung.com>
Date: Fri, 21 Aug 2015 18:43:41 +0900
Subject: rtc: s5m: fix to update ctrl register

From: Joonyoung Shim <jy0922.shim@samsung.com>

commit ff02c0444b83201ff76cc49deccac8cf2bffc7bc upstream.

According to datasheet, the S2MPS13X and S2MPS14X should update write
buffer via setting WUDR bit to high after ctrl register is written.

If not, ALARM interrupt of rtc-s5m doesn't happen first time when i use
tools/testing/selftests/timers/rtctest.c test program and hour format is
used to 12 hour mode in Odroid-XU3 board.

One more issue is the RTC doesn't keep time on Odroid-XU3 board when i
turn on board after power off even if RTC battery is connected. It can
be solved as setting WUDR & RUDR bits to high at the same time after
RTC_CTRL register is written. It's same with condition of only writing
ALARM registers, so this is for only S2MPS14 and we should set WUDR &
A_UDR bits to high on S2MPS13.

I can't find any reasonable description about this like fix from
datasheet, but can find similar codes from rtc driver source of
hardkernel kernel and vendor kernel.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/rtc/rtc-s5m.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/rtc/rtc-s5m.c
+++ b/drivers/rtc/rtc-s5m.c
@@ -635,6 +635,16 @@ static int s5m8767_rtc_init_reg(struct s
 	case S2MPS13X:
 		data[0] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 		ret = regmap_write(info->regmap, info->regs->ctrl, data[0]);
+		if (ret < 0)
+			break;
+
+		/*
+		 * Should set WUDR & (RUDR or AUDR) bits to high after writing
+		 * RTC_CTRL register like writing Alarm registers. We can't find
+		 * the description from datasheet but vendor code does that
+		 * really.
+		 */
+		ret = s5m8767_rtc_set_alarm_reg(info);
 		break;
 
 	default:


Patches currently in stable-queue which might be from jy0922.shim@samsung.com are

queue-4.2/rtc-s5m-fix-to-update-ctrl-register.patch
queue-4.2/rtc-s3c-fix-disabled-clocks-for-alarm.patch