linux-kernel - Re: [rtc-linux] [PATCH] rtc: s5m: fix to update ctrl register

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Date:	Mon, 17 Aug 2015 10:47:53 +0900
From:	Joonyoung Shim <jy0922.shim@...sung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	rtc-linux@...glegroups.com
Cc:	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org, a.zummo@...ertech.it,
	alexandre.belloni@...e-electrons.com, sbkim73@...sung.com
Subject: Re: [rtc-linux] [PATCH] rtc: s5m: fix to update ctrl register

Hi,

On 08/13/2015 07:02 PM, Krzysztof Kozlowski wrote:
> W dniu 13.08.2015 o 17:49, Joonyoung Shim pisze:
>> According to datasheet, the S2MPS13X and S2MPS14X should update write
>> buffer via setting WUDR bit to high after ctrl register is updated.
> 
> Hi,
> 
> I cannot find this information in S2MPS14 datasheet. On which page is it?
> 

I got below information from S2MPS14_Data Sheet_REV0.1 document.

5.2.2.3 RTC_UPDATE
...

NOTE: 
1.  For write Time Registers (0x00, 0x04~0x0A) & Alarm 0&1 Registers 
(0x0B~0x18), set WUDR bit to high.

> 
>>
>> 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.
> 
> Two questions here:
> 1. Earlier you mentioned S2MPS1[34], now Odroid XU3 which has S2MPS11.
> Are you sure that this applies to all of them (S2MPS11, S2MPS13 and
> S2MP14)? There are some minor differences between them so I would not be
> surprised if only some of them required this action.
> 

I'm not sure about that because i don't have S2MPS11 datasheet. I just
got the information that S2MPS11 also use S2MPS14 rtc from sec-core mfd
driver,

static const struct mfd_cell s2mps11_devs[] = {                                                                       
        {                                                                                                             
                .name = "s2mps11-pmic",                                                                               
        }, {                                                                                                          
                .name = "s2mps14-rtc",                                                                                
        }, {                                                                                                          
                .name = "s2mps11-clk",                                                                                
                .of_compatible = "samsung,s2mps11-clk",                                                               
        }                                                                                                             
};

> 2. The driver operates in 24-hour omode. Actually it sets the 24-hour
> mode just before your new regmap_update_bits() call. What do you mean by
> 12-hour mode?
> 

RTC_CTRL register value is 0 until write buffer is updated, so it is
used to 12-hour mode.

>> Signed-off-by: Joonyoung Shim <jy0922.shim@...sung.com>
>> Cc: <stable@...r.kernel.org>
> 
> Thanks for putting a cc-stable tag. How far this should be ported? If
> this is needed only for S2MPS11 then v4.1. If all of them then probably
> for earlier version?
> 

If find exact version, i think it will be a version after below commit
was applied.

The commit 0c5deb1ea92f("rtc: s5m: add support for S2MPS14 RTC")

$ git name-rev 0c5deb1ea92f
0c5deb1ea92f tags/v3.16-rc1~53^2~1

Thanks.

> Best regards,
> Krzysztof
> 
>> ---
>>  drivers/rtc/rtc-s5m.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/rtc/rtc-s5m.c b/drivers/rtc/rtc-s5m.c
>> index 8c70d78..03828bb 100644
>> --- a/drivers/rtc/rtc-s5m.c
>> +++ b/drivers/rtc/rtc-s5m.c
>> @@ -635,6 +635,18 @@ static int s5m8767_rtc_init_reg(struct s5m_rtc_info *info)
>>  	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;
>> +
>> +		ret = regmap_update_bits(info->regmap,
>> +				info->regs->rtc_udr_update,
>> +				info->regs->rtc_udr_mask,
>> +				info->regs->rtc_udr_mask);
>> +		if (ret < 0)
>> +			break;
>> +
>> +		ret = s5m8767_wait_for_udr_update(info);
>> +
>>  		break;
>>  
>>  	default:
>>
> 
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