linux-kernel - Re: [PATCH v2] rtc: max8997: Add driver for max8997 rtc.

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Date:	Fri, 08 Feb 2013 11:19:42 +0900
From:	jonghwa3.lee@...sung.com
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, a.zummo@...ertech.it,
	rtc-linux@...glegroups.com
Subject: Re: [PATCH v2] rtc: max8997: Add driver for max8997 rtc.

On 2013년 02월 08일 06:44, Andrew Morton wrote:
> On Thu, 07 Feb 2013 20:01:27 +0900
> Jonghwa Lee <jonghwa3.lee@...sung.com> wrote:
> 
>> This patch adds rtc driver for Maxim 8997 multifunction chip.
>> Max8997 has rtc module in it. and it can be used for timekeeping
>> clock and system alarm. It provide various operational mode those are
>> BCD/binary, 24/12hour, am/pm. Driver sets binary/24/ for default.
>> Maxim 8997 also supports SMPL(Sudden Momentary Power Loss), WTSR
>> (Watchdog Timeout and Software Reset).
>>
>> Signed-off-by: Jonghwa Lee <jonghwa3.lee@...sung.com>
>> ---
>> v2
>>  - Add module parameter to enable/disable WTSR, SMPL fuction.
>>  - Add unregister_rtc_device() for accidental exit in probing.
>>
>> ...
>>
>> +/* Module parameter for WTSR function control */
>> +static int wtsr_en = 1;
>> +module_param(wtsr_en, int, 0444);
>> +MODULE_PARM_DESC(wtsr_en, "Wachdog Timeout & Sofware Reset (default=on)");
>> +/* Module parameter for SMPL function control */
>> +static int smpl_en = 1;
>> +module_param(smpl_en, int, 0444);
>> +MODULE_PARM_DESC(smpl_en, "Sudden Momentary Power Loss (default=on)");
> 
> "default=on" is interesting.  For what reasons would a user ever want
> to set this "off"?  Can we just remove the options and leave these
> things enabled all the time for everyone?
>

System with WTSR will be postponed to reset more than 58.6ms(250 ~ 1000ms) even if AP sends
POWERHOLD signal low. (By default(without WTSR) it keeps PMIC on 58.6ms , then re-check the
POWERHOLD signal to determine whether it needs PMIC off)
And with SMPL option enabled, system will be automatically re-boot when power has been recovered
before SMPL's timer is expired.

Those all functions are just optional not significant. And someone may not want to them, so
I think the better idea is leave it selectable. If you don't thinks so, I remove options and
keep it enabled for all.

Thanks,
Jonghwa.

> 
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