Date:	Thu, 14 Jan 2016 22:50:07 -0300
From:	Javier Martinez Canillas <javier@...hile0.org>
To:	Laxman Dewangan <ldewangan@...dia.com>
Cc:	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Alexandre Courbot <gnurou@...il.com>,
	Lee Jones <lee.jones@...aro.org>,
	Mark Brown <broonie@...nel.org>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linux GPIO List <linux-gpio@...r.kernel.org>,
	rtc-linux@...glegroups.com, Stephen Warren <swarren@...dia.com>,
	Thierry Reding <treding@...dia.com>
Subject: Re: [PATCH V2 5/6] rtc: max77xxx: add RTC driver for Maxim MAX77xxx
 series RTC IP

Hello,

On Thu, Jan 14, 2016 at 8:50 AM, Laxman Dewangan <ldewangan@...dia.com> wrote:
> On Thursday 14 January 2016 06:50 AM, Krzysztof Kozlowski wrote:
>> On 14.01.2016 09:50, Krzysztof Kozlowski wrote:

[snip]

>>>
>>> The max77802 does exactly the same (BTW, these should be merged as
>>> well... I'll add this to the TODO list) so I think this is necessary.
>>
>> How about merging max77802 to max77686 first? The only differences I
>> found are:
>> 1. It uses main MFD/PMIC regmap.
>>     This can be solved as part of decoupling code. The driver will get
>> MFD's regmap and set up its own (only on max77686). The max77802 will
>> only use parent's regmap.
>>
>> 2. It has different register address.
>>     We need a register-layout/configuration structure. The logic is the
>> same except few differences (e.g. presence of MAX77802_RTC_AE1).
>>
>> It may be easier to merge them now, before adding support for max77620?

Agreed.

When I originally posted the max77802 support, I had separate MFD,
RTC, regulator and clock drivers and the feedback (IIRC) was that the
MFD and clock blocks were too similar to the max77686 so I extended
those drivers instead of adding new ones. But that the RTC and
regulator blocks were different so a separate driver was justified...
but it's true that are not that different and rtc-max77686 could be
extended and rtc-max77802 removed.

In fact, the ChromiumOS vendor tree has a single RTC driver for both
max77686 and max77802:

https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-3.8/drivers/rtc/rtc-max77xxx.c

>> I could handle this probably next week or in the following week
>> (assuming someone would test max77802 because I don't have the hardware).
>>

I could also work on this next week if you want. After all I feel
guilty for the code duplication :-)

>> Anyway I think we should develop these RTC patches having this in mind:
>> merge all of them.
>>
>
> I think we can do the merging of max77802 and max77686 at second step.
>
> At first, lets decouple the rtc-max77686.c with its mfd driver. This will
> give better picture how will it be done.

I don't quite understand what you mean by decoupling here, the
max77686 MFD driver today is not highly coupled to their cells devices
drivers since it supports both max77802 and max77686 already. Yes,
some changes will be needed but I think those should be small.

> Once this is there then max77620 can use this and in parallel, can be work
> for max77802 to use the same driver.
>
>
> Let's first conclude and get accpepted for max77686 and max77620 as both of
> us have related HW to verify the changes.
>

I agree with Krzysztof that merging first before extending makes more
sense but I don't have a strong opinion on this and can be done as a
followup as well.

Best regards,
Javier

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