linux-kernel - Re: [PATCH] regulator: Rename files for Maxim PMIC drivers

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Message-ID: <56EB6AD6.7050407@osg.samsung.com>
Date:	Thu, 17 Mar 2016 23:41:26 -0300
From:	Javier Martinez Canillas <javier@....samsung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	linux-kernel@...r.kernel.org
Cc:	Liam Girdwood <lgirdwood@...il.com>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH] regulator: Rename files for Maxim PMIC drivers

Hello Krzysztof,

Thanks a lot for your review.

On 03/17/2016 09:07 PM, Krzysztof Kozlowski wrote:
> On 18.03.2016 02:54, Javier Martinez Canillas wrote:
>> Most Maxim PMIC regulator drivers are for sub-devices of Multi-Function
>> Devices with drivers under drivers/mfd. But for many of these, the same
>> object file name was used for both the MFD and the regulator drivers.
>>
>> Having 2 different drivers with the same name causes a lot of confusion
>> to Kbuild, specially if these are built as module since only one module
>> will be installed and also exported symbols will be undefined due being
>> overwritten by the other module during modpost.
> 
> These regulator drivers do not export symbols. In case of max14577 only
> main MFD driver exports symbols so what do you mean by "overwriting by
> other module"?
>

That's correct, what I meant is that if only the MFD driver is built, then
Kbuild / modpost are able to obtain the exported symbols and add it to the
Module.symvers file.

But if the regulator driver is also built, then the build system isn't able
to handle that case and the exported symbols from Module.symvers disappear.

So IIUC what happens is that the build system gets the exported symbols from
the max14755 MFD module but then finds another module that has the same name
(with no exported symbols) and so discards the list of symbols that previously
had for that module. That's why I used the "overwriting by the other module".

> Beside that comment the patch itself is okay:
> 
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
> 
> 
> 
> Best regards,
> 
> Krzysztof
> 

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America