From: Steve Twiss <stwiss.opensource@diasemi.com>
To: Paul Gortmaker <paul.gortmaker@windriver.com>
CC: Support Opensource <Support.Opensource@diasemi.com>,
        Lee Jones <lee.jones@linaro.org>, Eric Miao <eric.miao@marvell.com>,
        Mike Rapoport <mike@compulab.co.il>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 1/4] mfd: da903x: Make it explicitly non-modular
Thread-Topic: [PATCH 1/4] mfd: da903x: Make it explicitly non-modular
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Date: Tue, 6 Jun 2017 15:27:50 +0000
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Hi Paul,

On 05 June 2017 20:30, Paul Gortmaker wrote:

> Subject: Re: [PATCH 1/4] mfd: da903x: Make it explicitly non-modular
> 
> [RE: [PATCH 1/4] mfd: da903x: Make it explicitly non-modular]
> On 05/06/2017 (Mon 10:30) Steve Twiss wrote:
> 
> > On 03 June 2017 14:04 Paul Gortmaker wrote:
> > > The Kconfig currently controlling compilation of this code is:
> > >
> > > drivers/mfd/Kconfig:config PMIC_DA903X
> > > drivers/mfd/Kconfig:    bool "Dialog Semiconductor DA9030/DA9034 PMIC
> > > Support"
> > >
> > > ...meaning that it currently is not being built as a module by anyone.
> >
> > With regards to your four patches,
> >
> >  [4/4] mfd: da9055-i2c: Make it explicitly non-modular	- - -	2017-06-03
> >  [3/4] mfd: da9055-core: make it explicitly non-modular	- - -	2017-06-03
> >  [2/4] mfd: da9052-*: Make it explicitly non-modular	- - -	2017-06-03
> >  [1/4] mfd: da903x: Make it explicitly non-modular	- - -	2017-06-03
> >
> > Is there an reason not to make the Kconfig tristate?
> > Would that not be simpler?
> 
> I explicitly covered that in the 0/4 e-mail:

Apologies, I don't seem to have been CC'ed on the 0/4 e-mail, although I
got the others. Dialog's developer e-mail addresses come as part of the
Support Opensource e-mail distribution list.

>    As always, the option exists for someone with the hardware and the desire
>    to extend the functionality to make any given driver tristate.  But given
>    the number of these tree wide and the fact that I can't test that new
>    extended functionality in all cases, I just make the code consistent with
>    existing Kconfig/Makefile settings that currently restrict them to "bool".

I see your point, however we have many customers and it is unclear whether
they are using modules for any of these drivers. 
Even if that feature in Kconfig is not enabled, it is possible a tristate change has
been made and is being used, but has not been pushed back into the Linux
mainline.

So I would recommend against removing this feature.

The driver code is being supported by Dialog Semiconductor, where possible.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/MAINTAINERS?h=v4.12-rc4#n3984
If there is a question about supporting modules in these drivers, we have the
ability to test on target for da9055/52.

Regards,
Steve