linux-kernel - Re: [PATCH] regmap: Add a config option for making regmap debugfs writable

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Date:	Fri, 4 Dec 2015 17:37:09 +0100
From:	Pavel Machek <pavel@....cz>
To:	Mark Brown <broonie@...nel.org>
Cc:	Anatol Pomozov <anatol.pomozov@...il.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regmap: Add a config option for making regmap debugfs
 writable

On Tue 2015-10-13 21:07:00, Mark Brown wrote:
> On Tue, Oct 13, 2015 at 11:33:13AM -0700, Anatol Pomozov wrote:
> > On Tue, Oct 13, 2015 at 10:55 AM, Mark Brown <broonie@...nel.org> wrote:
> 
> > > This is deliberately not a Kconfig option because it is a terrible idea
> > > to do this in production and making it either selectable or the default
> > > is an invitation to abuse.
> 
> > What kind of abuse are you talking about?
> 
> Using it as a standard interface to control systems in production rather
> than having appropriate support in the relevant driver.
> 
> > Having an easy way of modifying chip registers is extremely useful
> > during bringup / driver development. And during device development
> > phase I regularly have situations when I need to change a register to
> > see if it fixes an issue. Sometimes I need to test it remotely when
> > users located at another end of the Earth.
> 
> This is exactly the sort of use case this feature is intended for, and
> is the sort of situation where a custom kernel is not going to be any
> kind of practical problem.

Well.. we support iopl(0) and we have /dev/mem. I don't see how this
is different.

And yes, CONFIG_ option would be nice, so that this gets compile test
coverage....
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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