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

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Date:	Tue, 13 Oct 2015 11:33:13 -0700
From:	Anatol Pomozov <anatol.pomozov@...il.com>
To:	Mark Brown <broonie@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regmap: Add a config option for making regmap debugfs writable

Hi

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?

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.

Current kernel source suggests I need to modify regmap-debugfs.c
directly. But my kernel tree is shared by multiply products and some
of the products in production already. I do not want to enable
writable remap for production products. I would like to have a
per-product compile-time configuration and .config serves exactly this
purpose.

> We want to place a barrier here so that
> users know that this is something that they have taken a decision to
> enable, not something that is in any way supported (this is also why we
> taint the kernel when people do write).

Honestly I am not convinced. Why to put obstacles on a feature that is
very useful during development?
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