From mboxrd@z Thu Jan  1 00:00:00 1970
From: Laurentiu Palcu <laurentiu.palcu@intel.com>
Subject: Re: [PATCH v2 07/13] power: bq24257: Extend scope of mutex protection
Date: Thu, 10 Sep 2015 16:43:10 +0300
Message-ID: <20150910134309.GI21512@lpalcu-desk>
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To: Andreas Dannenberg <dannenberg@ti.com>
Cc: Sebastian Reichel <sre@kernel.org>, Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>, David Woodhouse <dwmw2@infradead.org>, Krzysztof Kozlowski <k.kozlowski@samsung.com>, linux-pm@vger.kernel.org, devicetree@vger.kernel.org
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On Tue, Sep 08, 2015 at 07:12:31PM -0500, Andreas Dannenberg wrote:
> This commit extends the use of the existing mutex to pave the way for
> using direct device access inside sysfs getter/setter routines in a
> way that the access during interrupts and timer routines does not
> interfere with device access by the CPU or between multiple cores.
> 
> This also addresses a potential race condition that could be caused
> by bq24257_irq_handler_thread() and bq24257_iilimit_autoset() accessing
> the device simultaneously.
What potential race? AFAIK, we're doing all the operations through
regmap, and regmap operations are serialized. It has its own mutex for
this. Unless I got it all wrong...

So, IMHO, you don't need to protect against simultaneous device access.
It's taken care of by regmap. Chip state data protection should be enough.

laurentiu