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Date: Sat, 23 Jul 2011 11:43:34 +0100
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Shawn Guo <shawn.guo@freescale.com>,
        ashishj3 <ashish.jangam@kpitcummins.com>,
        Dajun <dajun.chen@diasemi.com>, sameo@openedhand.com,
        linaro-dev@lists.linaro.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/11] MFD: DA9052 MFD core module v2
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On Sat, Jul 23, 2011 at 11:50:30AM +0200, Arnd Bergmann wrote:

> Yes, that makes sense. There are also cases where a mutex should really
> be a spinlock (which is by definition not interruptible), or vice
> versa. I don't know if this is one of them.

We would be using spinlocks except the underlying buses sleep waiting
for the hardware to complete the transfer - the operations are quick
enough from a user perspective but at the very low level we want the CPU
to be able to go off and do other things while they're happening.