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Date: Tue, 18 Jun 2013 16:11:16 +0100
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
        Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
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Subject: Re: [PATCH v4 02/10] pinctrl: mvebu: dove pinctrl driver
Message-ID: <20130618151116.GZ2718@n2100.arm.linux.org.uk>
References: <1344689809-6223-1-git-send-email-sebastian.hesselbarth@gmail.com> <1347550912-18021-1-git-send-email-sebastian.hesselbarth@gmail.com> <1347550912-18021-3-git-send-email-sebastian.hesselbarth@gmail.com> <20130618113606.GA26763@n2100.arm.linux.org.uk> <CACRpkdZTVN2O-Rv4u-Ccb9EzV0At3zc7GYQyTq=HkseOi=GTeg@mail.gmail.com>
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On Tue, Jun 18, 2013 at 05:02:49PM +0200, Linus Walleij wrote:
> Nowadays I would do the above with regmap_update_bits().
> 
> Mutual exclusion for read-modify-write of individual bits in a
> register is one of those cases where doing a regmap over
> a memory-mapped register range makes a lot of sense.
> (drivers/mfd/syscon.c being a nice example)

So, for that solution we need to have some kind of global regmap per
register or somesuch.  Then you run into regmap needing a struct
device - well, with a shared register, which struct device do you
use, or do you have to invent one?

That sounds more heavy-weight than is really necessary.