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Date: Thu, 20 Oct 2011 15:18:27 +0100
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>, Shawn Guo <shawn.guo@freescale.com>,
        Linus Walleij <linus.walleij@stericsson.com>,
        linux-kernel@vger.kernel.org, Stephen Warren <swarren@nvidia.com>,
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        Sascha Hauer <s.hauer@pengutronix.de>,
        David Brown <davidb@codeaurora.org>,
        Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [PATCH 2/2] pinctrl: add a generic control interface
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On Thu, Oct 20, 2011 at 04:04:47PM +0200, Linus Walleij wrote:

> I think (and of course this may be completely wrong, but it's my
> working hypthesis) that the things that software wants to do to
> pins are:

The other question is if it's worth bouncing through too much of an
abstraction layer when both ends of the API are fixed.

> Yet again, can I have some examples of what
> PIN_CONFIG_USER may *actually* be, which would be
> absolutely impossible to express in some neutral way, and
> ridiculous to have in the generic enum?

One fun example is that we have some devices with pins which have
runtime controllable voltage domains, there's no obvious SI unit mapping
for those.