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Date: Wed, 08 Nov 2006 14:12:20 -0800
From: David Brownell <david-b@pacbell.net>
To: hskinnemoen@atmel.com
Subject: Re: [-mm patch 1/4] GPIO framework for AVR32
Cc: linux-kernel@vger.kernel.org, andrew@sanpeople.com, akpm@osdl.org
References: <20061107122507.6f1c6e81@cad-250-152.norway.atmel.com>
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> The request/free calls aren't really arch-specific, are they?

Remember that where one platform may use numbers 32-159 for GPIOs, another
might use 0-71 ... GPIO numbering has an arch-specific core, but whether
a given board adds more GPIOs from an FPGA or other non-SOC chip is even
more variable than "arch-specific".


> I implement the actual allocation mechanism using atomic bitops.

That's a fair way to implement it, sure; but if you look at e.g. how
OMAP does it, the bitmap is inside a per-controller structure.  When
one chip has two different _types_ of GPIO controller, and multiple
instances of one (plus restrictions applying to specific instances),
the notion of an arch-neutral implementation there seems unworkable.

- Dave

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