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From: David Brownell <david-b@pacbell.net>
To: "Hennerich, Michael" <Michael.Hennerich@analog.com>
Subject: Re: [PATCH 02/12] Blackfin arch: Add label to call new GPIO API
Date: Fri, 17 Aug 2007 14:29:31 -0700
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Cc: "Mike Frysinger" <vapier.adi@gmail.com>, "Bryan Wu" <bryan.wu@analog.com>,
       torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
       akpm@linux-foundation.org
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On Friday 17 August 2007, Hennerich, Michael wrote:
> What Mike wants to point out is that a external IRQ is first a GPIO and
> needs to be configured like an INPUT GPIO and then a specific bit needs
> to be set unmask it as IRQ.
> 
> So why not use the GPIO infrastructure to setup this pin as GPIO?

My comments about the advantages of using that infrastructure
for *early* binding captured the key points ... it's "failfast".

For IRQs you're probably on decently firm ground, since it's
extremely rare that people not handle request_irq() errors.

Remember, I just pointed out that the "late fail" strategy
is unusual.  That doesn't mean it's wrong ... just it'll be
a bit of surprise, some cognitive dissonance to developers
picking up a Blackfin project, potentially more error prone.

- Dave

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