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From: daniel@caiaq.de (Daniel Mack)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm pxa: remove "direction input" forcing for IRQ GPIOs
Date: Tue, 17 Nov 2009 13:34:22 +0100	[thread overview]
Message-ID: <20091117123422.GU14091@buzzloop.caiaq.de> (raw)
In-Reply-To: <20091117120501.GC8008@gundam.enneenne.com>

On Tue, Nov 17, 2009 at 01:05:01PM +0100, Rodolfo Giometti wrote:
> On Tue, Nov 17, 2009 at 12:44:29PM +0100, Daniel Mack wrote:
> > On Tue, Nov 17, 2009 at 12:21:46PM +0100, Rodolfo Giometti wrote:
> > > PXA CPUs may use their GPIOs as IRQ lines even if they are selected as
> > > outputs (see for example figure 24-1 into PXA27x Processor Family
> > > Developer's Manual). So forcing GPIOs IRQ lines as inputs is not
> > > correct.
> > > 
> > > Programmers should set up GPIOs direction according to their usage and
> > > the function pxa_gpio_irq_type() should simply enable the IRQ
> > > detection.
> > 
> > Interesting. Is this an academic issue or do you actually use that?
> > That would mean you externally drive the IO pin level to something else
> > than the output driver provides, which isn't healthy at all.
> 
> It's a real configuration with no electrical drawbacks at all! Of
> course the driver's output must be passive (I use it to detect a CARD
> insert) but it's functional.

For such situations, the pullup/pulldown functions are normally used.
Have you tried that?

Daniel

  parent reply	other threads:[~2009-11-17 12:34 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-17 11:21 [PATCH] arm pxa: remove "direction input" forcing for IRQ GPIOs Rodolfo Giometti
2009-11-17 11:44 ` Daniel Mack
2009-11-17 12:05   ` Rodolfo Giometti
2009-11-17 12:12     ` Eric Miao
2009-11-17 12:34     ` Daniel Mack [this message]
2009-11-17 12:37       ` Rodolfo Giometti
2009-11-17 12:43         ` Daniel Mack
2009-11-17 12:59           ` Rodolfo Giometti
2009-11-17 13:06             ` Daniel Mack
2009-11-17 13:16               ` Rodolfo Giometti
2009-11-17 14:38               ` Rodolfo Giometti
2009-11-17 17:11                 ` Daniel Mack
2009-11-17 18:02                   ` Rodolfo Giometti
2009-11-17 19:28                     ` Russell King - ARM Linux
2009-11-17 17:00   ` H Hartley Sweeten

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