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From: shc_work@mail.ru (Alexander Shiyan)
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: dts: i.MX27: Configure GPIOs as "input" by default
Date: Wed, 04 Dec 2013 13:04:00 +0400	[thread overview]
Message-ID: <1386147840.110296074@f57.i.mail.ru> (raw)
In-Reply-To: <20131204095703.236ccbe0@ipc1.ka-ro>

> > On Tue, Dec 03, 2013 at 04:46:27PM +0800, Shawn Guo wrote:
> > > On Sat, Nov 30, 2013 at 11:03:20AM +0400, Alexander Shiyan wrote:
> > > > This patch changes the default direction for pins used
> > > > as GPIO to "input". This prevents a short circuit on the
> > > > configuration stage when GPIO-pin is connected to the
> > > > other output pin.
> > > 
> > > Markus,
> > > 
> > > Does it make sense to you?
> > 
> > I am not sure if this really happens. However, it does make sense and I
> > can't see any disadvantages in changing the default GPIO mux direction to
> > input.
> > 
> What happens, if the bootloader already set up a pin as output and
> linux later does the pinconfig stuff?
> If the pin is reconfigured as input then, this may produce an unwanted
> glitch on the pin. IMO the pinconfig driver should not touch the pin
> direction, but leave it to the gpio driver to set that up. 

Such pin can be overridden by board DTS.

---

  reply	other threads:[~2013-12-04  9:04 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-30  7:03 [PATCH] ARM: dts: i.MX27: Configure GPIOs as "input" by default Alexander Shiyan
2013-12-03  8:46 ` Shawn Guo
2013-12-03 13:30   ` Markus Pargmann
2013-12-04  8:57     ` Lothar Waßmann
2013-12-04  9:04       ` Alexander Shiyan [this message]
2013-12-04  9:13         ` Lothar Waßmann
2013-12-04  9:24           ` Alexander Shiyan
2013-12-04 10:07             ` Lothar Waßmann
2013-12-04 10:16               ` Alexander Shiyan
2013-12-04 11:15                 ` Lothar Waßmann
2013-12-04 11:33                   ` Alexander Shiyan
2013-12-04 11:58                     ` Lothar Waßmann
2013-12-03 13:37 ` Shawn Guo

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