From: LW@KARO-electronics.de (Lothar Waßmann)
To: linux-arm-kernel@lists.infradead.org
Subject: GPIO sysfs 'default' values
Date: Thu, 21 Feb 2013 08:37:18 +0100 [thread overview]
Message-ID: <20773.52910.72747.877165@ipc1.ka-ro> (raw)
In-Reply-To: <1361430680.10390.7.camel@gitbox>
Hi,
Tony Prisk writes:
> Hi Grant, Linus.
>
> I was testing our new gpio/pinctrl driver today and noticed something a
> little weird.
>
> I exported gpio0 via sysfs and echoed the direction value - it was 'in'.
> This pin is used to control an LCD panel, and is actually in 'out' mode.
> If I write 'in' to direction, it changes mode to 'in' and the panel
> turns off. Setting it back to 'out' and value=0, and the panel turns on
> again.
>
> I noticed that I had no gpiochip->get_direction, so I added it, but the
> result was the same.
>
> Any idea what I've missed?
>
You missed to report on what platform this happens.
The platform specific GPIO driver obviously does not initialize the
shadow variables for the hardware registers correctly.
Lothar Wa?mann
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prev parent reply other threads:[~2013-02-21 7:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-21 7:11 GPIO sysfs 'default' values Tony Prisk
2013-02-21 7:27 ` Tony Prisk
2013-02-21 7:37 ` Lothar Waßmann [this message]
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