From: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
To: Johannes Stezenbach <js-FF7aIK3TAVNeoWH0uzbU5w@public.gmane.org>
Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: DT GPIO numbering?
Date: Sun, 5 Aug 2012 12:06:03 +0200 [thread overview]
Message-ID: <CACRpkdZryc95WpSXddCrLvZGDsv4x-ndX9XcVzoxaDCT53AFLw@mail.gmail.com> (raw)
In-Reply-To: <20120801152240.GA16388-FF7aIK3TAVNeoWH0uzbU5w@public.gmane.org>
On Wed, Aug 1, 2012 at 5:22 PM, Johannes Stezenbach <js-FF7aIK3TAVNeoWH0uzbU5w@public.gmane.org> wrote:
> I'm currently learning how Linux devicetree support works,
> here is one question I couldn't find an answer for.
>
> I understand that within the devicetree GPIOs are referenced by phandle,
> thus the numbers are irrelevant. However, in sysfs the number is
> what is used to access the GPIO, e.g. for debugging or
> blinkenlight apps. How does this fit together?
I think it simply does not fit together.
Grant & me has been claiming the GPIO sysfs interface is a bit
crazy from time to time.
My long-term plan would be to replace it with /dev/gpio/gpioN
device nodes per-gpiochip and use ioctl etc to control these
beasts instead. However one does not do that overnight,
and my life is too busy, and other refactorings also need to
happen :-/
Yours,
Linus Walleij
next prev parent reply other threads:[~2012-08-05 10:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-01 15:22 DT GPIO numbering? Johannes Stezenbach
[not found] ` <20120801152240.GA16388-FF7aIK3TAVNeoWH0uzbU5w@public.gmane.org>
2012-08-05 10:06 ` Linus Walleij [this message]
2012-08-06 2:18 ` Stephen Warren
2012-08-06 6:35 ` Linus Walleij
2012-08-06 9:58 ` Johannes Stezenbach
[not found] ` <20120806095805.GA16607-FF7aIK3TAVNeoWH0uzbU5w@public.gmane.org>
2012-08-06 11:10 ` Mitch Bradley
2012-08-10 9:34 ` Johannes Stezenbach
2012-08-14 10:00 ` Linus Walleij
2012-08-14 13:05 ` Johannes Stezenbach
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