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From: Kent Gibson <warthog618@gmail.com>
To: Drew Fustini <drew@pdp7.com>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [RFC] gpio: expose pull-up/pull-down line flags to userspace
Date: Thu, 10 Oct 2019 07:59:38 +0800
Message-ID: <20191009235938.GA10263@sol> (raw)
In-Reply-To: <20191009133037.GA17244@x1>

On Wed, Oct 09, 2019 at 03:30:37PM +0200, Drew Fustini wrote:
> On Wed, Oct 09, 2019 at 02:55:24PM +0800, Kent Gibson wrote:
> > Safe to assume your code is in your topic/gpio-uapi-config branch?
> > I hope so, cos I've forked from that into github.com/warthog618/linux 
> > and have started working on it.
> 
> Do you also have a fork of libgpiod that you are working in?
> 
> In case it is of any use, I just posted the libgpiod patch for pull-up/down
> flags that I had been using to test with.
> 
> I help maintain Adafruit_Blinka [1] so I would like try testing pull-up/down.
> I already have a Raspberry Pi 3 booting a cross-compiled kernel with my (now
> outdated) patch applied and a patched libgpiod.
> 
It is basically working for me on my Pi4:

pi@quoll:~ $ ./gpiodctl get gpiochip0 7
0
pi@quoll:~ $ ./gpiodctl get -u gpiochip0 7
1
pi@quoll:~ $ ./gpiodctl get gpiochip0 7
1
pi@quoll:~ $ ./gpiodctl get -d gpiochip0 7
0
pi@quoll:~ $ ./gpiodctl get gpiochip0 7
0

That is using the gpiodctl tool from my gpiod library.
My gpiod test suite also passes, but it doesn't do much to
exercise the UAPI.
I was intending to run my uapi test suite, which is more thorough,
but it turns out that only targets gpio-mockup, whereas my gpiod
test suite can target either.
Something else for the todo list.

Hopefully it is obvious what gpiodctl is doing. (-u sets the 
pull-up flag, -d sets the pull-down flag)
Looks like the pulls stick when the line is released, and the
subsequent get, without pull-up set, either doesn't clear the
pull-up/down or the line stays floating at the old pull level.
More investigation required, but that will have to wait til 
I get back to this later in the day.

Oh, and that is running on the rpi-5.3.3 kernel patched with everything
on my topic/gpio-uapi-config branch from 5.4-rc2 onward.

Cheers,
Kent.

  parent reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-21 10:25 Drew Fustini
2019-09-23  8:38 ` Bartosz Golaszewski
2019-10-02 11:10   ` Drew Fustini
2019-10-03 12:47   ` Linus Walleij
2019-10-04  7:22     ` Bartosz Golaszewski
2019-10-04 12:46       ` Bartosz Golaszewski
2019-10-05 17:02       ` Linus Walleij
2019-10-06  3:12         ` Kent Gibson
2019-10-06 21:06           ` Linus Walleij
2019-10-07  4:37             ` Kent Gibson
2019-10-08  6:15 ` Kent Gibson
2019-10-08 20:56   ` Bartosz Golaszewski
2019-10-08 23:21     ` Kent Gibson
2019-10-08 23:30       ` Bartosz Golaszewski
2019-10-08 23:56         ` Kent Gibson
2019-10-09  0:03           ` Bartosz Golaszewski
2019-10-09  0:22             ` Kent Gibson
2019-10-09  6:55               ` Kent Gibson
2019-10-09 12:57                 ` Drew Fustini
2019-10-09 13:23                   ` Kent Gibson
2019-10-09 13:30                 ` Drew Fustini
2019-10-09 14:11                   ` Kent Gibson
2019-10-09 15:50                     ` Bartosz Golaszewski
2019-10-09 16:19                       ` Kent Gibson
2019-10-09 23:59                   ` Kent Gibson [this message]
2019-10-10  7:47                     ` Drew Fustini
2019-10-10 10:14                       ` Kent Gibson
2019-10-10 11:17                         ` Kent Gibson
2019-10-11 13:04                           ` Drew Fustini
2019-10-11 13:06                         ` Drew Fustini
2019-10-11 13:49                           ` Kent Gibson
2019-10-09 11:32               ` Drew Fustini
2019-10-09 13:57       ` Drew Fustini
2019-10-09 14:01         ` Kent Gibson
2019-10-09 11:46   ` Drew Fustini

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