From: Michael Welling <mwelling@ieee.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
Alexandre Courbot <acourbot@nvidia.com>,
Markus Pargmann <mpa@pengutronix.de>,
Lee Campbell <leecam@google.com>,
Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>,
Grant Likely <grant.likely@linaro.org>,
Arnd Bergmann <arnd@arndb.de>, Mark Brown <broonie@kernel.org>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Johan Hovold <johan@kernel.org>
Subject: Re: [PATCH 2/2] tools/gpio: add the gpio-hammer tool
Date: Tue, 31 May 2016 22:43:43 -0500 [thread overview]
Message-ID: <20160601034343.GA3749@deathstar> (raw)
In-Reply-To: <CACRpkdYr8GSmQ-=G4XcTtfrBcKsXUsJOvE7W35Fk-ovDiyaPJA@mail.gmail.com>
On Tue, May 31, 2016 at 01:59:42PM +0200, Linus Walleij wrote:
> On Wed, Apr 27, 2016 at 6:00 PM, Michael Welling <mwelling@ieee.org> wrote:
> > On Tue, Apr 26, 2016 at 10:54:26AM +0200, Linus Walleij wrote:
> >> The gpio-hammer is used from userspace as an example of how
> >> to retrieve a GPIO handle for one or several GPIO lines and
> >> hammer the outputs from low to high and back again. It will
> >> pulse the selected lines once per second for a specified
> >> number of times or indefinitely if no loop count is
> >> supplied.
> >>
> >> Example output:
> >> $ gpio-hammer -n gpiochip0 -o5 -o6 -o7
> >> Hammer lines [5, 6, 7] on gpiochip0, initial states: [1, 1, 1]
> >> [-] [5: 0, 6: 0, 7: 0]
> >>
> >> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> >
> > Tested-by: Michael Welling <mwelling@ieee.org>
>
> Thanks! :)
No problem. I wish I could help more.
I like how the support has progressed.
Did you ever find a solution for the exhausted char dev problem?
>
> > Below is the output from my target.
>
> You can now get rid of all the "unnamed" in the first column
> by supplying the line/rail names in gpio-line-names = "A", "B" ...;
> in the GPIO controller node in the device tree for the platform,
> if it uses device tree too boot.
Yeah I saw that.. not bored enough to name all of the GPIOs.
>
> > You will notice that a kernel warning is
> > spewed out if I use the mcp23s08.
> > The processor GPIOs work fine as verified by blinking LEDs.
> >
> > root@som3517-som200:~# ./lsgpio
> > GPIO chip: gpiochip4, "mcp23s08", 8 GPIO lines
> > line 0: unnamed unused
> > line 1: unnamed unused
> > line 2: unnamed unused
> > line 3: unnamed unused
> > line 4: unnamed unused
> > line 5: unnamed unused
> > line 6: unnamed unused
> > line 7: unnamed unused
>
> > root@som3517-som200:~# ./gpio-hammer -n gpiochip4 -o0
> > [ 187.511606] ------------[ cut here ]------------
> > [ 187.516949] WARNING: CPU: 0 PID: 830 at /home/michael/projects/linux/linux-git/drivers/gpio/gpiolib.c:1907 gpiod_get_value+0x60/0xa4
>
> Ah that's right, I have to use gpiod_get_value_cansleep(). Will
> fix that.
>
> Yours,
> Linus Walleij
next prev parent reply other threads:[~2016-06-01 3:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-26 8:54 [PATCH 1/2] gpio: userspace ABI for reading/writing GPIO lines Linus Walleij
2016-04-26 8:54 ` [PATCH 2/2] tools/gpio: add the gpio-hammer tool Linus Walleij
2016-04-27 16:00 ` Michael Welling
2016-05-31 11:59 ` Linus Walleij
2016-06-01 3:43 ` Michael Welling [this message]
2016-06-01 17:35 ` Linus Walleij
2016-06-01 18:09 ` Michael Welling
2016-06-01 21:40 ` Linus Walleij
2016-06-02 14:59 ` Michael Welling
2016-06-15 9:48 ` Linus Walleij
2016-04-28 7:47 ` Alexander Stein
2016-04-26 16:44 ` [PATCH 1/2] gpio: userspace ABI for reading/writing GPIO lines Dmitry Torokhov
2016-05-27 13:22 ` Linus Walleij
2016-05-27 17:36 ` Dmitry Torokhov
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