Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller

From	Linus Walleij <linus.walleij@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller
Date	2015-10-16 22:00 +0200
Message-ID	<qkjku-80a-31@gated-at.bofh.it> (permalink)
References	<qgimZ-6vn-3@gated-at.bofh.it> <qgv0T-7Vp-29@gated-at.bofh.it> <qhmHU-UH-17@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Oct 8, 2015 at 6:55 PM, Andreas Werner <andy@wernerandy.de> wrote:

> The register is currently impelemented as a read/write register
> which means the pin mode is configurable by software to
> Push Pull or Open Drain.

OK then you can set it in accordance to what clients request.

> There is also the possiblity (normal way) that the HW (FPGA) configures
> each pin to the correct mode.
>
> Is there actually a way to set an output mode from userland or by the gpio API?

As per <linux/gpio/machine.h> you can specify per-line if it should be
open drain using GPIO_OPEN_DRAIN, this will push through to the
gpio descriptor and those lines with this flag set will be handled specially.
We have merged device tree bindings for OD/OS but not code to
handle these, but I might have some code from Laurent Pinchart cooking
for the DT in-kernel backend too.

> I did not find anything about that.

git grep OPEN_DRAIN

Yours,
Linus Walleij
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Thread

Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller Linus Walleij <linus.walleij@linaro.org> - 2015-10-06 09:40 +0200
  Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller Andreas Werner <andy@wernerandy.de> - 2015-10-06 20:00 +0200
  Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller Andreas Werner <andy@wernerandy.de> - 2015-10-08 19:00 +0200
    Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller Linus Walleij <linus.walleij@linaro.org> - 2015-10-16 22:00 +0200
  Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller Andreas Werner <andy@wernerandy.de> - 2015-10-08 21:50 +0200
    Re: [PATCH] gpio: Add driver for MEN 16Z127 GPIO controller Linus Walleij <linus.walleij@linaro.org> - 2015-10-16 22:00 +0200

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