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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Fri, 26 Apr 2019 20:20:19 +0300
Message-ID: <CAHp75VfonL_f1GjRFFhp59R8U+bGzT9pcC7p8XDJ32-_cxT29g@mail.gmail.com>
Subject: Re: [PATCH 2/2] gpio: sch: Add interrupt support
To:     Jan Kiszka <jan.kiszka@siemens.com>
Cc:     "Enrico Weigelt, metux IT consult" <lkml@metux.net>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
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Sender: linux-kernel-owner@vger.kernel.org
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On Fri, Apr 26, 2019 at 7:05 PM Jan Kiszka <jan.kiszka@siemens.com> wrote:
>
> On 26.04.19 16:42, Enrico Weigelt, metux IT consult wrote:
> > On 26.04.19 15:36, Jan Kiszka wrote:
> >
> >> At the same time, there are no real alternatives - to my> knowledge - for the value it brings (various bindings) to simply
> > switch> the engine.
> > Which value exactly does that collection of crude wrappers and broken
> > attempts to buypass the kernel (driving gpios via /dev/mem *facepalm*)
> > provide ?
>
> Leaving that blunt hack aside:
>
> import mraa
>
> pin = mraa.Gpio(13)
> pin.dir(mraa.DIR_OUT)
> pin.write(1)
>
> And the same goes for nodejs, java and c++.
>
> Moreover, this allows you to abstract away where "Pin 13" actually came from on
> that board if the kernel changes (BSP -> upstream...) or the extension board or
> ...

The problem here is opaque number. This has to be chip + *relative* pin number/
See this:
https://stackoverflow.com/questions/55532410/how-do-linux-gpio-numbers-get-their-values/55579640#55579640

-- 
With Best Regards,
Andy Shevchenko