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From: Mihaita Ivascu <mihaita_ivascu@trimble.com>
Date: Fri, 3 Aug 2018 10:22:52 +0200
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Subject: Re: Cannot set GPIOs in barebox
To: andrew.smirnov@gmail.com
Cc: barebox@lists.infradead.org, aleksander@aleksander.es

Ok, thanks for the clarification.
On Mon, Jul 30, 2018 at 10:40 PM Andrey Smirnov
<andrew.smirnov@gmail.com> wrote:
>
> On Mon, Jul 30, 2018 at 12:28 PM Aleksander Morgado
> <aleksander@aleksander.es> wrote:
> >
> > Hey,
> >
> > >
> > >     This topic could be ignored. GPIO set/get value functions from
> > > barebox are working fine BUT gpioinfo function has some bug it reports
> > > unchanged status for gpios value.
> > >
> >
> > Not that I got into much detail, but when I saw that same issue (I
> > have some WIP patches to manage GPIOs via RATP) I just assumed that we
> > can reliably gpio_get_value() on input GPIOs, and gpio_set_value() on
> > output GPIOs. Trying to "read" the output GPIO value with
> > gpio_get_value() may not be reliable or even supported at all. Is that
> > assumption correct?
>
> AFAIK/IMHO this would really depend on the hardware platform. On
> i.MX(also depending on IOMUX IP used as well) appropriate IOMUX
> configuration is necessary in order to be able to "sense" the actual
> logical level of a GPIO configured as . If I recall things correctly,
> i.MX51/6/8, would require a SION bit set and i.MX7/VF610 would require
> input buffer to be enabled, otherwise output GPIOs would always report
> the same value via gpio_get_value().
>
> Thanks,
> Andrey Smirnov

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