Cannot set GPIOs in barebox

Cannot set GPIOs in barebox

[Mihaita Ivascu]

Hello,

    I would like to set gpio direction and values from barebox. I use:

gpio_direction_output(133, 1);
        mdelay(2);
        gpio_set_value(133, 1);
        mdelay(2);
        gpio_direction_output(137, 1);
        mdelay(2);
        gpio_set_value(137, 1);

from my board.c or using commands in the barebox shell. Setting
direction is working but setting value it not performed.

GPIOs 128-159, chip 20ac000.gpio:
             dir val requested  label
  GPIO  128:  in  lo        false
  GPIO  129:  in  lo        false
  GPIO  130:  in  lo        false
  GPIO  131:  in  lo        false
  GPIO  132:  in  lo        false
  GPIO  133: out  lo         true  gpio
  GPIO  134:  in  lo        false
  GPIO  135:  in  lo        false
  GPIO  136:  in  lo        false
  GPIO  137: out  lo         true  gpio
  GPIO  138:  in  lo        false


    What could be the issue? And what could be the workaround? I would
really need to set some GPIOs high from the barebox.

Thanks,
      Mihaita

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Re: Cannot set GPIOs in barebox

[Mihaita Ivascu]

Hello,

    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.

Best regards,
         Mihaita Ivascu

On Thu, Jul 19, 2018 at 11:05 AM Mihaita Ivascu
<mihaita_ivascu@trimble.com> wrote:
>
> Hello,
>
>     I would like to set gpio direction and values from barebox. I use:
>
> gpio_direction_output(133, 1);
>         mdelay(2);
>         gpio_set_value(133, 1);
>         mdelay(2);
>         gpio_direction_output(137, 1);
>         mdelay(2);
>         gpio_set_value(137, 1);
>
> from my board.c or using commands in the barebox shell. Setting
> direction is working but setting value it not performed.
>
> GPIOs 128-159, chip 20ac000.gpio:
>              dir val requested  label
>   GPIO  128:  in  lo        false
>   GPIO  129:  in  lo        false
>   GPIO  130:  in  lo        false
>   GPIO  131:  in  lo        false
>   GPIO  132:  in  lo        false
>   GPIO  133: out  lo         true  gpio
>   GPIO  134:  in  lo        false
>   GPIO  135:  in  lo        false
>   GPIO  136:  in  lo        false
>   GPIO  137: out  lo         true  gpio
>   GPIO  138:  in  lo        false
>
>
>     What could be the issue? And what could be the workaround? I would
> really need to set some GPIOs high from the barebox.
>
> Thanks,
>       Mihaita

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Re: Cannot set GPIOs in barebox

[Aleksander Morgado]

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?

-- 
Aleksander
https://aleksander.es

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Re: Cannot set GPIOs in barebox

[Andrey Smirnov]

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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Re: Cannot set GPIOs in barebox

[Mihaita Ivascu]

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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