Re: Need help with libgpiod gpiod_line_request_both_edges_events()

[Gasper Zejn <zejn@xxxxxxxxx>]

In my experience the line needs to be free (=not requested) before
calling any of the gpiod_line_request* functions.


Kind regards, Gasper


On 06. 03. 2018 02:05, Timur Tabi wrote:
> I'm trying to test event handling with a loopback GPIO.  I have two
> GPIOs, 37 and 38.  On my board, they are wired together.  I set 37 to
> output and 38 to input.  If I write 1 to 37, I read a 1 from 38.  Same
> thing with 0.
>
> So I'm trying to test GPIO interrupts now.  I have this code:
>
>         ret = gpiod_line_request_both_edges_events(input, NULL);
>
> This function immediately returns with -1.  While debugging it, it
> appears that the code in core.c is expecting the GPIO to be configured
> as output.  Is that correct?  If so, that doesn't make any sense.  I'm
> trying to receive an event when a GPIO transitions from 0 to 1 (or 1
> to 0) on input.
>
> I missing be missing something fundamental.
>

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