Re: A problem with gpios on my sunxi board.

[Kent Gibson <warthog618@xxxxxxxxx>]

On Mon, Jan 31, 2022 at 08:59:24AM +0800, Kent Gibson wrote:
> On Fri, Jan 28, 2022 at 10:12:13PM +0800, Gasai Maple wrote:
> > I posted a question on stackoverflow, it's basically about me having
> > problems operating gpio with libgpiod, and a user advised me to drop a
> > message, the link is here
> > https://stackoverflow.com/questions/70863283/libgpiod-tests-fails-on-pcduino3-nano
> 
> It would be helpful to restate your question rather than providing the
> link.  But anyway...
> 
> My best guess is that your kernel is built with only v2 of the GPIO CDEV ABI.
> libgpiod support for v2 is a WIP, and 1.6.3 only supports ABI v1.
> The CHIP_INFO ioctl is common to both, so will still work.
> But all the line request ioctls changed so they wont.
> So libgpiod is probably making ioctl calls that your kernel doesn't
> support.
> 

On re-reading your issue I realise it is the LINE_INFO ioctl that is
working for you, not CHIP_INFO.  That indicates ABI v1 is present in
your kernel, so the above is wrong.

That brings me back to using strace to see what is happening in the
ioctl calls.

And what does gpioget return?

Cheers,
Kent.