Re: BeagleBone Black and GPIO issues

[Lloyd Parkes <lloyd%must-have-coffee.gen.nz@localhost>]

On Fri, 2024-10-11 at 17:34 -0600, Brook Milligan wrote:
> Yes, it would be really helpful to have all the pull-up/pull-
> down/etc. states of the pins reported or at least discoverable via
> gpioctl.  Anyone have an idea how to do this?

I don't have time to work on this right now, but I did some discovery
work on this a while back because I have an application that needs
control over pullups.

What follows could be quite misleading because I am probably
remembering things incorrectly.

The pullups/pulldowns are controlled by the Control Module on the TI
chip in a well defined subsection of the Control Module's address
space. The registers that control pullup/down also control the
multiplexing of peripherals to the pin being pulled up/down. It
shouldn't be too hard to work with this.

In contrast, I _think_ the Broadcom chips in the Raspberry Pis have the
pullup/down control in with the GPIO registers which makes life much
simpler for the device driver author.

Ngā mihi,
Lloyd