PocketBeagle 9.2 image: getting EBUSY when accessing GPIOs while loading fbtft_device module

[Henner Zeller]

Hi,
I've seen a regression in bone-debian-9.2-iot-armhf-2017-10-10-4gb.img
- Loading the fbtft LCD drivers fail because they can't open GPIOs

This worked in the previous bone-debian-9.1-iot-armhf-2017-09-21-4gb image:

modprobe fbtft_device cs=1 busnum=2 name=tm022hdh26 gpios=dc:45,reset:86

(GPIO 45 is on Pin 33 on the PocketBeagle, GPIO 86 is Pin 35; both
configured to be default pinmuxed as GPIO).

Now, in the 9.2 image, this fails with the following:
[ 90.487929] fb_ili9341 spi2.1: fbtft_request_gpios:
gpio_request_one('dc'=45) failed with -16
[ 90.496974] fb_ili9341: probe of spi2.1 failed with error -16

-16 is EBUSY, which indicates that somehow the GPIO pins are already grabbed.

What changed ? How can this be fixed ?
Is there a simple way to see _who_ is using a GPIO (like an lsof for GPIOs?)
(I guess these are questions for Robert :) ).

-h