I've got a custom cape for BeagleBone Black which has several peripherals 
including a 5-switch joystick.  I have device tree nodes for each 
peripheral which I add to a copy of am335x-boneblack.dts and use as a fixed 
device tree (no overlays) loaded by u-boot.  The joystick pins are bound to 
gpio-keys using the gpios property, but I don't specify the interrupts 
property.

All peripherals work fine on 3.8.13-bone79, including the joystick (using 
evtest).

On 4.1.16-ti-rt-r44 the joystick does not work.  The input device is 
created, and evtest displays the keys it supports, but does not generate 
events when the joystick is manipulated.

I've reassigned the pins to gpio-of-helper and written an application using 
sysfs to detect edge transitions.  This works fine on 3.8.13-bone79 and on 
4.1.16-ti-rt-r44, so there's nothing wrong with the hardware or the ability 
of these lines to get interrupts.

The only significant change I've found in updating to jessie is that under 
3.8.13-bone79 the pins using gpio-of-helper were automatically exported to 
sysfs, while this is not done in 4.1.16-ti-rt-r44.  From what I can tell 
this is intentional, but also not clearly related to the problem of 
gpio-keys not generating events.

The only candidate I have now is that I don't specify interrupts in the 
gpio-keys binding, but that wasn't necessary in 3.8.13-bone79 and I don't 
see it generally done in any other example.

Can anybody suggest what might be going wrong?

Thanks.

Peter

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