Imx6ull strange behavior on gpio1_10


I’m using (amongst others) gpio 1_10 on the imx6ull as a gpio key. It is externally pulled to 3.3V and a switch pulls it to ground when pressed.

device tree entry:
front-switch8 {
label = “front_switch_8”;
gpios = <&gpio1 10 GPIO_ACTIVE_LOW>;
linux,code = <KEY_F8>;
debounce-interval = <10>;

pin mux setup:

I noticed that compared to other gpio’ s used in the gpio keys, this one generated a lot of interrupts even hanging the system. I measured the voltage on the line and it does not get pulled to 3.3Volt but only reached ~1.7V

I saw that this pin in the Toradex software is used as a reset pin for Atmel maxtouch controller.
So I measured in the original setup and saw the Voltage at 1.8V.

I copied the mux setting used for the reset and set it to be:

Now the interrupt storm is fixed (Voltage is slightly higher) however I still only get 1.8V so somewhere I drop 1.5V

I could not find in the manual that is in a 1.8 Volt domain or so.

Can I use this gpio in this situation or should I not be using this gpio with 3.3V pullup?

hardware: imx6ull, custom base board,
software: Reference-Minimal-Image-colibri-imx6ull, Linux colibri-imx6ull 5.4.129

Best Regards,


can you share a little part of the schematic ?
Do you have an external pull up on this pin ?

Best Regards,

Hi Matthias,

Yes it is externally pulled to 3.3V.

See attached schematic part


Best Regards,

hello vincent,

can you you provide the device tree file ?
It could be that the internal Pull down is switched on ?

Best Regards,

Matthias Gohlke

hi Matthias,

it is also pulled up internally, if I dont pull it internally it does not even work.


Best Regards,

hello vincent,

can you provide the whole device tree file?

Matthias Gohlke

Hi @vincent ,

This X1 pin (106) is also a used as a JTAG_MOD and has a 10k pull down on a module. Please check Table 5-46 JTAG Signal Pins on SODIMM connector of Colibri iMX6ULL datasheet for details. So you either need to use a stronger external Pull up or select another pin.

Hi Alex,

Thanks, will move it to another gpio.

Best Regards,