How to use SPI1_IRQ_N as GPIO output?

Question

The "ConnectCore 6UL SBC Pro" has an interrupt line "SPI1_IRQ_N", connected to "GPIO5_08" on the SPI expansion connector. How can I use this GPIO as output?
I tried to do the following:
# echo 136 > export
# echo out > gpio136/direction
# echo 1 > gpio136/value
# cat gpio136/value
0
# echo 0 > gpio136/value
# cat gpio136/value
0

The fuses are set that the TAMPTER PINS are disabled. (Tamper 0-9 used as GPIO)

Any suggestions?

Best regards
Mario

Answer 1

set it explicitly in device tree as GPIO, making sure it is not set as anything else there.
https://community.nxp.com/thread/462559

Comments

Sorry, I only have minimal experience with the device tree. Therefore can you please show me some details how to do do it?

I tried to add:

&iomuxc_snvs {
    pinctrl-names = "default_snvs";
    pinctrl-0 = <&pinctrl_hog_2>;
    imx6ul-evk {
        pinctrl_hog_2: hoggrp-2 {
            fsl,pins = <
                MX6UL_PAD_SNVS_TAMPER0__GPIO5_IO00      0x80000000
                MX6UL_PAD_SNVS_TAMPER8__GPIO5_IO08      0x80000000
            >;
        };
    };
};

and

    soc {
        ...
        aips1: aips-bus@02000000 {
            ...
            iomuxc_snvs: iomuxc-snvs@02290000 {
                compatible = "fsl,imx6ull-iomuxc-snvs";
                reg = <0x02290000 0x10000>;
            };


but without any success...

Answer 2

I did it this way (http://jingyan.eeboard.com/article/74563) and I was able to set the output. But I still do not understand why it doesn't work from sysfs...