Android tv 7.1 use gpio not success

#1

in android tv 7.1（） adb shell, i use this commnad:

cd /sys/class/gpio
echo 157 > export

no gpio157 directory was generated, can you help me?

note: android download from https://github.com/radxa/rockpi4-android-tv-7.1/releases/download/20190314_1810_703e366/rockpi-4b-nougat-20190314_1810_703e366-gpt.zip,
sd card installed.

#2

The gpio you are applying for may be defined in DTS.
kernel/arch/arm64/boot/dts/rockchip/rk3399-rockpi-4b.dts

#3

thanks, i have been resolved