Userspace means after the system starts.
First of all, it is necessary to set the GPIO mode in Infinity2M-SSC011A-S01A-PADMUX-XXX. DTSI (refer to drivers to use GPIO) and load the GPIO SYSFS Interface module:
# ARCH=arm make menuconfig
With this configuration, we will see the /sys/class/ GPIO directory when the system starts up. In this directory, we can operate the input and output of GPIO.