I am trying get Openwrt in BPI-R64 working with Quectel EC25 but I cannot change the GPIO90 state, it is always asm_sel in lo. echo “499” > /sys/class/gpio/export says ”ash: write error: Resource busy”. I have tested almost all versions of Openwrt I could find. Is there anything I could still do?
Gpio 90 is reserved in dts for switching between pcie and sata. So you have to change it there (or via dt overlay).
See comment above the node
Maybe it is not blocked if the gpio-hog driver is not loaded (if used as module).