mboehmer Posted February 28, 2018 Posted February 28, 2018 Hi, maybe someone can give me a hint... I have a running system now on 128GB eMMC card, and wanto to use GPIO. I have /sys/class/gpio/ with export, and unexport files, and two gpiochip0 and gpiochip14 entries. Unfortunately I can't export pins, as export 231 > /sys/class/gpio/export gives me a (as user and root) bash: echo: write error: Invalid argument Any help is appreciated. EDIT: works now. It is somehow a bit complicated, as the "usual" numbers as known from 3.x kernels vanished. Debug output shows two "gpiochips", with a certain number of pins, which you have to correlate to the device tree enums for that "chips" - giving you finally the number you want. Maybe I simply don't get the simplicity of that new concept... So far, Michael
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