furumc

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  1. Hello guys! I haven't found any helpful regarding to my problem, maybe you are more professional as me! (I'm not really!) I would like to set an ordered DHT22 temp & humidity sensor to work on this SBC. OS is : NAME="Ubuntu" VERSION="18.04.3 LTS (Bionic Beaver)" Kernel : Linux cubieboard2 5.3.9-sunxi #19.11.3 SMP Mon Nov 18 18:49:43 CET 2019 armv7l armv7l armv7l GNU/Linux I can export a pin as GPIO, and control a simple led. I've built a kernel module for DHT22 found on github : https://github.com/edwardlintw/DHT22 The main problem is, after successful GPIO export : echo 202 > /sys/class/gpio/export cat /sys/kernel/debug/gpio | grep 202 gpio-202 ( |sysfs ) in lo can't read a value! It's all the same, I load a kernel module, or not, I get the following message : gpioget gpiochip0 202 gpioget: error reading GPIO values: Device or resource busy And with the kernel module : insmod dht22.ko gpio=202 insmod: ERROR: could not insert module dht22.ko: Device or resource busy In kernel.log I see followings : [ 906.815645] sun4i-pinctrl 1c20800.pinctrl: 1c20800.pinctrl supply vcc-pg not found, using dummy regulator [ 1224.340665] dht22: loading out-of-tree module taints kernel. [ 1224.342543] Loading dht22 module... [ 1224.359904] dht22 driver (major 241) installed [ 1224.377611] dht22 failed to request GPIO 202, unloaded If I don't create a pin for GPIO, result looks like : Invalid parameters! [ 97.922348] dht22: loading out-of-tree module taints kernel. [ 97.924030] Loading dht22 module... [ 97.942646] dht22 driver (major 241) installed [ 97.960523] sun4i-pinctrl 1c20800.pinctrl: 1c20800.pinctrl supply vcc-pg not found, using dummy regulator [ 97.961115] dht22 failed to get IRQ for GPIO 202, unloaded What do I wrong? Could somebody give me some hint?