topic Re: Device Tree and GPIO controll in i.MX Processors

Device Tree and GPIO controll

btarnowski — Wed, 20 Jul 2022 11:03:52 GMT

Hi all. I can not get work gpio.

In my case this is not working, I do not see any change on the physical GPIO pin

echo 47 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio47/direction

echo 1 > /sys/class/gpio/gpio47/value

Some additional details below. What can be wrong?

Re: Device Tree and GPIO controll

J_W — Wed, 20 Jul 2022 13:06:54 GMT

The pictures are a bit of a mess to follow. Try reading this application note and see if it helps:

https://www.nxp.com/docs/en/application-note/AN5078.pdf

Re: Device Tree and GPIO controll

btarnowski — Thu, 21 Jul 2022 06:52:03 GMT

Thanks for the Link.
I found problem, The Controll Mux register for specific pins had incorrect values.
The pins was set for peripheral purpose instead of gpio purpose (MUX_MODE)