GPIOs on Debian 18.01


#1

In the process of transitioning from a Bitbake made 4.9 image to the Linaro Debian 18.01 release on a DB410c.

We’ve hit a bit of a wall where we are unable to control:

  • GPIO2
  • GPIO3
  • GPIO114

We can export the pins in /sys/class/gpio but when inspecting the output with a logic analyzer, we’re not getting any action on the pins.

Any suggestions? (Thanks in advance!)


#2

We’ve hit a bit of a wall where we are unable to control:

  • GPIO2
  • GPIO3
  • GPIO114

Have you disabled the drivers that normally use these pins?


#3

No sir, was unaware of any drivers which may be using these pins. Running the stock Debian from Linaro.

Can you please tell me which driver is using these pins or how I might find it for myself?

Is this accurate for finding which drivers may be blocking access?


#4

yes, but you can check the device tree as well, in the kernel source tree:

git grep gpio -- arch/arm64/boot/dts/qcom/msm8916-pins.dts

you will deduce that gpio2 and gpio3 are use for UART1 (or SPI), and gpio114 for audio I2S.


#5

thank you so much!
You’re always so helpful!