How to use P9_19 / disable i2c2?

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1

I want to use P9_19 and P9_20 (so I have a set of contiguious GPIOs), but they are allocated by i2c2. Is there a way to free up these pins so I can use them in my overlay? I found a discussion in this thread but no clear answer.

Some options I’m considering:
Option 1: build a new kernel. I’d rather avoid this.
Option 2: decompile am335x-boneblack.dtsi and modify it. Would this work? I couldn’t find this file on my BBB.
Option 3: do something in the overlay? Is there a way to unallocate previously allocated pins?

Freeing up the HDMI pins was straightforward, just don’t load the overlay, but i2c2 seems to be more hardwired. Any suggestions?

Thanks,
Ken

2

Under /opt/source/dtb*/ you'll find a git repo with just the device
tree. Depending on what kernel your running there should be 1 to 3
different directories (dtb-4.4-ti/dtb-4.9-ti/dtb-4.14-ti)

make sure to do a git pull on any of those directies first, then make
your changes and just run:

make
sudo make install

and then reboot..

* this is the head repo for those dir's :
https://github.com/RobertCNelson/dtb-rebuilder

Regards,

3

Hi Ken,

This usually means you are referencing a node that doesn't exist in the
current live device tree blob...

Let's see your overlay..

Regards,

4

Thanks, Robert. You were correct - I had a typo in my node name and now it works.

Ken