i2c overlays for Armbian V25.2.3

[Bill Anderson]

I have have armbian V25.2.3 installed on a radxa Zero 2w linux kernel 6.12.17-current-meson64. The radxa uses i2c to talk to a PCA9685 which in turn drives three servos in a robot.

The issue is that the PCA9685 has two i2c busses, 0 and 1. But the radxa zero has only two i2c busses that can be enabled using armbian-config and they are i2c-3 and - ic2-5.

It seems I need to install a new overlay to describe the i2c busses in the device tree. But how do I do that?

[Werner]

Hi,

 

the manual way of enabling/disabling overlays is checking their availability in /boot/dtb/<family>/overlay and edit /boot/armbianEnv.txt.

 

In your case it seems that a new overlays needs to be written. You can decompile an existing one that is similar using the dtc utility.

Once you created a new dts file you can use armbian-add-overlay <filename>.dts to compile and enable it.

What exact values are necessary to achieve your particular case I don't know. I guess for that you have to dig through the datasheets of both your board and the SoC it is built around.