PINE64

I'm having trouble getting a port expander (MCP23017) connected over i2c to work and I'm not sure where things are breaking-down.

I'd like to start by confirming that I have all of the operating system/configuration bits in-place before diving into the hardware side of things.

What is the best way to check to make sure I have the right kernel/modules/etc. to make i2c work?  I'm using Armbian and have the i2s tools for Debian installed.

Thanks!

FWIW I changed the values of the pull-up resistors I was using on the i2c bus and things started working.

I'd still like to know how to tell from Linux if i2c is setup correctly software-wise, but I thought I should note that the underlying problem has been solved.