A-la documentation, our Mochabin has three three-color LEDs, all at the front to the right of the power LED. They are said to be I2C controlled.
How do I operate it? I very much like to make use of these LEDs (my previous box – Espressobin of course – had a plethora of GPIO pins, and I connected my own LEDs and operated them happily; Mochabin does not seem to expose GPIO pins, so I’d be really happy to be able to control the installed LEDs.
I tried some i2c stuff against it but with no success.
Thanks for any insight!
The LEDs are hooked up using i2c to a driver chip – a is31fl319x which has a corresponding userspace driver leds_is31fl319x
The is31fl319x is located on i2c bus 1 at 0x64, and on ArchLinux, the driver module leds_is31fl319x loads at boot. If you run i2cdetect -y 1 you see that 0x64 has the value UU, indicating that the driver is controlling that address. lsmod confirms this.
If you want to control the LEDs you can write code to talk to the driver.
Alternately you can remove the driver (rmmod leds_is31fl319x), which will allow access to 0x64, and you can use i2c (i2ctransfer) to send instructions to the is31fl319x directly.