Re: I2C: can't detect Adafruit Mini I2C Gamepad on Linux - other devices detected

[Michael Opdenacker <michael.opdenacker@rootcommit.com>]

Greetings

On 4/11/25 07:21, Michael Opdenacker wrote:
> Hi Anshul
>
> I contact you as the maintainer for the Adafruit Mini I2C Gamepad driver.
>
> I'm trying to use the Adafruit Seesaw I2C gamepad in my embedded Linux 
> training courses, to demonstrate driving I2C hardware, and the gamepad 
> would be perfect to play an ASCII Pac-Man clone 
> (https://github.com/michaelopdenacker/myman 
> <https://github.com/michaelopdenacker/myman>).
>
> Even before your driver is loaded, the device has to be detected. My 
> problem is the gamepad is never detected on Linux (running "i2cdetect 
> -r <num>"), while other I2C devices connected to the same bus are, 
> proving that the bus is correctly enabled. This happens on all these 
> boards running recent kernels:
> - BeaglePlay (Linux 6.14.2!)
> - BeagleBone Black
> - Raspberry Pi5
>
> I double checked my gamepads (I have 4 of them) and wires: they work 
> fine on Arduino Uno.
>
> Any clue why none of my 4 gamepads are never detected while two other 
> types of I2C devices are detected on the same bus, and the same 
> gamepads work on Arduino Uno?


Some progress here... On BeaglePlay, which is my primary target, I 
realized that if I declare the device in the device tree AND load the 
driver for the device, then the device seems to work fine. When I press 
the buttons, I get data in /dev/input/event<x>.

Plus "i2cdetect -r <num>" shows the device as UU for address 0x50, as 
usually happens with a driver is loaded.

I thought that connected I2C devices always showed in i2cdetect output, 
whether they are declared in the device tree and have a driver or not.

Cheers
Michael.

-- 
Michael Opdenacker
Root Commit
Yocto Project and OpenEmbedded Training course - Learn by doing:
https://rootcommit.com/training/yocto/