i2c port changes randomly

dgridish

Hi,
I'm using up squared.
I connect a device via the i2c port in the HAT40 connector.
when using i2cdetect, I detect the same device (identified by the address) on different ports.
Changes occur between reboots.

to my understanding, I may be able to resolve this by setting a rule in 'etc/udev/rules.d', but I'm not sure how to do this. specifically, I'm not sure how to filter the sensor to create the rule.
The 'kernel' I see is 'i2c-2', but I wonder if this will change on the next reboot.

Thank you.

Pratik_Kushwaha

Hi @dgridish ,

Can you please provide the UP Squared product info. (RAM/eMMC/Part Number), along with the current BIOS version on it?

Our tech team is trying to replicate your issue. I will keep you posted on the results/resolution.

Regards,
Pratik

camillus

Hi @dgridish ,

I saw a good tutorial that can guide you through creating the udev rule here

You can follow the steps below to filter the i2c device:

• With i2c device connected and you find the current port using i2cdetect and you find for example port 12c-2
• Run the following command to find the sensor attributes you will need for the udev rule
• udevadm info -a --p $(udevadm info -q path /sys/bus/pci/devices/*/i2c_designware.2/)
  With the details you can create udev rule.

**Note ** I added 2 at the end of the device path because I am assuming i2c device current port is detected on i2c-2

Kindly let us know the outcome and feel free to share with the community when the udev rule works.

Best regards,