I2C over Displayport

Autonomous Machines Jetson & Embedded Systems Jetson TK1
#1

I have an HP ZBook with the NVIDIA Corporation GK208GLM [Quadro K610M] (rev a1) (according to lspci) loaded, and NVidia driver 340.46 (freshly updated), and a DLP connected via Displayport.

I’m trying to use I2C (as purportedly supported in the NVidia driver by the release notes) with things like “i2cdetect”, but there are no /dev/i2c entries created. I see them in /sys/class/i2c-adapter like so:

rhand@rhand-HP-ZBook-17 /etc>[i] cat /sys/class/i2c-adapter/*/name
NVIDIA i2c adapter 0 at 1:00.0
NVIDIA i2c adapter 1 at 1:00.0
NVIDIA i2c adapter 10 at 1:00.0
NVIDIA i2c adapter 2 at 1:00.0
NVIDIA i2c adapter 6 at 1:00.0
NVIDIA i2c adapter 7 at 1:00.0
NVIDIA i2c adapter 8 at 1:00.0
NVIDIA i2c adapter 9 at 1:00.0
NVIDIA i2c adapter 13 at 1:00.0
NVIDIA i2c adapter 12 at 1:00.0
NVIDIA i2c adapter 11 at 1:00.0

Is there some “trick” to getting this to work? Do I need to manually create the device entries somehow?

#2

Just an addition: I modprobe’d i2c-dev which seems to have created the devices, but they don’t seem to be working. Running “i2cdetect -y N” on N from 0 - 9 shows all adapters blank.

#3

Whenever a /dev file is not there, I consider that either the driver is missing because of a required kernel module, or else udev has renamed it and it is there but you are looking for an old name.

In any case, instead of the i2cdetect, get the package read-edid, and try:

get-edid | parse-edid

(there are other variants)