I2C commands not working...

[Nathan Guyette]

I have an onion 2S+, running with root access, which will not run the following I2C command:
i2cset -y 2 84 21 16

I get a response of:
Could not open file /dev/i2c-1' or /dev/i2c/1': No such file or directory

I think the problem is that there isn't a bus 2 in some config file somewhere... How do we go through the process of adding bus 2? What is a bus?

[György Farkas]

@Nathan-Guyette I think the title of your post is fairly misleading.
Onion Omega2 Documentation Communicating with I2C Devices

All I2C interactions on the Omega2 are done using the virtual device file /dev/i2c-0 :
i2cdetect -y 0
i2cget -y 0 <DEVICE ADDRESS> <REGISTER>
i2cset -y 0 <DEVICE ADDRESS> <REGISTER> <VALUE>

Good luck!

[Nathan Guyette]

@György-Farkas,

Is there any way that could be overwritten from 0 to 2? I'm still not sure what the 0 indicates here.

[György Farkas]

@Nathan-Guyette 0 is the "name" of the default (dedicated) I2C bus of Omega2 - it's compiled into the kernel / firmware.

# Omega2+ firmware v0.3.2 b223

root@Omega-5BE1:/# ls -l /dev | grep -i i2c
crw-------    1 root     root       89,   0 Jan  1  1970 i2c-0

root@Omega-5BE1:/# i2cdetect -l
i2c-0	i2c       	10000900.i2c                    	I2C adapter

Why don't you use 0 (i2c-0 ie. i2c bus 0) instead of that 2 (i2c-2 ie. i2c bus 2) in your commands?

[Nathan Guyette]

How can you compile the kernel with a different number here?

[György Farkas]

@Nathan-Guyette Sorry, I don't know - I'm a simple, average Omega2 user.

[György Farkas]

@Nathan-Guyette Please use the Search function of this forum.
For example here you are a thread (although it's a little bit old):
I2C Detect Slave Method?

[crispyoz]

If you have a build systen installed You can tweak the kernel setup by using "make kernel_menuconfig"

Look under Device Drivers -> I2C Support, there is a several debugging options you can set in order to assist with debugging i2c.