Verdin IMX8M Mini I2C

Technical Support
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1

Hello, I’m little confused about the i2c bus id’s on the Verdin IMX8M Mini.

The documentation says that i2c-2 is i2c-4:
https://developer.toradex.com/linux-bsp/how-to/peripheral-access/i2c-linux/#verdin

ls -l /dev/verdin-i2c*:
lrwxrwxrwx 1 root root 5 Jul 4 13:22 /dev/verdin-i2c-on-module → i2c-0
lrwxrwxrwx 1 root root 5 Jul 4 13:22 /dev/verdin-i2c1 → i2c-3
lrwxrwxrwx 1 root root 5 Jul 4 13:22 /dev/verdin-i2c2 → i2c-1
lrwxrwxrwx 1 root root 5 Jul 4 13:22 /dev/verdin-i2c4 → i2c-2

so bus id 2 is the generic i2c bus on Pin 14/15, is that correct?

Bg, Markus

2

Dear @DrWenz,

Just for clarification, do you mean Pins 12/14, right?

In addition, it’s verdin-i2c-1 that points to i2c-3, the fourth on the array, the one that you’re looking for. If you have a look at the device tree for the module: https://github.com/toradex/device-trees/blob/toradex_5.4-2.3.x-imx/dts-arm64/imx8mm-verdin.dtsi#L556 it also shows this information. It’s also what was stated on that page you shared:

The Verdin module standard features only one generic I2C interface:

SoM Interface Pins on Verdin Standard Device nodes names Recommended usage
I2C1 SODIMM_12/14 /dev/verdin-i2c1 General Purpose

Please tell me if this helps.

Best regards,

3

yeah i mean Pins 12/14, sorry :slight_smile:

ok, so bus index 3 is the bus I can work with.

i2cdetect -y 3 on Dahlia Carrier Board:
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – – – – – – – – – – – – –
10: – – – – – – – – – – UU – – – – –
20: – – – – – – – – – – – – – – – –
30: – – – – – – – – – – – – – – – –
40: UU – – – – – – – UU UU UU 4b – – – UU
50: UU – – – – – – UU – – – – – – – –
60: – – – – – – – – – – – – – – – –
70: – – – – – – – –

I can match the following addresses, but unfortunately not the others. How can I find out?
0x1A → ??
0x40 → Current/Power Monitor
0x48 → lt8912
0x49 → ??
0x4a → maxtouch
0x4b → ??
0x4f → tmp75c
0x50 → ??
0x57 → EEPROM

Thanks for your help :slight_smile:

4

Hi @DrWenz,

You may find all this information on the device trees, not only on the one that I sent you.

For instance, on the same file I sent before, there is the mention to reg <0x50> on the eeprom_display_adapter.

Moreover, on this file:
device-trees/imx8mm-verdin-dahlia.dtsi at toradex_5.4-2.3.x-imx · toradex/device-trees · GitHub you have the Audio Codec on reg <0x1a>.

Please tell me if this helps you or if you need further clarification.

Best regards,

5

That helped me a lot, thank you very much for your help :smile:

1 Like
6

Hi @DrWenz,

I’m glad we could help you. Please feel free to comeback if you have any other issue.