I was wondering if anyone could help with the following issue,

 

We are working on a project utilized with an Orange Pi Lite, ALLWINNER H3 processor and Armbian stretch mainline kernel,

Now we are bundled a chip over GPIO, due to the chip frequency we looking for a library or setting file to modify and match I2C frequency with the chip,

 

BR,

As you can see in Mainline doc, you can use "clock-frequency" parameter directly either in main DT or in the i2c overlay.

https://elixir.bootlin.com/linux/v4.18.5/source/Documentation/devicetree/bindings/i2c/i2c.txt

Beware that kernel driver will probably only accept standard rates, either 100000 or 400000.

 

 

Tnx Martinayotte for your reply,

Sorry, I'm new to Armbian. Are you meaning that i should modify i2c dt source and recompile kernel or it's possible to establish changes in a working armbian.
 

3 hours ago, Aaron.energy said:

it's possible to establish changes in a working armbian.

Yes ! you simply need to decompile device-tree DTBO into DTS source using "dtc" compiler, edit the DTS by adding "clock-frequency = <100000>;" in the i2c node, and then re-compile it into DTBO (after having take care of doing a backup of original DTBO).

 

There are some dtbo files in the /boot directory. Which one of them should be modified with clock frequency?
Again tnx for your attention martin.

Tnx martin,
I found the the proper dtb file in /boot/dtb directory. According to my board version it was sun8i-h3-orangepi-lite.dtb which I recompiled it and successfully its i2c frequency changed.cd /boot/dtb
Following I insert my instructions maybe it can help some other people.
dtc -I dtb -O dts sun8i-h3-orangepi-lite.dtb -o sun8i-h3-orangepi-lite.dts
#modifiy dts file and set clock-frequency=0x009c40 in node i2c@01c2ac00
dtc -I dts -O dtb sun8i-h3-orangepi-lite.dts -o sun8i-h3-orangepi-lite.dtb
sudo reboot

i found a more recent dtc compiler which might be shipped in a 'future' release of debian (it isn't in nightly) that has the dynamic overlay and symbol substitution features

it is actually a more recent version of dtc bundled with the linux kernel. Some how that recent version didn't get bundled with the recent kernels which uses those features