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/dev/i2c-2 and /dev/i2c-3 (on UEXT) on A10 Lime

Hi,

I have installed armbian 5.23 on an olimex A10 lime.

 

After boot I find that the i2c devices on the UEXT interface do not show in /dev. They should be /dev/i2c-2 and /dev/i2c-3 and should be detectable using i2cdetect -y 2 (or 3).

 

I notice that the package linux-jessie-root-lime-a10_5.23_armhf.deb ships the .bin (fex) files that configure the ports on boot.

 

The file /boot/bin/lime-a10.bin and /boot/bin/lime-a10-lcd.bin have definitions for these ports but they are disabled.

So for now I make a new .bin file with these ports enabled.

 

Specifically I had to change the file like this (I made a new copy so that apt-get upgrade would not clobber my changes) as user 'root':

 

# cd /boot/bin

# bin2fex lime-a10.bin >lime-a10.fex

# cp lime-a10.fex lime-a10-i2c.fex

# nano lime-a10-i2c.fex

 

then starting on line 121 I made the file look like this:

 

[twi1_para]
twi1_used = 1
twi1_scl = port:PB18<2><default><default><default>
twi1_sda = port:PB19<2><default><default><default>

[twi2_para]
twi2_used = 1
twi2_scl = port:PB20<2><default><default><default>
twi2_sda = port:PB21<2><default><default><default>

 

Before the twi1_used = 0 and twi2_used=0

 

Then convert the file back to a .bin, change the symlink for script.bin and reboot

 

# fex2bin lime-a10-i2c.fex lime-a10-i2c.bin

# cd /boot

# rm -f script.bin

# ln -s bin/lime-a10-i2c.bin script.bin

# shutdown -r now

 

Question:

 

Why are these ports disabled on the A10 lime in the .bin file? Can this be changed for future versions?

 

Thank you in advance.

 

 


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