'ODROID-N2' on this page refers to the ODROID-N2 series (N2, N2+, N2L).
ODROID-N2/C4 I2C Controller(Device Node) Information
In ODROID-N2/C4, there are two I2C controllers, I2C0 and I2C1.
Here is the I2C controller information for our Ubuntu image.
| Pin Number | SDA(#GPIO) | SCL(#GPIO) | Default Speed | Max Speed | Device Node |
|---|---|---|---|---|---|
| 3(SDA), 5(SCL) | GPIOX.17(#493) | GPIOX.18(#494) | 400 KHz | 2 MHz | /dev/i2c-0 |
| 27(SDA), 28(SCL) | GPIOA.14(#474) | GPIOA.15(#475) | 100 KHz | 2 MHz | /dev/i2c-1 |
DTBO has been introduced in our ubuntu 20.04 official image. Follow the Ubuntu 20.04 guide if you use it, otherwise follow Ubuntu 18.04 guide.
See this link for more details of Device Tree Overlay.
Ubuntu 20.04
If you are using ODROID-C4 and the image “ubuntu-20.04-4.9-minimal-odroid-c4-20200526.img.xz” or before, you should upgrade as follow.
odroid@odroid:~$ uname -r 4.9.218-25 odroid@odroid:~$ sudo sed -i 's/bionic/focal/g' /etc/apt/sources.list.d/odroid.list odroid@odroid:~$ cat /etc/apt/sources.list.d/odroid.list deb http://deb.odroid.in/c4/ focal main odroid@odroid:~$ sudo apt update && sudo apt upgrade
Reboot when all the upgrade is done.
odroid@odroid:~$ sudo reboot odroid@odroid:~$ uname -r 4.9.230-32
Enable I2C with DT Overlays
If you are using Ubuntu 18.04 or lower, you have to follow this link.
By default, the two I2C buses are enabled without any edits.
Check your DT Overlays file in “/media/boot/config.ini”
odroid@odroid:~$ sudo vi /media/boot/config.ini
; Device Tree Overlay overlay_resize=16384 overlay_profile=hktft32 overlays="spi0 i2c0 i2c1 uart0"
Add the “i2c0” or “i2c1” you want in “overlays=” if they are absent.
After reboot, you can find the I2C node with this command.
odroid@odroid:~$ ls /dev/i2c* /dev/i2c-0 /dev/i2c-1
Disable I2C for use GPIO
If you want to use Pin #3, #5, #27, #28 in 40Pin as GPIO, you have to disable the I2C function first.
Open the “config.ini” file in “/media/boot”.
odroid@odroid:~$ sudo vi /media/boot/config.ini
And then, remove the i2c you want to disable.
This config.ini means that the i2c0 is disabled.
; Device Tree Overlay overlay_resize=16384 overlay_profile=hktft32 overlays="spi0 i2c1 uart0"
After reboot, you can check the “/dev/” node.
odroid@odroid:~$ ls /dev/i2c* /dev/i2c-1
Change I2C Speed
You can change speed of each I2C node by editing /sys/bus/i2c/devices/i2c-{0,1}/device/speed file.
- target
# Change user to root odroid@odroid:~$ su root # To change I2C0 clock from 400KHz to 100KHz root@odroid:~# cat /sys/bus/i2c/devices/i2c-0/device/speed 400000 root@odroid:~# echo 100000 > /sys/bus/i2c/devices/i2c-0/device/speed root@odroid:~# cat /sys/bus/i2c/devices/i2c-0/device/speed 100000
- target
# To change I2C1 clock from 100KHz to 400KHz root@odroid:~# cat /sys/bus/i2c/devices/i2c-1/device/speed 100000 root@odroid:~# echo 400000 > /sys/bus/i2c/devices/i2c-1/device/speed root@odroid:~# cat /sys/bus/i2c/devices/i2c-1/device/speed 400000
Ubuntu 18.04 or lower
Checking kernel version for I2C node number
Note that the device node numbers vary depending on the kernel version.
Please make sure that the kernel version you are using.
odroid@odroid:~$ uname -r 4.9.230-89
And then, refer to the node number of "I2C Pin information table"
I2C Pin information
| Pin Number | SDA(#GPIO) | SCL(#GPIO) | Default Speed | Max Speed | Device Node(kernel 4.9.230-73 or later) | Device Node(kernel 4.9.219-72 or lower) |
|---|---|---|---|---|---|---|
| 3(SDA), 5(SCL) | GPIOX.17(#493) | GPIOX.18(#494) | 400 KHz | 2 MHz | /dev/i2c-0 | /dev/i2c-2 |
| 27(SDA), 28(SCL) | GPIOA.14(#474) | GPIOA.15(#475) | 100 KHz | 2 MHz | /dev/i2c-1 | /dev/i2c-3 |
Enable I2C with device-tree-compiler
By default, ODROID-N2/C4 are configured to load I2C drivers and you can find two I2C buses, I2C0 and I2C1, In order to switch them to generic GPIOs, fdtput command is required and this command can be installed with the package device-tree-compiler.
root@odroid:~# apt install device-tree-compiler
Checking current mode
The default configuration is for I2C buses and can be checked with fdtget command. In order to apply the change, the changed device tree file must be located in the boot directory and ODROID-N2/C4 must be rebooted.
ODROID-N2
I2C0
root@odroid:~# fdtget /media/boot/meson64_odroidn2.dtb /soc/cbus@ffd00000/i2c@1d000 status okay
I2C1
root@odroid:~# fdtget /media/boot/meson64_odroidn2.dtb /soc/cbus@ffd00000/i2c@1c000 status okay
They can be switched to GPIO from I2C when the value of status is disabled.
I2C bus -> GPIO pins
I2C0
root@odroid:~# fdtput -t s /media/boot/meson64_odroidn2.dtb /soc/cbus@ffd00000/i2c@1d000 status disabled
I2C1
root@odroid:~# fdtput -t s /media/boot/meson64_odroidn2.dtb /soc/cbus@ffd00000/i2c@1c000 status disabled
GPIO pins -> I2C bus
I2C0
root@odroid:~# fdtput -t s /media/boot/meson64_odroidn2.dtb /soc/cbus@ffd00000/i2c@1d000 status okay
I2C1
root@odroid:~# fdtput -t s /media/boot/meson64_odroidn2.dtb /soc/cbus@ffd00000/i2c@1c000 status okay
ODROID-C4
I2C0
root@odroid:~# fdtget /media/boot/meson64_odroidc4.dtb /soc/cbus@ffd00000/i2c@1d000 status okay
I2C1
root@odroid:~# fdtget /media/boot/meson64_odroidc4.dtb /soc/cbus@ffd00000/i2c@1c000 status okay
They can be switched to GPIO from I2C when the value of status is disabled.
I2C bus -> GPIO pins
I2C0
root@odroid:~# fdtput -t s /media/boot/meson64_odroidc4.dtb /soc/cbus@ffd00000/i2c@1d000 status disabled
I2C1
root@odroid:~# fdtput -t s /media/boot/meson64_odroidc4.dtb /soc/cbus@ffd00000/i2c@1c000 status disabled
GPIO pins -> I2C bus
I2C0
root@odroid:~# fdtput -t s /media/boot/meson64_odroidc4.dtb /soc/cbus@ffd00000/i2c@1d000 status okay
I2C1
root@odroid:~# fdtput -t s /media/boot/meson64_odroidc4.dtb /soc/cbus@ffd00000/i2c@1c000 status okay
After rebooting, your change will be applied and if i2c_meson_master is loaded then I2C bus 0 or 1 are running as I2C buses, this can be checked with the command lsmod command.
root@odroid:~# lsmod | grep i2c i2c_meson_master 20480 0
You can unload the module if you want to use I2C gripped pins as on GPIO mode.
- target
# Unload root@odroid:~# modprobe -r i2c_meson_master root@odroid:~# ll /dev/i2c* ls: cannot access '/dev/i2c*': No such file or directory # Load root@odroid:~# modprobe i2c_meson_master root@odroid:~# ll /dev/i2c* crw-rw---- 1 root i2c 89, 2 Jan 11 12:09 /dev/i2c-0 crw-rw---- 1 root i2c 89, 3 Jan 11 12:09 /dev/i2c-1
Device Nodes
Check your I2C node number depending on your kernel version.
checking_kernel_version_for_i2c_node_number
In ODROID-N2/C4, I2C devices are mapped in /sys/bus/i2c/devices directory.
- target
root@odroid:~# ll /sys/bus/i2c/devices total 0 drwxr-xr-x 2 root root 0 Jan 1 1970 ./ drwxr-xr-x 4 root root 0 Jan 1 1970 ../ lrwxrwxrwx 1 root root 0 Jan 29 2018 1-0051 -> ../../../devices/platform/soc/ffd00000.cbus/ffd1c000.i2c/i2c-1/1-0051/ lrwxrwxrwx 1 root root 0 Jan 11 10:00 i2c-0 -> ../../../devices/platform/soc/ffd00000.cbus/ffd1d000.i2c/i2c-0/ lrwxrwxrwx 1 root root 0 Jan 11 10:01 i2c-1 -> ../../../devices/platform/soc/ffd00000.cbus/ffd1c000.i2c/i2c-1/
As an example, see the files in /sys/bus/i2c/devices/i2c-0 directory.
- target
root@odroid:~# ll /sys/bus/i2c/devices/i2c-0/ total 0 drwxr-xr-x 4 root root 0 Jan 29 2018 ./ drwxr-xr-x 4 root root 0 Jan 1 1970 ../ --w------- 1 root root 4096 Jan 11 10:01 delete_device lrwxrwxrwx 1 root root 0 Jan 11 10:00 device -> ../../ffd1d000.i2c/ drwxr-xr-x 3 root root 0 Jan 29 2018 i2c-dev/ -r--r--r-- 1 root root 4096 Jan 10 15:52 name --w------- 1 root root 4096 Jan 11 10:01 new_device lrwxrwxrwx 1 root root 0 Jan 11 10:01 of_node -> '../../../../../../firmware/devicetree/base/soc/cbus@ffd00000/i2c@1d000'/ drwxr-xr-x 2 root root 0 Jan 11 10:01 power/ lrwxrwxrwx 1 root root 0 Jan 29 2018 subsystem -> ../../../../../../bus/i2c/ -rw-r--r-- 1 root root 4096 Jan 29 2018 uevent
To know its properties in device tree, see of_node directory.
- target
root@odroid:~# ll /sys/bus/i2c/devices/i2c-0/of_node/ total 0 -r--r--r-- 1 root root 4 Jan 11 10:07 '#address-cells' -r--r--r-- 1 root root 4 Jan 11 10:07 '#size-cells' drwxr-xr-x 2 root root 0 Jan 11 10:01 ./ drwxr-xr-x 13 root root 0 Jan 11 10:01 ../ -r--r--r-- 1 root root 4 Jan 11 10:07 clock-frequency -r--r--r-- 1 root root 8 Jan 11 10:07 clock-names -r--r--r-- 1 root root 8 Jan 11 10:07 clocks -r--r--r-- 1 root root 23 Jan 11 10:07 compatible -r--r--r-- 1 root root 24 Jan 11 10:07 interrupts -r--r--r-- 1 root root 4 Jan 11 10:07 name -r--r--r-- 1 root root 4 Jan 11 10:07 phandle -r--r--r-- 1 root root 4 Jan 11 10:07 pinctrl-0 -r--r--r-- 1 root root 4 Jan 11 10:07 pinctrl-1 -r--r--r-- 1 root root 21 Jan 11 10:07 pinctrl-names -r--r--r-- 1 root root 16 Jan 11 10:07 reg -r--r--r-- 1 root root 5 Jan 11 10:07 status
Change I2C Speed
Check your I2C node number depending on your kernel version.
checking_kernel_version_for_i2c_node_number
You can change speed of each I2C node by editing /sys/bus/i2c/devices/i2c-{0,1}/device/speed file.
- target
# To change I2C0 clock from 400KHz to 100KHz root@odroid:~# cat /sys/bus/i2c/devices/i2c-0/device/speed 400000 root@odroid:~# echo 100000 > /sys/bus/i2c/devices/i2c-0/device/speed root@odroid:~# cat /sys/bus/i2c/devices/i2c-0/device/speed 100000
- target
# To change I2C1 clock from 100KHz to 400KHz root@odroid:~# cat /sys/bus/i2c/devices/i2c-1/device/speed 100000 root@odroid:~# echo 400000 > /sys/bus/i2c/devices/i2c-1/device/speed root@odroid:~# cat /sys/bus/i2c/devices/i2c-1/device/speed 400000
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