Linux 5.18 version landed in Fedora 36 and it includes a new ssd130x DRM driver for the Solomon OLED display controllers.
One of the supported devices is SSD1306, which seems to be a quite popular display controller for small and cheap (I bought a pack of 3 on Amazon for less than 15€) monochrome OLED panels.
I do a lot of development and testing on RPi boards and found that these small OLED panels are useful to get console output without the need to either connect a HDMI monitor or a serial console.
This blog post explains how to setup Fedora 36 to use a SSD1306 OLED connected through I2C.
First you need connect the SSD1306 display to the RPi, Adrafruit has an excellent article on how to do that.
Then you need to install Fedora 36, this can be done by downloading an aarch64 Fedora raw image (e.g: Workstation Edition) and executing the following command:
sudo arm-image-installer --image Fedora-Workstation-36-1.5.aarch64.raw.xz --target=rpi4 --media=$device --addconsole --addkey=id_rsa.pub --norootpass --resizefs
$device is the block device for your uSD (e.g:
Fedora 36 was released with Linux 5.17, but as mentioned the ssd130x DRM driver landed in 5.18, so you need to update the Fedora kernel:
sudo dnf update kernel -y
Finally you need to configure the RPi firmware to enable the I2C1 pins and load the
ssd1306 Device Tree Blob Overlay (dtbo) to register a SSD1306 I2C device, e.g:
sudo cat << EOF >> /boot/efi/config.txt dtparam=i2c1=on dtoverlay=ssd1306,inverted EOF
ssd1306.dtbo supports many parameters in case your display doesn’t match the defaults. Take a look to the RPi overlays README for more details about all these parameters and their possible values.
The ssd130x DRM driver registers an emulated fbdev device that can be bound with fbcon and use the OLED display to have a framebuffer console. If you want to do that, it’s convenient to change the virtual terminal console font to a smaller one, e.g:
sudo sed -i 's/FONT=.*/FONT="drdos8x8"/' /etc/vconsole.conf sudo dracut -f
And that’s it. If your SSD1306 uses SPI instead, this is supported since Linux 5.19 but that would be the topic for another post.