GNU/Linux Loadable Kernel Module Driver for SSD1306 OLED/PLED Driver.

Source code hierarchy:

                oled_sysfs
                    |
                 graphics
                    |
                 datalink
                    |
              driver  oled.dts

Tested on Linux raspberrypi 5.10.103-v7l+ #1529 SMP Tue Mar 8 12:24:00 GMT 2022 armv7l GNU/Linux.
(Raspberry Pi Buster.)

PDF documents generated (by doxygen) at /docs/latex/refman.pdf
To read the compiled pdf, git clone this repository, and open the softlink oled_driver_manual.pdf.

Demo: Displaying text and the dinosaur graphics from chrome browser.

Demo: Displaying oled_sysfs (kobject-mapped directory) from terminal.

Documentation.

To compile.

Setup compile environment
$ sudo make setup

Compile
$ sudo make

Successful compile message example:
pi@raspberrypi:~/Projects/raspberrypi-4b/drivers/oled $ make
    make -C /usr/src/linux-headers-5.10.103-v7l+ \
            ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- \
            M=/home/pi/Projects/raspberrypi-4b/drivers/oled modules
    make[1]: Entering directory '/usr/src/linux-headers-5.10.103-v7l+'
      CC [M]  /home/pi/Projects/raspberrypi-4b/drivers/oled/oled_sysfs.o
      LD [M]  /home/pi/Projects/raspberrypi-4b/drivers/oled/oled_driver.o
      MODPOST /home/pi/Projects/raspberrypi-4b/drivers/oled/Module.symvers
      CC [M]  /home/pi/Projects/raspberrypi-4b/drivers/oled/oled_driver.mod.o
      LD [M]  /home/pi/Projects/raspberrypi-4b/drivers/oled/oled_driver.ko
    make[1]: Leaving directory '/usr/src/linux-headers-5.10.103-v7l+'

To run:

Insert the kernel module

    $ sudo make insmod

To remove the kernel module:

    $ sudo make rmmod

To check for printk log:

    $ dmesg

To generate docs by doxygen

    $ make doxygen

    $ cd /docs/html

Kanban - TODO

• release-00: Minimal-viable kernel i2c bus module and simple configruation + fill-screen function.

  • Constructing Makefile, setup build-environment (linux kernel headers)
  • Understanding struct i2c_client , struct i2c_driver.
  • Implementing probe and remove callbacks when the kernel inserts/remove the driver.

• release-01: Add font / image support to the screen datalink layer.

  • Reading and implementing various display utitlities (change line, clear screen, set coordinate...etc) according to SSD1306 datasheet by Solomon Systech.

• release-02: Add oled_sysfs as an interface to user-space.

  • Understanding struct kobject, kobj_attrbute.
  • Implementing the creation of the oled device as a sysfs folder.
  • Implementing the creation of oled attributes such as display_text, brightness, etc. as files in that sysfs folder.
  • Implementing kthread in driver.c that flushes display_text stored through sysfs onto the screen.

• release-03: Develop the dinosaur game displaying on this screen.

  • Add multi-threading protection to critical sections.
  • Developing the Chrome dinosaur game, interacting with the kernel module through oled_sysfs.

• release-04: Unit testing.

  • TBD