TinyDRM: Support For Simple & Small Displays

New Linux kernel patches were posted today for introducing a "tinydrm" module for making it simpler to write DRM drivers against simplified displays.

Noralf Trønnes who developed this work explained the patch series as "The tinydrm module provides a very simplified view of DRM for displays that has onboard video memory and is connected through a slow bus like SPI/I2C. A driver using tinydrm has to provide a function that will be called from the dirtyfb ioctl and optionally drm_panel functions which can be used to set up the display controller and control backlight. Tinydrm also has fbdev support using fb_deferred_io which is tied in through the dirtyfb function call...The various display controllers can have library modules that handles display updates."

The patch series adds the support for the tiny LCD displays and the patches end with adding support for several Adafruit TFT displays to TinyDRM. Among the Adafruit MIPI DBI-compatible SPI displays then supported via this small DRM implementation is their 1.8-inch, 2.2-inch, and 2.8-inch screens. The 2.8-inch Adafruit panel supported is the TFT+touchscreen that's very popular with many Raspberry Pi fans. The TinyDRM code still needs to be cleaned up and reviewed, but hopefully it will be all tidied up in time for the Linux 4.7 kernel.