At the end of July, a couple of Motorola software engineers formed a Hackathon team to bring up the PaPiRus E-Ink display on a MotoZ phone using the new Mods Development Kit. Most of the work consisted of porting the existing open-source display driver (epd.c) from the Raspberry Pi running Linux to the MDK running NuttX. Although our team didn't have much prior hardware experience, we expected the porting effort should be relatively straight-forward since the MDK environment is designed to facilitate porting hardware and software from other platforms by making use of common hardware interfaces such as I2C, SPI and GPIO, and through it's RPi HAT Adapter card which aligns pins from RPi's GPIO to the MDK.
During the 2.5 day event (working late nights), the team was just able to bring up the display and draw an image. After completing the work, the team artificially diced up the code changes into a series of 8 commits posted to this MDK epd Github link which roughly align to milestones described in subsequent posts below. But I want to emphasize that this project was a learning experience for us, and was just done to the level of quality of a rushed hackathon project .
We hope this example demonstrates that without much experience, any software developer should be able to select a random hardware project from Raspberry Pi or other platforms and get them working on Motorola phones with relatively low effort. And also hopefully inspire someone to continue work on this MDK PaPiRus driver.