open-ep: From Hardware Design to Mainline Kernel — A Complete Open Source Practice for E-Paper Community

Most e-paper modules on the market rely on vendor-provided SPI userspace libraries and are primarily designed for MCU applications, making them incompatible with the standard Linux display stack. More critically, the hardware design and mechanical details of these modules are often opaque, leaving developers with no choice but to accept them as-is. open-ep is a community practicing "full-stack open source from hardware to kernel." Our PixPaper product line features:

1. Self-designed Hardware and Mechanical Structure

• PCB layout, connector selection, and mechanical design are all completed by the community without relying on ODMs

2. DRM Driver Upstream

• Merged into mainline Linux kernel and covered by LWN.net
• Since upstream review is time-consuming, we also implement DRM drivers in vendor kernels

3. Multi-OS Ecosystem Support

• Extended application scenarios across ARM Yocto BSP, Android AOSP, Ubuntu OS, FreeRTOS, and other systems

4. Security Considerations

• For BSP applications, we address SBOM generation and CVE vulnerability patching to comply with software security standards in different regions (such as the EU CRA)

This goes beyond "pushing drivers into the kernel" — it demonstrates how a small-scale community can:

Consider mainline compatibility from the circuit design phase Communicate with kernel maintainers to successfully upstream patches Balance "selling products for sustainability" with "promoting open source standardization" Build trust through technical communities like COSCUP, UBUCON ASIA and OSPN Japan.

We believe hardware open source is not just about "publishing schematics," but integrating open source ecosystem thinking from the design stage. open-ep aims to prove that even resource-limited communities relying on volunteer contributions can make substantial contributions to mainline Linux and industry standards.