M5Stack PaperS3 implementation

[KenVanHoeylandt]

Selectively imported code from @juicecultus fork
Full diff of code is here.

I'm very happy to have it building and running in the first attempt, so great job @juicecultus

Things not included:

• ESP-IDF 6.x changes: this will be done later this year
• Epub app: will be added later (juicecultus seems to be working on making it an external app)
• Fix for Launcher app: icons aren't visible now. I'll try to fix this by adding black&white icon alternatives later.
• Nullability changes: the annotations were recently removed. Regular code docs will be leading.
• EPDIY library (unused)
• Rewrites of various struct value assignments for various drivers. They are unsafe and shouldn't be used.

Summary by CodeRabbit

• New Features

  • Added M5Stack Paper S3 support: device metadata, device tree, hardware configuration, and module entry
  • New E‑ink display driver with grayscale rendering, LVGL integration, and full‑refresh API
  • Touch input and SD card device support with factory-style device creation

• Changes

  • Firmware SPI/RAM mode mapping adjusted (OPI→OCT)
  • Added FastEPD integration and component registrations
  • Board added to firmware build matrix

• Chores

  • Removed legacy device-selection block from firmware config

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds support for the M5Stack Paper S3: a new Devices/m5stack-papers3 tree (CMake, device.properties, devicetree, module, hardware Configuration, and factory functions for touch, display, and SD card). Introduces a FastEpdDisplay driver (new class and implementation) with LVGL integration and an idf dependency on FastEPD. Exposes DisplayDevice::requestFullRefresh() virtual method. Removes the TT_DEVICE_ID choice block from Firmware/Kconfig. Adds m5stack-papers3 (esp32s3) to the CI build matrix and maps SPI RAM mode OPI to OCT in device.py.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 5.56% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'M5Stack PaperS3 implementation' directly summarizes the main change: introducing support for the M5Stack PaperS3 device across the codebase.

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch m5stack-papers3

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[coderabbitai]

Actionable comments posted: 3

🧹 Nitpick comments (2)

device.py (1)

151-152: Consider adding a brief comment explaining the OPI→OCT mapping.

The remapping is correct since ESP-IDF uses CONFIG_SPIRAM_MODE_OCT for octal PSRAM mode, but device configurations may use "OPI" (Octal Peripheral Interface) terminology. A short comment would help future maintainers understand why this alias exists.

📝 Suggested comment

     mode = get_property_or_exit(device_properties, "hardware", "spiRamMode")
+    # ESP-IDF uses "OCT" for octal mode; accept "OPI" (Octal Peripheral Interface) as alias
     if mode == "OPI":
         mode = "OCT"

Firmware/idf_component.yml (1)

57-59: Consider adding target rules for FastEPD dependency.

Other display-related dependencies in this file use target rules to restrict which platforms include them. Since FastEPD is only used by the Paper S3 device (ESP32-S3), adding a rule would avoid pulling this dependency for other targets and maintain consistency with similar dependencies like esp_lcd_ili9341 and esp_lcd_st7735.

Proposed fix

   FastEPD:
     git: https://github.com/bitbank2/FastEPD.git
     version: 1.4.2
+    rules:
+      - if: "target == esp32s3"