Loongson MIPS platform glue (Loongson-3 hwmon, RS780E ACPI, LS2K1000 reset)
A small collection of board-specific helpers for Chinese-designed Loongson MIPS systems: temperature monitoring for the Loongson-3 CPUs, ACPI plumbing for the AMD RS780E south-bridge paired with them, and the reset controller for the LS2K1000 SoC. These chips powered government, industrial, and education-market machines in China through the late 2010s and early 2020s.
recommendation
Worth keeping but documenting its niche, because Loongson moved its entire product line to the new LoongArch architecture by mid-2022, with LS2K1000LA and LS3A5000 superseding the MIPS-era parts this code supports. The hardware is no longer sold new, yet installed Loongson MIPS systems remain in use and the files still received genuine maintenance in 2023 and 2024, so removal would be premature. An annotation noting the legacy status and the LoongArch successor would help future janitors.
repository signals
sources
- lore.kernel.org
cpu_hwmon.c still received upstream maintenance in September 2024 via a Loongson64 IOCSR header conversion touching this directory.
- lore.kernel.org
rs780e-acpi.c received upstream cleanup in December 2023, showing the code is not entirely dormant.
- lore.kernel.org
ls2k-reset.c saw a post-merge fix in January 2022, indicating real maintenance after its 2021 introduction.
- loongson.cn
Loongson said in May 2022 that LS2K1000LA marked its full transition to LoongArch and was a direct replacement for 2K1000, implying the original MIPS 2K1000 was being superseded.
- loongson.cn
Current official LS3A5000 product page says it is pin-compatible with the older 3A4000, showing current new sales are on LoongArch replacements rather than the older MIPS 3A4000 generation.
codex reasoning notes (technical)
Local tree inspection via exec_command showed three tiny, hardware-specific Loongson-era platform drivers: Loongson-3 hwmon, RS780E ACPI glue, and LS2K1000 reset. lore_activity on each file found only sporadic touches, but notably real maintenance in 2023-2024 rather than removal work; no clear removal series surfaced, and lore_file_timeline on the directory itself returned no aggregated hits. Official loongson.cn pages obtained via web search show Loongson had transitioned its product line to LoongArch by 2022, with LS2K1000LA directly replacing 2K1000 and LS3A5000 replacing/pin-matching 3A4000. That points to legacy-but-deployed hardware: likely still present in installed industrial/government systems, but not meaningfully sold new in 2025. Because upstream still carries occasional fixes/cleanups, this is better tagged legacy/annotated than actively deprecated for removal. No single upstream replacement driver exists because the directory covers several unrelated board/SoC-specific functions.