FMH GPIB FPGA controller core
An open-source GPIB (IEEE-488) controller written in VHDL by Frank Mori Hess and synthesized into an FPGA, used by labs to talk to legacy test-and-measurement instruments like oscilloscopes and signal generators. It is a soft core that engineers load onto their own FPGA hardware, typically described to Linux through device tree.
recommendation
Worth keeping but documenting its narrow niche. The hardware is a VHDL GPIB controller core that lab users program into an FPGA rather than a retail card you can buy, and enumeration relies on device tree or placeholder PCI IDs. Even so, it was promoted out of staging into drivers/gpib in late 2025 and received further fixes in early 2026, so it has an active, if small, user base of FPGA-equipped instrumentation labs.
repository signals
sources
- linux-gpib.sourceforge.io
Describes fmh_gpib_core as a GPIB chip written in VHDL for programming into an FPGA, with deployment via device-tree-defined FPGA resources rather than a mainstream retail board.
- cateee.net
Shows CONFIG_GPIB_FMH in mainline kernels after staging, and lists only the OF compatible "fmhess,fmh_gpib_core" plus bogus PCI IDs ffff:0000, indicating niche/nonstandard hardware enumeration.
- codebrowser.dev
Confirms the driver targets fmh_gpib_core, matches OF compatible "fmhess,fmh_gpib_core", and uses bogus Fluke PCI IDs rather than normal production IDs.
codex reasoning notes (technical)
This is a real driver directory. Local shell inspection of fmh_gpib.c confirmed module_init/module_exit and platform+PCI registration. Local `git -c safe.directory=... log --follow -- drivers/gpib/fmh_gpib` showed the driver was destaged into drivers/gpib on 2025-11-17 and received two non-mechanical fixes on 2026-01-16, which argues against deprecation/removal despite low commit volume. I could not get lore MCP access in this session, so upstream-attention evidence came from local git history instead. URL evidence was obtained by web search: `turn0search0`/`turn2search0` for the linux-gpib supported-hardware page, `turn0search2`/`turn2search2` for LKDDb, and `turn2search1` for codebrowser. Conclusion: extremely niche FPGA-based GPIB hardware, likely low deployment and not a mainstream new-sale product in 2025, but recently promoted from staging and still seeing fixes; keep it, with annotation that it serves a narrow legacy/lab FPGA niche.