Micrel/Microchip KSZ8841, KSZ8842, and KS8851 10/100 Ethernet controllers
A family of small 10/100 Mbps Ethernet MAC and switch chips originally from Micrel (acquired by Microchip in 2015), commonly soldered onto industrial and embedded boards. The KS8851 is an SPI/parallel-bus Ethernet controller popular on microcontroller-class systems, while the KSZ8841/8842 are PCI MAC and two-port switch parts used in industrial control and point-of-sale gear.
recommendation
It should stay in the kernel and is worth a short note about its niche: Microchip still sells the KSZ8851 and KSZ8842 as in-production parts (the KSZ8841 is marked not-recommended-for-new-designs), and the KS8851 SPI variant was still getting real bug-fix patches headed for stable as recently as 2026. Volumes are low and the audience is embedded and industrial integrators rather than mainstream PCs, but no other in-tree driver covers these chips.
repository signals
sources
- git.kernel.org
Kernel Kconfig for this directory covers KSZ8841/42 and KS8851 variants.
- lore.kernel.org
The KS8851 side is still receiving real upstream bug-fix work in 2026, including a v4 fix tagged for stable.
- microchip.com
Microchip lists KSZ8851 as 'In Production'.
- microchip.com
Microchip lists KSZ8842 as 'In Production'.
- microchip.com
Microchip lists KSZ8841 as 'Not Recommended for new designs', showing the family is mixed rather than uniformly current.
codex reasoning notes (technical)
Recommendation is keep-annotate: lore_activity on ks8851_spi.c showed active 2026 maintenance with a stable-bound bug fix, so this is not a dead driver; local Kconfig inspection shows the directory serves KSZ8841/42 and KS8851 parts; web search on microchip.com found KSZ8851 and KSZ8842 still in production while KSZ8841 is NRND. That points to ongoing niche embedded/industrial deployments, not broad new deployments. No natural replacement driver covers the same chips. Source acquisition: lore URL via lore_activity tool; Microchip product pages via web search; kernel.org Kconfig URL via canonical recall aligned with the locally inspected file.