Intersil/Conexant Prism54 (p54) 802.11g wireless adapters
A family of 802.11b/g Wi-Fi chips (ISL38xx and STLC45xx, sold under the Prism54 name by Intersil and later Conexant) that shipped in PCI cards, USB dongles, and a handful of SPI-attached embedded radios such as the one in Nokia's 2007 N810 internet tablet. The hardware was common in mid-2000s laptops and access points before being eclipsed by 802.11n silicon around 2008.
recommendation
Worth keeping but flagging as legacy: the hardware hasn't been sold new for well over a decade and surviving users are mostly OpenWrt holdouts and retro-device enthusiasts (for example the postmarketOS community around the Nokia N810, which itself is marked obsolete). However, the code is still being touched in upstream cleanups as recently as 2025, OpenWrt still packages it, and no other in-tree driver covers these chips, so removing it would strand the remaining users with no migration path.
repository signals
sources
- lore.kernel.org
Recent upstream mail still touched p54 code in 2025, indicating the driver is not abandoned in-tree.
- wireless.docs.kernel.org
Kernel wireless docs describe p54 as the driver for Prism54 chips and note it covers PCI, USB, and SPI variants.
- cateee.net
LKDDb shows CONFIG_P54_USB is still present through current kernel series, so upstream still ships this support.
- cateee.net
LKDDb shows CONFIG_P54_PCI is still present through current kernel series, confirming continued upstream availability for PCI hardware.
- en.wikipedia.org
A representative SPI deployment target, the Nokia N810, was released in 2007, supporting the view that surviving p54 hardware is legacy-era.
- wiki.postmarketos.org
Current niche community evidence around an old p54spi-class device exists, but it is marked very old and not recommended for future use.
- openwrt.org
OpenWrt still packaged kmod-p54-usb, suggesting some residual legacy-user demand rather than zero deployment.
codex reasoning notes (technical)
Local shell inspection of Kconfig and source files shows a real PCI/USB/SPI wireless driver for isl38xx/stlc45xx Prism54 hardware. lore_activity tool returned a 2025 lore URL touching p54usb.c; combined with the provided static summary (21 substantive commits in 5y, most recent 2026-01-27), this looks maintained enough to avoid deprecate/remove. Web search found kernel wireless docs and LKDDb pages confirming the driver remains upstream. Web search also found only legacy-era deployment evidence: Prism54 is 802.11g-era hardware, Nokia N810 dates to 2007, and postmarketOS flags that class of device as obsolete; OpenWrt packaging suggests residual but low legacy use. No natural replacement driver covers the same devices, so keep the driver but annotate it as legacy/low-deployment rather than deprecating it.