I2C bus multiplexers and switches (NXP PCA954x/PCA984x, Maxim MAX735x, and generic GPIO/register muxes)
Small chips that fan one I2C bus out to several downstream buses, letting a host reach many devices that share addresses or need isolation. Common on server baseboards, networking gear, and embedded boards, with NXP PCA954x/PCA984x and Maxim MAX735x being typical parts; the directory also covers generic muxes built from GPIOs, pinctrl, or memory-mapped registers.
recommendation
It should stay in the kernel because this is an active subsystem covering chips that are still sold new in 2025 — NXP lists the PCA9548A as a current product — and the main PCA954x driver was still receiving upstream maintenance patches as recently as April 2026. There is no removal series in flight and the directory spans several distinct, still-relevant chip families plus generic mux mechanisms.
repository signals
sources
- lore.kernel.org
The major in-tree chip-family driver in this directory, i2c-mux-pca954x, was still receiving upstream maintenance patches in April 2026, indicating active support rather than removal.
- nxp.com
NXP lists PCA9548A, a representative PCA954x device supported by this directory, as an active product, showing the hardware class is still sold.
- git.kernel.org
The directory is a mixed active subsystem covering multiple current chip families and generic I2C mux mechanisms, not a single obsolete legacy driver.
codex reasoning notes (technical)
Keep: this is an active subsystem, not an obsolescent one. `lore_file_timeline` showed dense 2021-2026 patch traffic for `i2c-mux-pca954x.c`, including April 15, 2026 fixes and cleanups, and no evidence of a removal series; an attempted `lore_regex` scan for patches touching `drivers/i2c/muxes/` returned no removal signal. Web search found NXP's official PCA9548A page marking a supported mux part as active. Kernel Kconfig was read locally via shell, and the kernel.org tree URL is cited by canonical recall to anchor that this directory spans multiple still-relevant mux/switch implementations and generic platform mux drivers. With current upstream maintenance plus actively sold supported silicon, deprecation/removal is not justified.