Linux's support for MIPI I3C, a modern successor to I2C used to connect sensors, power-management chips, and other low-speed peripherals on SoCs. It contains both the bus core and drivers for the host controllers built into recent ARM and x86 SoCs from vendors like NVIDIA, Intel, Qualcomm, and Synopsys.
It should stay in the kernel because I3C is an actively maintained subsystem with ongoing feature work in 2025-2026, including ACPI enumeration and runtime power management contributions from NVIDIA and Intel. New silicon, such as Intel's Agilex 3 SoC, continues to ship I3C controllers, and there is no replacement subsystem since this is itself the upstream Linux implementation of the bus.
repository signals
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monthly commits · 2021-04-21 → 2026-04-21 · 327 total · active in 48/61 months
Core I3C code in drivers/i3c/master.c was still receiving substantial upstream feature work in April 2026, including ACPI enumeration support for child devices.
Linux maintains current subsystem documentation for I3C protocol concepts and APIs, indicating this is an active supported subsystem rather than legacy-only code.
Intel's 2025 Agilex 3 SoC documentation describes integrated I3C controllers, showing I3C hardware remains present in new products in 2025.
codex reasoning notes (technical)
Local shell inspection showed drivers/i3c is the I3C core plus active master-controller support, not a dead helper directory. The two lore URLs were obtained via lore_file_timeline on drivers/i3c/master.c and drivers/i3c/device.c; both show recent feature development and no removal trend. The docs.kernel.org and Intel URLs were obtained via web search_query; together they support that I3C is a current Linux subsystem and still ships in new SoCs in 2025. No natural replacement driver exists because this is the upstream Linux I3C subsystem itself.