MIPI I3C master host controllers
Host-side controllers for MIPI I3C, the successor to I2C used to attach low-speed peripherals like sensors, power-management chips, and debug interfaces to modern SoCs and PCs. This directory holds the controller drivers from vendors including Cadence, Synopsys DesignWare, Silvaco, Renesas, Aspeed (AST2600), Analog Devices, and the generic MIPI HCI implementation found on recent Intel platforms.
recommendation
It should stay because I3C is a current, actively expanding bus standard with new silicon shipping in 2025 and 2026. The kernel mailing lists show fresh patches landing this year, including new Intel Panther Lake HCI enablement and ongoing fixes to the Synopsys DesignWare and MIPI HCI drivers, and Renesas is still selling new SoCs (such as the RZ/V2H) that depend on these controllers.
repository signals
sources
- docs.kernel.org
Mainline kernel documentation has a dedicated I3C subsystem and master-controller driver API, indicating an actively supported subsystem rather than a legacy holdover.
- lists.infradead.org
A 2025 upstreamed patch added MIPI I3C HCI PCI support for Intel Panther Lake, showing new platform enablement in this driver area.
- spinics.net
There was active March 31, 2026 discussion around fixing atomic register updates in mipi-i3c-hci, showing current maintenance traffic.
- spinics.net
There was active April 4, 2026 patch traffic fixing dw-i3c-master memory-management issues, showing current maintenance traffic.
- renesas.com
Renesas lists the RZ/V2H as an active product with 1 I3C channel and visible distributor inventory, showing current-market hardware using this class of controller.
codex reasoning notes (technical)
Local shell inspection of drivers/i3c/master/Kconfig/Makefile showed multiple real controller drivers (ADI, Cadence, Synopsys DW/AST2600, Silvaco, MIPI HCI, Renesas), so this is an active multi-vendor hardware-driver directory. URLs were obtained via web search/open: docs.kernel.org confirms the subsystem is current; infradead archive and spinics results show 2025-2026 new-feature and bug-fix traffic for files in this directory. I also searched lore-oriented terms and found maintenance/new-enablement hits but no removal/deprecation thread; that no-removal conclusion is an inference from the search results plus the directory's very recent substantive activity. Renesas product page was opened from web search and shows an active 2026-orderable SoC with I3C, so hardware is still sold and seeing new deployments. No single replacement driver exists because this directory contains the upstream controller-specific implementations for the use case.