This new "cros_ec_ucsi" driver provides a UCSI transport driver for use on ChromeOS with Chromebooks featuring the ChromeOS embedded controller (EC) and supporting a Platform Policy Manager (PPM). UCSI is the USB Type-C Connector System Software Interface for interfacing with the USB Type-C connectors on a system via various registers and data structures for the USB-C Platform Policy Manager.
The UCSI specification is documented at USB.org for those interested.
This patch was queued this week by Greg Kroah-Hartman into the USB subsystem's "usb-next" Git branch. With the ChromeOS UCSI driver queued in USB-next, it should be merged for the upcoming Linux 6.14 cycle barring any last minute issues being reported.