This week, Alexandre Belloni from Bootlin submitted a series of changes regarding the I3C protocol that were subsequently merged into the Linux 7.4 kernel. A primary focus of these updates is the adaptation of the core I3C master code to provide support for I3C hubs. This effort introduces a generic framework designed to expand and bridge communication across devices connected via MIPI I3C.
The patch series underwent an extensive review process, passing through 20 rounds of scrutiny before being finalized for inclusion in the mainline kernel. Beyond the core master changes required to enable hub functionality, the update also introduces a new driver specifically for the NXP P3H2x4x family of multi-port I3C hub devices.
In addition to hub support, Linux 7.4 incorporates fixes and clean-ups that activate HDR-DDR capabilities within the MIPI I3C Host Controller Interface (mipi-i3c-hci) driver. HDR-DDR facilitates high data rate modes for faster transfers by utilizing dual edge sampling. With this integration, the kernel now supports I3C High Data Rate Double Data Rate, achieving throughput speeds of up to 25 Mbps.
Sources: Phoronix.