Hello, On 1/26/2026 3:42 AM, Hugh Cole-Baker wrote: > On 19/01/2026 07:30, Chaoyi Chen wrote: >> From: Chaoyi Chen <[email protected]> >> >> This series focuses on adding Type-C DP support for USBDP PHY and DP >> driver. The USBDP PHY and DP will perceive the changes in cable status >> based on the USB PD and Type-C state machines provided by TCPM. Before >> this, the USBDP PHY and DP controller of RK3399 sensed cable state >> changes through extcon, and devices such as the RK3399 Gru-Chromebook >> rely on them. This series should not break them. >> >> ==== >> 1. DisplayPort HPD status notify >> >> Before v7, I implemented a variety of DP HPD status notify. However, >> they all had various problems and it was difficult to become a generic >> solution. >> >> Under the guidance of Heikki and Dmitry, a decoupled notification >> method between the TypeC and DRM subsystems was introduced in v7. >> First, a notification is sent when TypeC registers a new altmode. >> Then, a generic DP AUX HPD bridge is implemented on the DRM side. >> >> During v7-v10, we added a new notifier in typec to notify the altmode >> device register event. With the help of Greg and Heikki, we implemented >> the reuse of notifiers for the type bus itself in patch1 of v11. >> >> The USB subsystem related parts have already been merged into the >> usb-next branch in v13 [0][1]. Therefore, this series no longer includes >> these patches starting from v14. Thanks to Greg and Heikki! >> >> [0]: >> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/?h=usb-next&id=67ab45426215c7fdccb65aecd4cac15bbe4dfcbb >> [1]: >> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/?h=usb-next&id=4dee13db29de6dd869af9b3827e1ff569644e838 >> >> That makes it redundant for each Type-C controller driver to implement >> a similar DP AUX HPD bridge in embedded scenarios. >> >> ==== >> 2. Altmode switching and orientation switching for USBDP PHY >> >> For USB Type-C interfaces, an external Type-C controller chip assists >> by detecting cable attachment, determining plug orientation, and >> reporting USB PD message. The USB/DP combo PHY supports software >> configurable pin mapping and DisplayPort lane assignment. Based on >> these message, the combo PHY can perform both altmode switching and >> orientation switching via software. >> >> The RK3399 EVB IND board has a Type-C interface DisplayPort. It use >> fusb302 chip as Type-C controller. The connection diagram is shown below: >> >> fusb302 chip +---> USB2.0 PHY ----> DWC3 USB controller >> | >> +---> USB/DP PHY0 +--> CDN-DP controller >> | >> +--> DWC3 USB controller >> >> ==== >> 3. Multiple bridge model for RK3399 CDN-DP >> >> The RK3399 has two USB/DP combo PHY and one CDN-DP controller. And >> the CDN-DP can be switched to output to one of the PHYs. >> >> USB/DP PHY0 ---+ >> | <----> CDN-DP controller >> USB/DP PHY1 ---+ >> >> In previous versions, if both PHY ports were connected to DP, >> the CDN-DP driver would select the first PHY port for output. >> >> On Dmitry's suggestion, we introduced a multi-bridge model to support >> flexible selection of the output PHY port. For each PHY port, a >> separate encoder and bridge are registered. >> >> The change is based on the DRM AUX HPD bridge, rather than the >> extcon approach. This requires the DT to correctly describe the >> connections between the first bridge in bridge chain and DP >> controller. And Once the first bridge is obtained, we can get the >> last bridge corresponding to the USB-C connector, and then set the >> DRM connector's fwnode to the corresponding one to enable HPD >> notification. > > With a similar dts patch [1] on top of this series I tested a type-C to > DP adapter/cable for display output on the ROCKPro64 board, which also > pairs a FUSB302 with RK3399. Booting it up with the cable plugged in > works, as does hotplugging the cable after booting in both orientations. > The correct mode for the display is detected. I wasn't able to test > audio, only video output, as this display doesn't have speakers. > > I did once, after unplugging and reconnecting the cable a few times, > see it get into a state where it didn't detect the attached display. > Logs from that unplug/reconnect attempt are here [2] if of interest. > Nevertheless, hotplug seems to work the majority of the time, so > > Tested-by: Hugh Cole-Baker <[email protected]> > > [1]: > https://github.com/sigmaris/linux/commit/91724088b19bee7d248946442a801423e8cd0634 > [2]: https://gist.github.com/sigmaris/fa107384a7492583ceee1c2962f5030a >
Thank you for the test. I also have the same board, and I will try it later :) -- Best, Chaoyi
