On Fri, Jul 18, 2025 at 02:26:15PM +0800, Chaoyi Chen wrote:

From: Chaoyi Chen <redacted>

The RK3399 has two USB/DP combo PHY. With the help of external Type-C
controller, the PHY can switch altmode between USB and DP.

Their connection diagram is shown below:

external Type-C Chip0 ---> USB/DP PHY0 ---+
                                          | <----> CDN-DP controller
external Type-C Chip1 ---> USB/DP PHY1 ---+

It looks like your "external" controller is not described. Look at your
port property - "Connection to USB Type-C connector". Lack of proper
hardware description leads you to claim that the PHY is the mode switch.
I have doubts on that.

You already received the comments that you need to come with rationale
why making PHY a USB switch is correct. I don't see the arguments for
that.

Best regards,
Krzysztof