imx8dx use usbotg3 for usb2, try to change the source code about usbotg3 in the In fsl-imx8dxp.dtsi and fsl-imx8dxp.dtsi, you need to change according to your HW, I don't have such example for you
The usb2 of imx8dx is usb2.0, the hardware is the same as the official reference schematic diagram, as shown in the picture, there are not too many other components.
Is it possible to use cdns3 for USB2.0? The second USB2.0 port of imx8dx, according to the device tree configuration of cdns3, the second USB cannot be used. My USB only has DP DN. There are no other auxiliary devices. I haven't found a suitable modification method yet. If there is a good modification method, please tell me in time.