On 01/08/2023 20:07, Yu, Richard wrote: > >>> +title: HPE GXP USB Virtual EHCI controller > >> The word "virtual" in bindings pretty often raises questions, because we >> describe usually real hardware, not virtual. Some explanation in >> description would be useful. > > Here we are working with virtual devices that are created and have no Unfortunately I do not know what are virtual devices which do not exist physically. I have serious doubts that they fit Devicetree purpose... > physical presence. We have modeled our code off of ASPEED's VHUB > implementation to comply with the implementation in OpenBMC. > >>> + The HPE GXP USB Virtual EHCI Controller implements 1 set of USB EHCI >>> + register and several sets of device and endpoint registers to support >>> + the virtual EHCI's downstream USB devices. >>> + > > >> If this is EHCI controller, then I would expect here reference to usb-hcd. > > We will remove references to EHCI in code and documentation. It has been > modeled to following ASPEEDs approach as mentioned above. > >>> + hpe,vehci-downstream-ports: >>> + description: Number of downstream ports supported by the GXP > > >> Why do you need this property in DT and what exactly does it represent? >> You have one device - EHCI controller - and on some boards it is further >> customized? Even though it is the same device? > > That is correct. We can configure this VHUB Controller to have one to > 8 virtual ports. This is similar to the aspeed virtual USB HUB > "aspeed,vhub-downstream-ports" moving forward in the next patch > we are going to use "hpe,vhub-downstream-ports" Moving forward you need to address this lack of physical presence... Aren't these different devices and you just forgot to customize the compatible? Best regards, Krzysztof
