On Mon, Jun 27, 2022 at 02:54:03PM -0400, Alan Stern wrote: > On Mon, Jun 27, 2022 at 11:14:47AM -0700, Matthias Kaehlcke wrote: > > Maybe a bit more verbose documentation like this could help: > > > > Some background about the logic in this function, which can be a bit hard > > to follow: > > > > Root hubs don't have dedicated device tree nodes, but use the node of their > > HCD. The primary and secondary HCD are usually represented by a single DT > > node. That means the root hubs of the primary and secondary HCD share the > > same device tree node (the HCD node). As a result this function can be > > called twice with the same DT node for root hubs. We only want to create a > > single platform device for each physical onboard hub, hence for root hubs > > the loop is only executed for the primary hub. Since the function scans > > By "primary hub", you mean "root hub for the primary HCD", right? This > should be clarified. Ok, thanks for the suggestion! > > through all child nodes it still creates pdevs for onboard hubs connected > > to the secondary hub if needed. > > And likewise for "secondary hub". > > > > > Further there must be only one platform device for onboard hubs with a > > companion hub (the hub is a single physical device). To achieve this two > > What do you mean by "companion hub"? I think you are using the wrong > word here. If you're talking about the relation between the two logical > hubs (one attached to the SuperSpeed bus and one attached to the > Low/Full/High-speed bus) within a physical USB-3 hub, the correct term > for this is "peer". See the existing usages in hub.h, hub.c, and > port.c. > > "Companion" refers to something completely different (i.e., the UHCI or > OHCI controllers that handle Low/Full-speed connections on behalf of a > High-speed EHCI controller). Yes it's the relation between the two logical hub. The term 'companion-hub' stems from the binding and has been around since v6 of this series. I guess we should update the binding if the terminology isn't correct.
