On Tue, May 18, 2021 at 02:40:47PM -0700, Matthias Kaehlcke wrote:

Could you also have a look at "[4/5] usb: host: xhci-plat:
Create platform device for onboard hubs in probe()"
(https://lore.kernel.org/patchwork/patch/1425453/)? It's a
relatively short patch that creates the platform device for
the driver from xhci-plat as you suggested in the v4
discussion.

I'm not the maintainer for xhci-related drivers.

However, there is at least one thing about this patch which looks 
suspicious: Adding the onboard_hub_dev pointer to struct usb_hcd instead 
of to struct xhci_plat_priv, where it would make a lot more sense.

It's also worth mentioning that this approach won't work at all when the 
onboard hub is not at the top level (its parent isn't the root hub), or 
when more than one onboard hubs are connected to the same root hub.

Alan Stern