[PATCH] USB: OHCI/UHCI: Add soft dependencies on ehci_hcd

[Alan Stern]

On Sat, Jan 10, 2026 at 12:05:19PM +0800, Huacai Chen wrote:
> So I think we need a softdep between ohci-platform/uhci-platform and
> ehci-platform, which is similar to the PCI case.

Yes, on your platform.  But not on other platforms.  (For example, not 
on a platform that doesn't have an EHCI controller.)

I think the best way to do this is to create a new CONFIG_EHCI_SOFTDEPS 
Kconfig symbol, and add the soft dependency only if the symbol is 
defined.  Normally it will be undefined by default, but on your platform 
(and any others that need it) you can select it.

How does that sound?

> > There are other issues involving companion controllers, connected with
> > hibernation.  You should take a look at commit 6d19c009cc78 ("USB:
> > implement non-tree resume ordering constraints for PCI host
> > controllers"), which was later modified by commit 05768918b9a1 ("USB:
> > improve port transitions when EHCI starts up") and a few others.
> >
> > Also, read through the current code in hcd-pci.c (for_each_companion(),
> > ehci_pre_add(), ehci_post_add(), non_ehci_add(), ehci_remove(), and
> > ehci_wait_for_companions()).  Your non-PCI system will need to implement
> > some sort of equivalent to all these things.
> At least for the device probe, a softdep seems enough.

Does this platform support hibernation at all?

Alan Stern