Re: [PATCH] usb: phy: Move R-Car Gen2 driver registration to postcore_inictall

[Valentine <valentine.barshak@cogentembedded.com>]

On 11/01/2013 07:55 PM, Alan Stern wrote:
> On Fri, 1 Nov 2013, Valentine wrote:
>
>> The USB HDC PCI deferred probing could be used on R-Car. But I'm not sure how to make a particular
>> PCI USB HDC device attached to a particular PCI host controller on a particular SoC defer its probing
>> while waiting for the USB phy. At the same time other identical PCI USB HCD devices (with the same PCI id)
>> on the same SoC should be probed as usual.
>
> That is the hard part.  That's what we need to discuss.
>
> And not just on the linux-usb mailing list.  Get other people
> (especially PCI people) involved too.
>
>> We can't use PCI ids here to distinguish between PCI USB HCD devices. Neither can we use PCI busses
>> to distinguish between PCI host controllers, since bus numbers are assigned dynamically.
>
> There must be some way for you to tell which PCI devices use the PHY.
> But I'm not a PCI expert, and I'm not familiar with your platform.
>
>> It looks that it's quite hard to do that without bigger hacks in the PCI USB HCD driver that are
>> most likely not to be used on any other platforms except for R-Car.
>
> You never know what will happen in the future.  Besides, even if nobody
> else needs to do this for a PCI device, you can be certain that the
> same sort of thing will be needed for devices on other buses.  A
> suitably general solution would help them too.
>
> Alan Stern
>

OK, I've tried to come up with more or less universal solution to defer HCD probing
until the external USB phy is ready. I'll start a new thread with the RFC patches in a bit.

Thanks,
Val.