From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valentine Date: Tue, 05 Nov 2013 19:57:10 +0000 Subject: Re: [PATCH] usb: phy: Move R-Car Gen2 driver registration to postcore_inictall Message-Id: <52794D96.30209@cogentembedded.com> List-Id: References: <1383063666-4291-1-git-send-email-valentine.barshak@cogentembedded.com> In-Reply-To: <1383063666-4291-1-git-send-email-valentine.barshak@cogentembedded.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sh@vger.kernel.org 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.