From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arun Ramamurthy Subject: Re: [PATCH 1/2] phy: usbphy: Add dt documentation for Broadcom Cygnus USB PHY driver Date: Wed, 25 Feb 2015 16:24:06 -0800 Message-ID: <54EE67A6.609@broadcom.com> References: <1424200821-16368-1-git-send-email-arun.ramamurthy@broadcom.com> <2797126.uqvyZJisPk@wuerfel> <54E3AD2E.8050902@broadcom.com> <11865413.8NsXkQ6AUR@wuerfel> <54E53278.70705@broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <54E53278.70705@broadcom.com> Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Alan Stern Cc: Mark Rutland , devicetree@vger.kernel.org, Scott Branden , Pawel Moll , Ian Campbell , Ray Jui , linux-kernel@vger.kernel.org, Kishon Vijay Abraham I , Jonathan Richardson , Rob Herring , bcm-kernel-feedback-list@broadcom.com, Dmitry Torokhov , Kumar Gala , Anatol Pomazau List-Id: devicetree@vger.kernel.org Hello Alan and Arnd I wanted to follow up on this patch and ascertain what I would have to change. Please see below for my questions On 15-02-18 04:46 PM, Arun Ramamurthy wrote: > > > On 15-02-18 07:15 AM, Arnd Bergmann wrote: >> On Tuesday 17 February 2015 13:05:50 Arun Ramamurthy wrote: >>> On 15-02-17 12:53 PM, Arnd Bergmann wrote: >>>> On Tuesday 17 February 2015 12:00:49 Arun Ramamurthy wrote: >>>>> Arnd, I patched the ehci and ohci driver to accept multiple phys so >>>>> they >>>>> require different names and cannot both be "usb". That patch was >>>>> accepted by Alen Stern but I did not update the bindings >>>>> documentation. >>>>> I will send out another patch for that. Could we go with the naming >>>>> scheme of "usb" + "p" + port number or do you have other suggestions? >>>> >>>> I don't have a good idea, but I think it would be best if the first >>>> phy could remain named "usb" for compatibility with the existing >>>> binding. >>>> >>> The patch was written in a way that all the existing and new drivers can >>> continue to use "usb" if they are using only one phy so that we remain >>> compatible. The names need to be different only if more than one phy is >>> specified. In such cases i don't think the first phy should be "usb" as >>> it would be confusing to have >>> phy-names = "usb","usbp1" >> >> I see your patch now, as 7e7a0e67f2c ("usb: ehci-platform: add support >> for >> multiple phys per controller"), and I'm not too happy about the way you >> did this. > >> We already concluded that there should have been a binding change >> to go along with this, and that would have caught the fact that you >> circumvent the API here by reading the phy names manually. That >> part should never have made it into the kernel. >> >> I think we can do this either by defining specific names for the >> phy, or by changing the generic PHY binding to allow anonymous >> phy references (leaving out "phy-names" entirely), and adding a >> proper API for that. >> > Thanks Arnd, I will wait for Alan's comments before proceeding. I am > happy to patch the ehci-platform driver to use a new api instead of > devm_phy_get if that is the best option. > >>> Should I run this by Alan Stern? >> >> I've added him to Cc here. He clearly didn't know the background about >> the DT binding change, and should not need to, but he may have an opinion >> on what names we should use. >> > Arnd, should I re patch the ehci-platform driver to avoid phy-names entirely? Alan, if not do you have an opinion on what the usb phy names should be? The current patch uses "usbp" + port number such as "usbp0" , "usbp1" etc >>>> What is the reason for having two phys in your case? Are these >>>> identical phy devices connected to a single controller or do they >>>> server different purposes? >>>> >>> Yes, we have three identical phys connected to a single host controller >>> and one of the phys is also connected to the device controller >> >> Ok, no problem with that, let's just make sure we come up with a >> good binding for it. >> Arnd do you have any other comments on the phy driver itself? Thank you >> Arnd >>