From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754381AbcHXBG5 (ORCPT ); Tue, 23 Aug 2016 21:06:57 -0400 Received: from mail-ua0-f177.google.com ([209.85.217.177]:36763 "EHLO mail-ua0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753934AbcHXBGy (ORCPT ); Tue, 23 Aug 2016 21:06:54 -0400 MIME-Version: 1.0 In-Reply-To: References: <20160707222114.1673-1-stephen.boyd@linaro.org> <20160707222114.1673-4-stephen.boyd@linaro.org> <20160718022355.GA8568@rob-hp-laptop> <147043320014.26915.7483025835695600714@sboyd-linaro> From: Stephen Boyd Date: Tue, 23 Aug 2016 18:06:31 -0700 Message-ID: Subject: Re: [PATCH v2 03/22] usb: ulpi: Support device discovery via device properties To: Rob Herring Cc: Linux USB List , linux-arm-kernel , Linux Kernel Mailing List , linux-arm-msm , Andy Gross , Bjorn Andersson , Neil Armstrong , Arnd Bergmann , Felipe Balbi , Greg Kroah-Hartman , Heikki Krogerus , "devicetree@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 23, 2016 at 4:06 PM, Rob Herring wrote: > On Tue, Aug 23, 2016 at 3:00 PM, Stephen Boyd wrote: >> On Fri, Aug 5, 2016 at 2:40 PM, Stephen Boyd wrote: >>> Quoting Rob Herring (2016-07-17 19:23:55) >>>> On Thu, Jul 07, 2016 at 03:20:54PM -0700, Stephen Boyd wrote: >>>> > +------- >>>> > + >>>> > +usb { >>>> > + compatible = "vendor,usb-controller"; >>>> > + >>>> > + ulpi { >>>> > + phy { >>>> > + compatible = "vendor,phy"; >>>> > + ulpi-vendor = /bits/ 16 <0x1d6b>; >>>> > + ulpi-product = /bits/ 16 <0x0002>; >>>> > + }; >>>> > + }; >>>> >>>> I'm still having concerns about describing both phys and devices. If I >>>> have a controller with 2 ports and 2 devices attached, I'd have >>>> something like this under the USB controller: >>>> >>>> ulpi { >>>> phy@1 { >>>> }; >>>> phy@2 { >>>> }; >>>> }; >>> >>> My understanding is there would only be one status="ok" node on the ULPI >>> bus for the single phy that a usb controller would have. At the least, >>> the kernel's ULPI layer only seems to support one ULPI phy for a >>> controller right now. So even if there are two ports, it doesn't mean >>> there are two phys. >>> >>>> >>>> dev@1 { >>>> ... >>>> }; >>>> >>>> dev@2 { >>>> ... >>>> }; >>>> >>>> >>>> That doesn't seem the best, but I don't have a better suggestion. Maybe >>>> the device nodes need to go under the phy nodes? >>>> >>> >>> What if we moved the dev@1 and dev@2 to another sub node like "ports" or >>> "usb-devices"? Legacy code can support having those devices directly >>> underneath the usb controller, but future users would always need to put >>> them in a different sub-node so that we can easily differentiate the >>> different busses that a usb controller node may support? >>> >>> I'm not sure I see any need to relate the phy to the ports that are on >>> the controller, but if that is needed then perhaps you're right and we >>> should move the ports underneath the phy. USB core could be modified to >>> go through the legacy path or through the phy, if it even exists, to >>> find ports. >>> >>> Do we typically do this for other phy designs like sata or pci? The phy >>> always seemed like a parallel thing to the logical bus that the phy is >>> used for. >> >> Rob does this sound ok to you? > > Well, if there's only ever 1 phy under the controller, then as you had > it is fine. > Ok. For ULPI I believe that's the case, but in general usb controllers can have more than one phy.