Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752486AbbG2DZk (ORCPT ); Tue, 28 Jul 2015 23:25:40 -0400 Received: from mail-yk0-f175.google.com ([209.85.160.175]:33913 "EHLO mail-yk0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbbG2DZj (ORCPT ); Tue, 28 Jul 2015 23:25:39 -0400 MIME-Version: 1.0 In-Reply-To: References: <55B82716.1060008@sonymobile.com> From: Rob Herring Date: Tue, 28 Jul 2015 22:25:18 -0500 Message-ID: Subject: Re: Bug: shared usb dt document is incorrect To: Peter Chen Cc: Tim Bird , =?UTF-8?Q?Antoine_T=C3=A9nart?= , "linux-arm-msm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Linux USB List , Greg Kroah-Hartman , Bjorn Andersson Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2063 Lines: 47 On Tue, Jul 28, 2015 at 10:12 PM, Peter Chen wrote: > >> > I was just doing some testing with USB on a Qualcomm SoC. >> > >> > I followed the instructions in the binding document: >> > Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt >> > >> > which has a compatible for "qcom,ci-hdrc", and is, in general, for >> > chipidea-based USB controllers. >> > >> > It says in the document that the property usb-phy is deprecated, and >> > to use phys and phy-names instead. However, the Qualcomm driver for >> > this still uses usb-phy. That driver is in: >> > drivers/usb/chipidea/ci_hdrc_msm.c >> >> Deprecated means it still exists in the wild and should be maintained, but don't >> use it for new dts files. >> > > But how the new SoC (for new dts) which still uses current USB PHY driver? That's fine to use, but I would encourage people not to. > Maybe we should not add additional description for this property, > it depends on which PHY driver (Generic PHY vs USB PHY) this controller > will use, if it uses a new PHY driver, it must use generic PHY framework, and will > use 'phy' and 'phy-names' corresponding. We're thinking about this the wrong way around. The driver should not determine the binding used. The binding should be independent of the driver used. Either we should make the generic phy subsystem have feature parity with usb-phy, or make the usb-phy drivers use the same generic phy binding. Long term, I think we want the former and need a way to subclass the generic phy. Other phys have similar needs for additional protocol specific functions (e.g. configure the # of lanes for PCIe). The generic phy subsystem needs some love in my brief experience with it. For the latter case, this would make switching which phy driver is used transparent to DT. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/