From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0FE44C43387 for ; Thu, 17 Jan 2019 16:38:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA03620851 for ; Thu, 17 Jan 2019 16:38:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729022AbfAQQiW (ORCPT ); Thu, 17 Jan 2019 11:38:22 -0500 Received: from mail.bootlin.com ([62.4.15.54]:43756 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726854AbfAQQiW (ORCPT ); Thu, 17 Jan 2019 11:38:22 -0500 Received: by mail.bootlin.com (Postfix, from userid 110) id A3C09209EF; Thu, 17 Jan 2019 17:38:19 +0100 (CET) Received: from aptenodytes (aaubervilliers-681-1-37-87.w90-88.abo.wanadoo.fr [90.88.156.87]) by mail.bootlin.com (Postfix) with ESMTPSA id 6F1C120994; Thu, 17 Jan 2019 17:38:09 +0100 (CET) Message-ID: <1f8dcb9848a2da0eb87a0227913033d299d4e4a9.camel@bootlin.com> Subject: Re: [PATCH] usb: chipidea: Grab the (legacy) USB PHY by phandle first From: Paul Kocialkowski To: Peter Chen , Thomas Petazzoni Cc: "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Greg Kroah-Hartman Date: Thu, 17 Jan 2019 17:38:09 +0100 In-Reply-To: References: <20190116101051.21202-1-paul.kocialkowski@bootlin.com> <20190116115350.3daa9b4f@windsurf> <554a5b4f463df6551846cfdc3b043d3f1d99381f.camel@bootlin.com> <20190116144429.7df1d0c5@windsurf> Organization: Bootlin Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.4 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thu, 2019-01-17 at 06:44 +0000, Peter Chen wrote: > > > On Wed, 2019-01-16 at 14:44 +0100, Thomas Petazzoni wrote: > > > Well prior to your code, there was already a possibility for both > > > ci->phy and ci->usb_phy to be valid. I don't think it's really useful > > > to avoid the fallback when a generic PHY has already been found, it's > > > confusing. If really you want to clarify that, it should be: > > > > > > /* Let's first try to find a generic PHY */ > > > ci->phy = devm_phy_get(dev->parent, "usb-phy"); > > > if (IS_ERR(ci->phy)) { > > Please consider -EPROBE_DEFER case > > > > /* Fall back to legacy USB PHY */ > > > ci->usb_phy = devm_usb_get_phy_by_phandle(dev->parent, "phys", > > 0); > > Please consider -EPROBE_DEFER case > > > > if (IS_ERR(ci->usb_phy)) > > > ci->usb_phy = devm_usb_get_phy(dev->parent, > > USB_PHY_TYPE_USB2); > > > } > > > > > Below code > if (IS_ERR(ci->phy) && IS_ERR(ci->usb_phy)) { > ret = -EPROBE_DEFER; > goto ulpi_exit; > } > > needs to change as: > > if (PTR_ERR(ci->phy) ==-EPROBE_DEFER || PTR_ERR(ci->usb_phy) == -EPROBE_DEFER) { > ret = -EPROBE_DEFER; > goto ulpi_exit; > } Well I think this was more of a general outline than proper code to be included in the driver anyway :) I'm rather considering implementing what Thomas suggested at first, which is going for the fallback even if a generic PHY was found, as to stick more closely to the existing behavior. Cheers, Paul > Peter > > > > With that, you would only have either ci->phy or ci->usb_phy be valid, > > > and never both. With your change, you can have ci->phy and > > > ci->usb_phy both be valid if the legacy USB PHY was found using > > > devm_usb_get_phy_by_phandle(), but not if we fell back to > > > devm_usb_get_phy(). > > > > Okay that makes sense, your suggestion is indeed more consistent with the existing > > behavior. I'll go with that in the next revision! > > > > -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com