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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 1BA16C43387 for ; Wed, 16 Jan 2019 10:54:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2C66206C2 for ; Wed, 16 Jan 2019 10:54:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404118AbfAPKyE (ORCPT ); Wed, 16 Jan 2019 05:54:04 -0500 Received: from mail.bootlin.com ([62.4.15.54]:54674 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731772AbfAPKyD (ORCPT ); Wed, 16 Jan 2019 05:54:03 -0500 Received: by mail.bootlin.com (Postfix, from userid 110) id BD945207B0; Wed, 16 Jan 2019 11:54:00 +0100 (CET) Received: from windsurf (aaubervilliers-681-1-37-87.w90-88.abo.wanadoo.fr [90.88.156.87]) by mail.bootlin.com (Postfix) with ESMTPSA id 7EE7F20758; Wed, 16 Jan 2019 11:53:50 +0100 (CET) Date: Wed, 16 Jan 2019 11:53:50 +0100 From: Thomas Petazzoni To: Paul Kocialkowski Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Chen , Greg Kroah-Hartman Subject: Re: [PATCH] usb: chipidea: Grab the (legacy) USB PHY by phandle first Message-ID: <20190116115350.3daa9b4f@windsurf> In-Reply-To: <20190116101051.21202-1-paul.kocialkowski@bootlin.com> References: <20190116101051.21202-1-paul.kocialkowski@bootlin.com> Organization: Bootlin X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Thanks for the patch! On Wed, 16 Jan 2019 11:10:51 +0100, Paul Kocialkowski wrote: > According to the chipidea driver bindings, the USB PHY is specified via > the "phys" phandle node. However, this only takes effect for USB PHYs > that use the common PHY framework. For legacy USB PHYs, a simple lookup > based on the USB PHY type is done instead. > > This does not play out well when more than USB PHY is registered, since "more than *one*" > the first registered PHY matching the type will always be returned > regardless of what the driver was bound to. > > Fix this by looking up the PHY based on the "phys" phandle node. > Although generic PHYS and rather matched by their "phys-name" I'm confused by "Although generic PHYS and rather matched". Perhaps s/and/are/ ? Also PHYS -> PHYs > and not > the "phys" phandle directly, there is no helper for similar lookup on > legacy PHYs and it's probably not worth the effort to add it. > > When no legacy USB PHY is found by phandle, fallback to grabbing any > registered USB2 PHY. This ensures backward compatibility if some users > were actually relying on this mechanism. > > Signed-off-by: Paul Kocialkowski > --- > drivers/usb/chipidea/core.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c > index 7bfcbb23c2a4..11d3ee1e3fe5 100644 > --- a/drivers/usb/chipidea/core.c > +++ b/drivers/usb/chipidea/core.c > @@ -954,8 +954,14 @@ static int ci_hdrc_probe(struct platform_device *pdev) > } else if (ci->platdata->usb_phy) { > ci->usb_phy = ci->platdata->usb_phy; > } else { > + ci->usb_phy = devm_usb_get_phy_by_phandle(dev->parent, "phys", > + 0); > ci->phy = devm_phy_get(dev->parent, "usb-phy"); > - ci->usb_phy = devm_usb_get_phy(dev->parent, USB_PHY_TYPE_USB2); I'm not sure why you change the order of legacy PHY lookup vs. generic PHY lookup. > + > + /* Fallback to grabbing any registered USB2 PHY */ > + if (IS_ERR(ci->phy) && IS_ERR(ci->usb_phy)) > + ci->usb_phy = devm_usb_get_phy(dev->parent, > + USB_PHY_TYPE_USB2); Why is this conditional on the generic PHY lookup failing? Don't we simply want: ci->phy = devm_phy_get(dev->parent, "usb-phy"); ci->usb_phy = devm_usb_get_phy_by_phandle(dev->parent, "phys", 0); if (IS_ERR(ci->usb_phy)) ci->usb_phy = devm_usb_get_phy(dev->parent, USB_PHY_TYPE_USB2); ? Does this needs a "Fixes:" tag ? It's not fixing a regression because nobody complained until now, but it's really fixing a behavior that wasn't correct. Best regards, Thomas -- Thomas Petazzoni, CTO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com