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 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 BB4FCC43381 for ; Mon, 18 Feb 2019 08:32:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 914A12184E for ; Mon, 18 Feb 2019 08:32:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729292AbfBRIca (ORCPT ); Mon, 18 Feb 2019 03:32:30 -0500 Received: from relay2-d.mail.gandi.net ([217.70.183.194]:43249 "EHLO relay2-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728342AbfBRIc3 (ORCPT ); Mon, 18 Feb 2019 03:32:29 -0500 X-Originating-IP: 90.88.30.68 Received: from aptenodytes (aaubervilliers-681-1-89-68.w90-88.abo.wanadoo.fr [90.88.30.68]) (Authenticated sender: paul.kocialkowski@bootlin.com) by relay2-d.mail.gandi.net (Postfix) with ESMTPSA id 1DE9340005; Mon, 18 Feb 2019 08:32:23 +0000 (UTC) Message-ID: Subject: Re: [PATCH v3] usb: chipidea: Grab the (legacy) USB PHY by phandle first From: Paul Kocialkowski To: Peter Chen , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" Cc: Greg Kroah-Hartman , Thomas Petazzoni Date: Mon, 18 Feb 2019 09:32:23 +0100 In-Reply-To: References: <20190215162225.19284-1-paul.kocialkowski@bootlin.com> Organization: Bootlin Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5 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 Mon, 2019-02-18 at 03:04 +0000, Peter Chen 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 one USB PHY is registered, since 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 are rather matched by their "phys-name" 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 > > --- > > Changes since v2: > > * Fixed typos in commit message. > > > > Changes since v1: > > * Only consider legacy USB PHY error for fallback as suggested; > > * Checked against EPROBE_DEFER before entering fallback. > > > > drivers/usb/chipidea/core.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c index > > 7bfcbb23c2a4..016e4004fe9d 100644 > > --- a/drivers/usb/chipidea/core.c > > +++ b/drivers/usb/chipidea/core.c > > @@ -954,8 +954,15 @@ 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); > > + > > + /* Fallback to grabbing any registered USB2 PHY */ > > + if (IS_ERR(ci->usb_phy) && > > + PTR_ERR(ci->usb_phy) != -EPROBE_DEFER) > > + ci->usb_phy = devm_usb_get_phy(dev->parent, > > + USB_PHY_TYPE_USB2); > > > > I think you may need to do above if ci->phy is error, and not the error is -EPROBE_DEFER. As Thomas pointed out during the review of v1, the initial flow is to try and get both ci->usb_phy and ci->phy and let the code use ci->phy in priority later. This change attempts to keep this flow intact. The EPROBE_DEFER check is in case the initial ci->usb_phy is valid but deferred: we don't want to overwrite it by calling devm_usb_get_phy which might return an actual error and result in losing the EPROBE_DEFER information. Does that make sense to you? Cheers, Paul > Peter > > > /* if both generic PHY and USB PHY layers aren't enabled */ > > if (PTR_ERR(ci->phy) == -ENOSYS && > > -- > > 2.20.1 -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com