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 DCC57C43381 for ; Thu, 21 Feb 2019 08:22:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD11E20818 for ; Thu, 21 Feb 2019 08:22:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727465AbfBUIWv (ORCPT ); Thu, 21 Feb 2019 03:22:51 -0500 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:39241 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726075AbfBUIWu (ORCPT ); Thu, 21 Feb 2019 03:22:50 -0500 X-Originating-IP: 90.88.23.190 Received: from aptenodytes (aaubervilliers-681-1-81-190.w90-88.abo.wanadoo.fr [90.88.23.190]) (Authenticated sender: paul.kocialkowski@bootlin.com) by relay6-d.mail.gandi.net (Postfix) with ESMTPSA id CC31CC000C; Thu, 21 Feb 2019 08:22:47 +0000 (UTC) Message-ID: <3ed330798d31d01fdfbd40571d016a108c9c5040.camel@bootlin.com> 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: Thu, 21 Feb 2019 09:22:47 +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 Thu, 2019-02-21 at 03:29 +0000, Peter Chen wrote: > > > 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. > > > > If there is a generic PHY node under USB controller, and there is a USB PHY > at other sides, both ci->phy and ci->usb_phy are valid, I original thought it is > the problem you met. Right, this is not the problem we are having. The problem is that legacy USB PHYs are not grabbed from device-tree. Instead, they are currently matched with their type in the list of registered USB PHYs, making it impossible to use 2 distinct USB PHYs this way. > Since you are trying to fix the legacy USB PHY grab issue, I hope you could consider > the generic PHY as well. What do you have in mind about generic PHYs? Everything already works as expected with them. Cheers, Paul > > 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://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbootlin.com > > &data=02%7C01%7Cpeter.chen%40nxp.com%7Cadca65357daa4fe678dc08d > > 6957b9c49%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6368607554 > > 66805805&sdata=c%2FdLqUhFxe1yz7lrqUoXZCvINiq1rdKJmMAuaH6Fr1k%3 > > D&reserved=0 -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com