Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753778AbbFAOwk (ORCPT ); Mon, 1 Jun 2015 10:52:40 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:33560 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752967AbbFAOw1 (ORCPT ); Mon, 1 Jun 2015 10:52:27 -0400 X-Listener-Flag: 11101 Message-ID: <1433170337.12128.18.camel@mtksdaap41> Subject: Re: [PATCH 3/6] xhci: probe phy before add usb_hcd From: Yingjoe Chen To: CC: , Mark Rutland , , Mathias Nyman , "Sascha Hauer" , , , Rob Herring , , Matthias Brugger , , "Maxime Ripard" Date: Mon, 1 Jun 2015 22:52:17 +0800 In-Reply-To: <20150527121843.GA8611@saruman.tx.rr.com> References: <1432727283-20303-1-git-send-email-chunfeng.yun@mediatek.com> <1432727283-20303-4-git-send-email-chunfeng.yun@mediatek.com> <20150527121843.GA8611@saruman.tx.rr.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1368 Lines: 39 On Wed, 2015-05-27 at 07:18 -0500, Felipe Balbi wrote: > On Wed, May 27, 2015 at 07:48:00PM +0800, chunfeng.yun@mediatek.com wrote: > > From: Chunfeng Yun > > > > find the phy driver before add primary usb_hcd to avoid acessing > > xHCI register which may hangup the system when the phy is not loaded > > yet and the related powers or clocks put in phy driver are not > > enabled. > > it seems like the same clock is needed by PHY and XHCI. This patch looks > incorrect. Hi, I agree that the driver should enable clock it used by itself and not depends on init order. This should be fixed. But in general, I think it make sense to only add hcd after all required resource are ready. At least it remove unnecessary calls to usb_add_hcd/usb_remove_hcd. Is it better if the commit message is changed to something like the below? Currently xhci_plat_probe() call usb_add_hcd before trying to init the phy. However if the phy is not ready at the moment, it have to remove the hcd and probe again later Change the init order so we only add hcd when all required resource are ready. Joe.C -- 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/