From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753229AbaEHHaD (ORCPT ); Thu, 8 May 2014 03:30:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12331 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751552AbaEHHaA (ORCPT ); Thu, 8 May 2014 03:30:00 -0400 Message-ID: <536B324C.1040806@redhat.com> Date: Thu, 08 May 2014 09:29:16 +0200 From: Hans de Goede User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Maxime Ripard , Alan Stern CC: Emilio Lopez , Mike Turquette , kishon@ti.com, Boris Brezillon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-usb@vger.kernel.org, kevin.z.m.zh@gmail.com, sunny@allwinnertech.com, shuge@allwinnertech.com, zhuzhenhua@allwinnertech.com, linux-sunxi@googlegroups.com, Boris BREZILLON Subject: Re: [PATCH 4/7] usb: ehci-platform: add optional reset controller retrieval References: <1399434623-20383-5-git-send-email-maxime.ripard@free-electrons.com> <20140507220049.GC7047@lukather> In-Reply-To: <20140507220049.GC7047@lukather> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 05/08/2014 12:00 AM, Maxime Ripard wrote: > On Wed, May 07, 2014 at 10:25:55AM -0400, Alan Stern wrote: >> On Tue, 6 May 2014, Maxime Ripard wrote: >> >>> From: Boris BREZILLON >>> >>> On the Allwinner's A31 SoC the reset line connected to the EHCI IP has to >>> be deasserted for the EHCI block to be usable. >>> >>> Add support for an optional reset controller that will be deasserted on >>> power off and asserted on power on. >>> >>> Signed-off-by: Boris BREZILLON >>> Signed-off-by: Maxime Ripard >> >> Is this really a _reset_ line? That is, when you assert the reset >> line, does it actually reset the EHCI controller, or does it merely >> leave the controller in a partially powered-down state? > > It actually resets the whole controller. > >> The difference is important. During suspend, the controller is >> supposed to remember the state of the port connections as well as other >> settings. If it doesn't, the controller and all attached USB devices >> will have to be reinitialized every time the controller resumes, which >> will increase the latency. > > So you're saying that we should move this to the probe then? Yes. Regards, Hans