From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755483AbdC2J6j (ORCPT ); Wed, 29 Mar 2017 05:58:39 -0400 Received: from fllnx209.ext.ti.com ([198.47.19.16]:28614 "EHLO fllnx209.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755154AbdC2J6i (ORCPT ); Wed, 29 Mar 2017 05:58:38 -0400 Subject: Re: [PATCH v2 4/4] usb: dwc3: Workaround for super-speed host on dra7 in dual-role mode To: Felipe Balbi References: <1487250377-13653-1-git-send-email-rogerq@ti.com> <1487250377-13653-5-git-send-email-rogerq@ti.com> <87o9wlhd1j.fsf@linux.intel.com> CC: , , From: Roger Quadros Message-ID: Date: Wed, 29 Mar 2017 12:57:55 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <87o9wlhd1j.fsf@linux.intel.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/03/17 14:10, Felipe Balbi wrote: > > Hi, > > Roger Quadros writes: >> dra7 OTG core limits the host controller to USB2.0 (high-speed) mode >> when we're operating in dual-role. > > yeah, that's not a quirk. DRA7 supports OTGv2, not OTGv3. There was no > USB3 when OTGv2 was written. > > DRA7 just shouldn't use OTG core altogether. In fact, this is the very > thing I've been saying for a long time. Make the simplest implementation > possible. The dead simple, does-one-thing-only sort of implementation. > > All we need for Dual-Role (without OTG extras) is some input for ID and > VBUS, then we add/remove HCD/UDC conditionally and set PRTCAPDIR. > The catch is that on AM437x there is no way to get ID and VBUS events other than the OTG controller so we have to rely on the OTG controller for that. :( I agree on the simplicity part. Let's do what minimal is necessary first. cheers, -roger