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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 B6E0DC46460 for ; Wed, 15 Aug 2018 11:23:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 71F43215B2 for ; Wed, 15 Aug 2018 11:23:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 71F43215B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sntech.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729134AbeHOOO2 (ORCPT ); Wed, 15 Aug 2018 10:14:28 -0400 Received: from gloria.sntech.de ([185.11.138.130]:57720 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727141AbeHOOO1 (ORCPT ); Wed, 15 Aug 2018 10:14:27 -0400 Received: from wd0180.dip.tu-dresden.de ([141.76.108.180] helo=phil.localnet) by gloria.sntech.de with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1fptsq-0003pG-GY; Wed, 15 Aug 2018 13:22:36 +0200 From: Heiko Stuebner To: Enric Balletbo i Serra Cc: linux-kernel@vger.kernel.org, amstan@chromium.org, groeck@google.com, kieran.bingham@ideasonboard.com, kernel@collabora.com, bleung@chromium.org, devicetree@vger.kernel.org, Frank Wang , linux-rockchip@lists.infradead.org, Rob Herring , Kishon Vijay Abraham I , Mark Rutland , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/4] dt-bindings: phy-rockchip-inno-usb2: add documentation for extcon and utmi-avalid properties. Date: Wed, 15 Aug 2018 13:22:35 +0200 Message-ID: <4665926.GcjFtTh8TS@phil> In-Reply-To: <37512ec9-8d9a-6c0c-8808-6351b8501002@collabora.com> References: <20180815095934.11205-1-enric.balletbo@collabora.com> <2023816.cqyDmH3see@phil> <37512ec9-8d9a-6c0c-8808-6351b8501002@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Enric, Am Mittwoch, 15. August 2018, 13:08:00 CEST schrieb Enric Balletbo i Serra: > On 15/08/18 12:29, Heiko Stuebner wrote: > > Am Mittwoch, 15. August 2018, 11:59:32 CEST schrieb Enric Balletbo i Serra: > >> Commit 98898f3bc83c8 ("phy: rockchip-inno-usb2: support otg-port for > >> rk3399") introduces two new properties. The extcon property is used to > >> detect the cable-state, and the rockchip,utmi-avalid is used to indicate > >> which register should be used to detect the vbus state. > >> > >> Document these properties in the documentation binding. > >> > >> Fixes: 98898f3bc83c8 ("phy: rockchip-inno-usb2: support otg-port for rk3399") > >> Signed-off-by: Enric Balletbo i Serra [...] > >> @@ -45,6 +46,8 @@ Required properties (port (child) node): > >> Optional properties: > >> - phy-supply : phandle to a regulator that provides power to VBUS. > >> See ./phy-bindings.txt for details. > >> + - rockchip,utmi-avalid : boolean, use the avalid register to get vbus status. > >> + Otherwise, use the bvalid register. > > > > Not having looked to deeply into the usb2 phy, this might raise questions > > on why this is a hardware-description? Is this needed when something is not > > connected on the board? > > I asked myself the same question and even I thought in just remove that code. > > After some investigation, though, I saw that the UTMI+ specification [1] has two > signals similar to ID signal (page 11), the AValid signal is used to indicate if > the session for an A-peripheral is valid and the BValid signal that is used to > indicate if the session for a B-peripheral is valid. I suppose that use of one > or the other matters in some cases, but AFAICT this is not used and I didn't see > any binding using it. > > Maybe someone else can give us more clues on the importance or not of this property? so I've looked in mainline, chromeos-4.4 and the Rockchip vendor-kernel and the only board using that property at all is the rk3399-evb-rev1 and -rev2 in the vendor kernel. The existence of a further -rev3 (which also looks way better cared for compared rev1+2) indicates that the older ones are probably some sort of preproduction models, where some wiring (on the soc or board) may have gone wrong. So while I would keep all the avalid settings in the driver, we could just drop reading that property quietly - as Rob wrote some days ago "it's only an incompatible change if someone notices" [0] and from the above it doesn't look like it ;-) . Heiko [0] https://www.spinics.net/lists/devicetree/msg243978.html