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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 D6112C432BE for ; Wed, 25 Aug 2021 20:12:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B595B610C8 for ; Wed, 25 Aug 2021 20:12:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239003AbhHYUMz (ORCPT ); Wed, 25 Aug 2021 16:12:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237031AbhHYUMy (ORCPT ); Wed, 25 Aug 2021 16:12:54 -0400 Received: from mail-qk1-x72c.google.com (mail-qk1-x72c.google.com [IPv6:2607:f8b0:4864:20::72c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9195FC061757 for ; Wed, 25 Aug 2021 13:12:08 -0700 (PDT) Received: by mail-qk1-x72c.google.com with SMTP id 22so820558qkg.2 for ; Wed, 25 Aug 2021 13:12:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=vbP5UVTgmY2oS9CShjTY4KdaNELp9AGh568LVPRQ/jk=; b=RAjtwnACTWPvH7V/FtK/3NF3L+p0VuaFA4ON2soGuZMa791gAQoMQi/9tJ96yDeLQt yuZhqJRgsTnaZC+kFSyufkN3moBMPHP7mdVPJzbB4Wv9ATsAPcHkTuv3SmI3bHddewsz Ova2gkSoXbWPnsjc3k3ImYwM9PfUIAA0MQSSb+qCJUuihJm/6ei3rSAjRgaz3qaca9mz Ywge2QPkW5t14hwmBjUHqEugdmxGeaoZr5o66VXJ97iI/NxaODSOLJl+9dqrDGnbteEk 1GgJQQCU//QeWV0tpKfcau5T6MUwlCFnhFcge4OTpbwt60LQWydV8+XKXOplny8ngJ3k zd+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=vbP5UVTgmY2oS9CShjTY4KdaNELp9AGh568LVPRQ/jk=; b=QlFTxy45QnyV75aN3gPtfOps6EYPEm+cCDdhoRaQfY6I0E3gutNO+Ik/d723N4bHK8 POCuFyQytmH3WXSSLXvjL4ye46xKr/QHgttvvNJF5Q6+uP70riaAE22RsyPY3pZFPc63 A/muxhznDPYWBMkNSFy/nGQp09E0sM5UnsyZzqkI3OuI944Rf7e66zYAj9XJ0N+LZtvT wQZUxZtxy3WbXAUE69SxEe103q27pspZkGc8OcE1cIL66uIQ2lcTvr44ASaZyK6XIMVZ BgeVlEd9nBbjgRy1/Fs+6GV5/lJSQWxzpWOX+dT50y5xeoqqv1kMvjm6TrFutywIEsE7 XWcw== X-Gm-Message-State: AOAM532Z2P3sKQv1I/e1aCbihl/gq4n0SBLDYbPCNfwEahoFoUdk74IT jkrWNlh6jk0ZUOwNbXzWiUKfWK4ulJ2TlGelW0P2GJjjRe8= X-Google-Smtp-Source: ABdhPJw8T5T0B+womDxHAuRLjClmJiHJj/LY69irmQweQjoRskwL2b8WjDIO9jWvOSnVu8LVwn/Mx7z3OxWuiBhoTPI= X-Received: by 2002:a05:620a:1082:: with SMTP id g2mr341202qkk.138.1629922327665; Wed, 25 Aug 2021 13:12:07 -0700 (PDT) MIME-Version: 1.0 References: <20210704013314.200951-1-bryan.odonoghue@linaro.org> <20210707015704.GA28125@nchen> <20210708030631.GA22420@nchen> <87zgt65avm.fsf@kernel.org> <90d17c95-1cf3-89aa-94ad-920e4781f866@linaro.org> In-Reply-To: <90d17c95-1cf3-89aa-94ad-920e4781f866@linaro.org> From: Dmitry Baryshkov Date: Wed, 25 Aug 2021 23:11:54 +0300 Message-ID: Subject: Re: [PATCH 0/3] Implement role-switch notifications from dwc3-drd to dwc3-qcom To: "Bryan O'Donoghue" Cc: Bjorn Andersson , Felipe Balbi , Heikki Krogerus , Peter Chen , Rob Herring , Andy Gross , Greg Kroah-Hartman , Jack Pham , wcheng@codeaurora.org, linux-usb@vger.kernel.org, "open list:DRM DRIVER FOR MSM ADRENO GPU" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi, On Wed, 25 Aug 2021 at 20:57, Bryan O'Donoghue wrote: > > On 25/08/2021 16:53, Bjorn Andersson wrote: > > But in the case of Type-C altmode several of our boards have either an > > external gpio-based SBU-pin-swapper or some redriver on I2C with this > > functionality, so we need a way to tell both the PHY and this external > > contraption about the orientation. > > Its a very similar problem to orientation switch > > As an example > > - redriver may need to fix up signal integrity for > lane switching > > - PHY needs to toggle lanes from one IP block to another > > I don't think off the top of my head a USB controller or DPU cares much > about the orientation switch but for argument sake you could add one to > that list. > > I _think_ the type-c mux layer handles this though, as in what we did on > RB5 has PHY and redriver receiving and reacting to a type-c orientation > switch both with the existing type-c port driver and the new tcpm. > > + Dmitry - he did the mux work on the PHY and the redriver For the RB5 case I ended up with the redriver acting as a client for the type-c port orientation events, and then it would act as a source for the event being sent to the DP PHY. This chained approach is far from being ideal, but it allowed me to use the current framework without applying significant changes. I've had some ideas on how to improve the type-c framework, but I never had enough time to materialize them. > Seems to me that the type-c mux way of diseminating to more than one > place might fight role-switching well too. -- With best wishes Dmitry