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[188.141.3.169]) by smtp.gmail.com with ESMTPSA id o34sm6172398wms.10.2021.08.25.10.57.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 25 Aug 2021 10:57:49 -0700 (PDT) Subject: Re: [PATCH 0/3] Implement role-switch notifications from dwc3-drd to dwc3-qcom To: Bjorn Andersson Cc: Felipe Balbi , Heikki Krogerus , Peter Chen , Rob Herring , agross@kernel.org, gregkh@linuxfoundation.org, jackp@codeaurora.org, wcheng@codeaurora.org, linux-usb@vger.kernel.org, linux-arm-msm@vger.kernel.org, Dmitry Baryshkov References: <20210704013314.200951-1-bryan.odonoghue@linaro.org> <20210707015704.GA28125@nchen> <20210708030631.GA22420@nchen> <87zgt65avm.fsf@kernel.org> From: Bryan O'Donoghue Message-ID: <90d17c95-1cf3-89aa-94ad-920e4781f866@linaro.org> Date: Wed, 25 Aug 2021 18:59:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 Seems to me that the type-c mux way of diseminating to more than one place might fight role-switching well too.