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From: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
To: Stephen Boyd <swboyd@chromium.org>,
	balbi@kernel.org, gregkh@linuxfoundation.org,
	linux-usb@vger.kernel.org
Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	bjorn.andersson@linaro.org, jackp@codeaurora.org,
	robh@kernel.org, Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org
Subject: Re: [PATCH 2/7] dt-bindings: usb: dwc3: Add a gpio-usb-connector example
Date: Thu, 19 Mar 2020 15:22:14 +0000	[thread overview]
Message-ID: <aa6aa234-e2d1-bdcd-0f0e-64b2a7e497d3@linaro.org> (raw)
In-Reply-To: <158458013177.152100.17920784952083533825@swboyd.mtv.corp.google.com>

On 19/03/2020 01:08, Stephen Boyd wrote:
> Quoting Bryan O'Donoghue (2020-03-11 12:14:56)
>> A USB connector should be a child node of the USB controller
>> connector/usb-connector.txt. This patch adds an example of how to do this
>> to the dwc3 binding descriptions.
> 
> I read that as a child of the USB interface controller, which is not the
> same as the USB controller. For example, we're talking about having the
> usb connector be a child of the EC on ChromeOS devices because that
> manages the connector
> 
>>
>> It is necessary to declare a connector as a child-node of a USB controller
>> for role-switching to work, so this example should be helpful to others
>> implementing that.
> 
> Maybe it should be a virtual node at the root of the DT if it's GPIO
> controlled? And then the phy can be connected to the usb connector
> through the graph binding.

Graph binding can probably work.

Re: the PHY.

For myself the hardware model is

Connector -> PHY -> Host controller -> Host controller wrapper

Only

Connector -> Host controller -> Host controller wrapper

care about the USB role though.

If your PHY did care about the role, you'd really need to write a 
connector/phy type-c type driver, to detect the state and toggle your 
PHY bits before doing usb_role_switch_set_role() back to DWC3.

At least that's my understanding.

---
bod

  reply	other threads:[~2020-03-19 15:21 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 19:14 [PATCH 0/7] DWC3/Qualcomm connector based role-switching Bryan O'Donoghue
2020-03-11 19:14 ` [PATCH 1/7] usb: dwc3: Registering a role switch in the DRD code Bryan O'Donoghue
2020-03-11 19:14 ` [PATCH 2/7] dt-bindings: usb: dwc3: Add a gpio-usb-connector example Bryan O'Donoghue
2020-03-19  1:08   ` Stephen Boyd
2020-03-19 15:22     ` Bryan O'Donoghue [this message]
2020-03-19 16:40       ` Stephen Boyd
2020-03-19 18:03         ` Bryan O'Donoghue
2020-03-19 20:30           ` Stephen Boyd
2020-03-11 19:14 ` [PATCH 3/7] dt-bindings: usb: dwc3: Add a usb-role-switch to the example Bryan O'Donoghue
2020-03-11 19:14 ` [PATCH 4/7] usb: dwc3: qcom: Add support for usb-conn-gpio connectors Bryan O'Donoghue
2020-03-11 19:14 ` [PATCH 5/7] usb: dwc3: " Bryan O'Donoghue
2020-03-11 19:15 ` [PATCH 6/7] usb: dwc3: Add support for a role-switch notifier Bryan O'Donoghue
2020-07-23  8:13   ` Vincent Whitchurch
2020-03-11 19:15 ` [PATCH 7/7] usb: dwc3: qcom: Enable gpio-usb-conn based role-switching Bryan O'Donoghue
2020-03-17  6:31   ` Bjorn Andersson
2020-03-17 15:22     ` Bryan O'Donoghue

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