Re: [PATCH v4 6/7] phy: exynos5-usbdrd: subscribe to orientation notifier if required

From: William McVicker <willmcvicker@google.com>
To: "André Draszik" <andre.draszik@linaro.org>
Cc: Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Sylwester Nawrocki <s.nawrocki@samsung.com>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Peter Griffin <peter.griffin@linaro.org>,
	Tudor Ambarus <tudor.ambarus@linaro.org>,
	Sam Protsenko <semen.protsenko@linaro.org>,
	Roy Luo <royluo@google.com>,
	kernel-team@android.com, linux-phy@lists.infradead.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org
Subject: Re: [PATCH v4 6/7] phy: exynos5-usbdrd: subscribe to orientation notifier if required
Date: Thu, 26 Dec 2024 09:33:29 -0800	[thread overview]
Message-ID: <Z22TaVlsIiMw6jwk@google.com> (raw)
In-Reply-To: <20241206-gs101-phy-lanes-orientation-phy-v4-6-f5961268b149@linaro.org>

On 12/06/2024, André Draszik wrote:
> gs101's SS phy needs to be configured differently based on the
> connector orientation, as the SS link can only be established if the
> mux is configured correctly.
> 
> The code to handle programming of the mux is in place already, this commit
> now adds the missing pieces to subscribe to the Type-C orientation
> switch event.
> 
> Note that for this all to work we rely on the USB controller
> re-initialising us. It should invoke our .exit() upon cable unplug, and
> during cable plug we'll receive the orientation event after which we
> expect our .init() to be called.
> 
> Above reinitialisation happens if the DWC3 controller can enter runtime
> suspend automatically. For the DWC3 driver, this is an opt-in:
>     echo auto > /sys/devices/.../11110000.usb/power/control
> Once done, things work as long as the UDC is not bound as otherwise it
> stays busy because it doesn't cancel / stop outstanding TRBs. For now
> we have to manually unbind the UDC in that case:
>      echo "" > sys/kernel/config/usb_gadget/.../UDC
> 
> Note that if the orientation-switch property is missing from the DT,
> the code will behave as before this commit (meaning for gs101 it will
> work in SS mode in one orientation only). Other platforms are not
> affected either way.
> 
> Signed-off-by: André Draszik <andre.draszik@linaro.org>

Verified on my Pixel 6 Pro.

Tested-by: Will McVicker <willmcvicker@google.com>

Thanks,
Will

<snip>

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