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Date:   Sat, 4 Nov 2023 13:43:28 +0100
From:   Stefan Eichenberger <eichest@gmail.com>
To:     Johan Hovold <johan+linaro@kernel.org>
Cc:     Mathias Nyman <mathias.nyman@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Maxime Ripard <mripard@kernel.org>,
        Stanley Chang <stanley_chang@realtek.com>
Subject: Re: [PATCH] USB: xhci-plat: fix legacy PHY double inity
Message-ID: <ZUY8cGrofUtPOMV8@eichest-laptop>
References: <20231103164323.14294-1-johan+linaro@kernel.org>
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On Fri, Nov 03, 2023 at 05:43:23PM +0100, Johan Hovold wrote:
> Commits 7b8ef22ea547 ("usb: xhci: plat: Add USB phy support") and
> 9134c1fd0503 ("usb: xhci: plat: Add USB 3.0 phy support") added support
> for looking up legacy PHYs from the sysdev devicetree node and
> initialising them.
> 
> This broke drivers such as dwc3 which manages PHYs themself as the PHYs
> would now be initialised twice, something which specifically can lead to
> resources being left enabled during suspend (e.g. with the
> usb_phy_generic PHY driver).
> 
> As the dwc3 driver uses driver-name matching for the xhci platform
> device, fix this by only looking up and initialising PHYs for devices
> that have been matched using OF.
> 
> Note that checking that the platform device has a devicetree node would
> currently be sufficient, but that could lead to subtle breakages in case
> anyone ever tries to reuse an ancestor's node.
> 
> Fixes: 7b8ef22ea547 ("usb: xhci: plat: Add USB phy support")
> Fixes: 9134c1fd0503 ("usb: xhci: plat: Add USB 3.0 phy support")
> Cc: stable@vger.kernel.org      # 4.1
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Stanley Chang <stanley_chang@realtek.com>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>

Tested-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>