linux-kernel - [PATCH 1/1] usb: dwc3: Do not get extcon device when usb-role-switch is used

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Message-Id: <20221106214804.2814-1-j@jannau.net>
Date:   Sun,  6 Nov 2022 22:48:04 +0100
From:   Janne Grunau <j@...nau.net>
To:     linux-usb@...r.kernel.org
Cc:     Sven Peter <sven@...npeter.de>, stable@...nel.org,
        Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrey Smirnov <andrew.smirnov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/1] usb: dwc3: Do not get extcon device when usb-role-switch is used

The change breaks device tree based platforms with PHY device and use
usb-role-switch instead of an extcon switch. extcon_find_edev_by_node()
will return EPROBE_DEFER if it can not find a device so probing without
an extcon device will be deferred indefinitely. Fix this by
explicitly checking for usb-role-switch.
At least the out-of-tree USB3 support on Apple silicon based platforms
using dwc3 with tipd USB Type-C and PD controller is affected by this
issue.

Fixes: d182c2e1bc92 ("usb: dwc3: Don't switch OTG -> peripheral if extcon is present")
Cc: stable@...nel.org
Signed-off-by: Janne Grunau <j@...nau.net>
---
 drivers/usb/dwc3/core.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index c0e7c76dc5c8..1f348bc867c2 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1710,6 +1710,16 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
 	if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
 		return extcon_get_extcon_dev(name);
 
+	/*
+	 * Check explicitly if "usb-role-switch" is used since
+	 * extcon_find_edev_by_node() can not be used to check the absence of
+	 * an extcon device. In the absence of an device it will always return
+	 * EPROBE_DEFER.
+	 */
+	if (IS_ENABLED(CONFIG_USB_ROLE_SWITCH) &&
+	    device_property_read_bool(dev, "usb-role-switch"))
+		return NULL;
+
 	/*
 	 * Try to get an extcon device from the USB PHY controller's "port"
 	 * node. Check if it has the "port" node first, to avoid printing the
-- 
2.37.3