linux-kernel - [PATCH] usb: dwc2: drd: fix inconsistent mode if role-switch-default-mode="host"

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Message-ID: <SG2PR01MB2048C724CE08E7E3D6719C75C9A49@SG2PR01MB2048.apcprd01.prod.exchangelabs.com>
Date:   Tue, 21 Feb 2023 02:05:35 +0800
From:   hzy <hzyitc@...look.com>
To:     hminas@...opsys.com
Cc:     gregkh@...uxfoundation.org, fabrice.gasnier@...s.st.com,
        amelie.delaunay@...s.st.com, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, hzy <hzyitc@...look.com>
Subject: [PATCH] usb: dwc2: drd: fix inconsistent mode if role-switch-default-mode="host"

Some boards might use USB-A female connector for USB ports, however,
the port could be connected to a dual-mode USB controller, making it
also behaves as a peripheral device if male-to-male cable is connected.

In this case, the dts looks like this:

	&usb0 {
		status = "okay";
		dr_mode = "otg";
		usb-role-switch;
		role-switch-default-mode = "host";
	};

After boot, dwc2_ovr_init() sets GOTGCTL to GOTGCTL_AVALOVAL and call
dwc2_force_mode() with parameter host=false, which causes inconsistent
mode - The hardware is in peripheral mode while the kernel status is
in host mode.

What we can do now is to call dwc2_drd_role_sw_set() to switch to
device mode, and everything should work just fine now, even switching
back to none(default) mode afterwards.

Fixes: e14acb876985 ("usb: dwc2: drd: add role-switch-default-node support")
Signed-off-by: hzy <hzyitc@...look.com>
---
 drivers/usb/dwc2/drd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index d8d6493bc457..a8605b02115b 100644
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -35,7 +35,8 @@ static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)

 	spin_unlock_irqrestore(&hsotg->lock, flags);

-	dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST));
+	dwc2_force_mode(hsotg, (hsotg->dr_mode == USB_DR_MODE_HOST) ||
+				(hsotg->role_sw_default_mode == USB_DR_MODE_HOST));
 }

 static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
-- 
2.34.1