usb: mtu3: fix error of xhci port id when enable U3 dual role

If dual role mode is enabled, when switch u3port0 to device mode,
it will affect port id calculation of host(xHCI), specially when
host supports multi U2 ports or U3 ports, so need enable its dual
role mode, and fix it here.
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/mtu3/mtu3_core.c

@@ -107,8 +107,12 @@ static int mtu3_device_enable(struct mtu3 *mtu)
 		(SSUSB_U2_PORT_DIS | SSUSB_U2_PORT_PDN |
 		SSUSB_U2_PORT_HOST_SEL));
 
-	if (mtu->ssusb->dr_mode == USB_DR_MODE_OTG)
+	if (mtu->ssusb->dr_mode == USB_DR_MODE_OTG) {
 		mtu3_setbits(ibase, SSUSB_U2_CTRL(0), SSUSB_U2_PORT_OTG_SEL);
+		if (mtu->is_u3_ip)
+			mtu3_setbits(ibase, SSUSB_U3_CTRL(0),
+				     SSUSB_U3_PORT_DUAL_MODE);
+	}
 
 	return ssusb_check_clocks(mtu->ssusb, check_clk);
 }

drivers/usb/mtu3/mtu3_hw_regs.h

@@ -459,6 +459,7 @@
 
 /* U3D_SSUSB_U3_CTRL_0P */
 #define SSUSB_U3_PORT_SSP_SPEED	BIT(9)
+#define SSUSB_U3_PORT_DUAL_MODE	BIT(7)
 #define SSUSB_U3_PORT_HOST_SEL		BIT(2)
 #define SSUSB_U3_PORT_PDN		BIT(1)
 #define SSUSB_U3_PORT_DIS		BIT(0)