usb: mtu3: fix USB 3.0 dual-role-switch from device to host

Issue description:
  When an OTG port has been switched to device role and then switch back
  to host role again, the USB 3.0 Host (XHCI) will not be able to detect
  "plug in event of a connected USB 2.0/1.0 ((Highspeed and Fullspeed)
  devices until system reboot.

Root cause and Solution:
  There is a condition checking flag "ssusb->otg_switch.is_u3_drd" in
  toggle_opstate(). At the end of role switch procedure, toggle_opstate()
  will be called to set DC_SESSION and SOFT_CONN bit. If "is_u3_drd" was
  set and switched the role to USB host 3.0, bit DC_SESSION and SOFT_CONN
  will be skipped hence caused the port cannot detect connected USB 2.0
  (Highspeed and Fullspeed) devices. Simply remove the condition check to
  solve this issue.

Fixes: d0ed062a8b75 ("usb: mtu3: dual-role mode support")
Cc: stable@vger.kernel.org
Tested-by: Fabien Parent <fparent@baylibre.com>
Reviewed-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Signed-off-by: Tainping Fang <tianping.fang@mediatek.com>
Link: https://lore.kernel.org/r/20220419081245.21015-1-macpaul.lin@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/mtu3/mtu3_dr.c b/drivers/usb/mtu3/mtu3_dr.c
index a6b04831b20bf2943974f0bd54bfa5679e5d1ae0..9b8aded3d95e902e044b2dc1bf0bd9639a1e32c4 100644 (file)
--- a/drivers/usb/mtu3/mtu3_dr.c
+++ b/drivers/usb/mtu3/mtu3_dr.c
@@ -21,10 +21,8 @@ static inline struct ssusb_mtk *otg_sx_to_ssusb(struct otg_switch_mtk *otg_sx)
 
 static void toggle_opstate(struct ssusb_mtk *ssusb)
 {
-       if (!ssusb->otg_switch.is_u3_drd) {
-               mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
-               mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
-       }
+       mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
+       mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
 }
 
 /* only port0 supports dual-role mode */