[PATCH 3/5] usb: dwc2: hcd: fix possible successive vbus supply enables

[Fabrice Gasnier]

External VBUS supply may have already been enabled, before entering
dwc2_hcd_reinit (e.g. the controller is in host mode, without any device
plugged).
This results in vbus enable count to increase every time this occurs.
As consequence, dwc2_vbus_supply_exit won't disable vbus upon suspend
request.
Fix this by reading PWR bit before and after dwc2_hcd_reinit() call.

Fixes: cd7cd0e6cedf ("usb: dwc2: fix unbalanced use of external vbus-supply")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
---
 drivers/usb/dwc2/hcd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index cd0dc876b421..4ab058e6ef9a 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -4264,9 +4264,11 @@ static int _dwc2_hcd_start(struct usb_hcd *hcd)
 		return 0;	/* why 0 ?? */
 	}
 
+	hprt0 = dwc2_read_hprt0(hsotg);
+
 	dwc2_hcd_reinit(hsotg);
 
-	hprt0 = dwc2_read_hprt0(hsotg);
+	hprt0 ^= dwc2_read_hprt0(hsotg);
 	/* Has vbus power been turned on in dwc2_core_host_init ? */
 	if (hprt0 & HPRT0_PWR) {
 		/* Enable external vbus supply before resuming root hub */

-- 
2.43.0