usb: chipidea: vbus event may exist before starting gadget

BugLink: http://bugs.launchpad.net/bugs/1724772

[ Upstream commit c3b674a0 ]

At some situations, the vbus may already be there before starting
gadget. So we need to check vbus event after switching to gadget in
order to handle missing vbus event. The typical use cases are plugging
vbus cable before driver load or the vbus has already been there
after stopping host but before starting gadget.
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Tested-by: Stephen Boyd <stephen.boyd@linaro.org>
Reported-by: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/usb/chipidea/otg.c

@@ -134,9 +134,9 @@ void ci_handle_vbus_change(struct ci_hdrc *ci)
 	if (!ci->is_otg)
 		return;
 
-	if (hw_read_otgsc(ci, OTGSC_BSV))
+	if (hw_read_otgsc(ci, OTGSC_BSV) && !ci->vbus_active)
 		usb_gadget_vbus_connect(&ci->gadget);
-	else
+	else if (!hw_read_otgsc(ci, OTGSC_BSV) && ci->vbus_active)
 		usb_gadget_vbus_disconnect(&ci->gadget);
 }
 
@@ -175,14 +175,21 @@ static void ci_handle_id_switch(struct ci_hdrc *ci)
 
 		ci_role_stop(ci);
 
-		if (role == CI_ROLE_GADGET)
+		if (role == CI_ROLE_GADGET &&
+				IS_ERR(ci->platdata->vbus_extcon.edev))
 			/*
-			 * wait vbus lower than OTGSC_BSV before connecting
-			 * to host
+			 * Wait vbus lower than OTGSC_BSV before connecting
+			 * to host. If connecting status is from an external
+			 * connector instead of register, we don't need to
+			 * care vbus on the board, since it will not affect
+			 * external connector status.
 			 */
 			hw_wait_vbus_lower_bsv(ci);
 
 		ci_role_start(ci, role);
+		/* vbus change may have already occurred */
+		if (role == CI_ROLE_GADGET)
+			ci_handle_vbus_change(ci);
 	}
 }
 /**