linux-kernel - [PATCH 4.9 049/104] usb: chipidea: vbus event may exist before starting gadget

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Date:   Fri,  6 Oct 2017 10:51:27 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Peter Chen <peter.chen@....com>,
        Stephen Boyd <stephen.boyd@...aro.org>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.9 049/104] usb: chipidea: vbus event may exist before starting gadget

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Chen <peter.chen@....com>


[ Upstream commit c3b674a04b8ab62a1d35e86714d466af0a0ecc18 ]

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@....com>
Tested-by: Stephen Boyd <stephen.boyd@...aro.org>
Reported-by: Stephen Boyd <stephen.boyd@...aro.org>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/chipidea/otg.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

--- a/drivers/usb/chipidea/otg.c
+++ b/drivers/usb/chipidea/otg.c
@@ -134,9 +134,9 @@ void ci_handle_vbus_change(struct ci_hdr
 	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 c
 
 		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);
 	}
 }
 /**