linux-kernel - [PATCH review for 4.4 28/47] usb: chipidea: vbus event may exist before starting gadget

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Message-ID: <20170920044445.7392-28-alexander.levin@verizon.com>
Date:   Wed, 20 Sep 2017 04:45:06 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Peter Chen <peter.chen@....com>,
        "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
Subject: [PATCH review for 4.4 28/47] usb: chipidea: vbus event may exist
 before starting gadget

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>
---
 drivers/usb/chipidea/otg.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
index 0cf149edddd8..f36a1ac3bfbd 100644
--- a/drivers/usb/chipidea/otg.c
+++ b/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);
 	}
 }
 /**
-- 
2.11.0