From: Ramneek Mehresh <ramneek.mehresh@freescale.com>
To: <linux-kernel@vger.kernel.org>
CC: <balbi@ti.com>, <stern@rowland.harvard.edu>, <gregkh@linuxfoundation.org>,
        <linux-usb@vger.kernel.org>,
        Ramneek Mehresh <ramneek.mehresh@freescale.com>
Subject: [PATCH 7/7][v5]usb:fsl:otg: Add host-gadget drv sync delay
Date: Mon, 28 Dec 2015 16:42:34 +0530
Message-ID: <1451301154-14422-8-git-send-email-ramneek.mehresh@freescale.com>
In-Reply-To: <1451301154-14422-1-git-send-email-ramneek.mehresh@freescale.com>
References: <1451301154-14422-1-git-send-email-ramneek.mehresh@freescale.com>
MIME-Version: 1.0
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Dec 2015 10:55:40.5487
 (UTC)
X-MS-Exchange-CrossTenant-Id: 710a03f5-10f6-4d38-9ff4-a80b81da590d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=710a03f5-10f6-4d38-9ff4-a80b81da590d;Ip=[192.88.158.2];Helo=[az84smr01.freescale.net]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR0301MB1580
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1542
Lines: 43

Resolve synchronization issue between host
and gadget drivers upon role-reversal.

Signed-off-by: Ramneek Mehresh <ramneek.mehresh@freescale.com>
Reviewed-by: Li Yang-R58472 <LeoLi@freescale.com>
Reviewed-by: Fleming Andrew-AFLEMING <AFLEMING@freescale.com>
Tested-by: Fleming Andrew-AFLEMING <AFLEMING@freescale.com>
---
 drivers/usb/phy/phy-fsl-usb.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/phy/phy-fsl-usb.c b/drivers/usb/phy/phy-fsl-usb.c
index 689516d..5d678ea 100644
--- a/drivers/usb/phy/phy-fsl-usb.c
+++ b/drivers/usb/phy/phy-fsl-usb.c
@@ -544,8 +544,18 @@ int fsl_otg_start_gadget(struct otg_fsm *fsm, int on)
 	dev = otg->gadget->dev.parent;
 
 	if (on) {
-		if (dev->driver->resume)
+		/*
+		 * Delay gadget resume to synchronize between host and gadget
+		 * drivers. Upon role-reversal host drv is shutdown by kernel
+		 * worker thread. By the time host drv shuts down, controller
+		 * gets programmed for gadget role. Shutting host drv after
+		 * this results in controller getting reset, and it stops
+		 * responding to otg events
+		 */
+		if (dev->driver->resume) {
+			msleep(1000);
 			dev->driver->resume(dev);
+		}
 	} else {
 		if (dev->driver->suspend)
 			dev->driver->suspend(dev, otg_suspend_state);
-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/