usb: refine phy notify operation during connection and disconnection

At commit 925aa46ba9, Richard Zhao
<richard.zhao@freescale.com> adds the phy notification callback
when port change occurs. In fact, this phy notification should
be added according to below rules:

1. Only set HW_USBPHY_CTRL.ENHOSTDISCONDETECT
during high speed host mode.
2. Do not set HW_USBPHY_CTRL.ENHOSTDISCONDETECT
during the reset and speed negotiation period.
3. Do not set HW_USBPHY_CTRL.ENHOSTDISCONDETECT
during host suspend/resume sequence.

Please refer: i.mx23RM(page: 413) for below rules.
http://www.freescale.com/files/dsp/doc/ref_manual/IMX23RM.pdf

Freescale i.MX SoC, i.mx23, i.mx28 and i.mx6(i.mx6SL does not
need to follow the 3rd rule) need to follow above rules.

Current code set connect notification (HW_USBPHY_CTRL.ENHOSTDISCONDETECT)
at hub_port_connect_change, it conflicts with above the 2th rule.

The correct notification setting method should be:
1. Set connect notify after the second bus reset.
2. Set disconnect notify after disconnection.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Tested-by: Mike Thompson <mpthompson@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -4038,6 +4038,9 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 	if (retval)
 		goto fail;
 
+	if (hcd->phy && !hdev->parent)
+		usb_phy_notify_connect(hcd->phy, port1);
+
 	/*
 	 * Some superspeed devices have finished the link training process
 	 * and attached to a superspeed hub port, but the device descriptor
@@ -4232,8 +4235,12 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 	}
 
 	/* Disconnect any existing devices under this port */
-	if (udev)
+	if (udev) {
+		if (hcd->phy && !hdev->parent &&
+				!(portstatus & USB_PORT_STAT_CONNECTION))
+			usb_phy_notify_disconnect(hcd->phy, port1);
 		usb_disconnect(&hub->ports[port1 - 1]->child);
+	}
 	clear_bit(port1, hub->change_bits);
 
 	/* We can forget about a "removed" device when there's a physical
@@ -4256,13 +4263,6 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 		}
 	}
 
-	if (hcd->phy && !hdev->parent) {
-		if (portstatus & USB_PORT_STAT_CONNECTION)
-			usb_phy_notify_connect(hcd->phy, port1);
-		else
-			usb_phy_notify_disconnect(hcd->phy, port1);
-	}
-
 	/* Return now if debouncing failed or nothing is connected or
 	 * the device was "removed".
 	 */