usb: otg: don't set a_alt_hnp_support feature for OTG 2.0 device

Since a_alt_hnp_support is obsolete in OTG 2.0, HNP capable host should
send this set feature request only if the otg device is connecting to a
non-HNP port and it's compliant with OTG 1.x revision. This is done by
checking its otg descriptor length, OTG 2.0 uses usb_otg20_descriptor
which has different length than OTG 1.x using usb_otg_descriptor.

Signed-off-by: Li Jun <jun.li@freescale.com>
Acked-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -2239,39 +2239,49 @@ static int usb_enumerate_device_otg(struct usb_device *udev)
 			&& udev->parent == udev->bus->root_hub) {
 		struct usb_otg_descriptor	*desc = NULL;
 		struct usb_bus			*bus = udev->bus;
+		unsigned			port1 = udev->portnum;
 
 		/* descriptor may appear anywhere in config */
-		if (__usb_get_extra_descriptor(udev->rawdescriptors[0],
-					le16_to_cpu(udev->config[0].desc.wTotalLength),
-					USB_DT_OTG, (void **) &desc) == 0) {
-			if (desc->bmAttributes & USB_OTG_HNP) {
-				unsigned		port1 = udev->portnum;
+		err = __usb_get_extra_descriptor(udev->rawdescriptors[0],
+				le16_to_cpu(udev->config[0].desc.wTotalLength),
+				USB_DT_OTG, (void **) &desc);
+		if (err || !(desc->bmAttributes & USB_OTG_HNP))
+			return 0;
 
-				dev_info(&udev->dev,
-					"Dual-Role OTG device on %sHNP port\n",
-					(port1 == bus->otg_port)
-						? "" : "non-");
-
-				/* enable HNP before suspend, it's simpler */
-				if (port1 == bus->otg_port)
-					bus->b_hnp_enable = 1;
-				err = usb_control_msg(udev,
-					usb_sndctrlpipe(udev, 0),
-					USB_REQ_SET_FEATURE, 0,
-					bus->b_hnp_enable
-						? USB_DEVICE_B_HNP_ENABLE
-						: USB_DEVICE_A_ALT_HNP_SUPPORT,
-					0, NULL, 0, USB_CTRL_SET_TIMEOUT);
-				if (err < 0) {
-					/* OTG MESSAGE: report errors here,
-					 * customize to match your product.
-					 */
-					dev_info(&udev->dev,
-						"can't set HNP mode: %d\n",
-						err);
-					bus->b_hnp_enable = 0;
-				}
+		dev_info(&udev->dev, "Dual-Role OTG device on %sHNP port\n",
+					(port1 == bus->otg_port) ? "" : "non-");
+
+		/* enable HNP before suspend, it's simpler */
+		if (port1 == bus->otg_port) {
+			bus->b_hnp_enable = 1;
+			err = usb_control_msg(udev,
+				usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE, 0,
+				USB_DEVICE_B_HNP_ENABLE,
+				0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+			if (err < 0) {
+				/*
+				 * OTG MESSAGE: report errors here,
+				 * customize to match your product.
+				 */
+				dev_err(&udev->dev, "can't set HNP mode: %d\n",
+									err);
+				bus->b_hnp_enable = 0;
 			}
+		} else if (desc->bLength == sizeof
+				(struct usb_otg_descriptor)) {
+			/* Set a_alt_hnp_support for legacy otg device */
+			err = usb_control_msg(udev,
+				usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE, 0,
+				USB_DEVICE_A_ALT_HNP_SUPPORT,
+				0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+			if (err < 0)
+				dev_err(&udev->dev,
+					"set a_alt_hnp_support failed: %d\n",
+					err);
 		}
 	}
 #endif