usb: gadget: serial: allocate and init otg descriptor by otg capabilities

Allocate and initialize usb otg descriptor according to gadget otg
capabilities, add it for each usb configurations. If otg capability
is not defined, keep its original otg descriptor unchanged.

Reviewed-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Li Jun <jun.li@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/legacy/serial.c

@@ -79,20 +79,7 @@ static struct usb_device_descriptor device_desc = {
 	.bNumConfigurations =	1,
 };
 
-static struct usb_otg_descriptor otg_descriptor = {
-	.bLength =		sizeof otg_descriptor,
-	.bDescriptorType =	USB_DT_OTG,
-
-	/* REVISIT SRP-only hardware is possible, although
-	 * it would not be called "OTG" ...
-	 */
-	.bmAttributes =		USB_OTG_SRP | USB_OTG_HNP,
-};
-
-static const struct usb_descriptor_header *otg_desc[] = {
-	(struct usb_descriptor_header *) &otg_descriptor,
-	NULL,
-};
+static const struct usb_descriptor_header *otg_desc[2];
 
 /*-------------------------------------------------------------------------*/
 
@@ -191,6 +178,18 @@ static int gs_bind(struct usb_composite_dev *cdev)
 	serial_config_driver.iConfiguration = status;
 
 	if (gadget_is_otg(cdev->gadget)) {
+		if (!otg_desc[0]) {
+			struct usb_descriptor_header *usb_desc;
+
+			usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
+			if (!usb_desc) {
+				status = -ENOMEM;
+				goto fail;
+			}
+			usb_otg_descriptor_init(cdev->gadget, usb_desc);
+			otg_desc[0] = usb_desc;
+			otg_desc[1] = NULL;
+		}
 		serial_config_driver.descriptors = otg_desc;
 		serial_config_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 	}
@@ -208,13 +207,15 @@ static int gs_bind(struct usb_composite_dev *cdev)
 				"gser");
 	}
 	if (status < 0)
-		goto fail;
+		goto fail1;
 
 	usb_composite_overwrite_options(cdev, &coverwrite);
 	INFO(cdev, "%s\n", GS_VERSION_NAME);
 
 	return 0;
-
+fail1:
+	kfree(otg_desc[0]);
+	otg_desc[0] = NULL;
 fail:
 	return status;
 }
@@ -227,6 +228,10 @@ static int gs_unbind(struct usb_composite_dev *cdev)
 		usb_put_function(f_serial[i]);
 		usb_put_function_instance(fi_serial[i]);
 	}
+
+	kfree(otg_desc[0]);
+	otg_desc[0] = NULL;
+
 	return 0;
 }