usb: gadget: composite: add USB_DT_OTG request handling

Copy usb_otg_descriptor from config's descriptor if host requests
USB_DT_OTG.

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

drivers/usb/gadget/composite.c

@@ -19,6 +19,7 @@
 #include <linux/utsname.h>
 
 #include <linux/usb/composite.h>
+#include <linux/usb/otg.h>
 #include <asm/unaligned.h>
 
 #include "u_os_desc.h"
@@ -1540,6 +1541,32 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 				value = min(w_length, (u16) value);
 			}
 			break;
+		case USB_DT_OTG:
+			if (gadget_is_otg(gadget)) {
+				struct usb_configuration *config;
+				int otg_desc_len = 0;
+
+				if (cdev->config)
+					config = cdev->config;
+				else
+					config = list_first_entry(
+							&cdev->configs,
+						struct usb_configuration, list);
+				if (!config)
+					goto done;
+
+				if (gadget->otg_caps &&
+					(gadget->otg_caps->otg_rev >= 0x0200))
+					otg_desc_len += sizeof(
+						struct usb_otg20_descriptor);
+				else
+					otg_desc_len += sizeof(
+						struct usb_otg_descriptor);
+
+				value = min_t(int, w_length, otg_desc_len);
+				memcpy(req->buf, config->descriptors[0], value);
+			}
+			break;
 		}
 		break;