Add media keys USB descriptors

teensy3/usb_desc.c

         0x29, 0xE7,             //  Usage Maximum (231),
         0x15, 0x00,             //  Logical Minimum (0),
         0x25, 0x01,             //  Logical Maximum (1),
-        0x81, 0x02,             //  Input (Data, Variable, Absolute), ;Modifier byte
+        0x81, 0x02,             //  Input (Data, Variable, Absolute), ;Modifier keys
         0x95, 0x08,             //  Report Count (8),
         0x75, 0x01,             //  Report Size (1),
         0x15, 0x00,             //  Logical Minimum (0),
         0x19, 0x00,             //  Usage Minimum (0),
         0x29, 0x7F,             //  Usage Maximum (104),
         0x81, 0x00,             //  Input (Data, Array),                ;Normal keys
-        0xc0                    // End Collection
+        0xC0                    //  End Collection
+};
+#endif
+
+#ifdef KEYMEDIA_INTERFACE
+static uint8_t keymedia_report_desc[] = {
+        0x05, 0x0C,             //  Usage Page (Consumer)
+        0x09, 0x01,             //  Usage (Consumer Controls)
+        0xA1, 0x01,             //  Collection (Application)
+        0x75, 0x0A,             //  Report Size (10)
+        0x95, 0x04,             //  Report Count (4)
+        0x19, 0x00,             //  Usage Minimum (0)
+        0x2A, 0x9C, 0x02,       //  Usage Maximum (0x29C)
+        0x15, 0x00,             //  Logical Minimum (0)
+        0x26, 0x9C, 0x02,       //  Logical Maximum (0x29C)
+        0x81, 0x00,             //  Input (Data, Array)
+        0xC0,                   //  End Collection
+        0x05, 0x01,             //  Usage Page (Generic Desktop)
+        0x09, 0x80,             //  Usage (System Control)
+        0xA1, 0x01,             //  Collection (Application)
+        0x75, 0x08,             //  Report Size (8)
+        0x95, 0x03,             //  Report Count (3)
+        0x19, 0x00,             //  Usage Minimum (0)
+        0x29, 0xB7,             //  Usage Maximum (0xB7)
+        0x15, 0x00,             //  Logical Minimum (0)
+        0x26, 0xB7, 0x00,       //  Logical Maximum (0xB7)
+        0x81, 0x00,             //  Input (Data, Array)
+        0xC0                    //  End Collection
 };
 #endif
 
 #define MTP_INTERFACE_DESC_SIZE	0
 #endif
 
-#define CONFIG_DESC_SIZE		MTP_INTERFACE_DESC_POS+MTP_INTERFACE_DESC_SIZE
+#define KEYMEDIA_INTERFACE_DESC_POS	MTP_INTERFACE_DESC_POS+MTP_INTERFACE_DESC_SIZE
+#ifdef  KEYMEDIA_INTERFACE
+#define KEYMEDIA_INTERFACE_DESC_SIZE	9+9+7
+#define KEYMEDIA_HID_DESC_OFFSET	KEYMEDIA_INTERFACE_DESC_POS+9
+#else
+#define KEYMEDIA_INTERFACE_DESC_SIZE	0
+#endif
+
+#define CONFIG_DESC_SIZE		KEYMEDIA_INTERFACE_DESC_POS+KEYMEDIA_INTERFACE_DESC_SIZE
 
 
 
         MTP_EVENT_SIZE, 0,                      // wMaxPacketSize
         MTP_EVENT_INTERVAL,                     // bInterval
 #endif // MTP_INTERFACE
+
+#ifdef KEYMEDIA_INTERFACE
+        // interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
+        9,                                      // bLength
+        4,                                      // bDescriptorType
+        KEYMEDIA_INTERFACE,                     // bInterfaceNumber
+        0,                                      // bAlternateSetting
+        1,                                      // bNumEndpoints
+        0x03,                                   // bInterfaceClass (0x03 = HID)
+        0x00,                                   // bInterfaceSubClass
+        0x00,                                   // bInterfaceProtocol
+        0,                                      // iInterface
+        // HID interface descriptor, HID 1.11 spec, section 6.2.1
+        9,                                      // bLength
+        0x21,                                   // bDescriptorType
+        0x11, 0x01,                             // bcdHID
+        0,                                      // bCountryCode
+        1,                                      // bNumDescriptors
+        0x22,                                   // bDescriptorType
+        LSB(sizeof(keymedia_report_desc)),      // wDescriptorLength
+        MSB(sizeof(keymedia_report_desc)),
+        // endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+        7,                                      // bLength
+        5,                                      // bDescriptorType
+        KEYMEDIA_ENDPOINT | 0x80,               // bEndpointAddress
+        0x03,                                   // bmAttributes (0x03=intr)
+        KEYMEDIA_SIZE, 0,                       // wMaxPacketSize
+        KEYMEDIA_INTERVAL,                      // bInterval
+#endif // KEYMEDIA_INTERFACE
 };
 
 
 #ifdef FLIGHTSIM_INTERFACE
 	{0x2200, FLIGHTSIM_INTERFACE, flightsim_report_desc, sizeof(flightsim_report_desc)},
 	{0x2100, FLIGHTSIM_INTERFACE, config_descriptor+FLIGHTSIM_HID_DESC_OFFSET, 9},
+#endif
+#ifdef KEYMEDIA_INTERFACE
+        {0x2200, KEYMEDIA_INTERFACE, keymedia_report_desc, sizeof(keymedia_report_desc)},
+        {0x2100, KEYMEDIA_INTERFACE, config_descriptor+KEYMEDIA_HID_DESC_OFFSET, 9},
 #endif
         {0x0300, 0x0000, (const uint8_t *)&string0, 0},
         {0x0301, 0x0409, (const uint8_t *)&usb_string_manufacturer_name, 0},

teensy3/usb_desc.h

   #define PRODUCT_NAME		{'K','e','y','b','o','a','r','d','/','M','o','u','s','e','/','J','o','y','s','t','i','c','k'}
   #define PRODUCT_NAME_LEN	23
   #define EP0_SIZE		64
-  #define NUM_ENDPOINTS         5
+  #define NUM_ENDPOINTS         6
   #define NUM_USB_BUFFERS	24
-  #define NUM_INTERFACE		4
+  #define NUM_INTERFACE		5
   #define SEREMU_INTERFACE      2	// Serial emulation
   #define SEREMU_TX_ENDPOINT    1
   #define SEREMU_TX_SIZE        64
   #define KEYBOARD_ENDPOINT     3
   #define KEYBOARD_SIZE         8
   #define KEYBOARD_INTERVAL     1
+  #define KEYMEDIA_INTERFACE    4	// Keyboard Media Keys
+  #define KEYMEDIA_ENDPOINT     6
+  #define KEYMEDIA_SIZE         8
+  #define KEYMEDIA_INTERVAL     4
   #define MOUSE_INTERFACE       1	// Mouse
   #define MOUSE_ENDPOINT        5
   #define MOUSE_SIZE            8
   #define ENDPOINT3_CONFIG	ENDPOINT_TRANSIMIT_ONLY
   #define ENDPOINT4_CONFIG	ENDPOINT_TRANSIMIT_ONLY
   #define ENDPOINT5_CONFIG	ENDPOINT_TRANSIMIT_ONLY
+  #define ENDPOINT6_CONFIG	ENDPOINT_TRANSIMIT_ONLY
 
 #elif defined(USB_SERIAL_HID)
   #define VENDOR_ID		0x16C0