Demos/Host/LowLevel/AndroidAccessoryHost/DeviceDescriptor.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2018.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2018  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaims all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  USB Device Descriptor processing routines, to determine the overall device parameters. Descriptors are special
  34  *  computer-readable structures which the host requests upon device enumeration, to determine information about
  35  *  the attached device.
  36  */
  37
  38 #include "DeviceDescriptor.h"
  39
  40 /** Reads and processes an attached device's Device Descriptor, to determine compatibility
  41  *
  42  *  This routine checks to ensure that the attached device's VID and PID matches Google's for Android devices.
  43  *
  44  *  \return An error code from the \ref AndroidHost_GetDeviceDescriptorDataCodes_t enum.
  45  */
  46 uint8_t ProcessDeviceDescriptor(void)
  47 {
  48         USB_Descriptor_Device_t DeviceDescriptor;
  49
  50         /* Send the request to retrieve the device descriptor */
  51         if (USB_Host_GetDeviceDescriptor(&DeviceDescriptor) != HOST_SENDCONTROL_Successful)
  52           return DevControlError;
  53
  54         /* Validate returned data - ensure the returned data is a device descriptor */
  55         if (DeviceDescriptor.Header.Type != DTYPE_Device)
  56           return InvalidDeviceDataReturned;
  57
  58         /* Check the product ID to determine if the Android device is in accessory mode */
  59         if ((DeviceDescriptor.ProductID != ANDROID_ACCESSORY_PRODUCT_ID) &&
  60             (DeviceDescriptor.ProductID != ANDROID_ACCESSORY_ADB_PRODUCT_ID))
  61         {
  62                 return NonAccessoryModeAndroidDevice;
  63         }
  64
  65         return AccessoryModeAndroidDevice;
  66 }
  67