tools/usb_gadget/hid_echo_gadget.py

   1 # Copyright 2014 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """A HID-class echo device.
   6
   7 This module provides a HID feature and HID device that can be used as an
   8 echo test for HID drivers. The device exposes vendor-specific input, output
   9 and feature usages that transmit 8 bytes of data. Data written sent as an
  10 output report is echoed as an input report. The value of the feature report
  11 can be written and read with control transfers.
  12 """
  13
  14 import struct
  15
  16 import hid_constants
  17 import hid_descriptors
  18 import hid_gadget
  19 import usb_constants
  20
  21
  22 class EchoFeature(hid_gadget.HidFeature):
  23
  24   REPORT_DESC = hid_descriptors.ReportDescriptor(
  25       hid_descriptors.UsagePage(0xFF00),  # Vendor Defined
  26       hid_descriptors.Usage(0),
  27       hid_descriptors.Collection(
  28           hid_constants.CollectionType.APPLICATION,
  29           hid_descriptors.LogicalMinimum(0, force_length=1),
  30           hid_descriptors.LogicalMaximum(255, force_length=2),
  31           hid_descriptors.ReportSize(8),
  32           hid_descriptors.ReportCount(8),
  33           hid_descriptors.Usage(0),
  34           hid_descriptors.Input(hid_descriptors.Data,
  35                                 hid_descriptors.Variable,
  36                                 hid_descriptors.Absolute),
  37           hid_descriptors.Usage(0),
  38           hid_descriptors.Output(hid_descriptors.Data,
  39                                  hid_descriptors.Variable,
  40                                  hid_descriptors.Absolute),
  41           hid_descriptors.Usage(0),
  42           hid_descriptors.Feature(hid_descriptors.Data,
  43                                   hid_descriptors.Variable,
  44                                   hid_descriptors.Absolute)
  45       )
  46   )
  47
  48   def __init__(self):
  49     super(EchoFeature, self).__init__()
  50     self._input_output_report = 0
  51     self._feature_report = 0
  52
  53   def SetInputReport(self, data):
  54     self._input_output_report, = struct.unpack('<Q', data)
  55     self.SendReport(struct.pack('<Q', self._input_output_report))
  56     return True
  57
  58   def SetOutputReport(self, data):
  59     self._input_output_report, = struct.unpack('<Q', data)
  60     self.SendReport(struct.pack('<Q', self._input_output_report))
  61     return True
  62
  63   def SetFeatureReport(self, data):
  64     self._feature_report, = struct.unpack('<Q', data)
  65     return True
  66
  67   def GetInputReport(self):
  68     return struct.pack('<Q', self._input_output_report)
  69
  70   def GetOutputReport(self):
  71     return struct.pack('<Q', self._input_output_report)
  72
  73   def GetFeatureReport(self):
  74     return struct.pack('<Q', self._feature_report)
  75
  76
  77 class EchoGadget(hid_gadget.HidGadget):
  78
  79   def __init__(self):
  80     self._feature = EchoFeature()
  81     super(EchoGadget, self).__init__(
  82         report_desc=EchoFeature.REPORT_DESC,
  83         features={0: self._feature},
  84         packet_size=8,
  85         interval_ms=1,
  86         out_endpoint=True,
  87         vendor_id=usb_constants.VendorID.GOOGLE,
  88         product_id=usb_constants.ProductID.GOOGLE_HID_ECHO_GADGET,
  89         device_version=0x0100)
  90     self.AddStringDescriptor(1, 'Google Inc.')
  91     self.AddStringDescriptor(2, 'HID Echo Gadget')
  92
  93
  94 def RegisterHandlers():
  95   from tornado import web
  96
  97   class WebConfigureHandler(web.RequestHandler):
  98
  99     def post(self):
 100       server.SwitchGadget(EchoGadget())
 101
 102   import server
 103   server.app.add_handlers('.*$', [
 104       (r'/hid_echo/configure', WebConfigureHandler),
 105   ])