ui/events/ozone/evdev/explain_proc_bus_input_devices.py

   1 #!/usr/bin/python
   2 # Copyright 2015 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 """Explain device capabilities from /proc/bus/input/devices.
   7
   8 This tool processes the contents of /proc/bus/input/devices, expanding bitfields
   9 of event codes into lists of names for those events.
  10 """
  11
  12 import argparse
  13 import evdev
  14 import sys
  15
  16
  17 def parse_bitfield(bitfield, word_bits):
  18   """Parse a serialized bitfield from /proc/bus/input/devices.
  19
  20   Returns a list of bits in the set.
  21
  22   Example: parse_bitfield('10 3', 64) == [0, 1, 68]
  23   """
  24   groups = bitfield.split(' ')
  25   group_count = len(groups)
  26   result_bits = []
  27
  28   for group_index in xrange(group_count):
  29     group_val = int(groups[group_count - 1 - group_index], 16)
  30
  31     for group_bit in xrange(word_bits):
  32       if group_val & (1 << group_bit):
  33         result_bits.append(group_index * word_bits + group_bit)
  34
  35   return result_bits
  36
  37
  38 PROP_NAMES = {
  39     0x0: 'INPUT_PROP_POINTER',
  40     0x1: 'INPUT_PROP_DIRECT',
  41     0x2: 'INPUT_PROP_BUTTONPAD',
  42     0x3: 'INPUT_PROP_SEMI_MT',
  43     0x4: 'INPUT_PROP_TOPBUTTONPAD',
  44 }
  45
  46
  47 KEY_NAMES = evdev.ecodes.bytype[evdev.ecodes.EV_KEY].copy()
  48
  49 # Fix keys with multiple names.
  50 KEY_NAMES[evdev.ecodes.KEY_MUTE] = 'KEY_MUTE'
  51 KEY_NAMES[evdev.ecodes.KEY_SCREENLOCK] = 'KEY_SCREENLOCK'
  52 KEY_NAMES[evdev.ecodes.KEY_HANGEUL] = 'KEY_HANGEUL'
  53 KEY_NAMES[evdev.ecodes.BTN_LEFT] = 'BTN_LEFT'
  54 KEY_NAMES[evdev.ecodes.BTN_TRIGGER] = 'BTN_TRIGGER'
  55 KEY_NAMES[evdev.ecodes.BTN_0] = 'BTN_0'
  56
  57
  58 BITFIELDS = [
  59   ('B: EV=', evdev.ecodes.EV),
  60   ('B: PROP=', PROP_NAMES),
  61   ('B: KEY=', KEY_NAMES),
  62   ('B: REL=', evdev.ecodes.bytype[evdev.ecodes.EV_REL]),
  63   ('B: MSC=', evdev.ecodes.bytype[evdev.ecodes.EV_MSC]),
  64   ('B: LED=', evdev.ecodes.bytype[evdev.ecodes.EV_LED]),
  65   ('B: ABS=', evdev.ecodes.bytype[evdev.ecodes.EV_ABS]),
  66   ('B: SW=', evdev.ecodes.bytype[evdev.ecodes.EV_SW]),
  67   ('B: REP=', evdev.ecodes.bytype[evdev.ecodes.EV_REP]),
  68   ('B: SND=', evdev.ecodes.bytype[evdev.ecodes.EV_SND]),
  69 ]
  70
  71
  72 def explain_bitfield(serialized_bits, bit_names, word_size, output_file):
  73   """Annotate a bitfield using the provided symbolic names for each bit."""
  74
  75   bits = parse_bitfield(serialized_bits, word_size)
  76   for bit in bits:
  77     if bit in bit_names:
  78       output_file.write('    %s\n' % bit_names[bit])
  79     else:
  80       output_file.write('    0x%x\n' % bit)
  81
  82
  83 def explain(input_file, output_file, word_size):
  84   """Annotate an input file formatted like /proc/bus/input/devices."""
  85
  86   for line in input_file:
  87     output_file.write(line)
  88     for prefix, bit_names in BITFIELDS:
  89       if line.startswith(prefix):
  90         explain_bitfield(line[len(prefix):], bit_names, word_size, output_file)
  91
  92
  93 def main(argv):
  94   parser = argparse.ArgumentParser()
  95   parser.add_argument('input_file', nargs='?',
  96       default='/proc/bus/input/devices',
  97       help="filename to read input from")
  98   parser.add_argument('output_file', nargs='?',
  99       help="filename to write output to")
 100   parser.add_argument('--word_size', type=int, default=64,
 101       help="word size of the system that generated the input file")
 102   args = parser.parse_args(argv)
 103
 104   input_file = sys.stdin
 105   if args.input_file:
 106     input_file = open(args.input_file, 'r')
 107
 108   output_file = sys.stdout
 109   if args.output_file:
 110     output_file = open(args.output_file, 'w')
 111
 112   explain(input_file, output_file, args.word_size)
 113
 114   return 0
 115
 116
 117 if __name__ == '__main__':
 118   sys.exit(main(sys.argv[1:]))