py/test/pytests/ectool_i2c_dev_id.py

# Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""A hardware test for checking EC connected I2C device's ID.

It uses ectool to read device ID from periphral and check for correctness.
"""

import re
import unittest

import factory_common  # pylint: disable=unused-import
from cros.factory.test import event_log
from cros.factory.utils.arg_utils import Arg
from cros.factory.utils import process_utils

RE_I2C_RESULT = re.compile(
    r'Read from I2C port \d+ at \S+ offset \S+ = (0x\S+)')


class EctoolI2CDevIdTest(unittest.TestCase):

  ARGS = [
      Arg('bus', int, 'I2C bus to probe.'),
      Arg('spec', list,
          'A list of tuples containing address/registers and expected '
          'values. Each tuple is in the following format:\n'
          '\n'
          '  (addr, reg, expected_value, bits)\n'
          '\n'
          '- addr: The I2C address of the peripheral.\n'
          '- reg: The register containing device ID.\n'
          '- expected_value: The expected device ID.\n'
          '- bits: The number of bits to read. Must be 8 (default) or 16.\n'
          '\n'
          'If the condition in any tuple matches, the test passes.'),
  ]

  def CheckDevice(self, bus, addr, reg, expected_value, bits=8):
    assert bits in (8, 16)
    cmd = 'ectool i2cread %d %d %d %d' % (bits, bus, addr, reg)
    output = process_utils.SpawnOutput(cmd.split(), log=True)
    match = RE_I2C_RESULT.search(output)
    if not match:
      return False
    return int(match.group(1), 16) == expected_value

  def runTest(self):
    result = [self.CheckDevice(self.args.bus, *spec) for spec in self.args.spec]
    event_log.Log('device_checked',
                  result=result, bus=self.args.bus, spec=self.args.spec)
    self.assertTrue(any(result), 'Device ID mismatches.')