py/device/hwmon.py

# Copyright 2016 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import shlex

from cros.factory.device import device_types


_HWMON_PATH = '/sys/class/hwmon'


class HardwareMonitorException(Exception):
  pass


class HardwareMonitorDevice(device_types.DeviceComponent):
  """A class representing a single hwmon device."""
  def __init__(self, dut, path):
    super().__init__(dut)
    self._path = path

  def GetAttribute(self, name):
    # yapf: disable
    return self._device.ReadFile(self._device.path.join(self._path, name))  # type: ignore #TODO(b/338318729) Fixit! # pylint: disable=line-too-long
    # yapf: enable

  def GetPath(self):
    return self._path


class HardwareMonitor(device_types.DeviceComponent):
  """Utility class for hardware monitor devices."""

  def __init__(self, dut, hwmon_path=_HWMON_PATH):
    super().__init__(dut)
    self._hwmon_path = hwmon_path

  def FindOneDevice(self, attr_name, attr_value):
    """Search hwmon devices that have specified attribute name and value.

    Args:
      attr_name: An attribute name.
      attr_value: An attribute value.

    Returns:
      The matching hwmon device.

    Raises:
      HardwareMonitorException not exactly one device match the critiria.
    """
    devices = self.FindDevices(attr_name, attr_value)
    if len(devices) != 1:
      raise HardwareMonitorException('Not exactly one device match given'
                                     ' critiria')
    return devices[0]

  def FindDevices(self, attr_name, attr_value):
    """Search hwmon devices that have specified attribute name and value.

    Args:
      attr_name: An attribute name.
      attr_value: An attribute value.

    Returns:
      A list of matching hwmon device.
    """
    # yapf: disable
    search_path = self._device.path.join(  # type: ignore #TODO(b/338318729) Fixit! # pylint: disable=line-too-long
    # yapf: enable
        self._hwmon_path, '*', shlex.quote(attr_name))
    output = self._device.CheckOutput(
        f'grep {search_path} -l -e {shlex.quote(f"^{attr_value}$")}')

    # yapf: disable
    return [HardwareMonitorDevice(self._device, self._device.path.dirname(path))  # type: ignore #TODO(b/338318729) Fixit! # pylint: disable=line-too-long
    # yapf: enable
            for path in output.splitlines()]