Adding battery control API for android.

build/android/pylib/android_commands.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Provides an interface to communicate with the device via the adb command.
 
 Assumes adb binary is currently on system path.
 """
 # pylint: disable-all
 
@@ skipping 55 matching lines @@
 KEYCODE_DPAD_UP = 19
 KEYCODE_DPAD_DOWN = 20
 KEYCODE_DPAD_RIGHT = 22
 KEYCODE_ENTER = 66
 KEYCODE_MENU = 82
 
 MD5SUM_DEVICE_FOLDER = constants.TEST_EXECUTABLE_DIR + '/md5sum/'
 MD5SUM_DEVICE_PATH = MD5SUM_DEVICE_FOLDER + 'md5sum_bin'
 MD5SUM_LD_LIBRARY_PATH = 'LD_LIBRARY_PATH=%s' % MD5SUM_DEVICE_FOLDER
 
+CONTROL_USB_CHARGING_COMMANDS = [
+  {
+    # Nexus 4
+    'witness_file': '/sys/module/pm8921_charger/parameters/disabled',
+    'enable_command': 'echo 0 > /sys/module/pm8921_charger/parameters/disabled',
+    'disable_command':
+        'echo 1 > /sys/module/pm8921_charger/parameters/disabled',
+  },
+]
 
 def GetAVDs():
   """Returns a list of AVDs."""
   re_avd = re.compile('^[ ]+Name: ([a-zA-Z0-9_:.-]+)', re.MULTILINE)
   avds = re_avd.findall(cmd_helper.GetCmdOutput(['android', 'list', 'avd']))
   return avds
 
 def ResetBadDevices():
   """Removes the blacklist that keeps track of bad devices for a current
      build.
@@ skipping 192 matching lines @@
     self.logcat_process = None
     self._logcat_tmpoutfile = None
     self._pushed_files = []
     self._device_utc_offset = None
     self._potential_push_size = 0
     self._actual_push_size = 0
     self._external_storage = ''
     self._util_wrapper = ''
     self._system_properties = system_properties.SystemProperties(self.Adb())
     self._push_if_needed_cache = {}
+    self._control_usb_charging_command = {
+        'command': None,
+        'cached': False,
+    }
 
   @property
   def system_properties(self):
     return self._system_properties
 
   def _LogShell(self, cmd):
     """Logs the adb shell command."""
     if self._device:
       device_repr = self._device[-4:]
     else:
@@ skipping 1520 matching lines @@
     out = self.RunShellCommand('sh %s %s %s' % (temp_script_file, source, dest),
                                timeout_time=120)
     if self._device:
       device_repr = self._device[-4:]
     else:
       device_repr = '????'
     for line in out:
       logging.info('[%s]> %s', device_repr, line)
     self.RunShellCommand('rm %s' % temp_script_file)
 
+  def _GetControlUsbChargingCommand(self):
+    if self._control_usb_charging_command['cached']:
+      return self._control_usb_charging_command['command']
+    self._control_usb_charging_command['cached'] = True
+    for command in CONTROL_USB_CHARGING_COMMANDS:
+      # Assert command is valid.
+      assert 'disable_command' in command
+      assert 'enable_command' in command
+      assert 'witness_file' in command
+      witness_file = command['witness_file']
+      if self.FileExistsOnDevice(witness_file):
+        self._control_usb_charging_command['command'] = command
+        return command
+    return None
+
+  def CanControlUsbCharging(self):
+    return self._GetControlUsbChargingCommand() is not None
+
+  def DisableUsbCharging(self):
+    command = self._GetControlUsbChargingCommand()
+    if not command:
+      raise Exception('Unable to act on usb charging.')
+    disable_command = command['disable_command']
+    self.RunShellCommand(disable_command)
+
+  def EnableUsbCharging(self):
+    command = self._GetControlUsbChargingCommand()
+    if not command:
+      raise Exception('Unable to act on usb charging.')
+    disable_command = command['enable_command']
+    self.RunShellCommand(disable_command)
+
 
 class NewLineNormalizer(object):
   """A file-like object to normalize EOLs to '\n'.
 
   Pexpect runs adb within a pseudo-tty device (see
   http://www.noah.org/wiki/pexpect), so any '\n' printed by adb is written
   as '\r\n' to the logfile. Since adb already uses '\r\n' to terminate
   lines, the log ends up having '\r\r\n' at the end of each line. This
   filter replaces the above with a single '\n' in the data stream.
   """
   def __init__(self, output):
     self._output = output
 
   def write(self, data):
     data = data.replace('\r\r\n', '\n')
     self._output.write(data)
 
   def flush(self):
     self._output.flush()