devlib initial commit.

devlib/instrument/hwmon.py

@@ -0,0 +1,89 @@
+#    Copyright 2015 ARM Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+from __future__ import division
+import re
+
+from devlib.instrument import Instrument, Measurement, INSTANTANEOUS
+from devlib.exception import TargetError
+
+
+class HwmonInstrument(Instrument):
+
+    name = 'hwmon'
+    mode = INSTANTANEOUS
+
+    # sensor kind --> (meaure, standard unit conversion)
+    measure_map = {
+        'temp': ('temperature', lambda x: x / 1000),
+        'in': ('voltage', lambda x: x / 1000),
+        'curr': ('current', lambda x: x / 1000),
+        'power': ('power', lambda x: x / 1000000),
+        'energy': ('energy', lambda x: x / 1000000),
+    }
+
+    def __init__(self, target):
+        if not hasattr(target, 'hwmon'):
+            raise TargetError('Target does not support HWMON')
+        super(HwmonInstrument, self).__init__(target)
+
+        self.logger.debug('Discovering available HWMON sensors...')
+        for ts in self.target.hwmon.sensors:
+            try:
+                ts.get_file('input')
+                measure = self.measure_map.get(ts.kind)[0]
+                if measure:
+                    self.logger.debug('\tAdding sensor {}'.format(ts.name))
+                    self.add_channel(_guess_site(ts), measure, name=ts.name, sensor=ts)
+                else:
+                    self.logger.debug('\tSkipping sensor {} (unknown kind "{}")'.format(ts.name, ts.kind))
+            except ValueError:
+                message = 'Skipping sensor {} because it does not have an input file'
+                self.logger.debug(message.format(ts.name))
+                continue
+
+    def take_measurement(self):
+        result = []
+        for chan in self.active_channels:
+            convert = self.measure_map[chan.sensor.kind][1]
+            value = convert(chan.sensor.get('input'))
+            result.append(Measurement(value, chan))
+        return result
+
+
+def _guess_site(sensor):
+    """
+    HWMON does not specify a standard for labeling its sensors, or for
+    device/item split (the implication is that each hwmon device a separate chip
+    with possibly several sensors on it, but not everyone adheres to that, e.g.,
+    with some mobile devices splitting a chip's sensors across multiple hwmon
+    devices.  This function processes name/label of the senors to attempt to
+    identify the best "candidate" for the site to which the sensor belongs.
+    """
+    if sensor.name == sensor.label:
+        # If no label has been specified for the sensor (in which case, it
+        # defaults to the sensor's name), assume that the "site" of the sensor
+        # is identified by the HWMON device
+        text = sensor.device.name
+    else:
+        # If a label has been specified, assume multiple sensors controlled by
+        # the same device and the label identifies the site.
+        text = sensor.label
+    # strip out sensor kind suffix, if any, as that does not indicate a site
+    for kind in ['volt', 'in', 'curr', 'power', 'energy',
+                 'temp', 'voltage', 'temperature', 'current']:
+        if kind in text.lower():
+            regex = re.compile(r'_*{}\d*_*'.format(kind), re.I)
+            text = regex.sub('', text)
+    return text.strip()