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authorPau Espin Pedrol <pespin@sysmocom.de>2018-03-08 20:54:56 +0100
committerPau Espin Pedrol <pespin@sysmocom.de>2018-03-15 19:54:36 +0100
commit19c508c3047c0a4e40507583bbf75ba1aea53037 (patch)
treead04e15a250208e927d839c9d6f015b88918b281 /src/osmo_gsm_tester/powersupply_sispm.py
parent651cdc9b0f0cdf36e636ffb8a1fd90877dc569df (diff)
Introduce PowerSupply interface and PowerSupplySispm
File powersupply.py defines the interface to be used by child classes implementing it. It also provides helpers to allocate a child class based on configuration provided ('type' field). File powersupply_sispm.py is an implementation using pysispm [1], as it's the one used to control the programmable power socket we have right now. This kind of class will be used in later commits by Nanobts class, as we want to poweroff the Nanobts completelly when not in use. Using it requires the following extra dependencies: $ apt-get install python3-usb $ pip3 install pysispm Related: OS#3040 [1] https://github.com/xypron/pysispm Change-Id: I981c260eca1a61657147e6d83b4226618088223c
Diffstat (limited to 'src/osmo_gsm_tester/powersupply_sispm.py')
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diff --git a/src/osmo_gsm_tester/powersupply_sispm.py b/src/osmo_gsm_tester/powersupply_sispm.py
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+++ b/src/osmo_gsm_tester/powersupply_sispm.py
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+# osmo_gsm_tester: class defining a Power Supply object
+#
+# Copyright (C) 2018 by sysmocom - s.f.m.c. GmbH
+#
+# Author: Pau Espin Pedrol <pespin@sysmocom.de>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+import sispm
+from usb.core import USBError
+
+from . import log, event_loop
+from .powersupply import PowerSupply
+
+class PowerSupplySispm(PowerSupply):
+ """PowerSupply implementation using pysispm.
+
+ The device object from sismpm is not cached into an attribute of the class
+ instance because it is actually a libusb object keeping the device assigned
+ to it until it destroyed, meaning it will block other users to use the whole
+ device until the object is released. Instead, we pick the object in the
+ smallest scope possible, and we re-try if we receive a "Resource Busy" error
+ because we know it will be available in short time.
+ """
+
+ def _retry_usberr(self, func, *args):
+ """Run function until it runs successfully, retry on spurious errors.
+
+ Sometimes when operating the usb device, libusb reports the following spurious exception:
+ [Errno 16] Resource busy -> This can appear if another instance is using the device.
+ [Errno 110] Operation timed out
+
+ Retrying after that it's usually enough.
+ """
+ while True:
+ try:
+ ret = func(*args)
+ return ret
+ except USBError as e:
+ if e.errno == 16 or e.errno==110:
+ self.log('skip usb error, retry', repr(e))
+ event_loop.sleep(self, 0.1)
+ continue
+ raise e
+
+ def _get_device(self):
+ """Get the sispm device object.
+
+ It should be kept alive as short as possible as it blocks other users
+ from using the device until the object is released.
+ """
+ mydevid = self.conf.get('device')
+ devices = self._retry_usberr(sispm.connect)
+ for d in devices:
+ did = self._retry_usberr(sispm.getid, d)
+ self.dbg('detected device:', did)
+ if did == mydevid:
+ self.dbg('found matching device: %s' % did)
+ return d
+ return None
+
+
+########################
+# PUBLIC - INTERNAL API
+########################
+ def __init__(self, conf):
+ super().__init__(conf, 'sispm')
+ mydevid = conf.get('device')
+ if mydevid is None:
+ raise log.Error('No "device" attribute provided in supply conf!')
+ self.set_name('sispm-'+mydevid)
+ myport = conf.get('port')
+ if myport is None:
+ raise log.Error('No "port" attribute provided in power_supply conf!')
+ if not int(myport):
+ raise log.Error('Wrong non numeric "port" attribute provided in power_supply conf!')
+ self.port = int(myport)
+ device = self._get_device()
+ if device is None:
+ raise log.Error('device with with id %s not found!' % mydevid)
+ dmin = self._retry_usberr(sispm.getminport, device)
+ dmax = self._retry_usberr(sispm.getmaxport, device)
+ if dmin > self.port or dmax < self.port:
+ raise log.Error('Out of range "port" attribute provided in power_supply conf!')
+
+ def is_powered(self):
+ """Get whether the device is powered on or off."""
+ return self._retry_usberr(sispm.getstatus, self._get_device(), self.port)
+
+ def power_set(self, onoff):
+ """Turn on (onoff=True) or off (onoff=False) the device."""
+ if onoff:
+ self.dbg('switchon')
+ self._retry_usberr(sispm.switchon, self._get_device(), self.port)
+ else:
+ self.dbg('switchoff')
+ self._retry_usberr(sispm.switchoff, self._get_device(), self.port)
+
+
+# vim: expandtab tabstop=4 shiftwidth=4