Same as write_value(), but returns a context manager that will write
back the old value on exit.
Also add batch_revertable_write_value() that takes a list of kwargs
dict, and will call revertable_write_value() on each of them, returning
a single combined context manager.
This allows using an TraceCollector instance as a context manager, so
tracing will stop even if the devlib application is interrupted, or if
an exception is raised.
Add BaylibreAcmeInstrument, a new instrument providing support for the
Baylibre ACME board as a wrapper for the IIO interface. This class
provides better access to the ACME hardware (e.g. the ability to control
the sampling frequency) and to the retrieved samples than what the other
instrument, AcmeCapeInstrument, provides. Furthermore, it removes an
unnecessary and limiting dependency by interfacing directly with the IIO
drivers instead of relying on an intermediate script ("iio-capture") potentially
introducing unexpected bugs. Finally, it allows handling multiple probes
(the ACME can have up to 8) through an easy-to-use single instance of this
class instead of having to have an instance of AcmeCapeInstrument per channel
potentially (untested) leading to race conditions between the underlying
scripts for accessing the hardware.
This commit does not overwrite AcmeCapeInstrument as
BaylibreAcmeInstrument does not provide interface compatibility with
that class. Anyhow, we believe that anything that can be achieved with
AcmeCapeInstrument can be done with BaylibreAcmeInstrument (the
reciprocal is not true) so that BaylibreAcmeInstrument might eventually
replace AcmeCapeInstrument.
Add BaylibreAcmeInstrument documentation detailing the class interface
and the ACME instrument itself and discussing the way it works and its
potential limitations.
Add system_id attribute to targets. This ID is supposed unique for a
combination of hardware, kernel, and the file system, and contains
elements from each.
1. Hardware is identified by the concatenation of MAC addresses of
'link/ether' network interfaces on the system. This method is used,
as DMI tables are often unimplemented on ARM targets.
2. The kernel is identified by its version.
3. The file system is identified by the concatenation of UUID's of the
target's partitions. It would be more correct to only use UUID of
the root partition, as system_id is not intended to be affected by
removable, media, however, there is no straight-forward way of
reliably identifying that without root.
system_id is intended to be used as an key for the purposes of caching
information about a particular device (e.g. so that it does not need to
be probed on each run).
Add two new methods to target that allow querying values of all sysfs
nodes in a sub-directory structure all at once. The difference is that
read_tree_values_flat returns a flat dict of path->value mappings;
read_tree_values returns a nested dict structure that mimics the
scanned sub-directories tree.
- Add process_raw() method to the API. This is inteneded to be invoked
on any raw output (i.e. not MeasurmentCsv) generated by an Instrument.
- Both process() process_raw() are portional to be overriden by
impolementation; the default behavior is to return an empty list.
- The output specification for both is extened to allow
MeasurementCsv's, as well as DerivedMetric's.
- Documentation has been reworded for clarity.
DerivedMeasurments processors now return DerviedMetrics rather than
measurments. The notion of an InstrumentChannel doesn't really make
sense in the context of DerivedMeasurments, which are not directly
measured on the target. Since Measurement's require a channel, a simpler
DerviedMetric is added that only requires a name and a type.
Derived metrics may be calculated form data in raw output that is not
present in the resulting MeasurementCSV. This adds a method to provide
uniform access to raw artifacts generated by an instrument.
- Fix missing parameter in the documentation
- Clarify meaning of `sites` and `kinds` in the documentation.
- With the current implementation the `channels` argument is
useless: if `sites` and `kinds` are not also specified then all
channels are enabled anyway. Fix that by making those parameters
ignored when `channels` is provided.
