The previous architecture proved unable to support user expectations,
so the API has been rebuilt from first principles. Backward
compatibility cannot be maintained for this change.
Key changes include:
* Formerly the service-provided transition functions were allowed to
sleep, and the manager took care to not invoke them from ISR
context, instead returning an error if unable to initiate a
transition. In the new architecture transition functions are
required to work regardless of calling context: it is the service's
responsibility to guarantee the transition will proceed even if it
needs to be transferred to a thread. This eliminates state machine
complexities related to calling context.
* Constants identifying the visible state of the manager are exposed
to clients through both notification callbacks and a new monitor API
that allows clients to be notified of all state changes.
* Formerly the release operation was async, and would be delayed for the
last release to ensure a client would exist to be notified of any
failures. It is now synchronous.
* Formerly the cancel operation would fail on the last client associated
with a transition. The cancel operation is now synchronous.
* A helper function is provided to safely synchronously release a
request regardless of whether it has completed or is in progress,
satisfying the use case underlying #22974.
* The user-data parameter to asynchronous notification callbacks has
been removed as user data can be retrieved from the CONTAINER_OF
the client data.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
The original API was misnamed, as the intent was to provide a manager
that decoupled state management from the service that needed to be
turned on or off. Update all the names, shortening them where
appropriate removing unncessary internal components like _service.
Also remove some API that misled developers into believing that onoff
managers are normally expected to be exposed directly to consumers.
While this is a use case, in most situations there are service or
client-specific actions that need to be coupled to transition events.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
k_poll() for a signal is often desired for notification of completion
of asynchronous operations, but there are APIs where it may be
necessary to invoke "asynchronous" operations from contexts where
sleep is disallowed, or before the kernel has been initialized.
Extract the general notification solution from the on-off service into
a utility that can be used for other APIs.
Also move documentation out to a resource management section.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
