doc: nrf-bm: lib: add event scheduler documentation

Add documentation for event scheduler.

Signed-off-by: Eivind Jølsgard <[email protected]>

Author: eivindj-nordic

doc/nrf-bm/api/api.rst

@@ -51,6 +51,8 @@ Bare Metal Buttons library
    :inner:
    :members:
 
+.. _api_event_scheduler:
+
 Bare Metal Event Scheduler library
 ==================================
 

doc/nrf-bm/libraries/event_scheduler.rst

@@ -0,0 +1,49 @@
+.. _lib_event_scheduler:
+
+Event Scheduler
+###############
+
+.. contents::
+   :local:
+   :depth: 2
+
+The event scheduler is used for transferring execution from the interrupt context to the main context.
+
+Overview
+********
+
+In some applications it is beneficial to defer the execution of certain interrupts, for example some SoftDevice interrupts, to the main application function.
+This shortens the time spent in the interrupt service routine (ISR) and allows for other (low priority) events to be raised before the previous event is fully processed.
+Note that the application must take care to only defer events that can be interleaved by the processing of other interrupts.
+
+Configuration
+*************
+
+The library is enabled using the Kconfig system.
+Set the :kconfig:option:`CONFIG_EVENT_SCHEDULER` Kconfig option to enable the library.
+
+The size of the event scheduler buffer, that the events are copied into, is set using the :kconfig:option:`CONFIG_EVENT_SCHEDULER_BUF_SIZE` Kconfig option.
+
+Initialization
+==============
+
+The library is initialized automatically on application startup.
+
+Usage
+*****
+
+The SoftDevice event handler can call the :c:func:`event_scheduler_defer` function to schedule an event for execution in the main thread.
+The :c:func:`event_scheduler_process` function must be called regulary from the main function to process the deferred events.
+
+Dependencies
+************
+
+This library does not have any dependencies.
+
+API documentation
+*****************
+
+| Header file: :file:`include/event_scheduler.h`
+| Source files: :file:`lib/event_scheduler/`
+
+:ref:`Event Scheduler library API reference <api_event_scheduler>`