From d67811aa9a7d85793e73bead898f30139265c3c2 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Fri, 20 Jan 2023 14:46:05 -0700 Subject: [PATCH] event: Document dynamic event handlers Add mention of this feature in the event documentation. Signed-off-by: Simon Glass --- doc/develop/event.rst | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/doc/develop/event.rst b/doc/develop/event.rst index 6951ec97e7..4ff5934837 100644 --- a/doc/develop/event.rst +++ b/doc/develop/event.rst @@ -64,3 +64,26 @@ in an image, use $(CROSS_COMPILE)nm:: nm u-boot |grep evspy |grep list 00000000002d6300 D _u_boot_list_2_evspy_info_2_EVT_MISC_INIT_F + +Logging is also available. Events use category `LOGC_EVENT`, so you can enable +logging on that, or add `#define LOG_DEBUG` to the top of `common/event.c` to +see events being sent. + + +Dynamic events +-------------- + +Static events provide a way of dealing with events known at build time. In some +cases we want to attach an event handler at runtime. For example, we may wish +to be notified when a particular device is probed or removed. + +This can be handled by enabling `CONFIG_EVENT_DYNAMIC`. It is then possible to +call `event_register()` to register a new handler for a particular event. + +Dynamic event handlers are called after all the static event spy handlers have +been processed. Of course, since dynamic event handlers are created at runtime +it is not possible to use the `event_dump.py` to see them. + +At present there is no way to list dynamic event handlers from the command line, +nor to deregister a dynamic event handler. These features can be added when +needed. -- 2.39.5