openthread: Move OpenThread implementation from net to modules

doc/releases/migration-guide-4.2.rst

@@ -332,9 +332,102 @@ Networking
   the server commands, enable :kconfig:option:`NET_ZPERF_SERVER`. If server support
   is not needed, :kconfig:option:`ZVFS_POLL_MAX` can possibly be reduced.
 
-* The OpenThread-related Kconfig options from ``subsys/net/l2/openthread/Kconfig`` have been moved to
-  ``modules/openthread/Kconfig``. All the Kconfig options remain the same. You can still use them in the
-  same way as before, but to modify them, use the new path in the menuconfig or guiconfig.
+OpenThread
+==========
+
+* The OpenThread stack integration in Zephyr has undergone a major refactor.
+  The implementation has been moved from the Zephyr networking layer (``subsys/net/l2/openthread/``)
+  to a dedicated module (``modules/openthread/``).
+
+* OpenThread is now a standalone module in Zephyr.
+  It can be used independently of Zephyr's networking stack (L2 and IEEE802.15.4 shim layers).
+  This enables new use cases, such as applications that use OpenThread directly with their
+  own IEEE802.15.4 driver, or that do not need the full Zephyr networking stack.
+
+* Most functions in the :zephyr_file:`include/zephyr/net/openthread.h` file have been deprecated.
+  These deprecated APIs are still available for backward compatibility, but new applications should
+  use the new APIs provided by the OpenThread module. The following list summarizes the changes:
+
+  * Mutex handling:
+
+    * Previously:
+
+      * ``openthread_api_mutex_lock``
+      * ``openthread_api_mutex_try_lock``
+      * ``openthread_api_mutex_unlock``
+
+    * Now use:
+
+      * :c:func:`openthread_mutex_lock`
+      * :c:func:`openthread_mutex_try_lock`
+      * :c:func:`openthread_mutex_unlock`
+
+  * OpenThread starting:
+
+    * Previously: ``openthread_start``
+    * Now use: :c:func:`openthread_run`
+
+  * Callback registration:
+
+    * Previously:
+
+      * ``openthread_state_changed_cb_register``
+      * ``openthread_state_changed_cb_unregister``
+
+    * Now use:
+
+      * :c:func:`openthread_state_changed_callback_register`
+      * :c:func:`openthread_state_changed_callback_unregister`
+
+  * Callback structure:
+
+    * Previously: ``openthread_state_changed_cb``
+    * Now use: :c:struct:`openthread_state_changed_callback`
+
+  * The following :c:struct:`openthread_context` struct fields are deprecated and shall not be used
+    in new code anymore:
+
+    * ``instance``
+    * ``api_lock``
+    * ``work_q``
+    * ``api_work``
+    * ``state_change_cbs``
+
+  * The new functions that were not present before:
+
+    * :c:func:`openthread_init` to initialize the OpenThread stack.
+    * :c:func:`openthread_stop` to stop and disable the OpenThread stack.
+    * :c:func:`openthread_set_receive_cb` to set the receive callback for the OpenThread stack.
+
+* The OpenThread-related Kconfig options from ``subsys/net/l2/openthread/Kconfig``
+  have been moved to :zephyr_file:`modules/openthread/Kconfig`. All Kconfig options remain the same.
+  You can still use them in the same way as before, but to modify them, use the new path in the
+  menuconfig or guiconfig.
+
+* If the :kconfig:option:`CONFIG_NET_L2_OPENTHREAD` Kconfig option is enabled, Zephyr's L2 layer
+  will use the new OpenThread module API as its backend. The L2 layer no longer implements
+  OpenThread itself, but delegates the implementation to the module.
+
+* For existing applications using OpenThread through Zephyr's networking stack:
+
+  * Your application should continue to work, as the old APIs are still available for compatibility.
+    However, you are encouraged to migrate to the new APIs for future-proofing and use the new
+    modular structure.
+  * Update any references to OpenThread Kconfig options to use the new path
+    (``modules/openthread/Kconfig``) in your configuration tools.
+
+* For applications using :c:struct:`openthread_context` or other deprecated APIs:
+
+  * Begin migrating to the new APIs. The deprecated APIs will be removed in a future release.
+  * Avoid direct use of :c:struct:`openthread_context` and related fields; use the new
+    initialization and callback registration functions instead.
+
+* For new applications or those using OpenThread without Zephyr L2:
+
+  * Use the new initialization (:c:func:`openthread_init`), run (:c:func:`openthread_run`),
+    and callback registration APIs (:c:func:`openthread_state_change_callback_register`).
+  * You can now use OpenThread directly, without enabling Zephyr's L2 or IEEE802.15.4 layers, if
+    your use case allows.
 
 SPI
 ===

doc/releases/release-notes-4.2.rst

@@ -175,7 +175,12 @@ New APIs and options
 
   * OpenThread
 
-    * Moved OpenThread-related Kconfig options from ``subsys/net/l2/openthread/Kconfig`` to ``modules/openthread/Kconfig``.
+    * Moved OpenThread-related Kconfig options from ``subsys/net/l2/openthread/Kconfig`` to
+      ``modules/openthread/Kconfig``.
+    * OpenThread has been refactored into a standalone module, decoupled from Zephyr's networking
+      stack. Most old APIs have been deprecated and the new APIs are used by the Zephyr L2 layer to
+      maintain backward compatibility. For migration steps and details, see the
+      :ref:`migration guide <migration_4.2>`.
 
 * Sensor
 

drivers/hdlc_rcp_if/hdlc_rcp_if_nxp.c

@@ -58,7 +58,7 @@ static void hdlc_iface_init(struct net_if *iface)
 
 	ctx->ot_context = net_if_l2_data(iface);
 
-	otPlatRadioGetIeeeEui64(ctx->ot_context->instance, eui64.m8);
+	otPlatRadioGetIeeeEui64(openthread_get_default_instance(), eui64.m8);
 	net_if_set_link_addr(iface, eui64.m8, OT_EXT_ADDRESS_SIZE, NET_LINK_IEEE802154);
 }