doc: samples: lwm2m_carrier: Add overlay and doc for SoftBank and LG U+

Add overlay and improve the Kconfigs and documentation to calrify the
extra configurations needed to successfully use SoftBank and/or LG U+.

Signed-off-by: Håvard Vermeer <havard.vermeer@nordicsemi.no>

applications/serial_lte_modem/doc/slm_description.rst

@@ -309,7 +309,14 @@ The following configuration files are provided:
   If you need to use native TLS with Thingy:91, you must disable features to free up flash memory.
 
 * :file:`overlay-carrier.conf` - Configuration file that adds |NCS| :ref:`liblwm2m_carrier_readme` support.
-  See :ref:`slm_carrier_library_support` for more information on how to connect to an operator's device management platform.
+    See :ref:`slm_carrier_library_support` for more information on how to connect to an operator's device management platform.
+
+  * :file:`overlay-carrier-softbank.conf` Configuration file that adds SoftBank configurations for the carrier libray.
+    Used in conjunction with :file:`overlay-carrier.conf`.
+    For more information see the :ref:`lwm2m_carrier_dependent` section of the :ref:`liblwm2m_carrier_readme` documentation.
+  * :file:`overlay-carrier-lgu.conf` Configuration file that adds LG U+ configurations for the carrier libray.
+    Used in conjunction with :file:`overlay-carrier.conf`.
+    For more information see the :ref:`lwm2m_carrier_dependent` section of the :ref:`liblwm2m_carrier_readme` documentation.
 
 * :file:`overlay-full_fota.conf` - Configuration file that adds full modem FOTA support.
   See :ref:`SLM_AT_FOTA` for more information on how to use full modem FOTA functionality.

applications/serial_lte_modem/overlay-carrier-lgu.conf

@@ -0,0 +1,15 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+# LG U+
+CONFIG_LWM2M_CARRIER_LG_UPLUS=y
+
+# Application FOTA
+CONFIG_DFU_TARGET_MCUBOOT=y
+CONFIG_IMG_MANAGER=y
+CONFIG_STREAM_FLASH=y
+CONFIG_STREAM_FLASH_ERASE=y
+CONFIG_FLASH_MAP=y

applications/serial_lte_modem/overlay-carrier-softbank.conf

@@ -0,0 +1,23 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+# SoftBank
+CONFIG_LWM2M_CARRIER_SOFTBANK=y
+CONFIG_LWM2M_CARRIER_SOFTBANK_DIVIDED_FOTA=y
+
+# Override default PDP context
+CONFIG_PDN_DEFAULTS_OVERRIDE=y
+CONFIG_PDN_DEFAULT_FAM_NONIP=y
+
+# Set NB-IoT system mode
+CONFIG_LTE_NETWORK_MODE_NBIOT=y
+
+# Application FOTA
+CONFIG_DFU_TARGET_MCUBOOT=y
+CONFIG_IMG_MANAGER=y
+CONFIG_STREAM_FLASH=y
+CONFIG_STREAM_FLASH_ERASE=y
+CONFIG_FLASH_MAP=y

doc/nrf/libraries/bin/lwm2m_carrier/requirements.rst

@@ -35,12 +35,12 @@ Following are some of the requirements and limitations of the application while
 
 * The LwM2M carrier library uses the TLS socket for FOTA.
 
+  * The application can still use one DTLS session and one TLS session (or two DTLS sessions).
   * If the application is using the TLS socket, it must immediately close it when the :c:macro:`LWM2M_CARRIER_EVENT_FOTA_START` event is received.
   * The socket is released by the library again upon the next reboot, or in the event of a FOTA error.
   * If the application always needs a TLS socket, it can use `Mbed TLS`_.
 
-* When in the Verizon network, the LwM2M carrier library uses both the DTLS sessions made available through the modem.
-  Therefore, the application cannot run any DTLS or TLS sessions.
+
 
   * In other networks, the application can still use one DTLS session and one TLS session (or two DTLS sessions).
   * For more information, see the :c:macro:`LWM2M_CARRIER_EVENT_FOTA_START` event in :ref:`lwm2m_events`.
@@ -58,6 +58,37 @@ Following are some of the requirements and limitations of the application while
 * The LwM2M carrier library uses the following NVS record key range: ``0xCA00`` to ``0xCAFF``.
   This range must not be used by the application.
 
+.. _lwm2m_carrier_dependent:
+
+Carrier Dependent
+*****************
+
+In order for your device to comply with the carrier's specifications, the following additional requirements apply to your application to use the carrier's LwM2M device management:
+
+.. tabs::
+
+   .. group-tab:: Verizon
+
+        * When in the Verizon network, the LwM2M carrier library uses both the DTLS sessions made available through the modem.
+          Therefore, the application must expect to fail (or retry) if it attempts to establish a DTLS or TLS session.
+          The application should never use a DTLS session indefinetly. Since this will block the LwM2M carrier library.
+
+   .. group-tab:: SoftBank
+
+        * The application must support application FOTA.
+        * The device must connect using a non-ip APN.
+
+        The :ref:`lwm2m_carrier` sample folder features an extra config file to satisfy these :kconfig:option:`CONFIG_LWM2M_CARRIER_SOFTBANK` dependencies.
+
+        * The device must operate in the NB-IoT system mode.
+          If the ref:lte_lc_readme: library is used, the Kconfig :kconfig:option:`CONFIG_LTE_NETWORK_MODE_NBIOT` can be used.
+
+   .. group-tab:: LG U+
+
+        * The application must support application FOTA.
+          The :ref:`lwm2m_carrier` sample folder features an extra config file to satisfy these :kconfig:option:`CONFIG_LWM2M_CARRIER_LG_UPLUS` dependencies.
+        * The appplication must set the LG U+ specific configurations listed in :c:struct:`lwm2m_carrier_lg_uplus_config_t`.
+          If you are unsure about wich values to supply during certification, reach out to your carrier or your local Nordic Sales representative.
 
 .. _lwm2m_lib_size:
 

samples/cellular/lwm2m_carrier/overlay-lgu.conf

@@ -0,0 +1,15 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+# LG U+
+CONFIG_LWM2M_CARRIER_LG_UPLUS=y
+
+# Application FOTA
+CONFIG_DFU_TARGET_MCUBOOT=y
+CONFIG_IMG_MANAGER=y
+CONFIG_STREAM_FLASH=y
+CONFIG_STREAM_FLASH_ERASE=y
+CONFIG_FLASH_MAP=y

samples/cellular/lwm2m_carrier/overlay-softbank.conf

@@ -0,0 +1,23 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+# SoftBank
+CONFIG_LWM2M_CARRIER_SOFTBANK=y
+CONFIG_LWM2M_CARRIER_SOFTBANK_DIVIDED_FOTA=y
+
+# Override default PDP context
+CONFIG_PDN_DEFAULTS_OVERRIDE=y
+CONFIG_PDN_DEFAULT_FAM_NONIP=y
+
+# Set NB-IoT system mode
+CONFIG_LTE_NETWORK_MODE_NBIOT=y
+
+# Application FOTA
+CONFIG_DFU_TARGET_MCUBOOT=y
+CONFIG_IMG_MANAGER=y
+CONFIG_STREAM_FLASH=y
+CONFIG_STREAM_FLASH_ERASE=y
+CONFIG_FLASH_MAP=y

samples/cellular/lwm2m_carrier/sample_description.rst

@@ -101,6 +101,10 @@ The following files are available:
 
 * :file:`prj.conf` - Standard default configuration file.
 * :file:`overlay-shell.conf` - Enables the :ref:`lwm2m_carrier_shell` and :ref:`lib_at_shell`.
+* :file:`overlay-lgu.conf` Configuration file that adds LG U+ configurations for the carrier libray.
+  For more information see the :ref:`lwm2m_carrier_dependent` section of the :ref:`liblwm2m_carrier_readme` documentation.
+* :file:`overlay-lgu.conf` - Enables configurations for LG U+.
+  For more information see the :ref:`lwm2m_carrier_dependent` section of the :ref:`liblwm2m_carrier_readme` documentation.
 
 The sample can either be configured by editing the :file:`prj.conf` file and the relevant overlay files, or through menuconfig or guiconfig.
 
@@ -120,7 +124,7 @@ Building and running
 Building with overlay
 =====================
 
-To build with a Kconfig overlay, set :makevar:`EXTRA_CONF_FILE` to the :file:`overlay-shell.conf` file using the respective :ref:`CMake option <cmake_options>`, as shown in the following example:
+To build with a Kconfig overlay, set :makevar:`EXTRA_CONF_FILE` to the desired overlay file, using the respective :ref:`CMake option <cmake_options>`, as shown in the following example:
 
 .. parsed-literal::
    :class: highlight