samples: use nRF21540-EK shield instead of devicetree overlays

Thread and Zigbee samples used a devicetree overlay to enable
nRF21540 support. This patch removes the obsolete overlay and
updates documentation to properly use recently introduced
nRF21540-EK shield.

Signed-off-by: Hubert Miś <[email protected]>

Author: Hubert Miś

doc/nrf/includes/sample_fem_support.txt

@@ -5,30 +5,17 @@
 You can add support for the nRF21540 front-end module to the sample.
 See :ref:`ug_radio_fem` for more information.
 
-To add support for the nRF21540 FEM, add the provided :file:`dts-nrf21540-fem.overlay` devicetree overlay file when building.
-The file is located in the |fem_file_path| folder.
-Make sure that the GPIOs in the file correspond to those in which your front-end module is connected.
-
-.. note::
-   You must add the provided overlay file if you use the nRF21540 EK.
-   If you use the nRF21540 DK, build your application for the :ref:`nrf21540dk_nrf52840 <zephyr:nrf21540dk_nrf52840>` board.
-   The devicetree for the nRF21540 DK already contains the required FEM configuration, so you do not need to add the overlay file.
+To add support for the nRF21540 FEM, build the sample for a board containing nRF21540 FEM like nrf21540dk_nrf52840 or create a devicetree overlay file describing how FEM is connected to nRF5 SoC in your device.
 
 See :ref:`zephyr:set-devicetree-overlays` for different ways of adding the overlay file.
 
-The easiest way to add the file when building is to set it in the ``DTC_OVERLAY_FILE`` variable.
-However, doing so will override the default settings.
-For some boards, this sample requires additional overlay files, which are automatically included when building with the default settings.
-When you set the ``DTC_OVERLAY_FILE`` variable, you must specify all overlay files that are needed for building.
-Check the :file:`boards` folder to see the additional overlay files.
+.. note::
+   If you use the nRF21540 EK, append ``nrf21540_ek`` shield to your build command instructing build system to append the appropriate devicetree overlay file.
 
-Follow the instructions in :ref:`cmake_options` to specify the ``DTC_OVERLAY_FILE`` variable.
 For example, to build the sample from the command line for an nRF52833 DK with an attached nRF21540 EK, invoke the following command within the sample directory:
 
 .. code-block:: console
 
-    west build -b nrf52833dk_nrf52833 -- -DDTC_OVERLAY_FILE="boards/nrf52833dk_nrf52833.overlay;../common/dts-nrf21540-fem.overlay"
-
-Alternatively, you can copy the contents of :file:`dts-nrf21540-fem.overlay` to the board's overlay file.
+    west build -b nrf52833dk_nrf52833 -- -DSHIELD=nrf21540_ek
 
-To add support for other front-end modules, add the respective overlay files in the same way.
+To add support for other front-end modules, add the respective devicetree file entries to the board devicetree file or a devicetree overlay file.

samples/openthread/cli/README.rst

@@ -75,8 +75,6 @@ You can switch to USB transport by :ref:`activating the USB overlay extension <o
 FEM support
 ===========
 
-.. |fem_file_path| replace:: :file:`samples/openthread/common`
-
 .. include:: /includes/sample_fem_support.txt
 
 Requirements

samples/openthread/coap_client/README.rst

@@ -41,8 +41,6 @@ For more information about the multiprotocol feature, see :ref:`ug_multiprotocol
 FEM support
 ===========
 
-.. |fem_file_path| replace:: :file:`samples/openthread/common`
-
 .. include:: /includes/sample_fem_support.txt
 
 Device Firmware Upgrade extension

samples/openthread/coap_server/README.rst

@@ -29,8 +29,6 @@ For example usage of the Zephyr CoAp API, see the :ref:`coap_client_sample` samp
 FEM support
 ===========
 
-.. |fem_file_path| replace:: :file:`samples/openthread/common`
-
 .. include:: /includes/sample_fem_support.txt
 
 Requirements

samples/openthread/common/dts-nrf21540-fem.overlay

@@ -57,8 +57,6 @@ Use the :file:`overlay-logging.conf` overlay file as reference for this purpose.
 FEM support
 ===========
 
-.. |fem_file_path| replace:: :file:`samples/openthread/common`
-
 .. include:: /includes/sample_fem_support.txt
 
 Requirements

samples/openthread/coprocessor/README.rst

@@ -41,8 +41,6 @@ Configuration
 FEM support
 ===========
 
-.. |fem_file_path| replace:: :file:`samples/zigbee/common`
-
 .. include:: /includes/sample_fem_support.txt
 
 User interface

samples/zigbee/common/dts-nrf21540-fem.overlay

@@ -119,8 +119,6 @@ For more information about using configuration overlay files, see :ref:`zephyr:i
 FEM support
 ===========
 
-.. |fem_file_path| replace:: :file:`samples/zigbee/common`
-
 .. include:: /includes/sample_fem_support.txt
 
 .. _zigbee_light_switch_user_interface:

samples/zigbee/light_bulb/README.rst

@@ -158,8 +158,6 @@ to upgrade the dongle, you can use one of the following options:
 FEM support
 ===========
 
-.. |fem_file_path| replace:: :file:`samples/zigbee/common`
-
 .. include:: /includes/sample_fem_support.txt
 
 .. _zigbee_ncp_user_interface: