applications: serial_lte_modem: Remove use of CONFIG_UART_x_NRF_HW_ASYNC

Use of CONFIG_UART_x_NRF_HW_ASYNC has been mostly removed earlier from
SLM app side with PR nrfconnect#19720. Removing last few references.
This causes some overlays to become empty so they are deleted.
overlay-zephyr-modem-external-mcu.conf would only have
CONFIG_SLM_POWER_PIN so it's also removed and documentation updated
so that apps should define it.

Signed-off-by: Tommi Rantanen <[email protected]>

Author: trantanen

applications/serial_lte_modem/doc/nRF91_as_Zephyr_modem.rst

@@ -46,10 +46,9 @@ The following configuration files must be included:
 * :file:`overlay-zephyr-modem.conf` - To tailor SLM to how Zephyr's cellular modem driver works.
   This enables the :ref:`CONFIG_SLM_START_SLEEP <CONFIG_SLM_START_SLEEP>` Kconfig option, which makes the nRF91 Series SiP start only when the :ref:`power pin <CONFIG_SLM_POWER_PIN>` is toggled.
 
-In addition, if the controlling chip is an external MCU, the following files must also be included:
+In addition, if the controlling chip is an external MCU, the following configurations must also be included:
 
-* :file:`overlay-zephyr-modem-external-mcu.conf`- To define the power pin.
-  Make sure to update the defined pin so that it matches your setup.
+* :kconfig:option:`CONFIG_SLM_POWER_PIN` Kconfig option - To define the power pin so that it matches your setup.
 * :file:`overlay-external-mcu.overlay` - To configure which UART SLM will use.
   The actual configuration of the UART is defined in the :file:`*_ns.overlay` overlay file matching your board in the :file:`boards` directory.
   Make sure to update the UART configuration (pins, baud rate) so that it matches your setup.

applications/serial_lte_modem/doc/slm_description.rst

@@ -328,9 +328,6 @@ The following configuration files are provided:
   This disables most of the IP-based protocols available through AT commands (such as FTP and MQTT) as it is expected that the controlling chip's own IP stack is used instead.
   See :ref:`CONFIG_SLM_PPP <CONFIG_SLM_PPP>` and :ref:`SLM_AT_PPP` for more information.
 
-* :file:`overlay-ppp-without-cmux.conf` - Kconfig fragment that configures the UART to be used by PPP.
-  This configuration file should be included when building SLM with PPP and without CMUX.
-
 * :file:`overlay-ppp-without-cmux.overlay` - Devicetree overlay that configures the UART to be used by PPP.
   This configuration file should be included when building SLM with PPP and without CMUX, in addition to :file:`overlay-ppp.conf`.
   It can be customized to fit your configuration (UART, baud rate, and so on).
@@ -339,7 +336,8 @@ The following configuration files are provided:
 * :file:`overlay-memfault.conf` - Configuration file that enables `Memfault`_.
   For more information about Memfault features in |NCS|, see :ref:`mod_memfault`.
 
-* :file:`overlay-zephyr-modem.conf`, :file:`overlay-zephyr-modem-external-mcu.conf`, :file:`overlay-zephyr-modem-nrf9160dk-nrf52840.conf`, :file:`overlay-external-mcu.overlay`,  and :file:`overlay-zephyr-modem-nrf9160dk-nrf52840.overlay` - These configuration files are used when compiling SLM to turn an nRF91 Series SiP into a Zephyr-compatible standalone modem.
+* :file:`overlay-zephyr-modem.conf`, :file:`overlay-zephyr-modem-nrf9160dk-nrf52840.conf`, :file:`overlay-external-mcu.overlay`,  and :file:`overlay-zephyr-modem-nrf9160dk-nrf52840.overlay` - These configuration files are used when compiling SLM to turn an nRF91 Series SiP into a Zephyr-compatible standalone modem.
+  Also set :kconfig:option:`CONFIG_SLM_POWER_PIN` Kconfig option.
   See :ref:`slm_as_zephyr_modem` for more information.
 
 * :file:`boards/nrf9160dk_nrf9160_ns.conf` - Configuration file specific for the nRF9160 DK.

applications/serial_lte_modem/overlay-ppp-without-cmux.conf

@@ -4,9 +4,5 @@
 # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 #
 
-# Ensure that HW RX byte counting is enabled. This especially matters at higher baud rates.
-CONFIG_UART_1_NRF_HW_ASYNC=y
-CONFIG_UART_1_NRF_HW_ASYNC_TIMER=2
-
 # nRF52 <=> nRF91 interface pin 4 (see https://docs.nordicsemi.com/bundle/ug_nrf91_dk/page/UG/nrf91_DK/board_controller.html)
 CONFIG_SLM_POWER_PIN=22