We were using Nordic HAL for FEM modules to drive our PA/LNA using nRF52840 on zephyr (no NCS). It was only a basic configuration, where the PA and LNA pins were selected using simple_gpio library present on hal_nordic module with calls to nrf_fem_interface_configuration_get() and nrf_fem_interface_configuration_set() control functions.
With introduction of opensource MPSL on v2.5.0, I couldn't find the control function on the MPSL or anywhere on hal_nordic module, and the old functions were removed. It seems that nrfxlib used by nRF Connect SDK provides a proprietary (compiled) MPSL library. This could explain the "opensource" name on the SL folder on hal_nordic. Links: 1, 2.
Does Nordic pretends to bring back support to FEM control function on zephyr through its MPSL opensource or any other module/library? The hal for FEM on nrf52840 involves a lot of details, e.g. PPI, timers, interrupts, etc and... it was already there before zephyr v2.5.0, working fine.
There are no plans to provide FEM support in opensource implementation.
There is no FEM support for vanilla zephyr. The PR you are refering to is for 802.15.4 radio driver, which introduces open source 802.15.4 SL, not opensource MPSL. The opensource 802.15.4 SL is very basic and lacks almost all features from close source 802.14.4 SL.
Humm thanks Marjeris.
Although my confusion between MPSL and SL, we can see that the mentioned PR 64 that updated the radio driver to v1.9, removed the fem/simple_gpio folder that was added on v1.6.1. Later, the PR 73 has mentioned the introduction to MPSL FEM support on radio driver and also introduced a mpsl_fem_protocol_api.h header under SL opensource folder, but still without control functions (the ones to change LNA/PA pins, delay, etc). Is there intention to continue development there and to bring back simple gpio FEM support to open source?
Sad news, but anyway, thanks Marjeris Romero!