This is a list of things that need to be done to get this driver out of the
staging directory.

  - The HIF API is not yet clean enough.

  - Fix support for big endian architectures. See:
       https://lore.kernel.org/lkml/20191111202852.GX26530@ZenIV.linux.org.uk

  - The pointers returned by allocation functions are always checked.

  - The code that check the corectness of received message (in rx_helper()) can
    be improved. See:
       https://lore.kernel.org/driverdev-devel/2302785.6C7ODC2LYm@pc-42/

  - Support for SDIO with external IRQ is broken.

  - As suggested by Felix, rate control could be improved following this idea:
        https://lore.kernel.org/lkml/3099559.gv3Q75KnN1@pc-42/

  - When driver is about to loose BSS, it forge its own Null Func request (see
    wfx_cqm_bssloss_sm()). It should use mechanism provided by mac80211.

  - Monitoring mode is not implemented despite being mandatory by mac80211.

  - The "state" field from wfx_vif should be replaced by "vif->type".

  - It seems that wfx_upload_keys() is useless.

  - "event_queue" from wfx_vif seems overkill. These event are rare and they
     probably could be handled in a simpler fashion.

  - Feature called "secure link" should be either developed (using kernel
    crypto API) or dropped.

  - The device allows to filter multicast traffic. The code to support these
    filters exists in the driver but it is disabled because it has never been
    tested.

  - In wfx_cmd_send(), "async" allow to send command without waiting the reply.
    It may help in some situation, but it is not yet used. In add, it may cause
    some trouble:
      https://lore.kernel.org/driverdev-devel/alpine.DEB.2.21.1910041317381.2992@hadrien/
    So, fix it (by replacing the mutex with a semaphore) or drop it.