Direction finding functionality does antenna switching during CTE
reception in AoA mode and CTE transmission in AoD mode. Antennas are
switched according to user provided antenna switch pattern. If a CTE
length is enough to exhaust all antenna ids in a switch pattern then
radio should loopback to reference antenna and continue from switching
from that. Current implementation loops back to antenna that is just
after reference antenna in the switch pattern.
The commit fixes that by insertion of the reference antenna
at the end of switch pattern. Radio will operate as it was before,
it will restart switching from the same index in a switch pattern.
At the same time reference antenna will be inserted into the loop
if switching pattern is exhausted. That also means, the maximum
number of antenna ids in a switch pattern has to be decreased by
one.
The commit also fixes lower bound in the BT_CTLR_DF_MAX_ANT_SW_PATTERN-
_LEN that should be equal two. It was set to three, because in the
past the antenna at index zero was used for reception of a PDU.
Now this antenna ID is provided by device tree configuration.
Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>
0a497fcd55