Wpa supplicant/Setup for dhcpcd as network manager

First follow Network_management_using_DHCPCD.

Emerge (Version >=2.6-r2 is needed in order to get the CONFIG_MATCH_IFACE option added in April 2017.)

Complete its file with the   option for the wireless network interface:

In case authentication for the wired interface is needed this configuration file should look like

With the configuration done, run it as a service: