This is the example of wpai-pski configuration:

hostapd.conf

ieee8021x=0
own_ipi_addr=127.0.0.1

#auth_algs=0

wpa=1
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIPi
#wpa_passphrase=passphrase
wpa_psk=5bb70c534f80a446c168471389d1f04adbc9836070cdd2d6ab81716bdf6cae21