You can use these SNMP MIBS to achieve this:
Get list of clients with their physical addresses:
snmpwalk -Os -c public -v 2c 1.1.1.1 iso.3.6.1.private.enterprises.14823.2.2.1.1.2.1.1.2
userPhyAddress.172.16.206.246 = STRING: b8:17:c2:00:11:22
Get a list of locations per client IP:
snmpwalk -Os -c public -v 2c 1.1.1.1 iso.3.6.1.private.enterprises.14823.2.2.1.1.2.1.1.7
userLocation.172.16.206.246 = STRING: AP1
You can download the Aruba MIBS and documentation from the Aruba support website.