Do Availability Groups support Active/Passive? I am looking into the licensing of SQL Server 2012 when using Availability Groups with 2 servers.
It is not clear to me if Availability Groups are only available as Active/Active and not Active/Passive.
For reference I found a couple paragraphs in the SQL Server 2012 Licensing Reference Guide but it doesn't mention passive servers with respect to Always On.

Licensing SQL Server for High Availability SQL Server software can be
configured so that if one server fails, its processing will be picked
up, recovered and continued by another server. All editions of SQL
Server 2012 provide basic high availability features including backup
log shipping, database mirroring and two-node failover clustering.
Advanced (AlwaysOn) high availability features in SQL Server 2012
Enterprise Edition include enhanced support for multiple, active
(readable) secondary servers and support for multi-site failover
clustering. Log shipping and database mirroring take place at the
database level, whereas failover clustering takes place at the SQL
Server instance level.
AlwaysOn Availability Groups New for the SQL Server 2012 Enterprise
Edition, AlwaysOn Availability Groups enable customers to configure
multiple databases that will failover as a unit, with support for up
to four active secondary servers and two synchronous secondary
servers. The ability to use secondary servers for more than just
passive failover support can improve the performance of primary,
reporting and backup workloads due to better balancing of workloads
across instances, helping to provide better return on hardware
investment. Note: When secondary servers are actively used to support
these additional workload scenarios—that is, when the servers used for
failover purposes are no longer truly passive—they must be fully
licensed accordingly.
If you are talking about AlwaysON Availability Group in that case as long as secondary replica(s) are used strictly for Disaster Recovery or StandBy database then you do not need to license those replica in terms of SQL Server Licensing. 

Few weeks ago, I had similar question related to AlwaysON availability group and here is the official answer I got from our MS Licensing Rep.

"When the secondary server does any work at all, like taking requests or running backups off of it, or any of the readable features of AlwaysOn are enabled then it must be fully licensed.

If its sole purpose of replica is for fail-over and none of the readable features of AlwaysOnare enabled, then the fail-over right provided below will cover that server from a licensing standpoint and a second license is not required."

In terms AlwaysON FCSI (failover clustering) licensing stays the same. You only license active node. If you use log shipping for DR you do not license your DR server. 

If you are in North America region, you can call Microsoft 1-800-426-9400, Monday through Friday, 6:00 A.M. to 6:00 P.M. (Pacific Time)   to confirm this.