Fail over clustering with always

HI ALL,

We are planning to configure the fail-over clustering with always-on mechanization  between Primary DC to Secondary DC for SharePoint applications 

1. Primary SQL fail-over cluster 10.10.10.20 (10.10.10.21 and 10.10.10.22)

2. Secondary SQL Fail-over Cluster 10.10.11.30(10.10.11.28 and 10.10.11.29)

1. Do we need Listener?if how many listeners required for the above scenario

2.without listener can we configure always 

3. Automatic fail-over possible if so how do we configure

4.  What kind of share-point  DB will support always on