Well, in this blog post you will find information about how to migrate your disks in order to use AFD, keep in mind that in my environment I am using only one database and also one 1 Diskgroup, if you are planning to migrate from ASMLIb to AFD I recommend to migrate all your diskgroups.
To know which diskgroups I have:
[grid@db12102 trace]$ asmcmd lsdg
State Type Rebal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name
MOUNTED EXTERN N 512 4096 1048576 31455 29491 0 29491 0 N DATA/
What is the path of each disk used by my diskgroups? Remember to list all the disks used by all your diskgrups.
[grid@db12102 trace]$ asmcmd lsdsk -G data