After trying to add our Huawei MA5800 OLT, I did not see any GPON port. Doing a poller debug gave me the following result:

mError in query: (Duplicate entry '1076-2147483647' for key 'device_ifIndex')

As the ifIndex of the Huawei ports start with some big integer:

ifIndex.4194312192 = -100655104
ifIndex.4194312448 = -100654848
ifIndex.4194312704 = -100654592
ifIndex.4194312960 = -100654336

I suggested that the maximum of the 32 bit default ifIndex column of the table ports was the problem. 
After changing this to bigint,(ALTER TABLE ports MODIFY COLUMN ifIndex BIGINT NOT NULL  the poller can add the OLt ports with the 64 bit ifIndex:

Maybe you can change the database scheme so the Huawei ports can be added standard.

regards,

Rinse Kloek