i am facing slow charging on my one plus one it was normal before marshmallow update

slow charging of my opo facing since update of marsh mallow it charges at the rate of .35 amp and i m using stock rom non root and also using my opo charger and cable its totally annoying previously it used to charge at 2 hrs max now it lengthens up to 8 hrs i still dont know where the problem arose please help to make charge fast