NEXUS 7 2012 lollipop 5.1.1 grouper wifi OTG doesn't work please help :(

hello
NEXUS 7 2012 lollipop 5.1.1 grouper wifi... with lollipop 5.1.1 stock rom
with kernel 3.1.10-gf5d7b8b
nothing works in USB ;'( mouse , keyboard , pendrive
when i connect mouse or keyboard nothing happen ;/
please help :(