请问我在AM3352BZCZD60想用gadgetfs和user mode driver配置USB device无法成功，但是g_ether可以用，这个是什么问题？
我内核版本是3.2.0，下面是我的执行过程：
# insmod gadgetfs.ko
gadgetfs: USB Gadget filesystem, version 24 Aug 2004
# lsmod
Module Size Used by Tainted: G
gadgetfs 13958 0
8188eu 878681 0
# mkdir /dev/gadget
# mount -t gadgetfs none /dev/gadget/
nop musb-hdrc.1: failed to start (null): -120
# ls /dev/gadget/
musb-hdrc
# ls /sys/class/udc/
musb-hdrc.1
# cat /proc/driver/musb_hdrc.1
Status: MHDRC, Mode=Peripheral (Power=20, DevCtl=98)
OTG state: b_idle; inactive
Options: ?dma?, otg (peripheral+host), [eps=16]
Peripheral address: 00
Root port status: 00000000
CPPI: txcr=0 txsrc=0 txena=0; rxcr=0 rxsrc=280de80 rxena=0
Gadget driver: (none)
ep0 (hw0): 1buf, csr 0000 maxp 0000
(queue empty)
# uname -a
Linux rt335x 3.2.0 #139 Mon Jul 6 14:06:15 CST 2015 armv7l GNU/Linux
# cat /proc/cpuinfo
Processor : ARMv7 Processor rev 2 (v7l)
BogoMIPS : 598.35
Features : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x3
CPU part : 0xc08
CPU revision : 2
Hardware : am335xevm
Revision : 0000
Serial : 0000000000000000