一，问题描述

双USB接口，电容触摸跟电磁手写笔触摸会产生误触现象，所以需要在底层实现电磁笔优先级。
电磁屏优先（指当笔和手都放屏上，手不发信息），因为都是USB接口使用，电容触摸跟电磁手写笔触摸会产生误触现象；

rk3568:/ # getevent
add device 1: /dev/input/event5
  name:     "ILITEK ILITEK-TP"
add device 2: /dev/input/event0
  name:     "fdd70030.pwm"
add device 3: /dev/input/event1
  name:     "rk805 pwrkey"
add device 4: /dev/input/event4
  name:     "rk-headset"
add device 5: /dev/input/event3
  name:     "adc-keys"
add device 6: /dev/input/event2
  name:     "HUION Huion Monitor"

cat sys/kernel/debug/usb/devices 查看本地usb设备信息

rk3568:/ # cat sys/kernel/debug/usb/devices
T:  Bus=02 Lev=02 Prnt=02 Port=01 Cnt=01 Dev#=  3 Spd=12   MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=222a ProdID=0001 Rev= 0.02
S:  Manufacturer=ILITEK
S:  Product=ILITEK-TP
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=400mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=03(HID  ) Sub=00 Prot=00 Driver=usbhid
E:  Ad=81(I) Atr=03(Int.) MxPS=  64 Ivl=1ms
E:  Ad=02(O) Atr=03(Int.) MxPS=  64 Ivl=1ms


T:  Bus=03 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  2 Spd=12   MxCh= 0
D:  Ver= 2.00