study input device

http://www.mask.org.tw/blog/category/linux/
http://blog.csdn.net/colorant/archive/2007/04/12/1561837.aspx

Driver -> InputCore -> Eventhandler -> userspace

# EV_RST 0x00 Reset
# EV_KEY 0x01 按键
# EV_REL 0x02 相对坐标
# EV_ABS 0x03 绝对坐标
# EV_MSC 0x04 其它
# EV_LED 0x11 LED
# EV_SND 0x12 声音
# EV_REP 0x14 Repeat