SPI驱动模型参考
http://blog.chinaunix.net/uid-21501855-id-5211900.html
https://blog.csdn.net/droidphone/article/details/24353293
https://blog.csdn.net/lizuobin2/article/details/51735963
https://www.cnblogs.com/fly-fish/archive/2011/10/26/2225592.html
原文：https://www.cnblogs.com/retry/p/11935650.html