查询到的资料介绍
GPIO接口
https://blog.csdn.net/wumumang/article/details/54317508
gpio接口是干什么的?gpio怎么用?
http://www.elecfans.com/emb/jiekou/20171206595752.html
Kernel 中的 GPIO 定义和控制
https://www.cnblogs.com/lidabo/p/5319210.html
GPIO介绍
https://blog.csdn.net/liudongdong19/article/details/81534088
STM32开发 -- GPIO详解
https://blog.csdn.net/qq_29350001/article/details/80681244
I2C总线协议图解
https://www.cnblogs.com/aaronLinux/p/6218660.html
I2C
https://www.cnblogs.com/zzdbullet/p/9485464.html
