源码解析
实例:1.3.4版本at91sam系列
GPIO部分:
一、初始化:
include\asm-arm\arch-at91sam9\gpio.h
1.同一引脚的复用设置
2.输入输出初始化寄存器
3.得到基地址、设置值
二、写
include\asm-arm\arch-at91sam9\io.h
include\asm-arm\io.h
#define __raw_writel(v,a) __arch_putl(v,a)
#define __arch_putl(v,a) (*(volatile unsigned int *)(a) = (v))
三、读
include\asm-arm\io.h
#define __raw_readl(a) __arch_getl(a)
#define __arch_getl(a) (*(volatile unsigned int *)(a))
好记性不如烂笔头