1. 分析
FSMP1A 开发板的 LED1 灯的分析，以下是点亮该灯需要使用到的寄存器
PE10 GPIOE_MODER[21:20]->01 0X50006000 4字节 GPIOE_OTYPER 0X50006004 GPIOE_SPEEDR 0X50006008 GPIOE_PUPDR 0X5000600C GPIOE_IDR GPIOE_ODR[10]->1(输出高电平) 0（输出低电平） 0X50006014 4字节 RCC_AHB4ENSETR[4]->1 0X50000A28 4字节
2. 编写控制LED灯的应用程序
#include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <string.h> int main(int argc, char const *argv[]) { char buf[128] = { 0 }; int fd = open("/dev/mychrdev", O_RDWR); if (fd < 0) { printf("打开设备文件失败\n"); exit(-1); } while (1) { printf("请输入控制命令--1：开灯 0：关灯>"); fgets(buf, sizeof(buf), stdin); // 在终端读取 buf[strlen(buf) - 1] = '\0'; // 吃掉末尾的‘\n’; write(fd, buf, sizeof(buf)); } close(fd); return 0; }
3. 编写头文件
#ifndef __HEAD_H__ #define __HEAD_H__ #define PHY_LED1_MODER 0X50006000 #define PHY_LED1_ODR 0X50006014 #define PHY_RCC 0X50000A28 #endif
4. 编写驱动文件
#include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/uaccess.h> #include <linux/io.h> #include "head.h" int major; // 用于保存主设备号 char kbuf[128] = { 0 }; unsigned int *vir_moder; unsigned int *vir_odr; unsigned int *vir_rcc; // 封装操作方法 int mycdev_open(struct inode *inode, struct file *file) { printk("%s:%s:%d\n", __FILE__, __func__, __LINE__); return 0; } ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof) { int ret; if (sizeof(kbuf) < size) size = sizeof(kbuf); ret = copy_to_user(ubuf, kbuf, size); if (ret) { printk("copy_tO_user filed\n"); return -EIO; } printk("%s:%s:%d\n", __FILE__, __func__, __LINE__); return 0; } ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof) { int ret; if (sizeof(kbuf) < size) //判断用户空间的需求是否能被驱动满足，满足不了就给能给的最好的 size = sizeof(kbuf); ret = copy_from_user(kbuf, ubuf, size); if (ret) { printk("copy_from_user filed\n"); return -EIO; } if (kbuf[0] == '1') //开灯 { //开灯逻辑 (*vir_odr) |= (0x1 << 10); } else if (kbuf[0] == '0') //关灯 { //关灯 (*vir_odr) &= (~(0x1 << 10)); } printk("%s:%s:%d\n", __FILE__, __func__, __LINE__); return 0; } int mycdev_close(struct inode *inode, struct file *file) { printk("%s:%s:%d\n", __FILE__, __func__, __LINE__); return 0; } // 定义操作方法结构体变量并完成初始化 struct file_operations fops = { .open = mycdev_open, .read = mycdev_read, .write = mycdev_write, .release = mycdev_close, }; static int __init mycdev_init(void) { //字符设备驱动注册 major = register_chrdev(0, "mychrdev", &fops); if (major < 0) { printk("字符设备驱动注册失败\n"); return major; } printk("字符设备驱动注册成功major=%d\n", major); //映射物理寄存器 vir_moder = ioremap(PHY_LED1_MODER, 4); if (vir_moder == NULL) { printk("MODER寄存器地址映射表失败\n"); return -EFAULT; } vir_odr = ioremap(PHY_LED1_ODR, 4); if (vir_odr == NULL) { printk("ODR寄存器地址映射表失败\n"); return -EFAULT; } vir_rcc = ioremap(PHY_RCC, 4); if (vir_rcc == NULL) { printk("RCC寄存器地址映射表失败\n"); return -EFAULT; } printk("寄存器地址映射成功\n"); //寄存器初始化 (*vir_rcc) |= (0x1 << 4); //rcc使能 (*vir_moder) &= (~(0X3 << 20)); //设置为输出 (*vir_moder) |= (0x1 << 20); (*vir_odr) &= (~(0x1 << 10)); //灭灯 printk("硬件寄存器初始化成功\n"); return 0; } static void __exit mycdev_exit(void) { //取消寄存器地址映射 iounmap(vir_moder); iounmap(vir_odr); iounmap(vir_rcc); //字符设备驱动的注销 unregister_chrdev(major, "mychrdev"); } module_init(mycdev_init); module_exit(mycdev_exit); MODULE_LICENSE("GPL");
Appendix
三盏灯控制，且使用结构体：
