2019独角兽企业重金招聘Python工程师标准>>> 
by 韩大卫@吉林师范大学
转载请务必表明出处。
我的上篇文章《linux下i2c与E2PROM通信》给出了通过IIC总线，如何读写EEPROM相应位置的内容。
但是有一些功能没有实现：
比如： 只能单独操作一个寄存器地址，不能一次性写入大量内容；
只能读一个寄存器的数值，不能可选择性地一次读出大量内容；
这是由于为了做到通用化，我们的i2c没有一次性大量读写的功能。 在本程序中针对EEPROM做了一些改进,详细说明可以在help_info() 中找到。
FOR EXAMPLE:
eep -r 0x08 Display the contents of EEPROM from 0x00 to 0x08
eep -ro 0x08 Display the contents of EEPROM from 0x08
eep -r 0x02 0x80 Display the contents of EEPROM from address 0x20 to x080
eep -s 0x04 "hello world!" Write "hello world!" to EEPROM from 0x04
eep -d /dev/i2c-1 -s 0x04 "hello world!" Write "hello world!" to EEPROM from 0x04 with path"/dev/i2c-1"
*************************************************************
main.c
********************** *******************************
#include "i2c.h"
#define TIMEOUT 4
#define RETRY 2
#define READ_ONLY 1
static int fd ;
static int addr = 0x57;
static int offset;
static int offset_end;
inline int read_data(u16 addr, u8 offset, u8 *val){
int ret;
ret = i2c_read_data(addr,offset,val);
if(ret < 0){
printf("%s error!\n",__FUNCTION__);
exit(-1);
}
return 0;
}
inline int write_data(u16 addr, u8 offset, u8 val){
int ret;
ret = i2c_write_data(addr,offset,val);
if(ret < 0){
printf("%s:error = %s\n",__FUNCTION__,strerror(errno));
exit(-1);
}
usleep(10000);
return 0;
}
int eep_write(u16 addr,u8 offset,char* argv){
//u8 data = (u8)strtoul(argv,0,16);
int i,j,len = 0;
char* data = argv;
while( *data++ ){
len++;
}
data = argv;
printf("len = %d\n",len);
for( i = offset ,j = 0;i < offset + len ;i++,j++ ){
write_data(addr,i,data[j]);
}
printf("write success,data = %s\n",argv);
return 0;
}
int eep_read(u16 addr,u8 offset_start,u8 offset_end,int flags){
int i;
u8 buf[256] = {0};
if( flags ){
read_data(addr,offset_end,&buf[0]);
printf("read success,data[%d] = %c\n",offset,buf[0]);
}else{
printf("read success,data = ");
for(i = offset_start ; i <= offset_end ; i++){
read_data(addr,i,&buf[i]);
printf("%c",buf[i]);
}
printf("\n");
}
return 0;
}
void error_info(void){
printf("cmd error! ");
printf("Please input --help or -h for help information\n");
exit(-1);
}
void help_info(void){
printf("\nUsage: eep OPTIONS OFFSET [OFFSET_END] [DATA]\n");
printf("\nDisplay the contents of EEPROM ,or write DATA to EEPROM\n");
printf("\nOptions:\n");
printf("\n\t-r OFFST \t\t\t\tDisplay the contents of EEPROM from 0x00 to OFFSET\n");
printf("\n\t-r OFFSET OFFSET_END\t\t\tDisplay the contents of EEPROM from OFFSET to OFFSET_END\n");
printf("\n\t-s OFFSET DATA\t\t\t\twrite DATA to EEPROM form OFFSET\n");
printf("\n\t-h or --help\t\t\t\tshow help information\n");
printf("\nOFFSET\tFORMAT: 0xXX 0xXX can change from 00 to ff\n");
printf("\nFOR EXAMPLE:\n");
printf("\n\teep -r 0x08\t\t\t\tDisplay the contents of EEPROM from 0x00 to 0x08\n");
printf("\n\teep -ro 0x08\t\t\t\tDisplay the contents of EEPROM from 0x08\n");
printf("\n\teep -r 0x02 0x80\t\t\tDisplay the contents of EEPROM from address 0x20 to x080\n");
printf("\n\teep -s 0x04 \"hello world!\"\t\tWrite \"hello world!\" to EEPROM from 0x04\n\n");
}
int i2c_path(char * argv){
fd = i2c_open(argv,TIMEOUT,RETRY);
if( fd < 0 ){
printf("i2c_open error!\n");
exit(-1);
}
return 0;
}
int i2c_offs(char *argv){
return (u8)strtoul(argv,0,16);
}
int main(int argc,char* argv[]){
int flags;
switch(argc){
case 2 :{
if(!strcmp(argv[1],"-h") || !strcmp(argv[1],"--help")){
help_info();
}else
error_info();
}break;
case 3 :{
if(!strcmp(argv[1],"-r" )|| !strcmp(argv[1],"-ro" )){
flags = (!strcmp(argv[1],"-ro")) ? READ_ONLY : 0 ;
i2c_path("/dev/i2c-0");
offset = i2c_offs(argv[2]);
eep_read(addr,0,offset,flags);
}else
error_info();
}break;
case 4 :{
if(!strcmp(argv[1],"-r")){
i2c_path("/dev/i2c-0");
offset = i2c_offs(argv[2]);
offset_end = i2c_offs(argv[3]);
eep_read(addr,offset,offset_end,0);
}else if(!strcmp(argv[1],"-s")){
i2c_path("/dev/i2c-0");
offset = i2c_offs(argv[2]);
eep_write(addr,offset,argv[3]);
}else
error_info();
}break;
case 5 :{
if(!strcmp(argv[1],"-d")){
i2c_path(argv[2]);
if(!strcmp(argv[3],"-r") || !strcmp(argv[3],"-ro")){
i2c_offs(argv[4]);
flags = (!strcmp(argv[3],"-ro")) ? READ_ONLY : 0 ;
offset = i2c_offs(argv[4]);
eep_read(addr,0,offset,flags);
}else
error_info();
}else
error_info();
}break;
case 6 :{
if(!strcmp(argv[1],"-d")){
i2c_path(argv[2]);
if(!strcmp(argv[3],"-r")){
offset = i2c_offs(argv[4]);
offset_end = i2c_offs(argv[5]);
eep_read(addr,offset,offset_end,0);
}else if(!strcmp(argv[3],"-s")){
offset = i2c_offs(argv[4]);
eep_write(addr,offset,argv[5]);
}else
error_info();
}else
error_info();
}break;
default:
error_info();
}
return 0;
}
*************************** ********************************
i2c.c
*********************************************************
#include "i2c.h"
static int fd;
int
i2c_read_data(u16 addr, u8 offset, u8 *val)
{
int i,ret = 0;
struct i2c_rdwr_ioctl_data *data;
if ((data = (struct i2c_rdwr_ioctl_data *)malloc(sizeof(struct i2c_rdwr_ioctl_data))) == NULL)
return -1;
data->nmsgs = 2;
if ((data->msgs = (struct i2c_msg *)malloc(data->nmsgs * sizeof(struct i2c_msg))) == NULL) {
ret = -1;
goto errexit3;
}
if ((data->msgs[0].buf = (unsigned char *)malloc( EEPROM_PAGE_SIZE + 1 )) == NULL) {
ret = -1;
goto errexit2;
}
if ((data->msgs[1].buf = (unsigned char *)malloc( EEPROM_PAGE_SIZE + 1 )) == NULL) {
ret = -1;
goto errexit1;
}
data->msgs[0].addr = addr;
data->msgs[0].flags = I2C_M_WR;
data->msgs[0].len = 1;
data->msgs[0].buf[0] = offset;
data->msgs[1].addr = addr;
data->msgs[1].flags = I2C_M_RD;
data->msgs[1].len = 1;
data->msgs[1].buf[0] = 0;
if ((ret = __i2c_send(fd, data)) < 0)
goto errexit0;
for(i = 0 ;i < data->msgs[1].len; i++)
val[i] = data->msgs[1].buf[i];
errexit0:
free(data->msgs[1].buf);
errexit1:
free(data->msgs[0].buf);
errexit2:
free(data->msgs);
errexit3:
free(data);
return ret;
}
int
i2c_write_data(u16 addr, u8 offset, u8 val)
{
int ret = 0;
struct i2c_rdwr_ioctl_data *data;
if ((data = (struct i2c_rdwr_ioctl_data *)malloc(sizeof(struct i2c_rdwr_ioctl_data))) == NULL)
return -1;
data->nmsgs = 1;
if ((data->msgs = (struct i2c_msg *)malloc(data->nmsgs * sizeof(struct i2c_msg))) == NULL) {
ret = -1;
goto errexit2;
}
if ((data->msgs[0].buf = (unsigned char *)malloc( 2 * (EEPROM_PAGE_SIZE + 1))) == NULL) {
ret = -1;
goto errexit1;
}
data->msgs[0].addr = addr;
data->msgs[0].flags = 0;
data->msgs[0].len = 2;
data->msgs[0].buf[0] = offset;
data->msgs[0].buf[1] = val;
if ((ret = __i2c_send(fd, data)) < 0){
ret = -1;
goto errexit0;
}
errexit0:
free(data->msgs[0].buf);
errexit1:
free(data->msgs);
errexit2:
free(data);
return ret;
}
int
i2c_open(unsigned char* dev, unsigned int timeout, unsigned int retry)
{
if ((fd = open(dev, O_RDWR)) < 0)
return fd;
__i2c_set(fd, timeout, retry);
return fd;
}
static int
__i2c_send(int fd, struct i2c_rdwr_ioctl_data *data)
{
if (fd < 0)
return -1;
if (data == NULL)
return -1;
if (data->msgs == NULL || data->nmsgs == 0)
return -1;
return ioctl(fd, I2C_RDWR, (unsigned long)data) ;
}
static int
__i2c_set(int fd, unsigned int timeout, unsigned int retry)
{
if (fd == 0 )
return -1;
ioctl(fd, I2C_TIMEOUT, timeout ? timeout : I2C_DEFAULT_TIMEOUT);
ioctl(fd, I2C_RETRIES, retry ? retry : I2C_DEFAULT_RETRY);
return 0;
}
void
i2c_close(int fd)
{
if (fd < 0)
return;
close(fd);
}
unsigned bcd2bin(unsigned char val)
{
return (val & 0x0f) + (val >> 4) * 10;
}
unsigned char bin2bcd(unsigned val)
{
return ((val / 10) << 4) + val % 10;
}
******************************************************
i2c.h:
*********************************************************
#ifndef _EEPROM_IO_H
#define _EEPROM_TO_H
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define I2C_DEFAULT_TIMEOUT 1
#define I2C_DEFAULT_RETRY 2
#define I2C_M_WR 0 //定义写标志
#define MAX_MSG_NR 2 //根据AT24C02手册, 最大消息数为2
#define EEPROM_BLOCK_SIZE 256 //每个block容量256 bytes
#define EEPROM_PAGE_SIZE 8 //用页写，AT24C02页大小为8字节
#define I2C_MSG_SIZE (sizeof(struct i2c_msg))
typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned long long u64;
typedef signed char s8;
typedef short s16;
typedef int s32;
typedef long long s64;
unsigned bcd2bin(unsigned char val);
unsigned bcd2bin(unsigned char val);
static int
__i2c_send(int fd, struct i2c_rdwr_ioctl_data *data);
static int
__i2c_set(int fd, unsigned int timeout, unsigned int retry);
int
i2c_read_data(u16 addr, u8 offset, u8 *val);
int
i2c_write_data(u16 addr, u8 offset, u8 val);
int
i2c_open(unsigned char* dev, unsigned int timeout, unsigned int retry);
#endif
****************************************************************8