I2C的内核驱动测试代码

以上代码是通过我的测试没有问题的

/*
lulu  [e-mail]
 */
        #include <stdio.h>
        #include <linux/types.h>
        #include <stdlib.h>
        #include <fcntl.h>
        #include <unistd.h>
        #include <sys/types.h>
        #include <sys/ioctl.h>
        #include <errno.h>
        #define I2C_RETRIES 0x0701
        #define I2C_TIMEOUT 0x0702
        #define I2C_RDWR 0x0707
        /*********定义struct i2c_rdwr_ioctl_data和struct i2c_msg，要和内核一致*******/
struct i2c_msg
        {
                unsigned short addr;
                unsigned short flags;
#define I2C_M_TEN  0x0010 /* this is a ten bit chip address */
#define I2C_M_RD  0x0001 /* read data, from slave to master */
#define I2C_M_NOSTART  0x4000 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_NO_RD_ACK  0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_RECV_LEN  0x0400 /* length will be first received byte */
                unsigned short len;
                unsigned char *buf;
        };
struct i2c_rdwr_ioctl_data
        {
                struct i2c_msg *msgs;
                int nmsgs;
        /* nmsgs这个数量决定了有多少开始信号，对于“单开始时序”，取1*/
        };
/***********主程序***********/
        int main()
        {
                int fd,ret,i;
                struct i2c_rdwr_ioctl_data e2prom_data;
                fd=open("/dev/i2c-0",O_RDWR);
        /*
        * /dev/i2c-0是在注册i2c-dev.c后产生的，代表一个可操作的适配器。如果不使用i2c-dev.c
        *的方式，就没有，也不需要这个节点。
        */
                if(fd<0)
                {
                        perror("open error");
                }
                e2prom_data.nmsgs=2;
        /*
        *因为操作时序中，最多是用到2个开始信号（字节读操作中），所以此将
        *e2prom_data.nmsgs配置为2
        */
                e2prom_data.msgs=(struct i2c_msg*)malloc(e2prom_data.nmsgs*sizeof(struct i2c_msg));
                if(!e2prom_data.msgs)
                {
                        perror("malloc error");
                        exit(1);
                }
                ioctl(fd,I2C_TIMEOUT,5);/*超时时间*/
                ioctl(fd,I2C_RETRIES,1);/*重复次数*/
                /***write data to e2prom**/
                e2prom_data.nmsgs=1;
                (e2prom_data.msgs[0]).len=2; //1个 e2prom 写入目标的地址和1个数据
                (e2prom_data.msgs[0]).addr=0x45;//e2prom 设备地址
                (e2prom_data.msgs[0]).flags=0; //write
                (e2prom_data.msgs[0]).buf=(unsigned char*)malloc(2);
                (e2prom_data.msgs[0]).buf[0]=0xaa;// e2prom 写入目标的地址
                (e2prom_data.msgs[0]).buf[1]=0xf0;//the data to write
         ret=ioctl(fd,I2C_RDWR,(unsigned long)&e2prom_data);
                if(ret<0)
                {
                        perror("ioctl error1");
                }
                sleep(1);
        /******read data from e2prom*******/
//for(i=0;i<13;i++){
                e2prom_data.nmsgs=1;
                (e2prom_data.msgs[0]).len=3; //e2prom 目标数据的地址
                (e2prom_data.msgs[0]).addr=0x45; // e2prom 设备地址
               // (e2prom_data.msgs[0]).flags=0;//write
                //(e2prom_data.msgs[0]).buf[0]=0xaa;//e2prom数据地址
                /*(e2prom_data.msgs[1]).len=3;//读出的数据
                (e2prom_data.msgs[1]).addr=0x45;// e2prom 设备地址
                (e2prom_data.msgs[1]).flags=I2C_M_RD;//read
                (e2prom_data.msgs[1]).buf=(unsigned char*)malloc(3);//存放返回值的地址。
                (e2prom_data.msgs[1]).buf[0]=0;//初始化读缓冲
                (e2prom_data.msgs[1]).buf[1]=0;//初始化读缓冲
                (e2prom_data.msgs[1]).buf[2]=0;//初始化读缓冲*/
               
                (e2prom_data.msgs[0]).flags=1;//read
                (e2prom_data.msgs[0]).buf=(unsigned char*)malloc(3);//存放返回值的地址。
                (e2prom_data.msgs[0]).buf[0]=0;//初始化读缓冲
                (e2prom_data.msgs[0]).buf[1]=0;//初始化读缓冲
                (e2prom_data.msgs[0]).buf[2]=0;//初始化读缓冲
               
               
         ret=ioctl(fd,I2C_RDWR,(unsigned long)&e2prom_data);
                if(ret<0)
                {
                        perror("ioctl error2");
                }
                printf("buff[0]=%x\n",(e2prom_data.msgs[0]).buf[0]);
                printf("buff[1]=%x\n",(e2prom_data.msgs[0]).buf[1]);
                printf("buff[2]=%x\n",(e2prom_data.msgs[0]).buf[2]);
        /***打印读出的值，没错的话，就应该是前面写的0x58了***/
                close(fd);
                return 0;
        }