linux I2C 读写 tlv320dac3100

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <string.h>

#include <linux/i2c.h>

#include <linux/i2c-dev.h>



#define DAC3100_DEV  "/dev/i2c-2"

#define DAC3100_ADDR 0x18



static unsigned char g_page = 0xFF;



void dac3100_change_page(int fd, unsigned char page)

{

    int err;

    struct i2c_rdwr_ioctl_data data;

    struct i2c_msg msg;



    if (g_page == page) {

        return;

    }



    data.nmsgs = 1;

    data.msgs  = &msg;

    msg.addr  = DAC3100_ADDR;

    msg.flags = 0;

    msg.len   = 2;

    msg.buf   = (unsigned char*)malloc(2);

    msg.buf[0] = 0;

    msg.buf[1] = page;



    err = ioctl (fd, I2C_RDWR, (unsigned long)&data);

    if (err < 0) {

        printf("ERR: I2C_RDWR => %d\n", err);

    }

    g_page = page;

    free(msg.buf);

}





unsigned char dac3100_read(int fd,

        unsigned char page,

        unsigned char reg)

{

    int err;

    struct i2c_rdwr_ioctl_data data;

    struct i2c_msg msg[2];



    unsigned char rst;

    dac3100_change_page(fd, page);

    

    data.nmsgs = 2;

    data.msgs  = msg;

    msg[0].addr  = DAC3100_ADDR;

    msg[0].flags = 0;

    msg[0].len   = 1;

    msg[0].buf   = ®

    msg[1].addr  = DAC3100_ADDR;

    msg[1].flags = I2C_M_RD;

    msg[1].len   = 1;

    msg[1].buf   = &rst;



    err = ioctl(fd, I2C_RDWR, (unsigned long)&data);

    if (err < 0) {

        printf("ERR: DAC3100 READ => %d\n", err);

    }



    return rst;

}



int main(int argc, char** argv)

{

    int fd, err;

    int page, reg, pcnt = 3;

    unsigned char pages[] = {0, 1, 3};



    fd = open(DAC3100_DEV, 0, O_RDWR);

    if (fd < 0) {

        printf("ERR: device open failed!");

        return -1;

    }



    err = ioctl(fd, I2C_TENBIT, 0);

    if (err < 0) {

        printf("ERR: IOCTL I2C_TENBIT => %d\n", err);

    }



    for (page = 0; page < pcnt; page++) {

        printf("------- PAGE %d -------\n", pages[page]);

        for (reg = 0; reg < 128; reg++) {

            printf("%02X ", dac3100_read(fd, pages[page], reg));

            if ((reg % 8) == 7) {

                printf("\n");

            }

        }

    }





    close(fd);

    return 0;

}