版本：sdk-xgs-robo-6.3.8
平台：BCM53344
应用：控制POE芯片
描述：POE控制芯片使用PD69200，使用i2c与其通信，每次需要发送15字节数据，并接受15字节的返回数据。

1.更改函数
打开文件sdk-xgs-robo-6.3.8/src/soc/i2c/smbus.c
更改如下：
int
soc_i2c_block_read(int unit, i2c_saddr_t saddr,uint8 com, uint8* count, uint8* data)
{//... 省略 ...I2C_LOCK(unit);
// 53344芯片在定义了BCM_CMICM_SUPPORT,所以会运行下面的代码。
#ifdef BCM_CMICM_SUPPORTif(soc_feature(unit, soc_feature_cmicm) && !SOC_IS_SAND(unit)) {
retry:　　//这个函数是smbus协议的命令格式。与I2C有些区别。注释掉发送地址和com的地方。　　//直接读取数据
//        rval = SOC_I2C_TX_ADDR(saddr);
//        WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);
//        rval = com;
//        WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);rval = SOC_I2C_RX_ADDR(saddr);soc_reg_field_set(unit, CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr, &rval, MASTER_WR_STATUSf, 1); /* Last Byte */WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);//更改要接受的数据个数。默认是0，因此会读取0个数据。　　　　//查看芯片手册，需要将CMIC_I2CM_SMBus_Master_Command寄存器的最低8位（RD_BYTE_COUNT),设置为要读取的字节个数。
//        rval = 0;rval = *count;soc_reg_field_set(unit, CMIC_I2CM_SMBUS_MASTER_COMMANDr, &rval, SMBUS_PROTOCOLf, SMBUS_BLOCK_READ);WRITE_CMIC_I2CM_SMBUS_MASTER_COMMANDr(unit,rval);rv = smbus_start_wait(unit);if (rv == SOC_E_NONE) {　　　　//直接读取即可，这一部分也不需要，smbus协议才需要
//            READ_CMIC_I2CM_SMBUS_MASTER_DATA_READr(unit, &rval);
//            *count = (uint8) (rval & 0xff);ptr = data;for( i = 0; i < *count; i++, ptr++) {READ_CMIC_I2CM_SMBUS_MASTER_DATA_READr(unit, &rval);*ptr = (uint8) (rval & 0xff);}} else if (rt-- > 0) {goto retry;} else {rv = SOC_E_TIMEOUT;}} else　　//后面的不运行
#endif// ... 省略 ...}
//同理，write函数也进行注释
int
soc_i2c_block_write(int unit, i2c_saddr_t saddr,uint8 com, uint8 count, uint8* data)
{int i,rv = SOC_E_NONE;uint8* ptr = NULL;
#ifdef BCM_CMICM_SUPPORTuint32 rval;int rt = 5;
#endifsoc_cm_debug(DK_I2C, "i2c%d: soc_i2c_block_write %02x bytes @ %02x - %02x\n", unit, count, saddr, com);#ifdef BCM_CALADAN3_SVKif (unit == -1) {return cpu_i2c_block_write(unit, saddr, com, data, count);}
#endifI2C_LOCK(unit);
#ifdef BCM_CMICM_SUPPORTif(soc_feature(unit, soc_feature_cmicm) && !SOC_IS_SAND(unit)) {
retry:rval = SOC_I2C_TX_ADDR(saddr);WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);
//        rval = com;
//        WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);
//        rval = count;
//        WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);
ptr = data;for( i = 0; i < (int) (count - 1); i++, ptr++) {rval = (uint32) *ptr;WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);}rval = (uint32) *ptr;soc_reg_field_set(unit, CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr, &rval, MASTER_WR_STATUSf, 1); /* Last Byte */WRITE_CMIC_I2CM_SMBUS_MASTER_DATA_WRITEr(unit, rval);rval = 0;soc_reg_field_set(unit, CMIC_I2CM_SMBUS_MASTER_COMMANDr, &rval, SMBUS_PROTOCOLf, SMBUS_BLOCK_WRITE);WRITE_CMIC_I2CM_SMBUS_MASTER_COMMANDr(unit,rval);rv = smbus_start_wait(unit);if (rv != SOC_E_NONE && rt-- > 0) {goto retry;} else if (rt < 0) {rv = SOC_E_TIMEOUT;}} else
#endif

2.导出全局符号打开文件 sdk/systems/linux/kernel/modules/include/bcmx_export.h最后添加：　　#include <soc/i2c.h>　　EXPORT_SYMBOL(soc_i2c_is_attached);　　EXPORT_SYMBOL(soc_i2c_attach);　　EXPORT_SYMBOL(soc_i2c_block_read);　　EXPORT_SYMBOL(soc_i2c_block_write);

之后从新编译SDK即可。