int8_t I2C_write(uint8_t addr, uint8_t reg_addr, const uint8_t* data, uint8_t len)  // packet function
{
    HAL_StatusTypeDef  status =HAL_OK;
    uint16_t deviceWriteAddr = (addr << 1);    //7 bit write address shall be pre-processed
    status = HAL_I2C_Mem_Write(&hi2c1,deviceWriteAddr,(uint16_t)reg_addr,1,(uint8_t*)data,(uint16_t)len,I2C_READ_TIMEOUT);
    if (HAL_OK != status)
    {
8 n. l. X2 Y% X, i! l        printf("I2C Write Fail:%d\n\r",status);
        return status;
8 l+ B, n' L  @3 j6 ^    }
    return HAL_OK;
3 w5 X5 O& Y, d, `}

int8_t I2C_read(uint8_t addr, uint8_t reg_addr, const uint8_t* data, uint8_t len)  //re packet function
+ J- O) g5 e) X% j, ]4 s. p- |0 V{
    HAL_StatusTypeDef  status =HAL_OK;
   uint16_t deviceWriteAddr = addr << 1; //7 bit write address shall be pre-processed
; b! S4 k& \4 i9 z5 A1 m, j$ F      uint16_t deviceReadAddr = (addr << 1)|0x01;   //7 bit read address shall be pre-processed   
' m% `& ]3 M5 s+ ]   uint8_t regAddr = reg_addr;
         
9 V9 p6 w& \3 J" e# y9 A* d status = HAL_I2C_Master_Transmit(&hi2c1,deviceWriteAddr,&regAddr,1,I2C_READ_TIMEOUT);
$ u" H* N! B+ X   
if (HAL_OK != status)
    {
# W8 y+ O, G: U( `        printf("I2C readreg Fail:%d\n\r",status);
        return status;
1 e- a. t, t0 w5 E# P    }   

    status = HAL_I2C_Master_Receive(&hi2c1,deviceReadAddr,(uint8_t*)data,(uint16_t)len,I2C_READ_TIMEOUT); //
    if (HAL_OK != status)
    {
: ~5 E  V3 _: b5 |5 y, @        printf("I2C Read1 Fail:%d\n\r",status);
        return status;
+ _/ e' T9 e& ~2 Q' p    }
' v& p" O8 U+ F! q; X9 M    return HAL_OK;
1 p& {1 B2 n( @ }

# @0 w: b/ |! {- B写是用HAL_I2C_Mem_Write（) 重新打包；
, y0 v' t& m; f1 }读操作原本要用HAL_I2C_Mem_Read，发现多字节request时，返回 I2C error.
如上改过后，单字节，多字节 读写稳定。
( ~! I2 i) Y$ ], NHAL_I2C_Mem_Write/HAL_I2C_Mem_Read 都是cubeMX 工具生成的HAL库。
我是在STM32L4系列使用的。
我参考的I2C 协议参考：http://www.cnblogs.com/aaronLinux/p/6218660.html