Help! TDC gp21 SPI not working

static void transfer(int fd,uint8_t opcode, uint32_t config_reg_data,int gpio_fd)
{
Clear_GPIO146(gpio_fd);//set reset pin to 0
Clear_SS(gpio_fd);     // set SSN pin to 0

int ret;
uint8_t Data_Byte_Lo=config_reg_data;
uint8_t Data_Byte_Mid1=config_reg_data>>8;
uint8_t Data_Byte_Mid2=config_reg_data>>16;
uint8_t Data_Byte_Hi=config_reg_data>>24;

uint8_t tx[] ={opcode,Data_Byte_Hi,Data_Byte_Mid2,Data_Byte_Mid1,Data_Byte_Lo,};

	uint8_t rx[ARRAY_SIZE(tx)] = {0, };
	struct spi_ioc_transfer tr = {
		.tx_buf = (unsigned long)tx,
		.rx_buf = (unsigned long)rx,
		.len = ARRAY_SIZE(tx),
		.delay_usecs = 100,
		.speed_hz = speed,
		.bits_per_word = bits,
	};

	ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
	if (ret < 1)
		pabort("can't send spi message");

Set_GPIO146(gpio_fd);//set reset pin back to 1
Set_SS(gpio_fd);     //set SSN pin back to 1
}

static uint32_t Read_4_bytes(int fd,uint8_t opcode,int gpio_fd)
{
    uint32_t Read_result=0;
    uint8_t temp;
Clear_GPIO146(gpio_fd);//set reset pin to 0
Clear_SS(gpio_fd);     // set SSN pin to 0

  temp=Send_1byte(fd,opcode,gpio_fd);    //send the opcode 0x81/0x80

  temp=Sent_dummy(fd);    //send dummy 0xFF 
  Read_result |=temp;//read
  Read_result =Read_result<<8;
  printf("the first 8bit read is %.2X\n",temp);



  temp=Sent_dummy(fd);
  Read_result |=temp;//read
  Read_result =Read_result<<8;
  printf("the second 8bit read is %.2X\n",temp);

  temp=Sent_dummy(fd);
  Read_result |=temp;//read
  Read_result =Read_result<<8;
  printf("the third 8bit read is %.2X\n",temp);


  temp=Sent_dummy(fd);
  Read_result |=temp;//read
  printf("the last 8bit read is %.2X\n",temp);
  Set_GPIO146(gpio_fd);
  Set_SS(gpio_fd);

 Set_GPIO146(gpio_fd);//set reset pin back to 1
 Set_SS(gpio_fd);     //set SSN pin back to 1
  return Read_result;
}