AFE4300: How do I synchronize SPI clock with device clock?

Hello. I have a question.

Now I am trying to do 8.1.3 of AFE4300 datasheet.

I have a question here.

I don't quite understand the meaning of "Use an SPI clock with the device clock" in paragraph 2.

below is my code.

SPI communication clocks currently use 1 MHz.

How do I synchronize it? Please tell me more details.

void IQ_mode_measure(void)
{
	AFE4300_WRITE(ADDRESS_IQ_MODE_ENABLE,0x08,0x00);  //on IQ Mode, off FWR Mode
	
	signed long measure_I=0;
	signed long measure_Q=0;
	signed int magnitude = 0;
	
	if(Uart_flag==1)
	{
		send_data(0xFF);
		send_data(0xFF);
	}

	for(int i=1; i<5; i++) // frequency change 
	{
		for(int j=0; j<3; j++) // calibration change 
		{
	
			
			Act(j); // 0 = measure, 1 = reference 1, 2 = reference 2
			
			frequency_set_up(i); // 1 = 8k, 2 = 16k, 3 = 32k, 4 = 64k 

			//measurement I
			AFE4300_WRITE(ADDRESS_ADC_CONTROL_REGISTER2,0x00,0x63); // I
			
			
			//wait_for_stability();
			AFE4300_WRITE(ADDRESS_ADC_CONTROL_REGISTER1,0xC1,0xB0); // single shot
			while(rdychk==0) // if rdy change
			{
			}
			rdychk=0;
			READ_register(ADDRESS_ADC_DATA_RESULT);  
			
			measure_I = (long)Highvalue*256 + (long)Lowvalue;
			if(Uart_flag==1)
			{
				send_data(Highvalue);
				send_data(Lowvalue);
			}

			
			//measurement Q
			AFE4300_WRITE(ADDRESS_ADC_CONTROL_REGISTER2,0x00,0x65); // Q
			
			
			
			//wait_for_stability();
			AFE4300_WRITE(ADDRESS_ADC_CONTROL_REGISTER1,0xC1,0xB0); // single shot
			while(rdychk==0)
			{
			}
			rdychk=0;
			READ_register(ADDRESS_ADC_DATA_RESULT);
			
			measure_Q = (long)Highvalue*256 + (long)Lowvalue;
			if(Uart_flag==1)
			{
				send_data(Highvalue);
				send_data(Lowvalue);
			}

			if(j==0)
			{
				if(measure_I>=32768)
				{
					measure_I = (measure_I-65536)*-1;
				}
				else if(measure_Q>=32768)
				{
					measure_Q = (measure_Q-65536)*-1;
				}
				magnitude = sqrt((measure_I*measure_I)+(measure_Q*measure_Q));
				
			}
		}
	}
	

}