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Daisy Chaining two AD1938 codecs - ALSA System on Chip driver



		

			

									
					    henrix
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Oct 8, 2016 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hi there,
    
 
    we are trying to extend our audio system by daisy chaining two AD1938 audio codecs. From the datasheet I got the information that both codecs are configured equally (512 fs DACs / 256 fs ADCs / single line TDM mode). So, of course, both codecs appear as one codec to the platform DAI. I think it should work, if both codecs are configured equally in series via regmap in the codec driver. For example:
    
 
    static int ad193x_hw_params(...){
    
 
       ...
    
 
       regmap_update_bits(ad193x_0->regmap, AD193X_PLL_CLK_CTRL0, AD193X_PLL_INPUT_MASK, master_rate);
    
 
       regmap_update_bits(ad193x_1->regmap, AD193X_PLL_CLK_CTRL0, AD193X_PLL_INPUT_MASK, master_rate);
    
 
       ...
    
 
    }
    
 
    Does anybody know, how to pass two regmap configs to the driver, so that I can configure both codecs in the same way? Or any other idea how to get two daisy chained codecs working with ALSA?
    
 
    Thanks!
    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	















    
	
    
	
    
					



			








	
	
	
	



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													0
							
			
				
									
							        
			
			
			
        
            
			                            
                        
                on Oct 16, 2016 5:50 AM
            
            
					
        
	
        

		
		
        
					
        Hi,
        
 
        I found a way to register auxiliary devices in ASoC core. There is an extra property "aux_dev" in snd_soc_card structure for these applications. The connections of the codecs and the DSP (BeagleBone Green) are like this:
        
 
        - clock signals are connected as described in the circuit sketch. 
        
 
        - DAC TDM signal from DSP <-> DSDATA1 of "master" codec
        
 
        - DSDATA2 of "master" codec <-> DSDATA2 of "aux" codec
        
 
        - ADC TDM signal to DSP <-> ASDATA1 of "master" codec
        
 
        - ASDATA2 of "master" codec <-> ASDATA1 of "aux" codec
        
 
        - ASDATA2 of "aux" codec <-> GND
        
 
        The registers settings of the codecs are both like this:
        
 
        [ 477.090537] ad193x spi32766.0: AD193X register 0: 0x5
        [ 477.090685] ad193x spi32766.0: AD193X register 1: 0x0
        [ 477.090815] ad193x spi32766.0: AD193X register 2: 0x40
        [ 477.090946] ad193x spi32766.0: AD193X register 3: 0x3e //0x03 for aux codec (lbclk and lrclk slave (DACs))
        [ 477.091077] ad193x spi32766.0: AD193X register 4: 0x18
        [ 477.091208] ad193x spi32766.0: AD193X register 5: 0x0
        [ 477.091337] ad193x spi32766.0: AD193X register 6: 0x0
        [ 477.091465] ad193x spi32766.0: AD193X register 7: 0x0
        [ 477.091594] ad193x spi32766.0: AD193X register 8: 0x0
        [ 477.091724] ad193x spi32766.0: AD193X register 9: 0x0
        [ 477.091855] ad193x spi32766.0: AD193X register 10: 0x0
        [ 477.091986] ad193x spi32766.0: AD193X register 11: 0x0
        [ 477.092115] ad193x spi32766.0: AD193X register 12: 0x0
        [ 477.092245] ad193x spi32766.0: AD193X register 13: 0x0
        [ 477.092374] ad193x spi32766.0: AD193X register 14: 0x1
        [ 477.092503] ad193x spi32766.0: AD193X register 15: 0x23
        [ 477.093773] ad193x spi32766.0: AD193X register 16: 0x7c //0x34 for aux codec (lbclk and lrclk slave (ADCs))
        
 
        When I test the DAC outputs sequentially the master codec will correctly output the test signal (sine) from audio channel 9 to channel 15, but nothing happens with the aux codec. When I swap the DAC connections like this:
        
 
        - DAC TDM signal from DSP <-> DSDATA1 of "aux" codec
        
 
        - DSDATA2 of "aux" codec <-> DSDATA2 of "master" codec
        
 
        the sine test signal is available from channel 1 to channel 8 on "master" codec. So the hardware connections should be fine, but I don't get any output from the aux codec. Does the aux codec need a different configuration or anything else?
        
 
        Thanks a lot!
        
			
        

		
		
		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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													0
							
			
				
									
							        
			
			
			
          
            
			                            
                        
                on Oct 16, 2016 5:50 AM
            
            
					
          
	
          

		
		
          
					
          Hi,
          
 
          I found a way to register auxiliary devices in ASoC core. There is an extra property "aux_dev" in snd_soc_card structure for these applications. The connections of the codecs and the DSP (BeagleBone Green) are like this:
          
 
          - clock signals are connected as described in the circuit sketch. 
          
 
          - DAC TDM signal from DSP <-> DSDATA1 of "master" codec
          
 
          - DSDATA2 of "master" codec <-> DSDATA2 of "aux" codec
          
 
          - ADC TDM signal to DSP <-> ASDATA1 of "master" codec
          
 
          - ASDATA2 of "master" codec <-> ASDATA1 of "aux" codec
          
 
          - ASDATA2 of "aux" codec <-> GND
          
 
          The registers settings of the codecs are both like this:
          
 
          [ 477.090537] ad193x spi32766.0: AD193X register 0: 0x5
          [ 477.090685] ad193x spi32766.0: AD193X register 1: 0x0
          [ 477.090815] ad193x spi32766.0: AD193X register 2: 0x40
          [ 477.090946] ad193x spi32766.0: AD193X register 3: 0x3e //0x03 for aux codec (lbclk and lrclk slave (DACs))
          [ 477.091077] ad193x spi32766.0: AD193X register 4: 0x18
          [ 477.091208] ad193x spi32766.0: AD193X register 5: 0x0
          [ 477.091337] ad193x spi32766.0: AD193X register 6: 0x0
          [ 477.091465] ad193x spi32766.0: AD193X register 7: 0x0
          [ 477.091594] ad193x spi32766.0: AD193X register 8: 0x0
          [ 477.091724] ad193x spi32766.0: AD193X register 9: 0x0
          [ 477.091855] ad193x spi32766.0: AD193X register 10: 0x0
          [ 477.091986] ad193x spi32766.0: AD193X register 11: 0x0
          [ 477.092115] ad193x spi32766.0: AD193X register 12: 0x0
          [ 477.092245] ad193x spi32766.0: AD193X register 13: 0x0
          [ 477.092374] ad193x spi32766.0: AD193X register 14: 0x1
          [ 477.092503] ad193x spi32766.0: AD193X register 15: 0x23
          [ 477.093773] ad193x spi32766.0: AD193X register 16: 0x7c //0x34 for aux codec (lbclk and lrclk slave (ADCs))
          
 
          When I test the DAC outputs sequentially the master codec will correctly output the test signal (sine) from audio channel 9 to channel 15, but nothing happens with the aux codec. When I swap the DAC connections like this:
          
 
          - DAC TDM signal from DSP <-> DSDATA1 of "aux" codec
          
 
          - DSDATA2 of "aux" codec <-> DSDATA2 of "master" codec
          
 
          the sine test signal is available from channel 1 to channel 8 on "master" codec. So the hardware connections should be fine, but I don't get any output from the aux codec. Does the aux codec need a different configuration or anything else?
          
 
          Thanks a lot!
          
			
          

		
		
		
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
						
				
						
				
				
		
		
          
			
		
          
	
          

          

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