imx6DL fix cpufreq to 996Mhz

[jiujinhong]

Hi FSL, I want to fix imx6DL cpufreq to 996Mhz through imx6dl.dtsi,  but it fail in below issue.

20180907_17:43:01][    4.159719] cpu cpu0: _opp_add_dynamic: duplicate OPPs detected. Existing: freq: 996000000, volt: 1249998, enabled: 1. New: freq: 996000000, volt: 1249999, enabled: 1
20180907_17:43:01][    4.174658] cpu cpu0: of_init_opp_table: Failed to add OPP 996000000
20180907_17:43:01][    4.181070] cpu cpu0: _opp_add_dynamic: duplicate OPPs detected. Existing: freq: 996000000, volt: 1249998, enabled: 1. New: freq: 996000000, volt: 1250000, enabled: 1
20180907_17:43:01][    4.195961] cpu cpu0: of_init_opp_table: Failed to add OPP 996000000
20180907_17:43:01][    4.203221] cpu cpu0: failed to init cpufreq table: -61
20180907_17:43:01][    4.208537] imx6q-cpufreq: probe of imx6q-cpufreq.0 failed with error -61

 16     cpu0: cpu@0 {                                                                          
 15       compatible = "arm,cortex-a9";                                                        
 14       device_type = "cpu";                                                                 
 13       reg = <0>;                                                                           
 12       next-level-cache = <&L2>;                                                            
 11       operating-points = <                                                                 
 10         /* kHz    uV */                                                                    
  9         /* 996000  1250000                                                                 
  8         792000  1175000                                                                    
  7         396000  1150000 */                                                                 
  6         996000  1250000                                                                   
  5         996000  1250000                                                                  
  4         996000  1250000                                                                   
  3       >;                                                                                   
  2       fsl,soc-operating-points = <                                                         
  1         /* ARM kHz  SOC-PU uV */                                                           
40          /* 996000 1175000                                                                                                 
  1         792000  1175000                                                                    
  2         396000  1175000 */                                                                 
  3         996000 1175000                                                                    
  4         996000 1175000                                                                    
  5         996000 1175000                                                                    
  6       >;     

when fix cpufreq to 792000, kernel can boot-up successfully.    So 6DL can fix to 792 Only?

  9         /* 996000  1250000                                                                 
  8         792000  1175000                                                                    
  7         396000  1150000 */                                                                 
  6         792000  1175000                                                                    
  5         792000  1175000                                                                    
  4         792000  1175000                                                                    
  3       >;                                                                                   
  2       fsl,soc-operating-points = <                                                         
  1         /* ARM kHz  SOC-PU uV */                                                           
40          /* 996000 1175000                                                                                                 
  1         792000  1175000                                                                    
  2         396000  1175000 */                                                                 
  3         792000  1175000                                                                    
  4         792000  1175000                                                                    
  5         792000  1175000  

20180907_17:53:41][    4.154684] Key type dns_resolver registered
20180907_17:53:41][    4.159651] cpu cpu0: _opp_add_dynamic: duplicate OPPs detected. Existing: freq: 792000000, volt: 1175000, enabled: 1. New: freq: 792000000, volt: 1175000, enabled: 1
20180907_17:53:41][    4.174596] cpu cpu0: _opp_add_dynamic: duplicate OPPs detected. Existing: freq: 792000000, volt: 1175000, enabled: 1. New: freq: 792000000, volt: 1175000, enabled: 1
20180907_17:53:41][    4.189731] failed to disable 996 MHz OPP

[igorpadykov]

Hi jiu

one can try to debug it usng Chapter 23 CPU Frequency Scaling (CPUFREQ) Driver

attached Linux Manual. For settings cpu speed one can use examples given in that chapter.

Also note that some parts will not run at 996MHz, like below

https://www.nxp.com/docs/en/data-sheet/IMX6SDLIEC.pdf 

Best regards
igor
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