i.mx8mp cpufreq setting about reducing power comsumption

[rockylee]

1 、Basic information :

       i.mx8mp ，Linux5.10.35, Yocto hardknott 。

       i.mx8mp is designed as data acquisition devices .

2、Qustion:  

      How to extend i.mx8mp cpufreq setting  in imx8mp.dtsi  for  reducing cpu temperature ?

      Desired  cpufreq setting: 600MHz、800Mhz 、1GHz  。

      How to set  i.mx8mp voltage  with different frequces ?

3、Present situation

      The devices temperature is very high and   i.mx8mp is  difficult to touch .

       i.mx8mp frequces is  1.2G hz  and 1.6Hz described  as follow .

      

       The cpufreq setting  in imx8mp.dtsi  only has three parts , described  as follow

       a53_opp_table: opp-table {
           compatible = "operating-points-v2";
           opp-shared;

          opp-1200000000 {
              opp-hz = /bits/ 64 <1200000000>;
              opp-microvolt = <850000>;
              opp-supported-hw = <0x8a0>, <0x7>;
              clock-latency-ns = <150000>;
              opp-suspend;
         };

        opp-1600000000 {
            opp-hz = /bits/ 64 <1600000000>;
            opp-microvolt = <950000>;
            opp-supported-hw = <0xa0>, <0x7>;
            clock-latency-ns = <150000>;
            opp-suspend;
        };

      opp-1800000000 {
           opp-hz = /bits/ 64 <1800000000>;
           opp-microvolt = <1000000>;
           opp-supported-hw = <0x20>, <0x3>;
          clock-latency-ns = <150000>;
          opp-suspend;
      };
   }.

[Sanket_Parekh]

Hi @rockylee 

I hope you are doing well

One can add the opp-entries in the device tree opp-table to choose the frequency,

For the supported frequency please refer to the Table 25. PLL electrical parameters from the datasheet. For ARM_PLL it is between 800 MHz to 1800 MHz.

For the voltage-related information, kindly refer to section 3.1.4 Operating ranges from the datasheet and section 3.2.1 VDD voltage levels - Table 2 from i.MX 8M Plus Power Consumption Measurement

To reduce power consumption, kindly refer to section 3.10 Unused input/output terminations from the i.MX 8M Plus Hardware Developer’s Guide

I hope this information helps you.

Thanks & Regards

Sanket Parekh

[mengfei]

when cpufreq is 800Mhz，voltage is what? 3.2.1 VDD voltage levels only describe three voltage