AM5728: Reducing power consumption

Just FYI to the customer, the minimum voltage allowed on the SoC is determined by automated testing when the chip is manufactured. The determined voltage is stored in the AVS Class 0 registers (Table 18-26 of the AM572x TRM).

To minimize power consumption at idle, the general method is to turn off as many cores and peripherals as possible. The PRU cores, IPU cores, and VPE for example. This can be done in the device tree file (status = "disabled"). To diagnose and debug high power consumption one option is to perform a register dump on the PRCM module to see which peripherals are enabled.

In Linux, this command will display every clock in the system and whether it has any consumers:

$ cat /sys/kernel/debug/clk/clk_summary

Further optimization can be done with these methods:

• disable internal pull resistors if an external pull is present
• cool down the processor - the result would be a decrease in leakage

There is also a wiki guide on how to add 500 MHz support to Linux.
processors.wiki.ti.com/.../AM570x_Speed_Grades

The main take-away from the guide is to modify dra7.dtsi with an additional OPP entry for 500MHz. Find the section for "opp_table" in the dra7.dtsi file and add to the node the following text:

        opp_nom@500000000 {
                opp-hz = /bits/ 64 <500000000>;
                opp-microvolt = <1060000 850000 1150000>;
                opp-supported-hw = <0xFF 0x01>;
                opp-suspend;
        };