[IMX8ULP] Cannot disable power switches using uPower API

[sert1m]

Hello! 

We are trying to optimize power usage on imx8ulp. According to AN13951 it is recommended to disable unused modules. Thus, we are trying to disable HIFI4 with API call in M33 code and it returns success:

UPOWER_PowerOffSwitches((upower_ps_mask_t)(kUPOWER_PS_HIFI4));

 
Than we are monitoring power consumption with another API call:

upwr_vtm_power_measure(PowerSwitchSel_HIFI4, UPOWER_DummyCallback);
upwr_poll_req_status(sg, &sgf, &err, result, 0);

And we observe that it is not 0 as we expect:

HIFI4_POWER: I=44mA

How can we turn off power switch and make sure it is actually disabled?

[joanxie · Accepted solution]

refer to the i.mx8ulp domain, HIFI4 is belong to LPAV domain, for this, try to disable in the uboot via upwr_pwm_power_off

https://github.com/nxp-imx/uboot-imx/blob/4ddbad60eff308a5b356fb9ab8734ac382ddd692/arch/arm/mach-imx... 

[sert1m]

That helps, thank you!