i.mx8mm: Configure PAD control of GPIO to decrease power consumption before entering suspend mode

[richard_hu]

Hello, NXP team:

We would like to minimize power consumption in suspend mode(deep sleep mode).

One of those approaches is to decrease GPIO leakage current.

Optimizing IO Power Consumption - Texas Instruments Wiki 

1. We know the PAD control of GPIO has to be configured according to HW design.

From the following post, the  pull-up state doesn't take effect in suspend mode.

Does it mean we can only set GPIO as output driving low to save power?

can the gpio pull up state keep in mem sleep mode ? 

is it necessary to set GPIO pin to high-Z when entering Suspend mode in i.MX51 Androd 10.4? 

2. What is the proper place to put those PAD control settings for i.mx8mm platform?

For instance, on i.mx51, the settings is in arch/arm/mach-mx5/mx50_rdp.c.

(We found the old posts on i.mx51 has mentioned this part.)

iMX51 android 10.4 在suspend 時，需要對 gpio 作重新設置嗎? 

Thanks~!

BR,

Richard

[igorpadykov]

Hi Richard

1. if peripheral power is not removed, its  pull-up state is retained.

2. i.MX8 power management is handled in ATF, one can look at suspend/resume functions in

gpc.c\imx8mm\imx8m\imx\plat - imx-atf - i.MX ARM Trusted firmware 

Best regards
igor
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