I am debugging bottom current on my board, but find the 4GByte LPDDR4 is taking much current, around 70mA from NVCC_DRAM_1V1. Then I suspect my DDR4 does not enter deep sleep mode according to its specification.
There are below registers from DDR controller:
Low Power Control Register (PWRCTL)
Hardware Low Power Control Register (HWLPCTL)
Low Power Timing Register (PWRTMG)
I tried them on uboot drivers/ddr/imx8m/lpddr4_init.c, but could not let DDR4 enter deep sleep mode after "echo mem > /sys/power/state" suspend in yocto.
Have NXP already implemented deep sleep mode? Where is the kernel code that i can try? Thanks a lot!