We are using one time programmable "MMPF0100F0AEP" in our design based on i.MX6 solo processor "MCIMX6S5EVM10". We have used SW3A/B (single phase) power supply(1.5V) for the powering the "NVCC_DRAM" controller of processor. As we are using DDR3L in the design so want to reduce the SW3A/B voltage to 1.35V after board booting. And also want to reduce the 3.15V from SW4 to 3V for reducing the on-board power consumption.
We tried to write the registers from the u-boot. The PMIC is by default refusing the I2C writes in the normal running mode. We can able to read PMIC registers.
We probed the I2C pins also, data communication is requesting to the PMIC Chip with proper address, but the Chip is not give any acknowledgement to our write command.
It is mentioned in the PMIC datasheet, that it is one time programmable for its configuration. Also they are mentioning some power sequencing for programming the Chip.
I want to know that is there any way to write these registers & change these voltages on-the-fly or not. Thanks in advance.