Hi devs,

until now, I used 1.8V from the UART Debug Header to power my i2c device, because I thought it is electrically gone on my board. But after testing it with another HiKey Board (this time from LeMaker) with the same Firmware, I'm sure it has to be enabled anywhere. In the linux device tree source I found the following lines


                        ldo21: ldo21@a40 {
                                regulator-compatible = "LDO21";
                                regulator-min-microvolt = <1650000>;
                                regulator-max-microvolt = <2000000>;
                                regulator-enable-ramp-delay = <120>;

But, how to do this in Bare Metal? LDO5_1V8 seems to be enabled by default  but I can't find where it is done. How to configure the PMIC in early Bootloader stage?

Hope someone can solve this riddle for me.

Best Regards

On February 3, 2016 at 7:15 PM Grant Likely <grant.likely@linaro.org> wrote:

I just checked. The 4.4 kernel does not enable the 1.8V voltage rail
on the LS expansion connector. Do you know how to enable it?

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