PMIC connection with Linux

nexy_sm — Tue, 07 Nov 2017 15:52:39 GMT

Hi all,

I am using a board with i.MX6Q processor and LTC3676 PMIC. At the moment I would like to realize how is a PMIC actually connected and instantiated in Linux. I looked at the i.MX6 Linux user manual, and there was explained that the on the top sits the regulator core drive, followed by the PF100-core driver and followed by the PF100 regulator driver (although my current sources have only pfuze100-regulator driver).

I see that regulator core driver has very general commands which internally call API of the actual PMIC. I also see that inside the device tree, it is possible to have a PMIC entry with its child regulators.

What I do not understand at the moment is how Linux knows which regulator is used for SoC core voltage, which one provides VDD_ARM, etc. I belive that when scaling the frequency down, the system should know which voltage can be lowered.

Thank you!

Re: PMIC connection with Linux

igorpadykov — Tue, 07 Nov 2017 23:16:33 GMT

Hi Nemanja

linux knows which regulator to use looking at dts file, for example

linux/arch/arm/boot/dts/imx6dl.dtsi file entriy "arm-supply" and others

linux-imx.git - i.MX Linux Kernel

Also one can look at PFUZE regulator driver sources described in

Chapter PF100 Regulator Driver of Linux Reference Manual.

Best regards
igor
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PMIC connection with Linux

Re: PMIC connection with Linux