NVIDIA Tegra Power Management Controller (PMC)

Required properties:
- compatible: Should contain one of the following:
  - "nvidia,tegra186-pmc": for Tegra186
  - "nvidia,tegra194-pmc": for Tegra194
  - "nvidia,tegra234-pmc": for Tegra234
- reg: Must contain an (offset, length) pair of the register set for each
  entry in reg-names.
- reg-names: Must include the following entries:
  - "pmc"
  - "wake"
  - "aotag"
  - "scratch"
  - "misc" (Only for Tegra194 and later)

Optional properties:
- nvidia,invert-interrupt: If present, inverts the PMU interrupt signal.
- interrupt-controller: Identifies the node as an interrupt controller.
- #interrupt-cells: Specifies the number of cells needed to encode an
  interrupt source. The value must be 2.

Example:

SoC DTSI:

	pmc@c3600000 {
		compatible = "nvidia,tegra186-pmc";
		reg = <0 0x0c360000 0 0x10000>,
		      <0 0x0c370000 0 0x10000>,
		      <0 0x0c380000 0 0x10000>,
		      <0 0x0c390000 0 0x10000>;
		reg-names = "pmc", "wake", "aotag", "scratch";
	};

Board DTS:

	pmc@c360000 {
		nvidia,invert-interrupt;
	};

== Pad Control ==

On Tegra SoCs a pad is a set of pins which are configured as a group.
The pin grouping is a fixed attribute of the hardware. The PMC can be
used to set pad power state and signaling voltage. A pad can be either
in active or power down mode. The support for power state and signaling
voltage configuration varies depending on the pad in question. 3.3 V and
1.8 V signaling voltages are supported on pins where software
controllable signaling voltage switching is available.

Pad configurations are described with pin configuration nodes which
are placed under the pmc node and they are referred to by the pinctrl
client properties. For more information see
Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt.

The following pads are present on Tegra186:
csia		csib		dsi		mipi-bias
pex-clk-bias	pex-clk3	pex-clk2	pex-clk1
usb0		usb1		usb2		usb-bias
uart		audio		hsic		dbg
hdmi-dp0	hdmi-dp1	pex-cntrl	sdmmc2-hv
sdmmc4		cam		dsib		dsic
dsid		csic		csid		csie
dsif		spi		ufs		dmic-hv
edp		sdmmc1-hv	sdmmc3-hv	conn
audio-hv	ao-hv

Required pin configuration properties:
  - pins: A list of strings, each of which contains the name of a pad
	  to be configured.

Optional pin configuration properties:
  - low-power-enable: Configure the pad into power down mode
  - low-power-disable: Configure the pad into active mode
  - power-source: Must contain either TEGRA_IO_PAD_VOLTAGE_1V8 or
    TEGRA_IO_PAD_VOLTAGE_3V3 to select between signaling voltages.
    The values are defined in
    include/dt-bindings/pinctrl/pinctrl-tegra-io-pad.h.

Note: The power state can be configured on all of the above pads except
      for ao-hv. Following pads have software configurable signaling
      voltages: sdmmc2-hv, dmic-hv, sdmmc1-hv, sdmmc3-hv, audio-hv,
      ao-hv.

Pad configuration state example:
	pmc: pmc@7000e400 {
		compatible = "nvidia,tegra186-pmc";
		reg = <0 0x0c360000 0 0x10000>,
		      <0 0x0c370000 0 0x10000>,
		      <0 0x0c380000 0 0x10000>,
		      <0 0x0c390000 0 0x10000>;
		reg-names = "pmc", "wake", "aotag", "scratch";

		...

		sdmmc1_3v3: sdmmc1-3v3 {
			pins = "sdmmc1-hv";
			power-source = <TEGRA_IO_PAD_VOLTAGE_3V3>;
		};

		sdmmc1_1v8: sdmmc1-1v8 {
			pins = "sdmmc1-hv";
			power-source = <TEGRA_IO_PAD_VOLTAGE_1V8>;
		};

		hdmi_off: hdmi-off {
			pins = "hdmi";
			low-power-enable;
		}

		hdmi_on: hdmi-on {
			pins = "hdmi";
			low-power-disable;
		}
	};

Pinctrl client example:
	sdmmc1: sdhci@3400000 {
		...
		pinctrl-names = "sdmmc-3v3", "sdmmc-1v8";
		pinctrl-0 = <&sdmmc1_3v3>;
		pinctrl-1 = <&sdmmc1_1v8>;
	};

	...

	sor0: sor@15540000 {
		...
		pinctrl-0 = <&hdmi_off>;
		pinctrl-1 = <&hdmi_on>;
		pinctrl-names = "hdmi-on", "hdmi-off";
	};
