NVIDIA Tegra Power Management Controller (PMC)

The PMC block interacts with an external Power Management Unit. The PMC
mostly controls the entry and exit of the system from different sleep
modes. It provides power-gating controllers for SoC and CPU power-islands.

Required properties:
- name : Should be pmc
- compatible : Should contain "nvidia,tegra<chip>-pmc".
- reg : Offset and length of the register set for the device
- clocks : Must contain an entry for each entry in clock-names.
- clock-names : Must include the following entries:
  "pclk" (The Tegra clock of that name),
  "clk32k_in" (The 32KHz clock input to Tegra).

Optional properties:
- nvidia,invert-interrupt : If present, inverts the PMU interrupt signal.
  The PMU is an external Power Management Unit, whose interrupt output
  signal is fed into the PMC. This signal is optionally inverted, and then
  fed into the ARM GIC. The PMC is not involved in the detection or
  handling of this interrupt signal, merely its inversion.
- nvidia,suspend-mode : The suspend mode that the platform should use.
  Valid values are 0, 1 and 2:
  0 (LP0): CPU + Core voltage off and DRAM in self-refresh
  1 (LP1): CPU voltage off and DRAM in self-refresh
  2 (LP2): CPU voltage off
- nvidia,core-power-req-active-high : Boolean, core power request active-high
- nvidia,sys-clock-req-active-high : Boolean, system clock request active-high
- nvidia,combined-power-req : Boolean, combined power request for CPU & Core
- nvidia,cpu-pwr-good-en : Boolean, CPU power good signal (from PMIC to PMC)
			   is enabled.
- nvidia,reset-gpio : GPIO that can be used to warm reset the system.

Required properties when nvidia,suspend-mode is specified:
- nvidia,cpu-pwr-good-time : CPU power good time in uS.
- nvidia,cpu-pwr-off-time : CPU power off time in uS.
- nvidia,core-pwr-good-time : <Oscillator-stable-time Power-stable-time>
			      Core power good time in uS.
- nvidia,core-pwr-off-time : Core power off time in uS.

Required properties when nvidia,suspend-mode=<0>:
- nvidia,lp0-vec : <start length> Starting address and length of LP0 vector
  The LP0 vector contains the warm boot code that is executed by AVP when
  resuming from the LP0 state. The AVP (Audio-Video Processor) is an ARM7
  processor and always being the first boot processor when chip is power on
  or resume from deep sleep mode. When the system is resumed from the deep
  sleep mode, the warm boot code will restore some PLLs, clocks and then
  bring up CPU0 for resuming the system.

Example:

/ SoC dts including file
pmc@7000f400 {
	compatible = "nvidia,tegra20-pmc";
	reg = <0x7000e400 0x400>;
	clocks = <&tegra_car 110>, <&clk32k_in>;
	clock-names = "pclk", "clk32k_in";
	nvidia,invert-interrupt;
	nvidia,suspend-mode = <1>;
	nvidia,cpu-pwr-good-time = <2000>;
	nvidia,cpu-pwr-off-time = <100>;
	nvidia,core-pwr-good-time = <3845 3845>;
	nvidia,core-pwr-off-time = <458>;
	nvidia,core-power-req-active-high;
	nvidia,sys-clock-req-active-high;
	nvidia,lp0-vec = <0xbdffd000 0x2000>;
};

/ Tegra board dts file
{
	...
	clocks {
		compatible = "simple-bus";
		#address-cells = <1>;
		#size-cells = <0>;

		clk32k_in: clock {
			compatible = "fixed-clock";
			reg=<0>;
			#clock-cells = <0>;
			clock-frequency = <32768>;
		};
	};
	...
};

Wake up events

The PMC is the only device that can wake up the system from deep sleep
mode (i.e. LP0). There are some wake up events that in the PMC wake mask
register can be used to trigger PMC to wake up the system. The PMC wake
mask register defines which devices or siganls can be the source to
trigger PMC waking up. If the devices support waking up system from deep
sleep mode, then it needs to describe a property for PMC wake up events.
Here is the property defines the usage.

Required properties when nvidia,suspend-mode=<0>:
- nvidia,pmc-wakeup : <pmc_phandle event_type event_offset trigger_type>
		     pmc_phandle: the phandle of PMC device tree node
		     event_type: 0 = PMC_WAKE_TYPE_GPIO
				 1 = PMC_WAKE_TYPE_EVENT
		     event_offset: the offset of PMC wake mask register
		     trigger_type: set 0 when event_type is PMC_WAKE_TYPE_GPIO
				   if event_type is PMC_WAKE_TYPE_EVENT
				   0 = PMC_TRIGGER_TYPE_NONE
				   1 = PMC_TRIGGER_TYPE_RISING
				   2 = PMC_TRIGGER_TYPE_FALLING
				   4 = PMC_TRIGGER_TYPE_HIGH
				   8 = PMC_TRIGGER_TYPE_LOW
- #wake-cells : should be 3

Example:

/ SoC dts including file
pmc: pmc {
	compatible = "nvidia,tegra114-pmc";
	reg = <0x7000e400 0x400>;
	clocks = <&tegra_car 261>, <&clk32k_in>;
	clock-names = "pclk", "clk32k_in";
};

/ Tegra board dts file
{
	...
	pmc {
		...
		nvidia,suspend-mode = <0>;
		#wake-cells = <3>;
		...
	};
	...
	pmic {
		...
		nvidia,pmc-wakeup = <&pmc 1 18 8>;
		...
	};
	...
	rtc {
		...
		nvidia,pmc-wakeup = <&pmc 0 16 0>;
		...
	};
};