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- 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.
- 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>;
- };
- };
- ...
- };
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