Documentation/devicetree/bindings/regulator/nvidia,tegra-regulators-coupling.txt

   1 NVIDIA Tegra Regulators Coupling
   2 ================================
   3
   4 NVIDIA Tegra SoC's have a mandatory voltage-coupling between regulators.
   5 Thus on Tegra20 there are 3 coupled regulators and on NVIDIA Tegra30
   6 there are 2.
   7
   8 Tegra20 voltage coupling
   9 ------------------------
  10
  11 On Tegra20 SoC's there are 3 coupled regulators: CORE, RTC and CPU.
  12 The CORE and RTC voltages shall be in a range of 170mV from each other
  13 and they both shall be higher than the CPU voltage by at least 120mV.
  14
  15 Tegra30 voltage coupling
  16 ------------------------
  17
  18 On Tegra30 SoC's there are 2 coupled regulators: CORE and CPU. The CORE
  19 and CPU voltages shall be in a range of 300mV from each other and CORE
  20 voltage shall be higher than the CPU by N mV, where N depends on the CPU
  21 voltage.
  22
  23 Required properties:
  24 - nvidia,tegra-core-regulator: Boolean property that designates regulator
  25   as the "Core domain" voltage regulator.
  26 - nvidia,tegra-rtc-regulator: Boolean property that designates regulator
  27   as the "RTC domain" voltage regulator.
  28 - nvidia,tegra-cpu-regulator: Boolean property that designates regulator
  29   as the "CPU domain" voltage regulator.
  30
  31 Example:
  32
  33         pmic {
  34                 regulators {
  35                         core_vdd_reg: core {
  36                                 regulator-name = "vdd_core";
  37                                 regulator-min-microvolt = <950000>;
  38                                 regulator-max-microvolt = <1300000>;
  39                                 regulator-coupled-with = <&rtc_vdd_reg &cpu_vdd_reg>;
  40                                 regulator-coupled-max-spread = <170000 550000>;
  41
  42                                 nvidia,tegra-core-regulator;
  43                         };
  44
  45                         rtc_vdd_reg: rtc {
  46                                 regulator-name = "vdd_rtc";
  47                                 regulator-min-microvolt = <950000>;
  48                                 regulator-max-microvolt = <1300000>;
  49                                 regulator-coupled-with = <&core_vdd_reg &cpu_vdd_reg>;
  50                                 regulator-coupled-max-spread = <170000 550000>;
  51
  52                                 nvidia,tegra-rtc-regulator;
  53                         };
  54
  55                         cpu_vdd_reg: cpu {
  56                                 regulator-name = "vdd_cpu";
  57                                 regulator-min-microvolt = <750000>;
  58                                 regulator-max-microvolt = <1125000>;
  59                                 regulator-coupled-with = <&core_vdd_reg &rtc_vdd_reg>;
  60                                 regulator-coupled-max-spread = <550000 550000>;
  61
  62                                 nvidia,tegra-cpu-regulator;
  63                         };
  64                 };
  65         };