1NVIDIA Tegra Regulators Coupling
2================================
3
4NVIDIA Tegra SoC's have a mandatory voltage-coupling between regulators.
5Thus on Tegra20 there are 3 coupled regulators and on NVIDIA Tegra30
6there are 2.
7
8Tegra20 voltage coupling
9------------------------
10
11On Tegra20 SoC's there are 3 coupled regulators: CORE, RTC and CPU.
12The CORE and RTC voltages shall be in a range of 170mV from each other
13and they both shall be higher than the CPU voltage by at least 120mV.
14
15Tegra30 voltage coupling
16------------------------
17
18On Tegra30 SoC's there are 2 coupled regulators: CORE and CPU. The CORE
19and CPU voltages shall be in a range of 300mV from each other and CORE
20voltage shall be higher than the CPU by N mV, where N depends on the CPU
21voltage.
22
23Required 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
31Example:
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	};
66