power/regulator/overview.rst

11 The intention is to allow systems to dynamically control regulator power output
12 in order to save power and prolong battery life. This applies to both voltage
26   - Regulator
27                  - Electronic device that supplies power to other devices.
31                    Input Voltage -> Regulator -> Output Voltage
34   - PMIC
35                  - Power Management IC. An IC that contains numerous
39   - Consumer
40                  - Electronic device that is supplied power by a regulator.
41                    Consumers can be classified into two types:-
45                    power supply. Its supply voltage is set by the hardware,
52   - Power Domain
53                  - Electronic circuit that is supplied its input power by the
54                    output power of a regulator, switch or by another power
55                    domain.
59                      Regulator -+-> Switch-1 -+-> Switch-2 --> [Consumer A]
61                                 |             +-> [Consumer B], [Consumer C]
63                                 +-> [Consumer D], [Consumer E]
65                    That is one regulator and three power domains:
67                    - Domain 1: Switch-1, Consumers D & E.
68                    - Domain 2: Switch-2, Consumers B & C.
69                    - Domain 3: Consumer A.
73                    Domain-1 --> Domain-2 --> Domain-3.
75                    A power domain may have regulators that are supplied power
78                      Regulator-1 -+-> Regulator-2 -+-> [Consumer A]
80                                   +-> [Consumer B]
82                    This gives us two regulators and two power domains:
84                    - Domain 1: Regulator-2, Consumer B.
85                    - Domain 2: Consumer A.
89                    Domain-1 --> Domain-2
92   - Constraints
93                  - Constraints are used to define power levels for performance
100                      - voltage output is in the range 800mV -> 3500mV.
101                      - regulator current output limit is 20mA @ 5V but is
104                    Power Domain Level: This is defined in software by kernel
106                    power domain to a particular power range. i.e.
108                      - Domain-1 voltage is 3300mV
109                      - Domain-2 voltage is 1400mV -> 1600mV
110                      - Domain-3 current limit is 0mA -> 20mA.
117                    to through the levels as follows :-
124                    Power Domain: is the new current limit within the domain
125                    operating limits for this domain and system state (e.g.
126                    battery power, USB power)
139 relevant to non SoC devices and is split into the following four interfaces:-
149       systems with no regulator based power control.
151         See Documentation/power/regulator/consumer.rst
159         See Documentation/power/regulator/regulator.rst
170         See Documentation/power/regulator/machine.rst
175       userspace via sysfs. This could be used to help monitor device power
178         See Documentation/ABI/testing/sysfs-class-regulator