1## Overview
2
3The `phosphor-regulators` application configures and monitors voltage
4regulators. The application is controlled by a JSON configuration file.
5
6The application does not control how voltage regulators are enabled or how to
7monitor their Power Good (pgood) status. Those operations are typically
8performed by power sequencer hardware and related firmware.
9
10## Configuring Voltage Regulators
11
12The configuration of voltage regulators can be modified. Configuration changes
13usually override hardware default settings.
14
15The most common configuration change is setting the output voltage for a
16regulator rail. Other examples include modifying pgood thresholds and
17overcurrent settings.
18
19The configuration changes are applied early in the boot process before
20regulators are enabled.
21
22## Monitoring Voltage Regulators
23
24Two types of regulator monitoring are supported:
25
26- Sensor monitoring
27- Phase fault monitoring
28
29### Sensor Monitoring
30
31The sensor values for a voltage rail are read, such as voltage output, current
32output, and temperature. Sensor values are measured, actual values rather than
33target values.
34
35Sensors are read once per second. The sensor values are stored on D-Bus on the
36BMC, making them available to external interfaces like Redfish.
37
38### Phase Fault Monitoring
39
40Some voltage regulators contain redundant phases. If a redundant phase fails,
41the regulator can continue functioning normally. However redundancy has been
42lost, and the regulator may fail if another phase fails.
43
44Voltage regulators can be monitored for redundant phase faults. If a fault is
45detected, an error is logged on the BMC.
46
47## JSON Configuration File
48
49The JSON configuration file defines the following:
50
51- Voltage regulators in the system.
52- Operations to perform on those regulators, such as configuration or sensor
53  monitoring.
54
55Configuration files are stored in the `config_files` directory.
56
57See the [configuration file documentation](docs/config_file/README.md) for
58information on the file format, validation tool, and installation directories.
59