1# phosphor-regulators
2
3## Overview
4
5The `phosphor-regulators` application configures and monitors voltage
6regulators. The application is controlled by a JSON configuration file.
7
8The application does not control how voltage regulators are enabled or how to
9monitor their Power Good (pgood) status. Those operations are typically
10performed by power sequencer hardware and related firmware.
11
12## Configuring Voltage Regulators
13
14The configuration of voltage regulators can be modified. Configuration changes
15usually override hardware default settings.
16
17The most common configuration change is setting the output voltage for a
18regulator rail. Other examples include modifying pgood thresholds and
19overcurrent settings.
20
21The configuration changes are applied early in the boot process before
22regulators are enabled.
23
24## Monitoring Voltage Regulators
25
26Two types of regulator monitoring are supported:
27
28- Sensor monitoring
29- Phase fault monitoring
30
31### Sensor Monitoring
32
33The sensor values for a voltage rail are read, such as voltage output, current
34output, and temperature. Sensor values are measured, actual values rather than
35target values.
36
37Sensors are read once per second. The sensor values are stored on D-Bus on the
38BMC, making them available to external interfaces like Redfish.
39
40### Phase Fault Monitoring
41
42Some voltage regulators contain redundant phases. If a redundant phase fails,
43the regulator can continue functioning normally. However redundancy has been
44lost, and the regulator may fail if another phase fails.
45
46Voltage regulators can be monitored for redundant phase faults. If a fault is
47detected, an error is logged on the BMC.
48
49## JSON Configuration File
50
51The JSON configuration file defines the following:
52
53- Voltage regulators in the system.
54- Operations to perform on those regulators, such as configuration or sensor
55  monitoring.
56
57Configuration files are stored in the `config_files` directory.
58
59See the [configuration file documentation](docs/config_file/README.md) for
60information on the file format, validation tool, and installation directories.
61