phosphor-power-sequencer/docs/README.md

1 # phosphor-power-sequencer
5 The phosphor-power-sequencer application powers the chassis on/off and monitors
6 the power sequencer device.
8 If the chassis power good (pgood) status changes to false unexpectedly, the
9 application uses information from the power sequencer device to determine the
20 creates a collection of C++ objects. These objects represent the power sequencer
23 ## Power sequencer device
25 A power sequencer device enables (turns on) the voltage rails in the correct
28 This application currently supports the following power sequencer device types:
39   `org.openbmc.control.Power` D-Bus interface.
40 - The phosphor-power-sequencer application writes the value 1 to the named GPIO
41   `power-chassis-control`.
44 - The power sequencer device powers on all the voltage rails in the correct
46 - When all rails have been successfully powered on, the power sequencer device
47   sets the named `power-chassis-good` GPIO to the value 1.
50 - The phosphor-power-sequencer application sets the `pgood` property to 1 on the
51   `org.openbmc.control.Power` D-Bus interface.
57   `org.openbmc.control.Power` D-Bus interface.
58 - The phosphor-power-sequencer application writes the value 0 to the named GPIO
59   `power-chassis-control`.
60 - The power sequencer device powers off all the voltage rails in the correct
62 - When all rails have been successfully powered off, the power sequencer device
63   sets the named `power-chassis-good` GPIO to the value 0.
64 - The phosphor-power-sequencer application sets the `pgood` property to 0 on the
65   `org.openbmc.control.Power` D-Bus interface.
69 A power good (pgood) fault occurs in two scenarios:
71 - When attempting to power on the chassis:
72   - The power sequencer device is powering on all voltage rails in order, and
79 If the pgood fault occurs when attempting to power on the chassis, the chassis
84 chassis power good status by reading the named GPIO `power-chassis-good`.
93 - The power sequencer device type is supported by this application
115 still power the chassis on/off and detect chassis pgood faults. However, it will
121   - Defines the `org.openbmc.control.Power` D-Bus interface.
122   - The `state` property is set to power the chassis on or off. This contains
123     the desired power state.
124   - The `pgood` property contains the actual power state of the chassis.
128     `org.openbmc.control.Power` D-Bus interface.
130   - Finds power sequencer device information.
131   - Creates a sub-class of PowerSequencerDevice that matches power sequencer
133   - Powers the chassis on and off using the `power-chassis-control` named GPIO.
135     `power-chassis-good` named GPIO.
136   - Enforces a minimum power off time of 15 seconds from cold start and 25
137     seconds from power off.
139   - Finds power sequencer device information on D-Bus published by
142   - A voltage rail that is enabled or monitored by the power sequencer device.
144   - Abstract base class for a power sequencer device.
150   - Sub-class of StandardDevice for power sequencer devices that are bound to a
153   - Sub-class of PMBusDriverDevice for the UCD90X family of power sequencer
156   - Sub-class of UCD90xDevice representing a UCD90160 power sequencer device.
158   - Sub-class of UCD90xDevice representing a UCD90320 power sequencer device.