1# Named GPIOs 2 3## Chassis power control 4 5The main (non-standby) voltage rails in a chassis are powered on or off by 6toggling a named GPIO to the power sequencer device in the chassis. 7 8The GPIO name is defined in the Linux device tree. For single chassis systems, 9the standard GPIO name is `power-chassis-control`. See 10[Device Tree GPIO Naming in OpenBMC](https://github.com/openbmc/docs/blob/master/designs/device-tree-gpio-naming.md) 11for more information. 12 13The GPIO name in each chassis is specified in the 14[JSON configuration file](config_file/README.md). If no configuration file is 15found for the current system, the standard GPIO name is used. 16 17## Chassis power good (pgood) 18 19The power sequencer device provides a chassis power good (pgood) signal, 20indicating whether all the main (non-standby) rails are powered on. 21 22The `phosphor-power-sequencer` application reads the chassis power good signal 23from a named GPIO. 24 25The GPIO name is defined in the Linux device tree. For single chassis systems, 26the standard GPIO name is `power-chassis-good`. See 27[Device Tree GPIO Naming in OpenBMC](https://github.com/openbmc/docs/blob/master/designs/device-tree-gpio-naming.md) 28for more information. 29 30The GPIO name in each chassis is specified in the 31[JSON configuration file](config_file/README.md). If no configuration file is 32found for the current system, the standard GPIO name is used. 33