1*27ae70b8SShawn McCarney# Named GPIOs 2*27ae70b8SShawn McCarney 3*27ae70b8SShawn McCarney## Chassis power control 4*27ae70b8SShawn McCarney 5*27ae70b8SShawn McCarneyThe main (non-standby) voltage rails in a chassis are powered on or off by 6*27ae70b8SShawn McCarneytoggling a named GPIO to the power sequencer device in the chassis. 7*27ae70b8SShawn McCarney 8*27ae70b8SShawn McCarneyThe GPIO name is defined in the Linux device tree. For single chassis systems, 9*27ae70b8SShawn McCarneythe standard GPIO name is `power-chassis-control`. See 10*27ae70b8SShawn McCarney[Device Tree GPIO Naming in OpenBMC](https://github.com/openbmc/docs/blob/master/designs/device-tree-gpio-naming.md) 11*27ae70b8SShawn McCarneyfor more information. 12*27ae70b8SShawn McCarney 13*27ae70b8SShawn McCarneyThe GPIO name in each chassis is specified in the 14*27ae70b8SShawn McCarney[JSON configuration file](config_file/README.md). If no configuration file is 15*27ae70b8SShawn McCarneyfound for the current system, the standard GPIO name is used. 16*27ae70b8SShawn McCarney 17*27ae70b8SShawn McCarney## Chassis power good (pgood) 18*27ae70b8SShawn McCarney 19*27ae70b8SShawn McCarneyThe power sequencer device provides a chassis power good (pgood) signal, 20*27ae70b8SShawn McCarneyindicating whether all the main (non-standby) rails are powered on. 21*27ae70b8SShawn McCarney 22*27ae70b8SShawn McCarneyThe `phosphor-power-sequencer` application reads the chassis power good signal 23*27ae70b8SShawn McCarneyfrom a named GPIO. 24*27ae70b8SShawn McCarney 25*27ae70b8SShawn McCarneyThe GPIO name is defined in the Linux device tree. For single chassis systems, 26*27ae70b8SShawn McCarneythe standard GPIO name is `power-chassis-good`. See 27*27ae70b8SShawn McCarney[Device Tree GPIO Naming in OpenBMC](https://github.com/openbmc/docs/blob/master/designs/device-tree-gpio-naming.md) 28*27ae70b8SShawn McCarneyfor more information. 29*27ae70b8SShawn McCarney 30*27ae70b8SShawn McCarneyThe GPIO name in each chassis is specified in the 31*27ae70b8SShawn McCarney[JSON configuration file](config_file/README.md). If no configuration file is 32*27ae70b8SShawn McCarneyfound for the current system, the standard GPIO name is used. 33