docs/designs/device-tree-gpio-naming.md

12 subsystem. The replacement is a "descriptor-based" character device interface.
25 specific field used to name the GPIOs in the DTS is `gpio-line-names`. This
29 scheme in the face of a universe of potential use-cases.
37 - Ensure common function GPIOs within OpenBMC use the same naming convention
52 Pattern: `*-button`
55 BMC-less machines use a button to trigger system behavior and in a BMC-managed
59 #### power-button
68 - `host*-ready`: Host ready, active high
69 - `host*-ready-n`: Host ready, active low
73 - host0-ready
74 - host1-ready-n
75 - ...
79 Pattern: `led-*`
81 #### led-fault
83 #### led-identify
85 #### led-power
87 #### led-sys-boot-status
89 #### led-attention
91 #### led-hdd-fault
93 #### led-rear-fault
95 #### led-rear-power
97 #### led-rear-id
99 ### Power and Regulators
101 Pattern: `power-*`, `regulator-*`
103 #### power-chassis-control
105 Set to initiate power-on or power-off of the chassis.
107 #### power-chassis-good
109 Indicates the power good state of the chassis.
111 #### power-config-full-load
113 Output GPIO set by the power managing application that indicates to the hardware
114 the threshold of power supplies that are expected to be present and working for
116 different number of power supplies (example 2 or 4). Default is the lowest
117 number of power supplies expected of the two models. In the case when the number
118 of power supplies that are present are less than the ones indicated by this
122 #### power-ffs-sync-history
124 Output GPIO set by the power managing applications. The IBM Common Form Factor
125 power supplies use this line as an input. When set low and left low the power
127 resets the power supply input history (average and maximum power values over a
130 #### regulator-standby-faulted
132 This GPIO value represents the status of standby power regulator fault detection
134 non-faulted condition after AC power cycle when no standby power regulator fault
135 condition is present. The status will reflect a standby regulator power faulted
136 condition when an unexpected drop in standby power is detected.
138 #### rtc-battery-voltage-read-enable
144 Pattern: `presence-*`
146 #### presence-ps0, presence-ps1, ..., presence-ps\<N>
156 Pattern: `reset-cause-*`
158 #### reset-cause-pinhole
168 #### bmc-secure-boot
180 #### air-water
184 #### factory-reset-toggle
190 ### POWER Specific GPIOs
192 Below are GPIO names specific to the POWER processor based servers.
198 ##### cfam-reset
200 Utilized to issue a processor logic reset to a IBM POWER processor.
204 Utilized to indicate a IBM POWER processor has entered an unrecoverable error
209 - Continue to hard code a config file per system type that has the gpio bank and
213 - Have the device tree GPIO names match the hardware schematics and then have
228 [2]: https://www.kernel.org/doc/html/latest/driver-api/gpio/index.html
230   https://lore.kernel.org/linux-arm-kernel/20200306170218.79698-1-geissonator@yahoo.com/