commit	0d038f58f7ae2d8484ef2ba13116042088f133ff	[log] [tgz]
author	Patrick Williams <patrick@stwcx.xyz>	Wed May 10 07:50:40 2023 -0500
committer	Patrick Williams <patrick@stwcx.xyz>	Wed May 10 07:50:40 2023 -0500
tree	a0582e95f2b64f2a1b88f5d4325c2d40d21623c0
parent	395c764c2bb51a108b76dd80c3a7db16c8ec28d2 [diff]

tree: a0582e95f2b64f2a1b88f5d4325c2d40d21623c0

README.md

phosphor-buttons

Phosphor-buttons has a collection of IO event handler interfaces for physical inputs which are part of OCP front panel.

It defines an individual dbus interface object for each physical button/switch inputs such as power button, reset button etc. Each of this button interfaces monitors it's associated io for event changes and calls the respective event handlers.

Gpio defs config

In order to monitor a button/input interface the respective gpio config details should be mentioned in the gpio defs json file - /etc/default/obmc/gpio/gpio_defs.json

The button interface type name.
An array consists of single or multiple gpio configs associated with the specific button interface.

example gpio def Json config

{
    "gpio_definitions": [
        {
            "name": "POWER_BUTTON",
            "gpio_config" :[
               {
                "pin": "D0",
                "direction": "both"
               }
            ]
        },
        {
            "name": "RESET_BUTTON",
            "gpio_config" :[
                {
                "pin": "AB0",
                "direction": "both"
                 }
            ]
        },
        {
            "name" : "HOST_SELECTOR",

            "group_gpio_config" : [
            {
                "pin": "AA4",
                "direction": "both"
            },
            {
                "pin": "AA5",
                "direction": "both"
            },
            {
                "pin": "AA6",
                "direction": "both"
            },
            {
                "pin": "AA7",
                "direction": "both"
            }
            ]
        },

}

Single gpio config

This config is original config which can be used for configs with only single gpio such as power button,reset button, OCP debug card host select button.

{
    "name": "POWER_BUTTON",
    "pin": "D0",
    "direction": "both"
},

Note: this config is used by most of the other platforms so this format is kept as it is so that existing gpio configs do not get affected.

Group gpio config

The following configs are related to multi-host bmc systems more info explained in the design: https://github.com/openbmc/docs/blob/master/designs/multihost-phosphor-buttons.md

Host selector gpio config example

The host selector has four gpios associated. So the related gpios are mentioned in a json array named group_gpio_config.

name - This is name of the specific gpio line
pin - This represents the pin number from linux dts file.
polarity - polarity type of the gpio
max_position - This represents the max number of hosts in the multi-host bmc system.
host_selector_map - This map is oem specific host position map which has how the value read from the host selector gpios is mapped to the respective host number.

Example : The value of "7" derived from the 4 host select gpio lines are mapped to host position 1.

{
  "name": "HOST_SELECTOR",

  "group_gpio_config": [
    {
      "name": "host_select_0",
      "pin": "AA4",
      "direction": "both",
      "polarity": "active_high"
    },
    {
      "name": "host_select_1",
      "pin": "AA5",
      "direction": "both",
      "polarity": "active_high"
    },
    {
      "name": "host_select_2",
      "pin": "AA6",
      "direction": "both",
      "polarity": "active_high"
    },
    {
      "name": "host_select_3",
      "pin": "AA7",
      "direction": "both",
      "polarity": "active_high"
    }
  ],
  "max_position": 4,
  "host_selector_map": {
    "6": 0,
    "7": 1,
    "8": 2,
    "9": 3,
    "10": 4,
    "11": 0,
    "12": 1,
    "13": 2,
    "14": 3,
    "15": 4
  }
}

Serial uart mux config

Similar to host selector there are multiple gpios associated with the serial uart mux. These gpio configs are specificed as part of json array "group_gpio_config".

Here the serial uart mux output is accessed via OCP debug card. SO the OCP debug card present gpio is mentioned part of the group_gpio_config. The debug card present gpio is identified by its name "debug_card_present".

The other gpios part of the group gpio config is serial uart MUX gpio select lines and serial_uart_rx line.

name - this is name of the specific gpio line
pin - this represents the pin number from linux dts file.
polarity - polarity type of the gpio
serial_uart_mux_map - This is the map for selected host position to the serial uart mux select output value

{
  "name": "SERIAL_UART_MUX",

  "group_gpio_config": [
    {
      "name": "serial_uart_sel_0",
      "pin": "E0",
      "direction": "out",
      "polarity": "active_high"
    },
    {
      "name": "serial_uart_sel_1",
      "pin": "E1",
      "direction": "out",
      "polarity": "active_high"
    },
    {
      "name": "serial_uart_sel_2",
      "pin": "E2",
      "direction": "out",
      "polarity": "active_high"
    },
    {
      "name": "serial_uart_sel_3",
      "pin": "E3",
      "direction": "out",
      "polarity": "active_high"
    },
    {
      "name": "serial_uart_rx",
      "pin": "E4",
      "direction": "out",
      "polarity": "active_high"
    },
    {
      "name": "debug_card_present",
      "pin": "R3",
      "direction": "both",
      "polarity": "active_high"
    }
  ],
  "serial_uart_mux_map": {
    "0": 4,
    "1": 0,
    "2": 1,
    "3": 2,
    "4": 3
  }
}