docs/designs/multihost-phosphor-buttons.md

18 additional input types in phosphor button interfaces and event handling.
21 (power and reset).There may be cases where we need to create button interface
22 which monitors non gpio events and triggers button actions for example events
27 This feature is needed to support additional phosphor button interfaces
29 available in the front panel apart from existing power and reset button
34 The front panel of bmc has buttons like power button, reset button in general
44    |   | power button |      | reset button |     |
58 additional button in front panel.
67 |     |  power button  |-+  |                            |         +------------+
75 |     |  reset button  --|--------+   switch      |      |---------+  host 3     |
102 yosemiteV2 platform has 1 bmc and 4 hosts and only one power button and reset
103 button.
105 For example, when the power button is pressed, The value of the host selector
106 switch position(1 to 10) decides whether the power button action is needs to be
109 This option is to use same power button and reset button for multiple hosts.
111 The power/reset button press events are triggered based on the value of host
133 ## 3.OCP debug card host selector button
137 This is a extension which has three buttons : 1.Power button 2.reset button
138 3.host selector button
143 The host selector button purpose is same as that of the front panel host
144 selector switch in yosemitev2 front panel. The debug card host selector button
145 (push button) has different gpio lines than that of front panel host selector
146 switch gpios. Whenever the debug host selector button is pressed the host
153 Three high level changes are required in the phosphor button interface class
155 1. Add support for adding button interfaces which are monitoring more than one
158 2. Add support to monitor button / switch interface event based on dbus property
161 3. Each button interface class can be extended with the following overridable
168   respective button interface.This should be be called from the main even
174 button interface monitors these 4 gpio io events as sd-event based event loop
189 ## OCP Debug card host selector button interface
191 A separate interface for debug card host selector button is created.
193 This button interface monitors the corresponding gpio lines for debug card host
194 selection button press and release event via sd-event based loop.
196 ### OCP Debug card host selector button dbus interface details :
199    handler when the ocp debug card button is pressed and released.
201 When the event handler is called once the button is released, then the host
206 This way when power and reset button press events are handled, the Host selector
212 This button interface monitors for change in host selector switch Position dbus
222 ### Change in power button and reset button interface event handler
224 If selector button instance is available,then the power button and reset button
230 button handlers are calling dbus calls for single host power events. This calls