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.. SPDX-License-Identifier: GPL-2.0+
button command
==============
Synopsis
--------
::
button list
button <name>
Description
-----------
The button command is used to retrieve the status of a button. To show the
status of a button with name 'button1' you would issue the command
::
button button1
The status of the button is both written to the console as *ON* or *OFF* and
set in the return value variable *$?* as 0 (true) or 1 (false). To retrieve
the status of a button with name *button1* and to write it to environment
variable *status1* you would execute the commands
::
button button1
setenv status1 $?
A list of all available buttons and their status can be displayed using
::
button list
If a button device has not been probed yet, its status will be shown as
*<inactive>* in the list.
Configuration
-------------
To use the button command you must specify CONFIG_CMD_BUTTON=y and enable a
button driver. The available buttons are defined in the device-tree.
Return value
------------
The variable *$?* takes the following values
+---+-----------------------------+
| 0 | ON, the button is pressed |
+---+-----------------------------+
| 1 | OFF, the button is released |
+---+-----------------------------+
| 0 | button list was shown |
+---+-----------------------------+
| 1 | button not found |
+---+-----------------------------+
| 1 | invalid arguments |
+---+-----------------------------+
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