1.. SPDX-License-Identifier: GPL-2.0+
2
3button command
4==============
5
6Synopsis
7--------
8
9::
10
11    button list
12    button <name>
13
14Description
15-----------
16
17The button command is used to retrieve the status of a button. To show the
18status of a button with name 'button1' you would issue the command
19
20::
21
22    button button1
23
24The status of the button is both written to the console as *ON* or *OFF* and
25set in the return value variable *$?* as 0 (true) or 1 (false). To retrieve
26the status of a button with name *button1* and to write it to environment
27variable *status1* you would execute the commands
28
29::
30
31    button button1
32    setenv status1 $?
33
34A list of all available buttons and their status can be displayed using
35
36::
37
38    button list
39
40If a button device has not been probed yet, its status will be shown as
41*<inactive>* in the list.
42
43Configuration
44-------------
45
46To use the button command you must specify CONFIG_CMD_BUTTON=y and enable a
47button driver. The available buttons are defined in the device-tree.
48
49Return value
50------------
51
52The variable *$?* takes the following values
53
54+---+-----------------------------+
55| 0 | ON, the button is pressed   |
56+---+-----------------------------+
57| 1 | OFF, the button is released |
58+---+-----------------------------+
59| 0 | button list was shown       |
60+---+-----------------------------+
61| 1 | button not found            |
62+---+-----------------------------+
63| 1 | invalid arguments           |
64+---+-----------------------------+
65