mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-13 23:02:59 +00:00
65 lines
1.4 KiB
ReStructuredText
65 lines
1.4 KiB
ReStructuredText
|
.. 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 |
|
||
|
|
+---+-----------------------------+
|