mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-09-21 15:12:04 +00:00
doc: button command
Provide a description of the 'button' command. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
parent
51f65b506f
commit
24ceb441c7
2 changed files with 65 additions and 0 deletions
64
doc/usage/button.rst
Normal file
64
doc/usage/button.rst
Normal file
|
@ -0,0 +1,64 @@
|
||||||
|
.. 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 |
|
||||||
|
+---+-----------------------------+
|
|
@ -12,4 +12,5 @@ Shell commands
|
||||||
:maxdepth: 1
|
:maxdepth: 1
|
||||||
|
|
||||||
bootmenu
|
bootmenu
|
||||||
|
button
|
||||||
pstore
|
pstore
|
||||||
|
|
Loading…
Reference in a new issue