Provide a description of the 'button' command.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- doc/usage/button.rst | 64 ++++++++++++++++++++++++++++++++++++++++++++ doc/usage/index.rst | 1 + 2 files changed, 65 insertions(+) create mode 100644 doc/usage/button.rst
diff --git a/doc/usage/button.rst b/doc/usage/button.rst new file mode 100644 index 0000000000..b83a2610ce --- /dev/null +++ b/doc/usage/button.rst @@ -0,0 +1,64 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +button command +============== + +Synopsis +-------- + +.. code-block:: + + 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 + +.. code-block:: + + 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 + +.. code-block:: + + button button1 + setenv status1 $? + +A list of all available buttons and their status can be displayed using + +.. code-block:: + + button list + +If a button device has not been probed yet, its status will be shown as +*<inactive>* in the list. + +Configuration +------------- + +To use the button command you must specify CONFIG_CMD_BUTTON=y and enable a +button driver. The available buttons are defined in the device-tree. + +Return value +------------ + +The variable *$?* 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 | ++---+-----------------------------+ diff --git a/doc/usage/index.rst b/doc/usage/index.rst index d0f5a9f26e..6c4b5b9240 100644 --- a/doc/usage/index.rst +++ b/doc/usage/index.rst @@ -12,4 +12,5 @@ Shell commands :maxdepth: 1
bootmenu + button pstore -- 2.29.2