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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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