Marek VasutandHeinrich Schuchardt
dc3765ede5
The "env" command is the recommended environment management command, its "set" subcommand is the equivalent replacement for legacy "setenv" command. Update the documentation to use the contemporary "env set" command instead of legacy "setenv" command. Note that the "setenv" command is unlikely to be removed from U-Boot in the near future due to it being integral part of the command line ABI. Implemented using: $ sed -i 's@\<setenv\>@env set@g' $(git grep -li '\<setenv\>' doc/) README Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
68 lines
1.5 KiB
ReStructuredText
68 lines
1.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
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.. index::
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single: button (command)
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button command
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==============
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Synopsis
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--------
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::
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button list
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button <name>
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Description
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-----------
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The button command is used to retrieve the status of a button. To show the
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status of a button with name 'button1' you would issue the command
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::
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button button1
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The status of the button is both written to the console as *ON* or *OFF* and
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set in the return value variable *$?* as 0 (true) or 1 (false). To retrieve
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the status of a button with name *button1* and to write it to environment
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variable *status1* you would execute the commands
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::
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button button1
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env set status1 $?
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A list of all available buttons and their status can be displayed using
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::
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button list
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If a button device has not been probed yet, its status will be shown as
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*<inactive>* in the list.
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Configuration
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-------------
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To use the button command you must specify CONFIG_CMD_BUTTON=y and enable a
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button driver. The available buttons are defined in the device-tree.
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Return value
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------------
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The variable *$?* takes the following values
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+---+-----------------------------+
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| 0 | ON, the button is pressed |
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+---+-----------------------------+
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| 1 | OFF, the button is released |
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+---+-----------------------------+
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| 0 | button list was shown |
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+---+-----------------------------+
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| 1 | button not found |
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+---+-----------------------------+
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| 1 | invalid arguments |
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+---+-----------------------------+
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