1.. SPDX-License-Identifier: GPL-2.0+ 2 3button command 4============== 5 6Synopsis 7-------- 8 9:: 10 11 button list 12 button <name> 13 14Description 15----------- 16 17The button command is used to retrieve the status of a button. To show the 18status of a button with name 'button1' you would issue the command 19 20:: 21 22 button button1 23 24The status of the button is both written to the console as *ON* or *OFF* and 25set in the return value variable *$?* as 0 (true) or 1 (false). To retrieve 26the status of a button with name *button1* and to write it to environment 27variable *status1* you would execute the commands 28 29:: 30 31 button button1 32 setenv status1 $? 33 34A list of all available buttons and their status can be displayed using 35 36:: 37 38 button list 39 40If a button device has not been probed yet, its status will be shown as 41*<inactive>* in the list. 42 43Configuration 44------------- 45 46To use the button command you must specify CONFIG_CMD_BUTTON=y and enable a 47button driver. The available buttons are defined in the device-tree. 48 49Return value 50------------ 51 52The variable *$?* takes the following values 53 54+---+-----------------------------+ 55| 0 | ON, the button is pressed | 56+---+-----------------------------+ 57| 1 | OFF, the button is released | 58+---+-----------------------------+ 59| 0 | button list was shown | 60+---+-----------------------------+ 61| 1 | button not found | 62+---+-----------------------------+ 63| 1 | invalid arguments | 64+---+-----------------------------+ 65