doc/usage/cmd/gpio.rst

   1 .. SPDX-License-Identifier: GPL-2.0+:
   2
   3 .. index::
   4    single: gpio (command)
   5
   6 gpio command
   7 ============
   8
   9 Synopsis
  10 --------
  11
  12 ::
  13
  14     gpio <input|set|clear|toggle> <pin>
  15     gpio read <name> <pin>
  16     gpio status [-a] [<bank>|<pin>]
  17
  18 The gpio command is used to access General Purpose Inputs/Outputs.
  19
  20 gpio input
  21 ----------
  22
  23 Switch the GPIO *pin* to input mode.
  24
  25 gpio set
  26 --------
  27
  28 Switch the GPIO *pin* to output mode and set the signal to 1.
  29
  30 gpio clear
  31 ----------
  32
  33 Switch the GPIO *pin* to output mode and set the signal to 0.
  34
  35 gpio toggle
  36 -----------
  37
  38 Switch the GPIO *pin* to output mode and reverse the signal state.
  39
  40 gpio read
  41 ---------
  42
  43 Read the signal state of the GPIO *pin* and save it in environment variable
  44 *name*.
  45
  46 gpio status
  47 -----------
  48
  49 Display the status of one or multiple GPIOs. By default only claimed GPIOs
  50 are displayed.
  51 gpio status command output fields are::
  52
  53     <name>: <function>: <value> [x] <label>
  54
  55 *function* can take the following values:
  56
  57 output
  58     pin configured in gpio output, *value* indicates the pin's level
  59
  60 input
  61     pin configured in gpio input, *value* indicates the pin's level
  62
  63 func
  64     pin configured in alternate function, followed by *label*
  65     which shows pinmuxing label.
  66
  67 unused
  68     pin not configured
  69
  70 *[x]* or *[ ]* indicate respectively if the gpio is used or not.
  71
  72 *label* shows the gpio label.
  73
  74 Parameters
  75 ----------
  76
  77 -a
  78     Display GPIOs irrespective of being claimed.
  79
  80 bank
  81     Name of a bank of GPIOs to be displayed.
  82
  83 pin
  84     Name of a single GPIO to be displayed or manipulated.
  85
  86 Examples
  87 --------
  88
  89 Switch the status of a GPIO::
  90
  91     => gpio set a5
  92     gpio: pin a5 (gpio 133) value is 1
  93     => gpio clear a5
  94     gpio: pin a5 (gpio 133) value is 0
  95     => gpio toggle a5
  96     gpio: pin a5 (gpio 133) value is 1
  97     => gpio read myvar a5
  98     gpio: pin a5 (gpio 133) value is 1
  99     => echo $myvar
 100     1
 101     => gpio toggle a5
 102     gpio: pin a5 (gpio 133) value is 0
 103     => gpio read myvar a5
 104     gpio: pin a5 (gpio 133) value is 0
 105     => echo $myvar
 106     0
 107
 108 Show the GPIO status::
 109
 110     => gpio status
 111     Bank GPIOA:
 112     GPIOA1: func rgmii-0
 113     GPIOA2: func rgmii-0
 114     GPIOA7: func rgmii-0
 115     GPIOA10: output: 0 [x] hdmi-transmitter@39.reset-gpios
 116     GPIOA13: output: 1 [x] red.gpios
 117
 118     Bank GPIOB:
 119     GPIOB0: func rgmii-0
 120     GPIOB1: func rgmii-0
 121     GPIOB2: func uart4-0
 122     GPIOB7: input: 0 [x] mmc@58005000.cd-gpios
 123     GPIOB11: func rgmii-0
 124
 125 Configuration
 126 -------------
 127
 128 The *gpio* command is only available if CONFIG_CMD_GPIO=y.
 129 The *gpio read* command is only available if CONFIG_CMD_GPIO_READ=y.
 130
 131 Return value
 132 ------------
 133
 134 If the command succeds the return value $? is set to 0. If an error occurs, the
 135 return value $? is set to 1.