~funderscore blog cgit wiki get in touch
aboutsummaryrefslogtreecommitdiff
blob: ee902138f166da6065f847751cb7b7d09f4b328a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
.. SPDX-License-Identifier: GPL-2.0+:

gpio command
============

Synopsis
--------

::

    gpio <input|set|clear|toggle> <pin>
    gpio read <name> <pin>
    gpio status [-a] [<bank>|<pin>]

The gpio command is used to access General Purpose Inputs/Outputs.

gpio input
----------

Switch the GPIO *pin* to input mode.

gpio set
--------

Switch the GPIO *pin* to output mode and set the signal to 1.

gpio clear
----------

Switch the GPIO *pin* to output mode and set the signal to 0.

gpio toggle
-----------

Switch the GPIO *pin* to output mode and reverse the signal state.

gpio read
---------

Read the signal state of the GPIO *pin* and save it in environment variable
*name*.

gpio status
-----------

Display the status of one or multiple GPIOs. By default only claimed GPIOs
are displayed.
gpio status command output fields are::

    <name>: <function>: <value> [x] <label>

*function* can take the following values:

output
    pin configured in gpio output, *value* indicates the pin's level

input
    pin configured in gpio input, *value* indicates the pin's level

func
    pin configured in alternate function, followed by *label*
    which shows pinmuxing label.

unused
    pin not configured

*[x]* or *[ ]* indicate respectively if the gpio is used or not.

*label* shows the gpio label.

Parameters
----------

-a
    Display GPIOs irrespective of being claimed.

bank
    Name of a bank of GPIOs to be displayed.

pin
    Name of a single GPIO to be displayed or manipulated.

Examples
--------

Switch the status of a GPIO::

    => gpio set a5
    gpio: pin a5 (gpio 133) value is 1
    => gpio clear a5
    gpio: pin a5 (gpio 133) value is 0
    => gpio toggle a5
    gpio: pin a5 (gpio 133) value is 1
    => gpio read myvar a5
    gpio: pin a5 (gpio 133) value is 1
    => echo $myvar
    1
    => gpio toggle a5
    gpio: pin a5 (gpio 133) value is 0
    => gpio read myvar a5
    gpio: pin a5 (gpio 133) value is 0
    => echo $myvar
    0

Show the GPIO status::

    => gpio status
    Bank GPIOA:
    GPIOA1: func rgmii-0
    GPIOA2: func rgmii-0
    GPIOA7: func rgmii-0
    GPIOA10: output: 0 [x] hdmi-transmitter@39.reset-gpios
    GPIOA13: output: 1 [x] red.gpios

    Bank GPIOB:
    GPIOB0: func rgmii-0
    GPIOB1: func rgmii-0
    GPIOB2: func uart4-0
    GPIOB7: input: 0 [x] mmc@58005000.cd-gpios
    GPIOB11: func rgmii-0

Configuration
-------------

The *gpio* command is only available if CONFIG_CMD_GPIO=y.
The *gpio read* command is only available if CONFIG_CMD_GPIO_READ=y.

Return value
------------

If the command succeds the return value $? is set to 0. If an error occurs, the
return value $? is set to 1.