1 .. SPDX-License-Identifier: GPL-2.0
2
3 ===================================
4 GPIO Character Device Userspace API
5 ===================================
6
7 This is latest version (v2) of the character d
8 ``include/uapi/linux/gpio.h.``
9
10 First added in 5.10.
11
12 .. note::
13 Do NOT abuse userspace APIs to control hard
14 drivers. There may already be a driver for
15 kernel driver is sure to provide a superior
16 from userspace.
17
18 Read Documentation/driver-api/gpio/drivers-
19 kernel wheels in userspace.
20
21 Similarly, for multi-function lines there m
22 Documentation/spi/index.rst, Documentation/
23 Documentation/driver-api/pwm.rst, Documenta
24 provide suitable drivers and APIs for your
25
26 Basic examples using the character device API
27
28 The API is based around two major objects, the
29 :ref:`gpio-v2-line-request`.
30
31 .. _gpio-v2-chip:
32
33 Chip
34 ====
35
36 The Chip represents a single GPIO chip and is
37 files of the form ``/dev/gpiochipX``.
38
39 Each chip supports a number of GPIO lines,
40 :c:type:`chip.lines<gpiochip_info>`. Lines on
41 ``offset`` in the range from 0 to ``chip.lines
42
43 Lines are requested from the chip using gpio-v
44 and the resulting line request is used to acce
45 monitor the lines for edge events.
46
47 Within this documentation, the file descriptor
48 on the GPIO device file is referred to as ``ch
49
50 Operations
51 ----------
52
53 The following operations may be performed on t
54
55 .. toctree::
56 :titlesonly:
57
58 Get Line <gpio-v2-get-line-ioctl>
59 Get Chip Info <gpio-get-chipinfo-ioctl>
60 Get Line Info <gpio-v2-get-lineinfo-ioctl>
61 Watch Line Info <gpio-v2-get-lineinfo-watch
62 Unwatch Line Info <gpio-get-lineinfo-unwatc
63 Read Line Info Changed Events <gpio-v2-line
64
65 .. _gpio-v2-line-request:
66
67 Line Request
68 ============
69
70 Line requests are created by gpio-v2-get-line-
71 access to a set of requested lines. The line
72 via the anonymous file descriptor returned in
73 :c:type:`request.fd<gpio_v2_line_request>` by
74
75 Within this documentation, the line request fi
76 as ``req_fd``.
77
78 Operations
79 ----------
80
81 The following operations may be performed on t
82
83 .. toctree::
84 :titlesonly:
85
86 Get Line Values <gpio-v2-line-get-values-io
87 Set Line Values <gpio-v2-line-set-values-io
88 Read Line Edge Events <gpio-v2-line-event-r
89 Reconfigure Lines <gpio-v2-line-set-config-
90
91 Types
92 =====
93
94 This section contains the structs and enums th
95 as defined in ``include/uapi/linux/gpio.h``.
96
97 .. kernel-doc:: include/uapi/linux/gpio.h
98 :identifiers:
99 gpio_v2_line_attr_id
100 gpio_v2_line_attribute
101 gpio_v2_line_changed_type
102 gpio_v2_line_config
103 gpio_v2_line_config_attribute
104 gpio_v2_line_event
105 gpio_v2_line_event_id
106 gpio_v2_line_flag
107 gpio_v2_line_info
108 gpio_v2_line_info_changed
109 gpio_v2_line_request
110 gpio_v2_line_values
111 gpiochip_info
112
113 .. toctree::
114 :hidden:
115
116 error-codes
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