1 =========================
2 Using GPIO Lines in Linux
3 =========================
4
5 The Linux kernel exists to abstract and presen
6 as such are normally not user facing abstracti
7 and preferred way to use GPIO lines is to let
8 with them.
9
10 For examples of already existing generic drive
11 examples for any other kernel drivers you want
12 Documentation/driver-api/gpio/drivers-on-gpio.
13
14 For any kind of mass produced system you want
15 laptops, phones, tablets, routers, and any con
16 using appropriate kernel drivers is paramount.
17 in the upstream Linux kernel when you feel it
18 help to refine it, see Documentation/process/s
19
20 In Linux GPIO lines also have a userspace ABI.
21
22 The userspace ABI is intended for one-off depl
23 factory lines, maker community projects, works
24 industrial automation, PLC-type use cases, doo
25 of specialized equipment that is not produced
26 operators to have a deep knowledge of the equi
27 software-hardware interface to be set up. They
28 to any existing kernel subsystem and not be a
29 because of not being reusable or abstract enou
30 computer hardware related policy.
31
32 Applications that have a good reason to use th
33 from userspace will likely be a good fit for u
34 well.
35
36 Do not under any circumstances abuse the GPIO
37 any product development projects. If you use i
38 productify the prototype: rewrite it using pro
39 any circumstances deploy any uniform products
40
41 The userspace ABI is a character device for ea
42 These devices will appear on the system as ``/
43 ``/dev/gpiochipN``. Examples of how to directl
44 found in the kernel tree ``tools/gpio`` subdir
45
46 For structured and managed applications, we re
47 libgpiod_ library. This provides helper abstra
48 and arbitration for multiple simultaneous cons
49
50 .. _libgpiod: https://git.kernel.org/pub/scm/l
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