pkg.gl

// SPDX-FileCopyrightText: 2019 Kent Gibson [email protected] // // SPDX-License-Identifier: MIT

//go:build linux // +build linux

// A collection of code snippets contained in the READMEs. package main

import ( "fmt" "os" "time"

"github.com/warthog618/go-gpiocdev"
"github.com/warthog618/go-gpiocdev/device/rpi"
"github.com/warthog618/go-gpiocdev/uapi"
"golang.org/x/sys/unix"

)

func main() { // Chip Initialisation c, _ := gpiocdev.NewChip("gpiochip0", gpiocdev.WithConsumer("myapp"))

// Quick Start
in, _ := gpiocdev.RequestLine("gpiochip0", 2, gpiocdev.AsInput)
val, _ := in.Value()
out, _ := gpiocdev.RequestLine("gpiochip0", 3, gpiocdev.AsOutput(val))
in.Close()
out.Close()

// Line Requests
l, _ := gpiocdev.RequestLine("gpiochip0", 4)
l.Close()
l, _ = c.RequestLine(4)
l.Close()
l, _ = c.RequestLine(rpi.J8p7) // Using Raspberry Pi J8 mapping.
l.Close()
l, _ = c.RequestLine(4, gpiocdev.AsOutput(1))

ll, _ := gpiocdev.RequestLines("gpiochip0", []int{0, 1, 2, 3}, gpiocdev.AsOutput(0, 0, 1, 1))
ll.Close()

ll, _ = c.RequestLines([]int{0, 1, 2, 3}, gpiocdev.AsOutput(0, 0, 1, 1))

// Line Info
inf, _ := c.LineInfo(2)
fmt.Printf("name: %s\n", inf.Name) // ineffassign bypass
inf, _ = c.LineInfo(rpi.J8p7)
fmt.Printf("name: %s\n", inf.Name) // ineffassign bypass
inf, _ = l.Info()
infs, _ := ll.Info()
fmt.Printf("name: %s\n", inf.Name)
fmt.Printf("name: %s\n", infs[0].Name)

// Info Watch
inf, _ = c.WatchLineInfo(4, infoChangeHandler)
c.UnwatchLineInfo(4)

// Active Level
l, _ = c.RequestLine(4, gpiocdev.AsActiveLow) // during request
l.Reconfigure(gpiocdev.AsActiveHigh)          // once requested

// Direction
l.Reconfigure(gpiocdev.AsInput)        // Set direction to Input
l.Reconfigure(gpiocdev.AsOutput(1, 0)) // Set direction to Output (and values to active and inactive)

// Input
r, _ := l.Value() // Read state from line (active/inactive)
fmt.Printf("value: %d\n", r)

rr := []int{0, 0, 0, 0}
ll.Values(rr) // Read state from a group of lines

// Output
l.SetValue(1) // Set line active
l.SetValue(0) // Set line inactive

ll.SetValues([]int{0, 1, 0, 1}) // Set a group of lines

// Bias
l, _ = c.RequestLine(4, gpiocdev.WithPullUp) // during request
l.Reconfigure(gpiocdev.WithBiasDisabled)     // once requested

// Debounce
period := 10 * time.Millisecond
l, _ = c.RequestLine(4, gpiocdev.WithDebounce(period)) // during request
l.Reconfigure(gpiocdev.WithDebounce(period))           // once requested

// Edge Watches
l, _ = c.RequestLine(rpi.J8p7, gpiocdev.WithEventHandler(handler), gpiocdev.WithBothEdges)
l.Reconfigure(gpiocdev.WithoutEdges)

// Options
ll, _ = c.RequestLines([]int{0, 1, 2, 3}, gpiocdev.AsOutput(0, 0, 1, 1),
	gpiocdev.WithLines([]int{0, 3}, gpiocdev.AsActiveLow),
	gpiocdev.AsOpenDrain)
ll.Reconfigure(gpiocdev.WithLines([]int{0}, gpiocdev.AsActiveHigh))
ll.Reconfigure(gpiocdev.WithLines([]int{3}, gpiocdev.Defaulted))

// Line Requests (2)
l.Close()
ll.Close()

// Chip Initialisation (2)
c.Close()

}

func handler(evt gpiocdev.LineEvent) { // handle change in line state }

func infoChangeHandler(evt gpiocdev.LineInfoChangeEvent) { // handle change in line info }

func uapiV2() error { offset := 32 offsets := []int{1, 2, 3}

f, _ := os.OpenFile("/dev/gpiochip0", unix.O_CLOEXEC, unix.O_RDONLY)

// get chip info
ci, _ := uapi.GetChipInfo(f.Fd())
fmt.Print(ci)

// get line info
li, _ := uapi.GetLineInfo(f.Fd(), offset)
fmt.Print(li)

// request a line
lr := uapi.LineRequest{
	Lines: uint32(len(offsets)),
	Config: uapi.LineConfig{
		Flags: uapi.LineFlagV2Output,
	},
	// initialise Offsets, DefaultValues and Consumer...
}
err := uapi.GetLine(f.Fd(), &lr)
if err != nil {
	return err
}

// request a line with events
lr = uapi.LineRequest{
	Lines: uint32(len(offsets)),
	Config: uapi.LineConfig{
		Flags: uapi.LineFlagV2Input | uapi.LineFlagV2ActiveLow | uapi.LineFlagV2EdgeBoth,
	},
	// initialise Offsets and Consumer...
}
err = uapi.GetLine(f.Fd(), &lr)
if err != nil {
	// wait on lr.fd for events...

	// read event
	evt, _ := uapi.ReadLineEvent(uintptr(lr.Fd))
	fmt.Print(evt)
}

// get values
var values uapi.LineValues
err = uapi.GetLineValuesV2(uintptr(lr.Fd), &values)
if err != nil {
	return err
}

// set values
err = uapi.SetLineValuesV2(uintptr(lr.Fd), values)
if err != nil {
	return err
}

// update line config - change to outputs
err = uapi.SetLineConfigV2(uintptr(lr.Fd), &uapi.LineConfig{
	Flags:    uapi.LineFlagV2Output,
	NumAttrs: 1,
	// initialise OutputValues...
})

return err

}

func uapiV1() error { offset := 32 offsets := []int{1, 2, 3} value := 1

f, _ := os.OpenFile("/dev/gpiochip0", unix.O_CLOEXEC, unix.O_RDONLY)

// get chip info
ci, _ := uapi.GetChipInfo(f.Fd())
fmt.Print(ci)

// get line info
li, _ := uapi.GetLineInfo(f.Fd(), offset)
fmt.Print(li)

// request a line
hr := uapi.HandleRequest{
	Lines: uint32(len(offsets)),
	Flags: uapi.HandleRequestOutput,
	// initialise Offsets, DefaultValues and Consumer...
}
err := uapi.GetLineHandle(f.Fd(), &hr)
if err != nil {
	return err
}

// request a line with events
er := uapi.EventRequest{
	Offset:      uint32(offset),
	HandleFlags: uapi.HandleRequestActiveLow,
	EventFlags:  uapi.EventRequestBothEdges,
	// initialise Consumer...
}
err = uapi.GetLineEvent(f.Fd(), &er)
if err != nil {
	// wait on er.fd for events...

	// read event
	evt, _ := uapi.ReadEvent(uintptr(er.Fd))
	fmt.Print(evt)
}

// get values
var values uapi.HandleData
err = uapi.GetLineValues(uintptr(er.Fd), &values)
if err != nil {
	return err
}

// set values
values[0] = uint8(value)
err = uapi.SetLineValues(uintptr(hr.Fd), values)
if err != nil {
	return err
}

// update line config - change to active low
err = uapi.SetLineConfig(uintptr(hr.Fd), &uapi.HandleConfig{
	Flags: uapi.HandleRequestInput,
})

return err

}

# README