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mirror of https://github.com/kidoman/embd synced 2024-10-31 23:38:44 +01:00
embd/digitalpin.go

178 lines
3.0 KiB
Go

package embd
import (
"errors"
"fmt"
"os"
"path"
"strconv"
)
type digitalPin struct {
n int
dir *os.File
val *os.File
activeLow *os.File
edge *os.File
initialized bool
}
func newDigitalPin(n int) *digitalPin {
return &digitalPin{n: n}
}
func (p *digitalPin) init() error {
if p.initialized {
return nil
}
var err error
if err = p.export(); err != nil {
return err
}
if p.dir, err = p.directionFile(); err != nil {
return err
}
if p.val, err = p.valueFile(); err != nil {
return err
}
if p.activeLow, err = p.activeLowFile(); err != nil {
return err
}
p.initialized = true
return nil
}
func (p *digitalPin) export() error {
exporter, err := os.OpenFile("/sys/class/gpio/export", os.O_WRONLY, os.ModeExclusive)
if err != nil {
return err
}
defer exporter.Close()
_, err = exporter.WriteString(strconv.Itoa(p.n))
return err
}
func (p *digitalPin) unexport() error {
unexporter, err := os.OpenFile("/sys/class/gpio/unexport", os.O_WRONLY, os.ModeExclusive)
if err != nil {
return err
}
defer unexporter.Close()
_, err = unexporter.WriteString(strconv.Itoa(p.n))
return err
}
func (p *digitalPin) basePath() string {
return fmt.Sprintf("/sys/class/gpio/gpio%v", p.n)
}
func (p *digitalPin) openFile(path string) (*os.File, error) {
return os.OpenFile(path, os.O_RDWR, os.ModeExclusive)
}
func (p *digitalPin) directionFile() (*os.File, error) {
return p.openFile(path.Join(p.basePath(), "direction"))
}
func (p *digitalPin) valueFile() (*os.File, error) {
return p.openFile(path.Join(p.basePath(), "value"))
}
func (p *digitalPin) activeLowFile() (*os.File, error) {
return p.openFile(path.Join(p.basePath(), "active_low"))
}
func (p *digitalPin) SetDirection(dir Direction) error {
if err := p.init(); err != nil {
return err
}
str := "in"
if dir == Out {
str = "out"
}
_, err := p.dir.WriteString(str)
return err
}
func (p *digitalPin) Read() (int, error) {
if err := p.init(); err != nil {
return 0, err
}
buf := make([]byte, 1)
if _, err := p.val.Read(buf); err != nil {
return 0, err
}
var val int
if buf[0] == '1' {
val = 1
}
return val, nil
}
func (p *digitalPin) Write(val int) error {
if err := p.init(); err != nil {
return err
}
str := "0"
if val == High {
str = "1"
}
_, err := p.val.WriteString(str)
return err
}
func (p *digitalPin) ActiveLow(b bool) error {
if err := p.init(); err != nil {
return err
}
str := "0"
if b {
str = "1"
}
_, err := p.activeLow.WriteString(str)
return err
}
func (p *digitalPin) PullUp() error {
return errors.New("gpio: not implemented")
}
func (p *digitalPin) PullDown() error {
return errors.New("gpio: not implemented")
}
func (p *digitalPin) Close() error {
if !p.initialized {
return nil
}
if err := p.dir.Close(); err != nil {
return err
}
if err := p.val.Close(); err != nil {
return err
}
if err := p.activeLow.Close(); err != nil {
return err
}
if err := p.edge.Close(); err != nil {
return err
}
if err := p.unexport(); err != nil {
return err
}
p.initialized = false
return nil
}