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mirror of https://github.com/kidoman/embd synced 2024-12-23 05:10:05 +01:00
embd/host/generic/linux/gpio/digitalpin.go

115 lines
2.0 KiB
Go

package gpio
import (
"fmt"
"os"
"path"
"github.com/kidoman/embd/gpio"
)
type digitalPin struct {
n int
dir *os.File
val *os.File
activeLow *os.File
edge *os.File
}
func newDigitalPin(n int) (p *digitalPin, err error) {
p = &digitalPin{n: n}
err = p.init()
return
}
func (p *digitalPin) init() (err error) {
if p.dir, err = p.directionFile(); err != nil {
return
}
if p.val, err = p.valueFile(); err != nil {
return
}
if p.activeLow, err = p.activeLowFile(); err != nil {
return
}
return
}
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) SetDir(dir gpio.Direction) (err error) {
str := "in"
if dir == gpio.Out {
str = "out"
}
_, err = p.dir.WriteString(str)
return
}
func (p *digitalPin) Read() (val int, err error) {
buf := make([]byte, 1)
if _, err = p.val.Read(buf); err != nil {
return
}
val = 0
if buf[0] == '1' {
val = 1
}
return
}
func (p *digitalPin) Write(val int) (err error) {
str := "0"
if val == gpio.High {
str = "1"
}
_, err = p.val.WriteString(str)
return
}
func (p *digitalPin) ActiveLow(b bool) (err error) {
str := "0"
if b {
str = "1"
}
_, err = p.activeLow.WriteString(str)
return
}
func (p *digitalPin) Close() error {
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
}
return nil
}