mirror of https://github.com/kidoman/embd
114 lines
1.6 KiB
Go
114 lines
1.6 KiB
Go
// LED control support.
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package generic
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import (
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"fmt"
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"io/ioutil"
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"os"
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"strings"
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"github.com/kidoman/embd"
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)
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type led struct {
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id string
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brightness *os.File
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initialized bool
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}
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func NewLED(id string) embd.LED {
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return &led{id: id}
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}
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func (l *led) init() error {
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if l.initialized {
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return nil
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}
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var err error
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if l.brightness, err = l.brightnessFile(); err != nil {
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return err
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}
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l.initialized = true
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return nil
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}
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func (l *led) brightnessFilePath() string {
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return fmt.Sprintf("/sys/class/leds/%v/brightness", l.id)
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}
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func (l *led) openFile(path string) (*os.File, error) {
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return os.OpenFile(path, os.O_RDWR, os.ModeExclusive)
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}
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func (l *led) brightnessFile() (*os.File, error) {
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return l.openFile(l.brightnessFilePath())
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}
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func (l *led) On() error {
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if err := l.init(); err != nil {
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return err
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}
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_, err := l.brightness.WriteString("1")
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return err
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}
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func (l *led) Off() error {
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if err := l.init(); err != nil {
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return err
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}
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_, err := l.brightness.WriteString("0")
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return err
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}
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func (l *led) isOn() (bool, error) {
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l.brightness.Seek(0, 0)
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bytes, err := ioutil.ReadAll(l.brightness)
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if err != nil {
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return false, err
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}
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str := string(bytes)
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str = strings.TrimSpace(str)
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if str == "1" {
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return true, nil
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}
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return false, nil
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}
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func (l *led) Toggle() error {
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if err := l.init(); err != nil {
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return err
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}
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state, err := l.isOn()
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if err != nil {
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return err
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}
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if state {
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return l.Off()
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}
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return l.On()
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}
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func (l *led) Close() error {
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if !l.initialized {
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return nil
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}
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if err := l.brightness.Close(); err != nil {
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return err
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}
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l.initialized = false
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return nil
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}
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