122 lines
2.6 KiB
Go
122 lines
2.6 KiB
Go
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package rpi
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import (
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"errors"
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"fmt"
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"sync"
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"github.com/warthog618/gpiod"
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)
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const (
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// DefaultChipName to try to use if one is not provided
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DefaultChipName = "gpiochip0"
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)
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var (
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// ErrLineAlreadyRequested denotes that the requested line is not available because it has already been requested and not Closed
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ErrLineAlreadyRequested = errors.New("line has already been requested")
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// ErrLineNotRequested denotes that the given line cannot be acted on because it was not previously requested
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ErrLineNotRequested = errors.New("line was not previously requested")
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)
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// ManagerConfig configuration for a Manager
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type ManagerConfig struct {
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ChipName string
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}
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// GetChipName from the config
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func (mc *ManagerConfig) GetChipName() string {
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if mc.ChipName == "" {
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return DefaultChipName
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}
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return mc.ChipName
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}
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// Manager for overarching raspberry pi GPIO management
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type Manager struct {
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config *ManagerConfig
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chip *gpiod.Chip
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lines map[int]*gpiod.Line
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linesLock sync.Mutex
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}
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// NewManager creates a new Manager instance for the given config
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func NewManager(config ManagerConfig) (*Manager, error) {
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chip, err := gpiod.NewChip(config.GetChipName())
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if err != nil {
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return nil, fmt.Errorf("failed to open GPIO chip %s: %w", config.GetChipName(), err)
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}
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return &Manager{
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config: &config,
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chip: chip,
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lines: make(map[int]*gpiod.Line),
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}, nil
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}
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// GetBasicLight for the given pin if available
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func (m *Manager) GetBasicLight(pin int) (*BasicLight, error) {
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line, err := m.requestLine(pin)
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if err != nil {
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return nil, err
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}
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return &BasicLight{
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pin: pin,
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line: line,
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manager: m,
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}, nil
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}
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func (m *Manager) requestLine(pin int) (*gpiod.Line, error) {
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m.linesLock.Lock()
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defer m.linesLock.Unlock()
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_, exists := m.lines[pin]
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if exists {
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return nil, fmt.Errorf("%w pin %d", ErrLineAlreadyRequested, pin)
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}
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line, err := m.chip.RequestLine(pin, gpiod.AsOutput(0))
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if err != nil {
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return nil, fmt.Errorf("failed to request line for pin %d: %w", pin, err)
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}
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m.lines[pin] = line
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return line, nil
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}
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func (m *Manager) closeLine(pin int) error {
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m.linesLock.Lock()
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defer m.linesLock.Unlock()
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return m.closeLineHelper(pin)
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}
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func (m *Manager) closeLineHelper(pin int) error {
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line := m.lines[pin]
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if line == nil {
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return fmt.Errorf("%w pin %d", ErrLineNotRequested, pin)
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}
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delete(m.lines, pin)
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return line.Close()
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}
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// Close this Manager and all of its associated lines
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func (m *Manager) Close() error {
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m.linesLock.Lock()
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defer m.linesLock.Unlock()
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for pin := range m.lines {
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m.closeLineHelper(pin)
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}
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return m.chip.Close()
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}
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