Pin HAL to break dependency of drivers from TinyGo's machine package

rpio/pin.go

@@ -0,0 +1,35 @@
+// Implementation of the Pin interface for the Raspberry Pi GPIO pins.
+
+package rpio // import "tinygo.org/x/drivers/rpio"
+
+import go_rpio "github.com/stianeikeland/go-rpio/v4"
+
+type Pin struct {
+	modeSet bool
+	Mode    go_rpio.Mode
+	Pin     go_rpio.Pin
+}
+
+func NewPin(pinNumber int) *Pin {
+	return &Pin{Pin: go_rpio.Pin(pinNumber)}
+}
+
+func (p *Pin) Get() bool {
+	if !p.modeSet || p.Mode != go_rpio.Input {
+		p.Pin.Input()
+		p.Mode = go_rpio.Input
+	}
+	return p.Pin.Read() == go_rpio.High
+}
+
+func (p *Pin) Set(high bool) {
+	if !p.modeSet || p.Mode != go_rpio.Output {
+		p.Pin.Output()
+		p.Mode = go_rpio.Output
+	}
+	state := go_rpio.Low
+	if high {
+		state = go_rpio.High
+	}
+	p.Pin.Write(state)
+}

rpio/spi.go

@@ -0,0 +1,30 @@
+package rpio // import "tinygo.org/x/drivers/rpio"
+
+import go_rpio "github.com/stianeikeland/go-rpio/v4"
+
+type SPI struct {
+}
+
+func NewSPI() (s *SPI) {
+	if err := go_rpio.SpiBegin(go_rpio.Spi0); err != nil {
+		panic(err)
+	}
+	go_rpio.SpiSpeed(25_000_000) // 25 MHz
+	go_rpio.SpiChipSelect(0)
+	return &SPI{}
+}
+
+func (s *SPI) Tx(w, r []byte) error {
+	data := make([]byte, len(w))
+	copy(data, w)
+	go_rpio.SpiExchange(data)
+	copy(r, data)
+	return nil
+}
+
+func (s *SPI) Transfer(b byte) (byte, error) {
+	w := []byte{b}
+	r := make([]byte, len(w))
+	err := s.Tx(w, r)
+	return r[0], err
+}