machine/dummy: add hooks to override peripheral methods

src/machine/machine_dummy.go

@@ -12,29 +12,77 @@ const (
 )
 
 // Fake LED numbers, for testing.
-const (
-	LED  = LED1
-	LED1 = 0
-	LED2 = 0
-	LED3 = 0
-	LED4 = 0
+var (
+	LED  uint8 = LED1
+	LED1 uint8 = 0
+	LED2 uint8 = 0
+	LED3 uint8 = 0
+	LED4 uint8 = 0
 )
 
 // Fake button numbers, for testing.
-const (
-	BUTTON  = BUTTON1
-	BUTTON1 = 0
-	BUTTON2 = 0
-	BUTTON3 = 0
-	BUTTON4 = 0
+var (
+	BUTTON  uint8 = BUTTON1
+	BUTTON1 uint8 = 5
+	BUTTON2 uint8 = 6
+	BUTTON3 uint8 = 7
+	BUTTON4 uint8 = 8
+)
+
+// Fake SPI interfaces, for testing.
+var (
+	SPI0 = SPI{0}
+)
+
+var (
+	GPIOConfigure func(pin uint8, config GPIOConfig)
+	GPIOSet       func(pin uint8, value bool)
+	GPIOGet       func(pin uint8) bool
+	SPIConfigure  func(bus uint8, sck uint8, mosi uint8, miso uint8)
+	SPITransfer   func(bus uint8, w uint8) uint8
 )
 
 func (p GPIO) Configure(config GPIOConfig) {
+	if GPIOConfigure != nil {
+		GPIOConfigure(p.Pin, config)
+	}
 }
 
 func (p GPIO) Set(value bool) {
+	if GPIOSet != nil {
+		GPIOSet(p.Pin, value)
+	}
 }
 
 func (p GPIO) Get() bool {
+	if GPIOGet != nil {
+		return GPIOGet(p.Pin)
+	}
 	return false
 }
+
+type SPI struct {
+	Bus uint8
+}
+
+type SPIConfig struct {
+	Frequency uint32
+	SCK       uint8
+	MOSI      uint8
+	MISO      uint8
+	Mode      uint8
+}
+
+func (spi SPI) Configure(config SPIConfig) {
+	if SPIConfigure != nil {
+		SPIConfigure(spi.Bus, config.SCK, config.MOSI, config.MISO)
+	}
+}
+
+// Transfer writes/reads a single byte using the SPI interface.
+func (spi SPI) Transfer(w byte) (byte, error) {
+	if SPITransfer != nil {
+		return SPITransfer(spi.Bus, w), nil
+	}
+	return 0, nil
+}

src/machine/spi.go

@@ -1,4 +1,4 @@
-// +build nrf stm32f103xx atsamd21g18a
+// +build js,wasm nrf stm32f103xx atsamd21g18a
 
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