OneWire bus impl

onewire.go

@@ -0,0 +1,78 @@
+//OneWire support.
+
+package embd
+
+// W1Bus interface is used to interact with the OneWire bus.
+type W1Bus interface {
+
+	// List devices on the bus
+	ListDevices() (devices []string, err error)
+
+	// Open a device
+	Open(address string) (device W1Device, err error)
+
+	// Close releases the resources associated with the bus.
+	Close() error
+}
+
+// W1Device interface is user to interact with the OneWire device.
+type W1Device interface {
+	// ReadByte reads a byte from the device.
+	ReadByte() (value byte, err error)
+	// ReadByte number of bytes from the device.
+	ReadBytes(number int) (value []byte, err error)
+	// WriteByte writes a byte to the device.
+	WriteByte(value byte) error
+	// WriteBytes writes a slice bytes to the device.
+	WriteBytes(value []byte) error
+
+	// Close releases the resources associated with the device.
+	Close() error
+}
+
+// W1Driver interface interacts with the host descriptors to allow us
+// control of OneWire communication.
+type W1Driver interface {
+	Bus(l byte) W1Bus
+
+	// Close releases the resources associated with the driver.
+	Close() error
+}
+
+var w1DriverInitialized bool
+var w1DriverInstance W1Driver
+
+// InitW1 initializes the W1 driver.
+func InitW1() error {
+	if w1DriverInitialized {
+		return nil
+	}
+
+	desc, err := DescribeHost()
+	if err != nil {
+		return err
+	}
+
+	if desc.W1Driver == nil {
+		return ErrFeatureNotSupported
+	}
+
+	w1DriverInstance = desc.W1Driver()
+	w1DriverInitialized = true
+
+	return nil
+}
+
+// CloseW1 releases resources associated with the OneWire driver.
+func CloseW1() error {
+	return w1DriverInstance.Close()
+}
+
+// NewW1Bus returns a W1Bus.
+func NewW1Bus(l byte) W1Bus {
+	if err := InitW1(); err != nil {
+		panic(err)
+	}
+
+	return w1DriverInstance.Bus(l)
+}