spi: added write method to allow writing without transfer delays

host/generic/spibus.go

@@ -233,6 +233,13 @@ func (b *spiBus) ReceiveByte() (byte, error) {
 	return byte(d[0]), nil
 }
 
+func (b *spiBus) Write(data []byte) (n int, err error) {
+	if err := b.init(); err != nil {
+		return 0, err
+	}
+	return b.file.Write(data)
+}
+
 func (b *spiBus) Close() error {
 	b.mu.Lock()
 	defer b.mu.Unlock()

spi.go

@@ -2,6 +2,10 @@
 
 package embd
 
+import (
+	"io"
+)
+
 const (
 	spiCpha = 0x01
 	spiCpol = 0x02
@@ -21,6 +25,8 @@ const (
 
 // SPIBus interface allows interaction with the SPI bus.
 type SPIBus interface {
+	io.Writer
+
 	// TransferAndRecieveData transmits data in a buffer(slice) and receives into it.
 	TransferAndRecieveData(dataBuffer []uint8) error