First cut of the GoPiGo3 driver, lacking grove peripherals.

Makefile

@@ -57,4 +57,5 @@ deps:
 		go.bug.st/serial.v1 \
 		github.com/veandco/go-sdl2/sdl \
 		golang.org/x/net/websocket \
+		golang.org/x/exp/io/spi \
 		golang.org/x/sys/unix

drivers/spi/README.MD

@@ -0,0 +1,25 @@
+# SPI
+
+This package provides drivers for [spi](https://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus) devices. It must be used along with the [raspberry pi](https://gobot.io/documentation/platforms/raspi) adaptor that supports the needed interfaces for spi devices. This uses the experimental [spi package](https://github.com/golang/exp/tree/master/io/spi) which only works on linux systems.
+
+## Getting Started
+
+## Installing
+```
+go get -d -u gobot.io/x/gobot/...
+```
+
+## Hardware Support
+Gobot has a extensible system for connecting to hardware devices. The following spi devices are currently supported:
+
+- GoPiGo3 robotics board (built for Rapsberry Pi, but in theory it could be used in another platform)
+
+More drivers are coming soon...
+
+## Using A Different Bus or Address
+
+You can set a different SPI address or SPI bus than the default when initializing your SPI drivers by using optional parameters. Here is an example:
+
+```go
+blinkm := spi.NewGoPiGo3DriverDriver(e, spi.WithBus(0), spi.WithAddress(0x10), spi.With)
+```

drivers/spi/doc.go

@@ -0,0 +1,9 @@
+/*
+Package spi provides Gobot drivers for spi devices.
+Uses "golang.org/x/exp/io/spi" for spi
+Installing:
+	go get -d -u gobot.io/x/gobot
+For further information refer to spi README:
+https://github.com/hybridgroup/gobot/blob/master/drivers/spi/README.md
+*/
+package spi // import "gobot.io/x/gobot/drivers/spi"