Update raspi package for new gpio interface

platforms/raspi/raspi_adaptor.go

@@ -1,6 +1,7 @@
 package raspi
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -174,7 +175,7 @@ func (r *RaspiAdaptor) Finalize() error {
 }
 
 // digitalPin returns matched digitalPin for specified values
-func (r *RaspiAdaptor) digitalPin(pin string, dir string) sysfs.DigitalPin {
+func (r *RaspiAdaptor) digitalPin(pin string, dir string) (sysfsPin sysfs.DigitalPin, err error) {
 	var i int
 
 	if val, ok := pins[pin][r.revision]; ok {
@@ -182,33 +183,45 @@ func (r *RaspiAdaptor) digitalPin(pin string, dir string) sysfs.DigitalPin {
 	} else if val, ok := pins[pin]["*"]; ok {
 		i = val
 	} else {
-		panic("not valid pin")
+		err = errors.New("Not a valid pin")
+		return
 	}
 
 	if r.digitalPins[i] == nil {
 		r.digitalPins[i] = sysfs.NewDigitalPin(i)
-		r.digitalPins[i].Export()
+		if err = r.digitalPins[i].Export(); err != nil {
+			return
+		}
 	}
 
-	r.digitalPins[i].Direction(dir)
+	if err = r.digitalPins[i].Direction(dir); err != nil {
+		return
+	}
 
-	return r.digitalPins[i]
+	return r.digitalPins[i], nil
 }
 
 // DigitalRead reads digital value from pin
-func (r *RaspiAdaptor) DigitalRead(pin string) (i int) {
-	i, _ = r.digitalPin(pin, sysfs.IN).Read()
-	return
+func (r *RaspiAdaptor) DigitalRead(pin string) (val int, err error) {
+	sysfsPin, err := r.digitalPin(pin, sysfs.IN)
+	if err != nil {
+		return
+	}
+	return sysfsPin.Read()
 }
 
 // DigitalWrite writes digital value to specified pin
-func (r *RaspiAdaptor) DigitalWrite(pin string, val byte) {
-	r.digitalPin(pin, sysfs.OUT).Write(int(val))
+func (r *RaspiAdaptor) DigitalWrite(pin string, val byte) (err error) {
+	sysfsPin, err := r.digitalPin(pin, sysfs.OUT)
+	if err != nil {
+		return err
+	}
+	return sysfsPin.Write(int(val))
 }
 
 // PwmWrite Not Implemented
-func (r *RaspiAdaptor) PwmWrite(pin string, val byte) {
-	fmt.Println("PwmWrite Is Not Implemented")
+func (r *RaspiAdaptor) PwmWrite(pin string, val byte) (err error) {
+	return errors.New("PwmWrite is not yet implemented.")
 }
 
 // I2cStart starts a i2c device in specified address

platforms/raspi/raspi_adaptor_test.go

@@ -40,7 +40,7 @@ func TestRaspiAdaptorDigitalIO(t *testing.T) {
 	gobot.Assert(t, fs.Files["/sys/class/gpio/gpio4/value"].Contents, "1")
 
 	a.DigitalWrite("13", 1)
-	i := a.DigitalRead("13")
+	i, _ := a.DigitalRead("13")
 	gobot.Assert(t, i, 1)
 }