gpio: simplify and test the logic

gpiodriver.go

@@ -32,23 +32,12 @@ func (io *gpioDriver) digitalPin(key interface{}) (*digitalPin, error) {
 		return nil, fmt.Errorf("gpio: could not find pin matching %q", key)
 	}
 
-	id := pd.ID
-
-	p, ok := io.initializedPins[id]
-	if ok {
-		dp, ok := p.(*digitalPin)
-		if !ok {
-			return nil, fmt.Errorf("gpio: sorry, pin %q is already initialized for a different mode", key)
-		}
-		return dp, nil
-	}
-
 	if pd.Caps != CapNormal {
 		glog.Infof("gpio: pin %q is not a dedicated digital io pin. please refer to the system reference manual for more details", key)
 	}
 
 	dp := newDigitalPin(pd.DigitalLogical)
-	io.initializedPins[id] = dp
+	io.initializedPins[pd.ID] = dp
 
 	return dp, nil
 }

gpiodriver_test.go

@@ -0,0 +1,26 @@
+package embd
+
+import "testing"
+
+func TestGpioDriverDigitalPin(t *testing.T) {
+	var tests = []struct {
+		key interface{}
+		n   int
+	}{
+		{1, 1},
+	}
+	var pinMap = PinMap{
+		&PinDesc{ID: "P1_1", Aliases: []string{"1"}, Caps: CapNormal, DigitalLogical: 1},
+	}
+	driver := newGPIODriver(pinMap)
+	for _, test := range tests {
+		pin, err := driver.digitalPin(test.key)
+		if err != nil {
+			t.Errorf("Looking up %v: unexpected error: %v", test.key, err)
+			continue
+		}
+		if pin.n != test.n {
+			t.Errorf("Looking up %v: got %v, want %v", test.key, pin.n, test.n)
+		}
+	}
+}