diff --git a/bbb.go b/bbb.go
index 8eec247..feeb4b4 100644
--- a/bbb.go
+++ b/bbb.go
@@ -157,15 +157,18 @@ func bbbEnsureFeatureDisabled(id string) error {
 }
 
 type bbbAnalogPin struct {
-	n int
+	id string
+	n  int
+
+	drv GPIODriver
 
 	val *os.File
 
 	initialized bool
 }
 
-func newBBBAnalogPin(n int) AnalogPin {
-	return &bbbAnalogPin{n: n}
+func newBBBAnalogPin(pd *PinDesc, drv GPIODriver) AnalogPin {
+	return &bbbAnalogPin{id: pd.ID, n: pd.AnalogLogical, drv: drv}
 }
 
 func (p *bbbAnalogPin) N() int {
@@ -227,6 +230,10 @@ func (p *bbbAnalogPin) Read() (int, error) {
 }
 
 func (p *bbbAnalogPin) Close() error {
+	if err := p.drv.Unregister(p.id); err != nil {
+		return err
+	}
+
 	if !p.initialized {
 		return nil
 	}
@@ -257,6 +264,8 @@ const (
 type bbbPWMPin struct {
 	n string
 
+	drv GPIODriver
+
 	period   int
 	polarity Polarity
 
@@ -267,8 +276,8 @@ type bbbPWMPin struct {
 	initialized bool
 }
 
-func newBBBPWMPin(n string) PWMPin {
-	return &bbbPWMPin{n: n}
+func newBBBPWMPin(pd *PinDesc, drv GPIODriver) PWMPin {
+	return &bbbPWMPin{n: pd.ID, drv: drv}
 }
 
 func (p *bbbPWMPin) N() string {
@@ -463,6 +472,10 @@ func (p *bbbPWMPin) reset() error {
 }
 
 func (p *bbbPWMPin) Close() error {
+	if err := p.drv.Unregister(p.n); err != nil {
+		return err
+	}
+
 	if !p.initialized {
 		return nil
 	}
diff --git a/bbb_test.go b/bbb_test.go
new file mode 100644
index 0000000..534430d
--- /dev/null
+++ b/bbb_test.go
@@ -0,0 +1,41 @@
+package embd
+
+import "testing"
+
+func TestBBBAnalogPinClose(t *testing.T) {
+	pinMap := PinMap{
+		&PinDesc{ID: "P1_1", Aliases: []string{"1"}, Caps: CapAnalog},
+	}
+	driver := newGPIODriver(pinMap, nil, newBBBAnalogPin, nil)
+	pin, err := driver.AnalogPin(1)
+	if err != nil {
+		t.Fatalf("Looking up analog pin 1: got %v", err)
+	}
+	pin.Close()
+	pin2, err := driver.AnalogPin(1)
+	if err != nil {
+		t.Fatalf("Looking up analog pin 1: got %v", err)
+	}
+	if pin == pin2 {
+		t.Fatal("Looking up closed analog pin 1: but got the old instance")
+	}
+}
+
+func TestBBBPWMPinClose(t *testing.T) {
+	pinMap := PinMap{
+		&PinDesc{ID: "P1_1", Aliases: []string{"1"}, Caps: CapPWM},
+	}
+	driver := newGPIODriver(pinMap, nil, nil, newBBBPWMPin)
+	pin, err := driver.PWMPin(1)
+	if err != nil {
+		t.Fatalf("Looking up pwm pin 1: got %v", err)
+	}
+	pin.Close()
+	pin2, err := driver.PWMPin(1)
+	if err != nil {
+		t.Fatalf("Looking up pwm pin 1: got %v", err)
+	}
+	if pin == pin2 {
+		t.Fatal("Looking up closed pwm pin 1: but got the old instance")
+	}
+}
diff --git a/digitalpin.go b/digitalpin.go
index bffd450..0515919 100644
--- a/digitalpin.go
+++ b/digitalpin.go
@@ -14,7 +14,10 @@ import (
 )
 
 type digitalPin struct {
-	n int
+	id string
+	n  int
+
+	drv GPIODriver
 
 	dir       *os.File
 	val       *os.File
@@ -25,8 +28,8 @@ type digitalPin struct {
 	initialized bool
 }
 
-func newDigitalPin(n int) DigitalPin {
-	return &digitalPin{n: n, readBuf: make([]byte, 1)}
+func newDigitalPin(pd *PinDesc, drv GPIODriver) DigitalPin {
+	return &digitalPin{id: pd.ID, n: pd.DigitalLogical, drv: drv, readBuf: make([]byte, 1)}
 }
 
 func (p *digitalPin) N() int {
@@ -223,6 +226,10 @@ func (p *digitalPin) PullDown() error {
 }
 
 func (p *digitalPin) Close() error {
+	if err := p.drv.Unregister(p.id); err != nil {
+		return err
+	}
+
 	if !p.initialized {
 		return nil
 	}
diff --git a/digitalpin_test.go b/digitalpin_test.go
new file mode 100644
index 0000000..942e3d9
--- /dev/null
+++ b/digitalpin_test.go
@@ -0,0 +1,22 @@
+package embd
+
+import "testing"
+
+func TestDigitalPinClose(t *testing.T) {
+	pinMap := PinMap{
+		&PinDesc{ID: "P1_1", Aliases: []string{"1"}, Caps: CapDigital},
+	}
+	driver := newGPIODriver(pinMap, newDigitalPin, nil, nil)
+	pin, err := driver.DigitalPin(1)
+	if err != nil {
+		t.Fatalf("Looking up digital pin 1: got %v", err)
+	}
+	pin.Close()
+	pin2, err := driver.DigitalPin(1)
+	if err != nil {
+		t.Fatalf("Looking up digital pin 1: got %v", err)
+	}
+	if pin == pin2 {
+		t.Fatal("Looking up closed digital pin 1: but got the old instance")
+	}
+}
diff --git a/gpio.go b/gpio.go
index c58a26a..cc09dcd 100644
--- a/gpio.go
+++ b/gpio.go
@@ -103,6 +103,9 @@ type PWMPin interface {
 
 // GPIODriver implements a generic GPIO driver.
 type GPIODriver interface {
+	// Unregister unregisters the pin from the driver. Should be called when the pin is closed.
+	Unregister(string) error
+
 	// DigitalPin returns a pin capable of doing digital IO.
 	DigitalPin(key interface{}) (DigitalPin, error)
 
diff --git a/gpiodriver.go b/gpiodriver.go
index d36f9df..8d9b558 100644
--- a/gpiodriver.go
+++ b/gpiodriver.go
@@ -11,9 +11,9 @@ type pin interface {
 	Close() error
 }
 
-type digitalPinFactory func(n int) DigitalPin
-type analogPinFactory func(n int) AnalogPin
-type pwmPinFactory func(n string) PWMPin
+type digitalPinFactory func(pd *PinDesc, drv GPIODriver) DigitalPin
+type analogPinFactory func(pd *PinDesc, drv GPIODriver) AnalogPin
+type pwmPinFactory func(pd *PinDesc, drv GPIODriver) PWMPin
 
 type gpioDriver struct {
 	pinMap PinMap
@@ -36,6 +36,15 @@ func newGPIODriver(pinMap PinMap, dpf digitalPinFactory, apf analogPinFactory, p
 	}
 }
 
+func (io *gpioDriver) Unregister(id string) error {
+	if _, ok := io.initializedPins[id]; !ok {
+		return fmt.Errorf("gpio: pin %v is not registered yet, cannot unregister", id)
+	}
+
+	delete(io.initializedPins, id)
+	return nil
+}
+
 func (io *gpioDriver) DigitalPin(key interface{}) (DigitalPin, error) {
 	if io.dpf == nil {
 		return nil, errors.New("gpio: digital io not supported on this host")
@@ -46,7 +55,11 @@ func (io *gpioDriver) DigitalPin(key interface{}) (DigitalPin, error) {
 		return nil, fmt.Errorf("gpio: could not find pin matching %v", key)
 	}
 
-	p := io.dpf(pd.DigitalLogical)
+	if p, ok := io.initializedPins[pd.ID]; ok {
+		return p.(DigitalPin), nil
+	}
+
+	p := io.dpf(pd, io)
 	io.initializedPins[pd.ID] = p
 
 	return p, nil
@@ -62,7 +75,11 @@ func (io *gpioDriver) AnalogPin(key interface{}) (AnalogPin, error) {
 		return nil, fmt.Errorf("gpio: could not find pin matching %v", key)
 	}
 
-	p := io.apf(pd.AnalogLogical)
+	if p, ok := io.initializedPins[pd.ID]; ok {
+		return p.(AnalogPin), nil
+	}
+
+	p := io.apf(pd, io)
 	io.initializedPins[pd.ID] = p
 
 	return p, nil
@@ -78,7 +95,11 @@ func (io *gpioDriver) PWMPin(key interface{}) (PWMPin, error) {
 		return nil, fmt.Errorf("gpio: could not find pin matching %v", key)
 	}
 
-	p := io.ppf(pd.ID)
+	if p, ok := io.initializedPins[pd.ID]; ok {
+		return p.(PWMPin), nil
+	}
+
+	p := io.ppf(pd, io)
 	io.initializedPins[pd.ID] = p
 
 	return p, nil
diff --git a/gpiodriver_test.go b/gpiodriver_test.go
index cc15578..301545b 100644
--- a/gpiodriver_test.go
+++ b/gpiodriver_test.go
@@ -6,7 +6,10 @@ import (
 )
 
 type fakeDigitalPin struct {
-	n int
+	id string
+	n  int
+
+	drv GPIODriver
 }
 
 func (p *fakeDigitalPin) N() int {
@@ -41,12 +44,12 @@ func (*fakeDigitalPin) PullDown() error {
 	return nil
 }
 
-func (*fakeDigitalPin) Close() error {
-	return nil
+func (p *fakeDigitalPin) Close() error {
+	return p.drv.Unregister(p.id)
 }
 
-func newFakeDigitalPin(n int) DigitalPin {
-	return &fakeDigitalPin{n}
+func newFakeDigitalPin(pd *PinDesc, drv GPIODriver) DigitalPin {
+	return &fakeDigitalPin{id: pd.ID, n: pd.DigitalLogical, drv: drv}
 }
 
 func TestGpioDriverDigitalPin(t *testing.T) {
@@ -73,7 +76,10 @@ func TestGpioDriverDigitalPin(t *testing.T) {
 }
 
 type fakeAnalogPin struct {
-	n int
+	id string
+	n  int
+
+	drv GPIODriver
 }
 
 func (p *fakeAnalogPin) N() int {
@@ -92,8 +98,8 @@ func (*fakeAnalogPin) Close() error {
 	return nil
 }
 
-func newFakeAnalogPin(n int) AnalogPin {
-	return &fakeAnalogPin{n}
+func newFakeAnalogPin(pd *PinDesc, drv GPIODriver) AnalogPin {
+	return &fakeAnalogPin{id: pd.ID, n: pd.AnalogLogical, drv: drv}
 }
 
 func TestGpioDriverAnalogPin(t *testing.T) {
@@ -142,3 +148,32 @@ func TestGpioDriverUnavailablePinType(t *testing.T) {
 		t.Fatalf("Looking up analog pin 1: got error %q, expected %q", err, expected)
 	}
 }
+
+func TestGpioPinCaching(t *testing.T) {
+	pinMap := PinMap{
+		&PinDesc{ID: "P1_1", Aliases: []string{"1"}, Caps: CapDigital},
+	}
+	driver := newGPIODriver(pinMap, newFakeDigitalPin, nil, nil)
+	pin, err := driver.DigitalPin(1)
+	if err != nil {
+		t.Fatalf("Looking up digital pin 1: got %v", err)
+	}
+	// Lookup the same pin again
+	pin2, err := driver.DigitalPin(1)
+	if err != nil {
+		t.Fatalf("Looking up digital pin 1: got %v", err)
+	}
+	if pin != pin2 {
+		t.Fatalf("Looking up digital pin 1 for the second time: got %v, want %v", &pin2, &pin)
+	}
+	// Looking up a closed pin
+	pin.Close()
+	pin3, err := driver.DigitalPin(1)
+	if err != nil {
+		t.Fatalf("Looking up digital pin 1: got %v", err)
+		return
+	}
+	if pin == pin3 {
+		t.Fatal("Looking up a closed pin, but got the same old instance")
+	}
+}