Replace Safe functions with legacy.PinOutput

Author: ysoldak

bmi160/bmi160.go

@@ -4,6 +4,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // DeviceSPI is the SPI interface to a BMI160 accelerometer/gyroscope. There is
@@ -23,7 +24,7 @@ type DeviceSPI struct {
 // using this device.
 func NewSPI(csb drivers.PinOutput, spi drivers.SPI) *DeviceSPI {
 	return &DeviceSPI{
-		CSB: drivers.SafePinOutput(csb), // chip select
+		CSB: legacy.PinOutput(csb), // chip select
 		Bus: spi,
 	}
 }

buzzer/buzzer.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps a GPIO connection to a buzzer.
@@ -17,7 +18,7 @@ type Device struct {
 // New returns a new buzzer driver given which pin to use
 func New(pin drivers.PinOutput) Device {
 	return Device{
-		set:  drivers.SafePinOutput(pin).Set,
+		set:  legacy.PinOutput(pin).Set,
 		High: false,
 		BPM:  96.0,
 	}

dht/thermometer.go

@@ -45,9 +45,7 @@ type device struct {
 func (t *device) ReadMeasurements() error {
 	// initial waiting
 	state := powerUp(t.pin)
-	defer func() {
-		t.pin.Set(state)
-	}()
+	defer t.pin.Set(state)
 	err := t.read()
 	if err == nil {
 		t.initialized = true
@@ -213,7 +211,7 @@ func waitForDataTransmission(p drivers.PinInput) error {
 func NewDummyDevice(pin drivers.Pin, deviceType DeviceType) DummyDevice {
 	pin.Set(true)
 	return &device{
-		pin:          drivers.SafePin(pin),
+		pin:          pin,
 		measurements: deviceType,
 		initialized:  false,
 		temperature:  0,

dht/timesafethermometer.go

@@ -129,7 +129,7 @@ func New(pin drivers.Pin, deviceType DeviceType) Device {
 	pin.Set(true)
 	return &managedDevice{
 		t: device{
-			pin:          drivers.SafePin(pin),
+			pin:          pin,
 			measurements: deviceType,
 			initialized:  false,
 		},
@@ -146,7 +146,7 @@ func NewWithPolicy(pin drivers.Pin, deviceType DeviceType, updatePolicy UpdatePo
 	pin.Set(true)
 	result := &managedDevice{
 		t: device{
-			pin:          drivers.SafePin(pin),
+			pin:          pin,
 			measurements: deviceType,
 			initialized:  false,
 		},

examples/dht/main.go

@@ -1,14 +1,17 @@
+//go:build baremetal && tinygo
+
 package main
 
 import (
 	"fmt"
 	"machine"
 	"time"
+
 	"tinygo.org/x/drivers/dht"
 )
 
 func main() {
-	pin := machine.D6
+	pin := &machinePin{pin: machine.D6}
 	dhtSensor := dht.New(pin, dht.DHT11)
 	for {
 		temp, hum, err := dhtSensor.Measurements()
@@ -21,3 +24,27 @@ func main() {
 		time.Sleep(time.Second * 2)
 	}
 }
+
+// machinePin wraps machine.Pin to ensure correct pin mode is set when Get or Set methods are called.
+
+type machinePin struct {
+	pin     machine.Pin
+	mode    machine.PinMode
+	modeSet bool
+}
+
+func (p *machinePin) Get() bool {
+	if !p.modeSet || p.mode != machine.PinInput {
+		p.pin.Configure(machine.PinConfig{Mode: machine.PinInput})
+		p.mode = machine.PinInput
+	}
+	return p.pin.Get()
+}
+
+func (p *machinePin) Set(high bool) {
+	if !p.modeSet || p.mode != machine.PinOutput {
+		p.pin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+		p.mode = machine.PinOutput
+	}
+	p.pin.Set(high)
+}

internal/legacy/pinlegacy_generic.go

@@ -0,0 +1,9 @@
+//go:build !(baremetal && tinygo)
+
+package legacy
+
+import "tinygo.org/x/drivers"
+
+func PinOutput(pin drivers.PinOutput) drivers.PinOutput {
+	return pin
+}

internal/legacy/pinlegacy_tinygo.go

@@ -0,0 +1,16 @@
+//go:build baremetal && tinygo
+
+package legacy
+
+import (
+	"machine"
+
+	"tinygo.org/x/drivers"
+)
+
+func PinOutput(pin drivers.PinOutput) drivers.PinOutput {
+	if p, ok := pin.(machine.Pin); ok {
+		p.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	}
+	return pin
+}

pin.go

@@ -4,13 +4,17 @@ package drivers
 // allowing the use of different hardware or libraries without changing driver code.
 //
 // Note, pin mode functionality is not part of the Pin interface.
-// Implementations must ensure correct pin mode is set when Get or Set methods are called.
+// Client code is responsible for configuring pin modes correctly.
+// This can be done either before passing the pin to a driver constructor
+// or by ensuring correct pin mode is set when Get or Set methods are called.
+// See rpio package for an example of a pin implementation that does this.
 //
-// Drivers must use SafePin(), SafePinInput() and SafePinOutput() wrappers in constructors.
-// The client code can pass either machine.Pin or a custom implementation of the Pin interface.
-// Wrappers for TinyGo's machine.Pin are provided in pin_tinygo.go.
-// It's custom implementation's responsibility to configure the pin modes correctly as
-// Wrappers in pin_generic.go are no-ops.
+// Drivers that used to configure output pin mode in their constructors can use
+// legacy.PinOutput() wrapper to keep the same behavior for machine.Pin.
+// See internal/legacy/pinlegacy_tinygo.go and internal/legacy/pinlegacy_generic.go for details.
+//
+// All new drivers are encouraged to not configure pin modes in their constructors and
+// do not depend on either machine package or legacy wrappers.
 
 // PinInput is an interface for reading the state of a pin.
 type PinInput interface {