revision: modify proposed pin HAL.

Signed-off-by: deadprogram <ron@hybridgroup.com>

internal/pin/pin.go

@@ -0,0 +1,98 @@
+package pin
+
+import "errors"
+
+// OutputFunc is hardware abstraction for a pin which outputs a
+// digital signal (high or low level).
+//
+//	// Code conversion demo: from machine.Pin to pin.OutputFunc
+//	led := machine.LED
+//	led.Configure(machine.PinConfig{Mode: machine.PinOutput})
+//	var p pin.OutputFuncFunc = led.Set // Going from a machine.Pin to a pin.OutputFunc
+type OutputFunc func(level bool)
+
+func (o OutputFunc) High() {
+	o(true)
+}
+
+func (o OutputFunc) Low() {
+	o(false)
+}
+
+// InputFunc is hardware abstraction for a pin which receives a
+// digital signal and reads it (high or low level).
+//
+//	// Code conversion demo: from machine.Pin to pin.InputFunc
+//	input := machine.LED
+//	input.Configure(machine.PinConfig{Mode: machine.PinInputPulldown}) // or use machine.PinInputPullup or machine.PinInput
+//	var p pin.InputFunc = input.Get // Going from a machine.Pin to a drivers.PinInput
+type InputFunc func() (level bool)
+
+// PinOutput represents a pin hardware abstraction layer for a pin that can output a digital signal.
+// This is an wrapper to pin.OutputFunc abstraction which is a function type.
+//
+//	func New(p1, p2, p3 pin.Output) *Device {
+//		return NewWithPinfuncs(p1.Set, p2.Set, p3.Set)
+//	}
+//
+//	func NewWithPinfuncs(p1, p2, p3 pin.OutputFunc) *Device {
+//		return &Device{p1:p1, p2:p2, p3:p3}
+//	}
+//
+// [relevant issue]: https://github.com/tinygo-org/drivers/pull/749/files
+type Output interface {
+	Set(level bool)
+}
+
+// PinInput represents a pin hardware abstraction layer. See [PinOutput] for
+// more information on why this is "legacy".
+type Input interface {
+	Get() (level bool)
+}
+
+// ConfigureOutput is a legacy function used to configure pins as outputs.
+//
+// Deprecated: You should not configure pins in drivers.
+// This is a legacy feature and should only be used by drivers that
+// previously configured pins in initialization to avoid breaking users.
+func ConfigureOutput(po Output) {
+	configureOutput(po)
+}
+
+// ConfigureInput is a legacy function used to configure pins as inputs.
+//
+// Deprecated: You should not configure pins in drivers.
+// This is a legacy feature and should only be used by drivers that
+// previously configured pins in initialization to avoid breaking users.
+func ConfigureInputPulldown(pi Input) {
+	configureInputPulldown(pi)
+}
+
+// ConfigureInput is a legacy function used to configure pins as inputs.
+//
+// Deprecated: You should not configure pins in drivers.
+// This is a legacy feature and should only be used by drivers that
+// previously configured pins in initialization to avoid breaking users.
+func ConfigureInput(pi Input) {
+	configureInput(pi)
+}
+
+// ConfigureInputPullup is a legacy function used to configure pins as inputs.
+//
+// Deprecated: You should not configure pins in drivers.
+// This is a legacy feature and should only be used by drivers that
+// previously configured pins in initialization to avoid breaking users.
+func ConfigureInputPullup(pi Input) {
+	configureInputPullup(pi)
+}
+
+// IsNotPin returns true if the argument is a machine.Pin type and is the machine.NoPin predeclared type.
+//
+// Deprecated: Drivers should not require pin knowledge.
+func IsNotPin(pin any) bool {
+	return isNotPin(pin)
+}
+
+var (
+	ErrConfigBeforeInstantiated = errors.New("device must be instantiated with New before calling Configure method")
+)

internal/pin/pin_go.go

@@ -0,0 +1,9 @@
+//go:build !baremetal
+
+package pin
+
+func configureOutput(p Output)       {}
+func configureInput(p Input)         {}
+func configureInputPulldown(p Input) {}
+func configureInputPullup(p Input)   {}
+func isNotPin(a any) bool            { return false }

internal/pin/pin_nopulls.go

@@ -0,0 +1,10 @@
+//go:build baremetal && fe310
+
+package pin
+
+import "machine"
+
+const (
+	pulldown = machine.PinInput
+	pullup   = machine.PinInput
+)

internal/pin/pin_pulls.go

@@ -0,0 +1,13 @@
+//go:build baremetal && !fe310
+
+package pin
+
+import "machine"
+
+// If you are getting a build error here you then we missed adding
+// your CPU build tag to the list of CPUs that do not have pulldown/pullups.
+// Add it above and in pinhal_nopulls! You should also add a smoketest for it :)
+const (
+	pulldown = machine.PinInputPulldown
+	pullup   = machine.PinInputPullup
+)

internal/pin/pin_tinygo.go

@@ -0,0 +1,33 @@
+//go:build baremetal
+
+package pin
+
+import "machine"
+
+func configureOutput(p Output) {
+	configure(p, machine.PinOutput)
+}
+
+func configureInputPulldown(p Input) {
+	configure(p, pulldown) // some chips do not have pull down, in which case pulldown==machine.PinInput.
+}
+
+func configureInput(p Input) {
+	configure(p, machine.PinInput)
+}
+
+func configureInputPullup(p Input) {
+	configure(p, pullup) // some chips do not have pull up, in which case pullup==machine.PinInput.
+}
+
+func isNotPin(a any) bool {
+	p, ok := a.(machine.Pin)
+	return ok && p == machine.NoPin
+}
+
+func configure(p any, mode machine.PinMode) {
+	machinePin, ok := p.(machine.Pin)
+	if ok {
+		machinePin.Configure(machine.PinConfig{Mode: mode})
+	}
+}