l9110x: add support for L9110x h-bridge motor driver

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

l9110x/l9110x.go

@@ -0,0 +1,90 @@
+// Package l9110x provides a driver to the L9110/L9110S H-bridge chip
+// typically used to control DC motors.
+//
+// Datasheet: https://www.elecrow.com/download/datasheet-l9110.pdf
+//
+package l9110x // import "tinygo.org/x/drivers/l9110x"
+
+import (
+	"machine"
+)
+
+// Device is a motor without speed control.
+// ia and ib are the directional pins.
+type Device struct {
+	ia, ib machine.Pin
+}
+
+// New returns a new Motor driver for GPIO-only operation.
+func New(direction1, direction2 machine.Pin) Device {
+	return Device{
+		ia: direction1,
+		ib: direction2,
+	}
+}
+
+// Configure configures the Device.
+func (d *Device) Configure() {
+	d.ia.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	d.ib.Configure(machine.PinConfig{Mode: machine.PinOutput})
+
+	d.Stop()
+}
+
+// Forward turns motor on in forward direction.
+func (d *Device) Forward() {
+	d.ia.High()
+	d.ib.Low()
+}
+
+// Backward turns motor on in backward direction.
+func (d *Device) Backward() {
+	d.ia.Low()
+	d.ib.High()
+}
+
+// Stop turns motor off.
+func (d *Device) Stop() {
+	d.ia.Low()
+	d.ib.Low()
+}
+
+// PWMDevice is a motor with speed control.
+// ia and ib are the directional/speed PWM pins.
+type PWMDevice struct {
+	ia, ib machine.PWM
+}
+
+// NewWithSpeed returns a new PWMMotor driver that uses 2 PWM pins to control both direction and speed.
+func NewWithSpeed(direction1, direction2 machine.PWM) PWMDevice {
+	return PWMDevice{
+		ia: direction1,
+		ib: direction2,
+	}
+}
+
+// Configure configures the PWMDevice.
+func (d *PWMDevice) Configure() {
+	d.ia.Configure()
+	d.ib.Configure()
+
+	d.Stop()
+}
+
+// Forward turns motor on in forward direction at specific speed.
+func (d *PWMDevice) Forward(speed uint16) {
+	d.ia.Set(speed)
+	d.ib.Set(0)
+}
+
+// Backward turns motor on in backward direction at specific speed.
+func (d *PWMDevice) Backward(speed uint16) {
+	d.ia.Set(0)
+	d.ib.Set(speed)
+}
+
+// Stop turns motor off.
+func (d *PWMDevice) Stop() {
+	d.ia.Set(0)
+	d.ib.Set(0)
+}