add claim to piolib drivers

Author: soypat

rp2-pio/piolib/parallel8.go

@@ -20,6 +20,7 @@ type Parallel8Tx struct {
 const noDMA uint32 = 0xffff_ffff
 
 func NewParallel8Tx(sm pio.StateMachine, wr, dStart machine.Pin, baud uint32) (*Parallel8Tx, error) {
+	sm.Claim() // SM should be claimed beforehand, we just guarantee it's claimed.
 	const nPins = 8
 	if dStart+nPins > 31 {
 		return nil, errors.New("invalid D0..D7 pin range")

rp2-pio/piolib/pulsar.go

@@ -20,6 +20,7 @@ type Pulsar struct {
 
 // NewPulsar returns a new Pulsar ready for use.
 func NewPulsar(sm pio.StateMachine, pin machine.Pin) (*Pulsar, error) {
+	sm.Claim() // SM should be claimed beforehand, we just guarantee it's claimed.
 	Pio := sm.PIO()
 
 	offset, err := Pio.AddProgram(pulsarInstructions, pulsarOrigin)

rp2-pio/piolib/spi.go

@@ -16,6 +16,7 @@ type SPI struct {
 }
 
 func NewSPI(sm pio.StateMachine, spicfg machine.SPIConfig) (*SPI, error) {
+	sm.Claim() // SM should be claimed beforehand, we just guarantee it's claimed.
 	const nbits = 8
 	// https://github.com/raspberrypi/pico-examples/blob/eca13acf57916a0bd5961028314006983894fc84/pio/spi/spi.pio#L46
 	if !sm.IsValid() {

rp2-pio/piolib/ws2812.go

@@ -15,6 +15,7 @@ type WS2812 struct {
 }
 
 func NewWS2812(sm pio.StateMachine, pin machine.Pin, baud uint32) (*WS2812, error) {
+	sm.Claim() // SM should be claimed beforehand, we just guarantee it's claimed.
 	whole, frac, err := pio.ClkDivFromFrequency(baud, machine.CPUFrequency())
 	if err != nil {
 		return nil, err