fix issue #858

ws2812/ws2812.go

@@ -35,9 +35,10 @@ func NewWS2812(pin machine.Pin) Device {
 	return newWS2812Device(pin)
 }
 
-// New returns a new SK6812(RGBA) driver.
+// NewSK6812 returns a new SK6812W/RGBW driver (4 channels, GRBW order, 32-bit protocol), for the 3 channels version use NewWS2812
-// It does not touch the pin object: you have
+// Use this for SK6812W strips that have a dedicated white channel controlled via color.A.
-// to configure it as an output pin before calling New.
+// It does not touch the pin object: you have to configure it as an output pin before
+// calling this.
 func NewSK6812(pin machine.Pin) Device {
 	return Device{
 		Pin:            pin,

ws2812/ws2812_init_other.go

@@ -6,5 +6,5 @@ import "machine"
 
 // newWS2812Device creates a WS2812 device using the bit-bang driver.
 func newWS2812Device(pin machine.Pin) Device {
-	return Device{Pin: pin, writeColorFunc: writeColorsRGB}
+	return Device{Pin: pin, brightness: 255, writeColorFunc: writeColorsRGB}
 }

ws2812/ws2812_rp2_pio.go

@@ -15,11 +15,11 @@ import (
 func newWS2812Device(pin machine.Pin) Device {
 	sm, err := pio.PIO0.ClaimStateMachine()
 	if err != nil {
-		return Device{Pin: pin, writeColorFunc: writeColorsRGB}
+		return Device{Pin: pin, brightness: 255, writeColorFunc: writeColorsRGB}
 	}
 	ws, err := piolib.NewWS2812B(sm, pin)
 	if err != nil {
-		return Device{Pin: pin, writeColorFunc: writeColorsRGB}
+		return Device{Pin: pin, brightness: 255, writeColorFunc: writeColorsRGB}
 	}
 	return Device{
 		Pin:        pin,