add new

pkg/ws2812b/ws2812b.go

@@ -23,6 +23,7 @@ func Init(gpio, count, brightness int) (*LED, error) {
 
 	err := ws2811.Init(gpio, count, brightness)
 	if err != nil {
+		led = nil
 		return nil, err
 	}
 
@@ -36,15 +37,30 @@ func Init(gpio, count, brightness int) (*LED, error) {
 	return led, nil
 }
 
+func IsInit() bool {
+	if led == nil {
+		return false
+	}
+	return led.IsInit
+}
+
 func Close() {
 	ws2811.Clear()
 	ws2811.Fini()
+	led.IsInit = false
 }
 
 func ClearAll() {
 	ws2811.Clear()
 }
 
+func Len() int {
+	if led == nil {
+		return 0
+	}
+	return led.Count
+}
+
 func WriteColor(pos int, color uint32) error {
 	if pos < 0 || pos > led.Count {
 		return errors.New("position out of range")