add nimble mesh example

need meshctl installed on raspberrypi. nimble offical samples have a lot of pit ...

examples/nimble_mesh_light/ws2812.h

@@ -0,0 +1,42 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef __WS2812_H__
+#define __WS2812_H__
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define WS2812_PWM          0
+#define WS2812_GPIO         30
+#define WS2812_NUM_LED      32
+
+int ws2812_init(void);
+
+int ws2812_write(const uint32_t *rgb);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __WS2812_H__ */