- small corrections

- changes to use the same source code with ESP8266 (esp-open-rtos) and
  ESP32 (ESP-IDF)

extras/ccs811/ccs811_platform.h

@@ -0,0 +1,69 @@
+/*
+ * Driver for AMS CCS811 digital gas sensor connected to I2C.
+ *
+ * This driver is for the usage with the ESP8266 and FreeRTOS (esp-open-rtos)
+ * [https://github.com/SuperHouse/esp-open-rtos]. It is also working with ESP32
+ * and ESP-IDF [https://github.com/espressif/esp-idf.git] as well as Linux
+ * based systems using a wrapper library for ESP8266 functions.
+ *
+ * ---------------------------------------------------------------------------
+ *
+ * The BSD License (3-clause license)
+ *
+ * Copyright (c) 2017 Gunar Schorcht (https://github.com/gschorcht)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+ 
+/**
+ * Platform file: platform specific definitions, includes and functions
+ */
+
+#ifndef __CCS811_PLATFORM_H__
+#define __CCS811_PLATFORM_H__
+
+#if !defined(ESP_OPEN_RTOS)
+#define ESP_OPEN_RTOS 1
+#endif
+
+#ifdef ESP_OPEN_RTOS  // ESP8266
+
+// platform specific includes
+
+#include "FreeRTOS.h"
+#include "task.h"
+
+#include "espressif/esp_common.h"
+#include "espressif/sdk_private.h"
+
+#include "esp/uart.h"
+#include "i2c/i2c.h"
+
+#endif // ESP_OPEN_RTOS
+
+#endif // __CCS811_PLATFORM_H__