component/bt: modify comment formats for API headers

components/bt/bluedroid/api/include/esp_bt_stack_manager.h

@@ -1,14 +1,77 @@
+// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed 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 __ESP_BT_STACK_MANAGER_H__
 #define __ESP_BT_STACK_MANAGER_H__
 
 #include "esp_err.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ *
+ * @brief           This function is called to initialize the bluetooth stack
+ *
+ * @return          
+ *                  - ESP_OK: success
+ *                  - ESP_ERR_INVALID_STATE: if already initialized
+ *                  - ESP_FAIL: others
+ *
+ */
 esp_err_t esp_bt_init_stack(void);
 
+
+/**
+ *
+ * @brief           Deinit and free the resource for bluetooth
+ *
+ * @return          
+ *                  - ESP_OK: success
+ *                  - ESP_ERR_INVALID_STATE: if not initailized yet
+ *
+ */
 esp_err_t esp_bt_deinit_stack(void);
 
+
+/**
+ *
+ * @brief           Enable bluetooth, must after esp_bt_init_stack()
+ *
+ * @return          
+ *                  - ESP_OK: success
+ *                  - ESP_ERR_INVALID_STATE: if not initialized yet or already enabled
+ *                  - ESP_FAIL: others
+ *
+ */
 esp_err_t esp_bt_enable_stack(void);
 
+
+/**
+ * @brief           Disable bluetooth, must prior to esp_deinit_stack()
+ *
+ * @return
+ *                  - ESP_OK: success
+ *                  - ESP_ERR_INVALID_STATE: if not initialized yet or already enabled
+ *                  - ESP_FAIL: others
+ *
+ */
 esp_err_t esp_bt_disable_stack(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __ESP_BT_STACK_MANAGER_H__ */