add wifi connection

main/CMakeLists.txt

@@ -1,2 +1,2 @@
-idf_component_register(SRCS "main.c" "tic.c" "libteleinfo.cpp" "libteleinfo/src/LibTeleinfo.cpp"
+idf_component_register(SRCS "main.c" "tic.c" "wifi.c" "libteleinfo.cpp" "libteleinfo/src/LibTeleinfo.cpp"
                     INCLUDE_DIRS ".")

main/main.c

@@ -5,8 +5,17 @@
 #include "freertos/queue.h"
 #include "driver/uart.h"
 #include "esp_log.h"
+#include "nvs_flash.h"
+#include "nvs.h"
+
 #include "tic.h"
+#include "wifi.h"
 
 void app_main(void) {
+    // NVS is used to store wifi credentials. So, we need to initialize it first.
+    ESP_ERROR_CHECK(nvs_flash_init());
+
+    wifi_init_sta();
+    wifi_wait_for_online();
     tic_uart_init();
 }

main/wifi.c

@@ -0,0 +1,95 @@
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/event_groups.h"
+#include "esp_system.h"
+#include "esp_wifi.h"
+#include "esp_event.h"
+#include "esp_log.h"
+#include "nvs_flash.h"
+
+#include "lwip/err.h"
+#include "lwip/sys.h"
+
+#include "wifi.h"
+
+/* FreeRTOS event group to signal when we are connected*/
+static EventGroupHandle_t s_wifi_event_group;
+
+/* The event group allows multiple bits for each event, but we only care about one event:
+ * - we are connected to the AP with an IP
+ */
+#define WIFI_CONNECTED_BIT BIT0
+
+static const char *WIFI_LOGGER = "wifi";
+
+static void wifi_event_handler(void* arg, esp_event_base_t event_base,
+                                int32_t event_id, void* event_data) {
+    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
+        esp_wifi_connect();
+    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
+        ESP_LOGI(WIFI_LOGGER,"Connection to the AP failed!");
+        xEventGroupClearBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
+
+        ESP_LOGI(WIFI_LOGGER, "Retrying to connect to the AP...");
+        esp_wifi_connect();
+    } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
+        ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
+        ESP_LOGI(WIFI_LOGGER, "got ip:" IPSTR, IP2STR(&event->ip_info.ip));
+        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
+    }
+}
+
+void wifi_init_sta(void) {
+    s_wifi_event_group = xEventGroupCreate();
+
+    ESP_ERROR_CHECK(esp_netif_init());
+
+    ESP_ERROR_CHECK(esp_event_loop_create_default());
+    esp_netif_create_default_wifi_sta();
+
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
+
+    esp_event_handler_instance_t instance_any_id;
+    esp_event_handler_instance_t instance_got_ip;
+    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,
+                                                        ESP_EVENT_ANY_ID,
+                                                        &wifi_event_handler,
+                                                        NULL,
+                                                        &instance_any_id));
+    ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT,
+                                                        IP_EVENT_STA_GOT_IP,
+                                                        &wifi_event_handler,
+                                                        NULL,
+                                                        &instance_got_ip));
+
+    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
+    ESP_ERROR_CHECK(esp_wifi_start());
+
+    ESP_LOGI(WIFI_LOGGER, "wifi_init_sta finished.");
+}
+
+void wifi_wait_for_online(void) {
+    /* Waiting until the connection is established (WIFI_CONNECTED_BIT).
+     * The bits are set by wifi_event_handler() (see above)
+     */
+    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
+            WIFI_CONNECTED_BIT,
+            pdFALSE,
+            pdFALSE,
+            portMAX_DELAY);
+
+    /* xEventGroupWaitBits() returns the bits before the call returned, hence we can test which event actually
+     * happened. */
+    if (bits & WIFI_CONNECTED_BIT) {
+        ESP_LOGI(WIFI_LOGGER, "Connected to Wifi!");
+    } else {
+        ESP_LOGE(WIFI_LOGGER, "UNEXPECTED EVENT");
+    }
+
+    /* The event will not be processed after unregister */
+    //ESP_ERROR_CHECK(esp_event_handler_instance_unregister(IP_EVENT, IP_EVENT_STA_GOT_IP, instance_got_ip));
+    //ESP_ERROR_CHECK(esp_event_handler_instance_unregister(WIFI_EVENT, ESP_EVENT_ANY_ID, instance_any_id));
+    //vEventGroupDelete(s_wifi_event_group);
+}

main/wifi.h

@@ -0,0 +1,7 @@
+#ifndef __WIFI_H__
+#define __WIFI_H__
+
+void wifi_init_sta(void);
+void wifi_wait_for_online(void);
+
+#endif