feat(esp_wifi): Showcases the new scan by bitmap config

- Showcases the ability to scan by the bitmap config newly added
to the wifi_scan_config_t by implementing it in the scan config

examples/wifi/scan/README.md

@@ -23,7 +23,8 @@ Open the project configuration menu (`idf.py menuconfig`).
 In the `Example Configuration` menu:
 
 * Set the Example configuration.
-    * Use `Max size of scan list` to set the maximum nunber of access points in the list.
+    * Use `Max size of scan list` to set the maximum number of access points in the list.
+    * Use 'Scan Channel list' to list specific channels you wish to scan. For eg. 1,6,9,11. By Default all channels will be scanned.
 
 ### Build and Flash
 
@@ -47,7 +48,7 @@ As you run the example, you will see the following log:
 I (443) wifi:wifi firmware version: 6bff005
 I (443) wifi:wifi certification version: v7.0
 I (443) wifi:config NVS flash: enabled
-I (443) wifi:config nano formating: disabled
+I (443) wifi:config nano formatting: disabled
 I (453) wifi:Init data frame dynamic rx buffer num: 32
 I (453) wifi:Init management frame dynamic rx buffer num: 32
 I (463) wifi:Init management short buffer num: 32

examples/wifi/scan/main/Kconfig.projbuild

@@ -7,4 +7,11 @@ menu "Example Configuration"
         help
             The size of array that will be used to retrieve the list of access points.
 
+    config EXAMPLE_USE_SCAN_CHANNEL_BITMAP
+        bool "Scan only non overlapping channels using Channel bitmap"
+        default 0
+        help
+            Enable this to scan only the non overlapping channels i.e 1,6,11 by mentioning a channel bitmap
+            in scan config. If you wish to scan a different set of specific channels, please edit the channel_list
+            array in scan.c. Channels for a 2.4 ghz network range should range from 1-14.
 endmenu

examples/wifi/scan/main/scan.c

@@ -17,9 +17,16 @@
 #include "esp_log.h"
 #include "esp_event.h"
 #include "nvs_flash.h"
+#include "regex.h"
 
 #define DEFAULT_SCAN_LIST_SIZE CONFIG_EXAMPLE_SCAN_LIST_SIZE
 
+#ifdef CONFIG_EXAMPLE_USE_SCAN_CHANNEL_BITMAP
+#define USE_CHANNEL_BTIMAP 1
+#define CHANNEL_LIST_SIZE 3
+static uint8_t channel_list[CHANNEL_LIST_SIZE] = {1, 6, 11};
+#endif /*CONFIG_EXAMPLE_USE_SCAN_CHANNEL_BITMAP*/
+
 static const char *TAG = "scan";
 
 static void print_auth_mode(int authmode)
@@ -133,6 +140,17 @@ static void print_cipher_type(int pairwise_cipher, int group_cipher)
     }
 }
 
+#ifdef USE_CHANNEL_BTIMAP
+static void array_2_channel_bitmap(const uint8_t channel_list[], const uint8_t channel_list_size, wifi_scan_config_t *scan_config) {
+
+    for(uint8_t i = 0; i < channel_list_size; i++) {
+        uint8_t channel = channel_list[i];
+        scan_config->channel_bitmap.ghz_2_channels |= (1 << channel);
+    }
+}
+#endif /*USE_CHANNEL_BTIMAP*/
+
+
 /* Initialize Wi-Fi as sta and set scan method */
 static void wifi_scan(void)
 {
@@ -149,9 +167,23 @@ static void wifi_scan(void)
     uint16_t ap_count = 0;
     memset(ap_info, 0, sizeof(ap_info));
 
+
     ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
     ESP_ERROR_CHECK(esp_wifi_start());
+
+#ifdef USE_CHANNEL_BTIMAP
+    wifi_scan_config_t *scan_config = (wifi_scan_config_t *)calloc(1,sizeof(wifi_scan_config_t));
+    if (!scan_config) {
+        ESP_LOGE(TAG, "Memory Allocation for scan config failed!");
+        return;
+    }
+    array_2_channel_bitmap(channel_list, CHANNEL_LIST_SIZE, scan_config);
+    esp_wifi_scan_start(scan_config, true);
+
+#else
     esp_wifi_scan_start(NULL, true);
+#endif /*USE_CHANNEL_BTIMAP*/
+
     ESP_LOGI(TAG, "Max AP number ap_info can hold = %u", number);
     ESP_ERROR_CHECK(esp_wifi_scan_get_ap_records(&number, ap_info));
     ESP_ERROR_CHECK(esp_wifi_scan_get_ap_num(&ap_count));
@@ -165,7 +197,6 @@ static void wifi_scan(void)
         }
         ESP_LOGI(TAG, "Channel \t\t%d", ap_info[i].primary);
     }
-
 }
 
 void app_main(void)