power_save.c

/* Power save Example

   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/

/*
   this example shows how to use power save mode
   set a router or a AP using the same SSID&PASSWORD as configuration of this example.
   start esp32 and when it connected to AP it will enter power save mode
*/
#include <string.h>
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/event_groups.h"
#include "esp_wifi.h"
#include "esp_log.h"
#include "esp_event.h"
#include "esp_pm.h"
#include "nvs_flash.h"
#include "get_ap_info.h"

#define DEFAULT_LISTEN_INTERVAL CONFIG_EXAMPLE_WIFI_LISTEN_INTERVAL
#define DEFAULT_BEACON_TIMEOUT  CONFIG_EXAMPLE_WIFI_BEACON_TIMEOUT

#if CONFIG_EXAMPLE_POWER_SAVE_MIN_MODEM
#define DEFAULT_PS_MODE WIFI_PS_MIN_MODEM
#elif CONFIG_EXAMPLE_POWER_SAVE_MAX_MODEM
#define DEFAULT_PS_MODE WIFI_PS_MAX_MODEM
#elif CONFIG_EXAMPLE_POWER_SAVE_NONE
#define DEFAULT_PS_MODE WIFI_PS_NONE
#else
#define DEFAULT_PS_MODE WIFI_PS_NONE
#endif /*CONFIG_POWER_SAVE_MODEM*/

#if CONFIG_SOC_WIFI_SUPPORT_5G
#if CONFIG_EXAMPLE_WIFI_BAND_MODE_2G
#define DEFAULT_WIFI_BAND_MODE  WIFI_BAND_MODE_2G_ONLY
#elif CONFIG_EXAMPLE_WIFI_BAND_MODE_5G
#define DEFAULT_WIFI_BAND_MODE  WIFI_BAND_MODE_5G_ONLY
#else
#define DEFAULT_WIFI_BAND_MODE  WIFI_BAND_MODE_AUTO
#endif
#endif

static const char *TAG = "power_save";

static void 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_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(TAG, "got ip: " IPSTR, IP2STR(&event->ip_info.ip));
    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_BEACON_OFFSET_UNSTABLE) {
        wifi_event_sta_beacon_offset_unstable_t* event = (wifi_event_sta_beacon_offset_unstable_t*)event_data;
        ESP_LOGI(TAG, "unstable sample, beacon success rate: %.4f", event->beacon_success_rate);
#if CONFIG_EXAMPLE_POWER_SAVE_RESAMPLE
        esp_wifi_beacon_offset_sample_beacon();
#endif
    }
}

/*init wifi as sta and set power save mode*/
static void wifi_power_save(void)
{
    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    esp_netif_t *sta_netif = esp_netif_create_default_wifi_sta();
    assert(sta_netif);

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL, NULL));
    ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &event_handler, NULL, NULL));

    wifi_config_t wifi_config = {
        .sta = {
            .listen_interval = DEFAULT_LISTEN_INTERVAL,
        },
    };

    strcpy((char *)wifi_config.sta.ssid, get_ap_ssid());
    strcpy((char *)wifi_config.sta.password, get_ap_password());

    ESP_LOGI(TAG, "Connecting AP: %s with password: %s", wifi_config.sta.ssid, wifi_config.sta.password);

    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());
#if CONFIG_SOC_WIFI_SUPPORT_5G
    ESP_ERROR_CHECK(esp_wifi_set_band_mode(DEFAULT_WIFI_BAND_MODE));
#endif
    ESP_ERROR_CHECK(esp_wifi_set_inactive_time(WIFI_IF_STA, DEFAULT_BEACON_TIMEOUT));

    ESP_LOGI(TAG, "esp_wifi_set_ps().");
    esp_wifi_set_ps(DEFAULT_PS_MODE);
}

void app_main(void)
{
    // Initialize NVS
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK( ret );

#if CONFIG_EXAMPLE_GET_AP_INFO_FROM_STDIN
    get_ap_info_from_stdin();
#endif

#if CONFIG_PM_ENABLE
    // Configure dynamic frequency scaling:
    // maximum and minimum frequencies are set in sdkconfig,
    // automatic light sleep is enabled if tickless idle support is enabled.
    esp_pm_config_t pm_config = {
            .max_freq_mhz = CONFIG_EXAMPLE_MAX_CPU_FREQ_MHZ,
            .min_freq_mhz = CONFIG_EXAMPLE_MIN_CPU_FREQ_MHZ,
#if CONFIG_FREERTOS_USE_TICKLESS_IDLE
            .light_sleep_enable = true
#endif
    };
    ESP_ERROR_CHECK( esp_pm_configure(&pm_config) );
#endif // CONFIG_PM_ENABLE

    wifi_power_save();
}