example/deep_sleep: add example of EXT0 and using internal pullups

examples/system/deep_sleep/main/Kconfig.projbuild

@@ -19,8 +19,17 @@ menu "Example Configuration"
             the window defined by the initial temperature and a threshold
             around it.
 
+    config EXAMPLE_EXT0_WAKEUP
+        bool "Enable wakeup from GPIO (ext0)"
+        default y
+        depends on !IDF_TARGET_ESP32C3
+        help
+            This option enables wake up from deep sleep from GPIO3. They should be connected to LOW to avoid
+            floating pins. When triggering a wake up, connect one or both of the pins to HIGH. Note that floating
+            pins may trigger a wake up.
+
     config EXAMPLE_EXT1_WAKEUP
-        bool "Enable wakeup from GPIO"
+        bool "Enable wakeup from GPIO (ext1)"
         default y
         depends on !IDF_TARGET_ESP32C3
         help
@@ -28,6 +37,21 @@ menu "Example Configuration"
             floating pins. When triggering a wake up, connect one or both of the pins to HIGH. Note that floating
             pins may trigger a wake up.
 
+    config EXAMPLE_EXT1_USE_INTERNAL_PULLUPS
+        bool "Use internal pull-up/downs for EXT1 wakeup source"
+        default n
+        depends on EXAMPLE_EXT1_WAKEUP
+        help
+            When using EXT1 wakeup source without external pull-up/downs, you may want to make use of the internal
+            ones.
+
+            However, the RTC IO reside in the RTC Periph power domain. Enable this option to force that power domain
+            ON during deep sleep. Note that this will increase some power comsumption, so it's still suggested to use
+            external ones instead.
+
+            EXT0 wakeup source resides in the same power domain as RTCIO (RTC Periph), so internal pull-up/downs are
+            always available. There's no need to explicitly force it on for EXT0.
+
     config EXAMPLE_GPIO_WAKEUP
         bool "Enable wakeup from GPIO"
         default y

examples/system/deep_sleep/main/deep_sleep_example_main.c

@@ -103,6 +103,12 @@ void app_main(void)
     int sleep_time_ms = (now.tv_sec - sleep_enter_time.tv_sec) * 1000 + (now.tv_usec - sleep_enter_time.tv_usec) / 1000;
 
     switch (esp_sleep_get_wakeup_cause()) {
+#if CONFIG_EXAMPLE_EXT0_WAKEUP
+        case ESP_SLEEP_WAKEUP_EXT0: {
+            printf("Wake up from ext0\n");
+            break;
+        }
+#endif // CONFIG_EXAMPLE_EXT0_WAKEUP
 #ifdef CONFIG_EXAMPLE_EXT1_WAKEUP
         case ESP_SLEEP_WAKEUP_EXT1: {
             uint64_t wakeup_pin_mask = esp_sleep_get_ext1_wakeup_status();
@@ -174,6 +180,18 @@ void app_main(void)
     printf("Enabling timer wakeup, %ds\n", wakeup_time_sec);
     esp_sleep_enable_timer_wakeup(wakeup_time_sec * 1000000);
 
+#if CONFIG_EXAMPLE_EXT0_WAKEUP
+    const int ext_wakeup_pin_0 = 3;
+
+    printf("Enabling EXT0 wakeup on pin GPIO%d\n", ext_wakeup_pin_0);
+    esp_sleep_enable_ext0_wakeup(ext_wakeup_pin_0, 1);
+
+    // Configure pullup/downs via RTCIO to tie wakeup pins to inactive level during deepsleep.
+    // EXT0 resides in the same power domain (RTC_PERIPH) as the RTC IO pullup/downs.
+    // No need to keep that power domain explicitly, unlike EXT1.
+    rtc_gpio_pullup_dis(ext_wakeup_pin_0);
+    rtc_gpio_pulldown_en(ext_wakeup_pin_0);
+#endif // CONFIG_EXAMPLE_EXT0_WAKEUP
 #ifdef CONFIG_EXAMPLE_EXT1_WAKEUP
     const int ext_wakeup_pin_1 = 2;
     const uint64_t ext_wakeup_pin_1_mask = 1ULL << ext_wakeup_pin_1;
@@ -182,6 +200,17 @@ void app_main(void)
 
     printf("Enabling EXT1 wakeup on pins GPIO%d, GPIO%d\n", ext_wakeup_pin_1, ext_wakeup_pin_2);
     esp_sleep_enable_ext1_wakeup(ext_wakeup_pin_1_mask | ext_wakeup_pin_2_mask, ESP_EXT1_WAKEUP_ANY_HIGH);
+
+    /* If there are no external pull-up/downs, tie wakeup pins to inactive level with internal pull-up/downs via RTC IO
+     * during deepsleep. However, RTC IO relies on the RTC_PERIPH power domain. Keeping this power domain on will
+     * increase some power comsumption. */
+#  if CONFIG_EXAMPLE_EXT1_USE_INTERNAL_PULLUPS
+    esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON);
+    rtc_gpio_pullup_dis(ext_wakeup_pin_1);
+    rtc_gpio_pulldown_en(ext_wakeup_pin_1);
+    rtc_gpio_pullup_dis(ext_wakeup_pin_2);
+    rtc_gpio_pulldown_en(ext_wakeup_pin_2);
+#  endif //CONFIG_EXAMPLE_EXT1_USE_INTERNAL_PULLUPS
 #endif // CONFIG_EXAMPLE_EXT1_WAKEUP
 
 #ifdef CONFIG_EXAMPLE_GPIO_WAKEUP