bootloader: Small cleanup and docs for factory reset level config

- Add to docs & config descriptions
- Change to a "choice" to become self-documenting
- Keep the bootloader_common_check_long_hold_gpio() function for compatibility

components/bootloader/Kconfig.projbuild

@@ -117,8 +117,8 @@ menu "Bootloader config"
             Allows to reset the device to factory settings:
             - clear one or more data partitions;
             - boot from "factory" partition.
-            The factory reset will occur if there is a GPIO input pulled low while device starts up.
-            See settings below.
+            The factory reset will occur if there is a GPIO input held at the configured level while
+            device starts up. See settings below.
 
     config BOOTLOADER_NUM_PIN_FACTORY_RESET
         int "Number of the GPIO input for factory reset"
@@ -127,17 +127,23 @@ menu "Bootloader config"
         range 0 44 if IDF_TARGET_ESP32S2
         default 4
         help
-            The selected GPIO will be configured as an input with internal pull-up enabled.
-            To trigger a factory reset, this GPIO must be pulled low on reset.
-            Note that GPIO34-39 do not have an internal pullup and an external one must be provided.
+            The selected GPIO will be configured as an input with internal pull-up enabled (note that on some SoCs.
+            not all pins have an internal pull-up, consult the hardware datasheet for details.) To trigger a factory
+            reset, this GPIO must be held high or low (as configured) on startup.
 
-    config BOOTLOADER_PIN_LEVEL_FACTORY_RESET
-        int "Level of the GPIO input for factory reset"
+    choice BOOTLOADER_FACTORY_RESET_PIN_LEVEL
+        bool "Factory reset GPIO level"
         depends on BOOTLOADER_FACTORY_RESET
-        range 0 1
-        default 0
+        default BOOTLOADER_FACTORY_RESET_PIN_LOW
         help
-            Pin level for factory reset. 0 for LOW and 1 for HIGH.
+            Pin level for factory reset, can be triggered on low or high.
+
+        config BOOTLOADER_FACTORY_RESET_PIN_LOW
+            bool "Reset on GPIO low"
+
+        config BOOTLOADER_FACTORY_RESET_PIN_HIGH
+            bool "Reset on GPIO high"
+    endchoice
 
     config BOOTLOADER_OTA_DATA_ERASE
         bool "Clear OTA data on factory reset (select factory partition)"

components/bootloader/subproject/main/bootloader_start.c

@@ -79,7 +79,11 @@ static int selected_boot_partition(const bootloader_state_t *bs)
     if (bootloader_common_get_reset_reason(0) != DEEPSLEEP_RESET) {
         // Factory firmware.
 #ifdef CONFIG_BOOTLOADER_FACTORY_RESET
-        if (bootloader_common_check_long_hold_gpio(CONFIG_BOOTLOADER_NUM_PIN_FACTORY_RESET, CONFIG_BOOTLOADER_HOLD_TIME_GPIO, CONFIG_BOOTLOADER_PIN_LEVEL_FACTORY_RESET) == 1) {
+        bool reset_level = false;
+#if CONFIG_BOOTLOADER_FACTORY_RESET_PIN_HIGH
+        reset_level = true;
+#endif
+        if (bootloader_common_check_long_hold_gpio_level(CONFIG_BOOTLOADER_NUM_PIN_FACTORY_RESET, CONFIG_BOOTLOADER_HOLD_TIME_GPIO, reset_level) == GPIO_LONG_HOLD) {
             ESP_LOGI(TAG, "Detect a condition of the factory reset");
             bool ota_data_erase = false;
 #ifdef CONFIG_BOOTLOADER_OTA_DATA_ERASE

components/bootloader_support/include/bootloader_common.h

@@ -62,18 +62,36 @@ bool bootloader_common_ota_select_valid(const esp_ota_select_entry_t *s);
 bool bootloader_common_ota_select_invalid(const esp_ota_select_entry_t *s);
 
 /**
- * @brief Check if the GPIO input is a long hold or a short hold.
+ * @brief Check if a GPIO input is held low for a long period, short period, or not
+ * at all.
+ *
+ * This function will configure the specified GPIO as an input with internal pull-up enabled.
  *
- * Number of the GPIO input will be configured as an input with internal pull-up enabled.
  * If the GPIO input is held low continuously for delay_sec period then it is a long hold.
  * If the GPIO input is held low for less period then it is a short hold.
  *
  * @param[in] num_pin Number of the GPIO input.
  * @param[in] delay_sec Input must be driven low for at least this long, continuously.
- * @param[in] level Input pin level to trigger lang hold, 0 - LOW, 1 - HIGH
- * @return esp_comm_gpio_hold_t Defines type of hold a GPIO in low state.
+ * @return esp_comm_gpio_hold_t Type of low level hold detected, if any.
  */
-esp_comm_gpio_hold_t bootloader_common_check_long_hold_gpio(uint32_t num_pin, uint32_t delay_sec, int level);
+esp_comm_gpio_hold_t bootloader_common_check_long_hold_gpio(uint32_t num_pin, uint32_t delay_sec);
+
+/**
+ * @brief Check if a GPIO input is held low or high for a long period, short period, or not
+ * at all.
+ *
+ * This function will configure the specified GPIO as an input with internal pull-up enabled.
+ *
+ * If the GPIO input is held at 'level' continuously for delay_sec period then it is a long hold.
+ * If the GPIO input is held at 'level' for less period then it is a short hold.
+ *
+ * @param[in] num_pin Number of the GPIO input.
+ * @param[in] delay_sec Input must be driven to 'level' for at least this long, continuously.
+ * @param[in] level Input pin level to trigger on hold
+ * @return esp_comm_gpio_hold_t Type of hold detected, if any.
+ */
+esp_comm_gpio_hold_t bootloader_common_check_long_hold_gpio_level(uint32_t num_pin, uint32_t delay_sec, bool level);
+
 
 /**
  * @brief Erase the partition data that is specified in the transferred list.

components/bootloader_support/src/bootloader_common.c

@@ -39,7 +39,12 @@
 
 static const char* TAG = "boot_comm";
 
-esp_comm_gpio_hold_t bootloader_common_check_long_hold_gpio(uint32_t num_pin, uint32_t delay_sec, int level)
+esp_comm_gpio_hold_t bootloader_common_check_long_hold_gpio(uint32_t num_pin, uint32_t delay_sec)
+{
+    return bootloader_common_check_long_hold_gpio_level(num_pin, delay_sec, false);
+}
+
+esp_comm_gpio_hold_t bootloader_common_check_long_hold_gpio_level(uint32_t num_pin, uint32_t delay_sec, bool level)
 {
     esp_rom_gpio_pad_select_gpio(num_pin);
     if (GPIO_PIN_MUX_REG[num_pin]) {