fix(xtal): Add a way to change the XTAL frequency for SparkFun ESP32 Thing (#9844)

* fix(xtal): Add a way to change the XTAL frequency

Add support for boards like SparkFun ESP32 Thing that use 26MHz XTAL

* ci(pre-commit): Apply automatic fixes

* feat(dbg): Print the XTAL frequency in the debug report

---------
Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>

cores/esp32/chip-debug-report.cpp

@@ -96,7 +96,8 @@ static void printChipInfo(void) {
   chip_report_printf("  Cores             : %d\n", info.cores);
   rtc_cpu_freq_config_t conf;
   rtc_clk_cpu_freq_get_config(&conf);
-  chip_report_printf("  Frequency         : %lu MHz\n", conf.freq_mhz);
+  chip_report_printf("  CPU Frequency     : %lu MHz\n", conf.freq_mhz);
+  chip_report_printf("  XTAL Frequency    : %d MHz\n", rtc_clk_xtal_freq_get());
   chip_report_printf("  Embedded Flash    : %s\n", (info.features & CHIP_FEATURE_EMB_FLASH) ? "Yes" : "No");
   chip_report_printf("  Embedded PSRAM    : %s\n", (info.features & CHIP_FEATURE_EMB_PSRAM) ? "Yes" : "No");
   chip_report_printf("  2.4GHz WiFi       : %s\n", (info.features & CHIP_FEATURE_WIFI_BGN) ? "Yes" : "No");

cores/esp32/esp32-hal-misc.c

@@ -252,9 +252,6 @@ extern bool btInUse();
 void initArduino() {
   //init proper ref tick value for PLL (uncomment if REF_TICK is different than 1MHz)
   //ESP_REG(APB_CTRL_PLL_TICK_CONF_REG) = APB_CLK_FREQ / REF_CLK_FREQ - 1;
-#ifdef F_CPU
-  setCpuFrequencyMhz(F_CPU / 1000000);
-#endif
 #if CONFIG_SPIRAM_SUPPORT || CONFIG_SPIRAM
   psramInit();
 #endif

cores/esp32/main.cpp

 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "esp_task_wdt.h"
+#include "soc/rtc.h"
 #include "Arduino.h"
 #if (ARDUINO_USB_CDC_ON_BOOT | ARDUINO_USB_MSC_ON_BOOT | ARDUINO_USB_DFU_ON_BOOT) && !ARDUINO_USB_MODE
 #include "USB.h"
@@ -78,6 +79,15 @@ void loopTask(void *pvParameters) {
 }
 
 extern "C" void app_main() {
+#ifdef F_XTAL_MHZ
+#if !CONFIG_IDF_TARGET_ESP32S2  // ESP32-S2 does not support rtc_clk_xtal_freq_update
+  rtc_clk_xtal_freq_update((rtc_xtal_freq_t)F_XTAL_MHZ);
+  rtc_clk_cpu_freq_set_xtal();
+#endif
+#endif
+#ifdef F_CPU
+  setCpuFrequencyMhz(F_CPU / 1000000);
+#endif
 #if ARDUINO_USB_CDC_ON_BOOT && !ARDUINO_USB_MODE
   Serial.begin();
 #endif

variants/esp32thing/pins_arduino.h

@@ -3,6 +3,8 @@
 
 #include <stdint.h>
 
+#define F_XTAL_MHZ 26  //SparkFun ESP32 Thing has 26MHz Crystal
+
 static const uint8_t LED_BUILTIN = 5;
 #define BUILTIN_LED LED_BUILTIN  // backward compatibility
 #define LED_BUILTIN LED_BUILTIN  // allow testing #ifdef LED_BUILTIN