esp32[c3]: Add XTWDT support

Documentation/platforms/risc-v/esp32c3/boards/esp32c3-generic/index.rst

@@ -241,6 +241,11 @@ To test it, just run the following command::
 
 Where X is the watchdog instance.
 
+To test the XTWDT(/dev/watchdog3) an interrupt handler needs to be
+implemented because XTWDT does not have system reset feature. To implement
+an interrupt handler `WDIOC_CAPTURE` command can be used. When interrupt
+rises, XTAL32K clock can be restored with `WDIOC_RSTCLK` command.
+
 wifi
 ----
 

arch/risc-v/src/common/espressif/Kconfig

@@ -251,6 +251,10 @@ endmenu # Bootloader and Image Configuration
 
 menu "Peripheral Support"
 
+config ESPRESSIF_RTC
+	bool "Real Time Clock (RTC)"
+	default y
+
 config ESPRESSIF_UART
 	bool
 	default n
@@ -360,6 +364,37 @@ config ESPRESSIF_RWDT
 		to have the RTC module reset, please, use the Timers' Module WDTs.
 		They will only reset Main System.
 
+config ESPRESSIF_XTWDT
+	bool "XTAL32K Watchdog Timer"
+	depends on ARCH_CHIP_ESP32C3_GENERIC
+	depends on ESPRESSIF_RTCIO_IRQ
+	depends on ESPRESSIF_RTC_CLK_EXT_OSC || ESPRESSIF_RTC_CLK_EXT_XTAL
+	default n
+	select ESPRESSIF_WDT
+	---help---
+		Includes XTWDT. This watchdog timer monitors the status of the
+		external 32 kHz crystal oscillator (XTAL32K). When XTAL32K_CLK works
+		as the clock source of RTC_SLOW_CLK and it stops oscillating, the
+		XTAL32K watchdog timer first switches to BACKUP32K_CLK derived from
+		RC_SLOW_CLK (if ESP32S2_XTWDT_BACKUP_CLK_ENABLE) and, then, generates
+		an interrupt that could be captured by WDIOC_CAPTURE.
+
+config ESPRESSIF_XTWDT_TIMEOUT
+	int "XTAL32K watchdog timeout period"
+	depends on ESPRESSIF_XTWDT
+	range 1 255
+	default 200
+	help
+		Timeout period configuration for the XTAL32K watchdog timer based on RTC_CLK.
+
+config ESPRESSIF_XTWDT_BACKUP_CLK_ENABLE
+	bool "Automatically switch to BACKUP32K_CLK when timer expires"
+	depends on ESPRESSIF_XTWDT
+	default y
+	---help---
+		Enable this to automatically switch to BACKUP32K_CLK as the source of
+		RTC_SLOW_CLK when the watchdog timer expires.
+
 config ESPRESSIF_BROWNOUT_DET
 	bool "Brownout Detector"
 	default y
@@ -925,6 +960,49 @@ config ESPRESSIF_STORAGE_MTD_SIZE
 
 endmenu # SPI Flash Configuration
 
+menu "RTC Configuration"
+	depends on ESPRESSIF_RTC
+
+choice ESPRESSIF_RTC_CLK_SRC
+	prompt "RTC clock source"
+	default ESPRESSIF_RTC_CLK_INT_RC
+	---help---
+		Choose which clock is used as RTC clock source.
+
+		- "Internal 90KHz oscillator" option provides lowest deep sleep current
+			consumption, and does not require extra external components. However
+			frequency stability with respect to temperature is poor, so time may
+			drift in deep/light sleep modes.
+		- "External 32KHz crystal" provides better frequency stability, at the
+			expense of slightly higher (1uA) deep sleep current consumption.
+		- "External 32KHz oscillator" allows using 32KHz clock generated by an
+			external circuit. In this case, external clock signal must be connected
+			to 32K_XN pin. Amplitude should be <1.2V in case of sine wave signal,
+			and <1V in case of square wave signal. Common mode voltage should be
+			0.1 < Vcm < 0.5Vamp, where Vamp is the signal amplitude.
+			Additionally, 1nF capacitor must be connected between 32K_XP pin and
+			ground. 32K_XP pin can not be used as a GPIO in this case.
+		- "Internal 8.5MHz oscillator divided by 256" option results in higher
+			deep sleep current (by 5uA) but has better frequency stability than
+			the internal 90KHz oscillator. It does not require external components.
+
+config ESPRESSIF_RTC_CLK_INT_RC
+	bool "Internal 90KHz RC oscillator"
+
+config ESPRESSIF_RTC_CLK_EXT_XTAL
+	bool "External 32KHz crystal"
+	select ESP_SYSTEM_RTC_EXT_XTAL
+
+config ESPRESSIF_RTC_CLK_EXT_OSC
+	bool "External 32KHz oscillator at 32K_XN pin"
+	select ESP_SYSTEM_RTC_EXT_XTAL
+
+config ESPRESSIF_RTC_CLK_INT_8MD256
+	bool "Internal 8.5MHz oscillator, divided by 256 (~33kHz)"
+
+endchoice
+endmenu # "RTC Configuration"
+
 menu "LEDC configuration"
 	depends on ESPRESSIF_LEDC
 

arch/risc-v/src/common/espressif/Make.defs

@@ -107,7 +107,7 @@ endif
 
 ESP_HAL_3RDPARTY_REPO   = esp-hal-3rdparty
 ifndef ESP_HAL_3RDPARTY_VERSION
-	ESP_HAL_3RDPARTY_VERSION = ee8c7b0ad6a117465312d4c9a6e654cb7b2b9469
+	ESP_HAL_3RDPARTY_VERSION = 6c58b9c8d29fc2faa8cb6273a169340b80229df5
 endif
 
 ifndef ESP_HAL_3RDPARTY_URL