soc: espressif: esp32c2: Enable deep sleep support

Adds support for deep sleep mode on the ESP32-C2 SoC, allowing
significant power savings.

Signed-off-by: Sylvio Alves <[email protected]>

Author: sylvioalves

soc/espressif/esp32c2/CMakeLists.txt

@@ -10,3 +10,6 @@ zephyr_sources(
 zephyr_include_directories(.)
 
 zephyr_sources_ifndef(CONFIG_BOOTLOADER_MCUBOOT hw_init.c)
+
+zephyr_library_sources_ifdef(CONFIG_PM power.c)
+zephyr_library_sources_ifdef(CONFIG_POWEROFF poweroff.c)

soc/espressif/esp32c2/Kconfig

@@ -12,6 +12,8 @@ config SOC_SERIES_ESP32C2
 	select RISCV_ISA_EXT_C
 	select RISCV_ISA_EXT_ZICSR
 	select HAS_ESPRESSIF_HAL
+	select HAS_PM
+	select HAS_POWEROFF
 
 if SOC_SERIES_ESP32C2
 

soc/espressif/esp32c2/power.c

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/pm/pm.h>
+#include <zephyr/irq.h>
+#include <esp_sleep.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_DECLARE(soc, CONFIG_SOC_LOG_LEVEL);
+
+/* Invoke Low Power/System Off specific Tasks */
+void pm_state_set(enum pm_state state, uint8_t substate_id)
+{
+	ARG_UNUSED(substate_id);
+
+	switch (state) {
+	case PM_STATE_STANDBY:
+		/* Nothing to do. */
+		break;
+	default:
+		LOG_DBG("Unsupported power state %u", state);
+		break;
+	}
+}
+
+/* Handle SOC specific activity after Low Power Mode Exit */
+void pm_state_exit_post_ops(enum pm_state state, uint8_t substate_id)
+{
+	ARG_UNUSED(substate_id);
+
+	switch (state) {
+	case PM_STATE_STANDBY:
+		irq_unlock(MSTATUS_IEN);
+		__asm__ volatile("wfi");
+		esp_light_sleep_start();
+		break;
+	default:
+		LOG_DBG("Unsupported power state %u", state);
+		break;
+	}
+}

soc/espressif/esp32c2/poweroff.c

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/sys/poweroff.h>
+
+#include <esp_sleep.h>
+
+void z_sys_poweroff(void)
+{
+	/* Forces RTC domain to be always on */
+	esp_sleep_pd_config(ESP_PD_DOMAIN_XTAL, ESP_PD_OPTION_ON);
+	esp_deep_sleep_start();
+}