drivers: esp32: temp: CPU die temperature sensor

Support for the measuring the CPU die temperature
for the ESP32 targets S2,C3. The ESP32 support
was ommited due to lack of offset calibration.

Signed-off-by: Marek Matej <marek.matej@espressif.com>

drivers/sensor/CMakeLists.txt

@@ -112,6 +112,7 @@ add_subdirectory_ifdef(CONFIG_ADC_CMP_NPCX	nuvoton_adc_cmp_npcx)
 add_subdirectory_ifdef(CONFIG_TACH_IT8XXX2	ite_tach_it8xxx2)
 add_subdirectory_ifdef(CONFIG_VCMP_IT8XXX2	ite_vcmp_it8xxx2)
 add_subdirectory_ifdef(CONFIG_PCNT_ESP32	pcnt_esp32)
+add_subdirectory_ifdef(CONFIG_ESP32_TEMP	esp32_temp)
 
 if(CONFIG_USERSPACE OR CONFIG_SENSOR_SHELL OR CONFIG_SENSOR_SHELL_BATTERY)
 # The above if() is needed or else CMake would complain about

drivers/sensor/Kconfig

@@ -263,4 +263,6 @@ source "drivers/sensor/ite_vcmp_it8xxx2/Kconfig"
 
 source "drivers/sensor/pcnt_esp32/Kconfig"
 
+source "drivers/sensor/esp32_temp/Kconfig"
+
 endif # SENSOR

drivers/sensor/esp32_temp/CMakeLists.txt

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources(esp32_temp.c)

drivers/sensor/esp32_temp/Kconfig

@@ -0,0 +1,10 @@
+# Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+config ESP32_TEMP
+	bool "ESP32 Temperature Sensor"
+	default y
+	depends on DT_HAS_ESPRESSIF_ESP32_TEMP_ENABLED
+	depends on !SOC_ESP32
+	help
+	  Enable driver for temperature sensor on certain ESP targets.

drivers/sensor/esp32_temp/esp32_temp.c

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT espressif_esp32_temp
+
+#include <driver/temp_sensor.h>
+
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/sensor.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(esp32_temp, CONFIG_SENSOR_LOG_LEVEL);
+
+#if CONFIG_SOC_ESP32
+#error "Temperature sensor not supported on ESP32"
+#endif /* CONFIG_IDF_TARGET_ESP32 */
+
+struct esp32_temp_data {
+	struct k_mutex mutex;
+	temp_sensor_config_t temp_sensor;
+	float temp_out;
+};
+
+struct esp32_temp_config {
+	temp_sensor_dac_offset_t range;
+};
+
+static int esp32_temp_sample_fetch(const struct device *dev, enum sensor_channel chan)
+{
+	struct esp32_temp_data *data = dev->data;
+	int rc = 0;
+
+	k_mutex_lock(&data->mutex, K_FOREVER);
+
+	if (temp_sensor_read_celsius(&data->temp_out) != ESP_OK) {
+		LOG_ERR("Temperature read error!");
+		rc = -EFAULT;
+		goto unlock;
+	}
+
+unlock:
+	k_mutex_unlock(&data->mutex);
+
+	return rc;
+}
+
+static int esp32_temp_channel_get(const struct device *dev, enum sensor_channel chan,
+					struct sensor_value *val)
+{
+	struct esp32_temp_data *data = dev->data;
+	const struct esp32_temp_config *cfg = dev->config;
+
+	if (chan != SENSOR_CHAN_DIE_TEMP) {
+		return -ENOTSUP;
+	}
+
+	return sensor_value_from_double(val, data->temp_out);
+}
+
+static const struct sensor_driver_api esp32_temp_driver_api = {
+	.sample_fetch = esp32_temp_sample_fetch,
+	.channel_get = esp32_temp_channel_get,
+};
+
+static int esp32_temp_init(const struct device *dev)
+{
+	struct esp32_temp_data *data = dev->data;
+	const struct esp32_temp_config *conf = dev->config;
+
+	k_mutex_init(&data->mutex);
+	temp_sensor_get_config(&data->temp_sensor);
+	data->temp_sensor.dac_offset = conf->range;
+	temp_sensor_set_config(data->temp_sensor);
+	temp_sensor_start();
+	LOG_DBG("Temperature sensor started. Offset %d, clk_div %d",
+		data->temp_sensor.dac_offset, data->temp_sensor.clk_div);
+
+	return 0;
+}
+
+#define ESP32_TEMP_DEFINE(inst)									\
+	static struct esp32_temp_data esp32_temp_dev_data_##inst = {				\
+		.temp_sensor = TSENS_CONFIG_DEFAULT(),						\
+	};											\
+												\
+	static const struct esp32_temp_config esp32_temp_dev_config_##inst = {			\
+		.range = (temp_sensor_dac_offset_t) DT_INST_PROP(inst, range),			\
+	};											\
+												\
+	SENSOR_DEVICE_DT_INST_DEFINE(inst, esp32_temp_init, NULL,				\
+			      &esp32_temp_dev_data_##inst, &esp32_temp_dev_config_##inst,	\
+			      POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,				\
+			      &esp32_temp_driver_api);						\
+
+DT_INST_FOREACH_STATUS_OKAY(ESP32_TEMP_DEFINE)

dts/bindings/sensor/espressif,esp32-temp.yaml

@@ -0,0 +1,24 @@
+# Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+description: ESP32 family temperature sensor node
+
+compatible: "espressif,esp32-temp"
+
+include: sensor-device.yaml
+
+properties:
+    range:
+      type: int
+      description: |
+        The temperature sensor is available on the ESP32-S2, ESP32-C3. Note
+        that it is unavailable on the ESP32 due to missing offset calibration.
+        Temperature range is defined by the temperature offset which is used
+        during calculation of the output temperature from the measured value.
+      default: 2
+      enum:
+      - 0    # measure range: 50°C ~ 125°C, error < 3°C
+      - 1    # measure range: 20°C ~ 100°C, error < 2°C
+      - 2    # measure range:-10°C ~  80°C, error < 1°C
+      - 3    # measure range:-30°C ~  50°C, error < 2°C
+      - 4    # measure range:-40°C ~  20°C, error < 3°C

dts/riscv/espressif/esp32c3.dtsi

@@ -224,6 +224,13 @@
 			status = "disabled";
 		};
 
+		coretemp: coretemp@0x60040058 {
+			compatible = "espressif,esp32-temp";
+			friendly-name = "coretemp";
+			reg = <0x60040058 0x4>;
+			status = "disabled";
+		};
+
 	};
 
 };

dts/xtensa/espressif/esp32s2.dtsi

@@ -262,6 +262,12 @@
 			interrupt-parent = <&intc>;
 			clocks = <&rtc ESP32_PERIPH_SARADC_MODULE>;
 			#io-channel-cells = <1>;
+		};
+
+		coretemp: coretemp@3f408800 {
+			compatible = "espressif,esp32-temp";
+			friendly-name = "coretemp";
+			reg = <0x3f408800 0x4>;
 			status = "disabled";
 		};
 	};