drivers: sensor: Add LPC internal temperature sensor

drivers/adc/adc_mcux_lpadc.c

@@ -225,6 +225,16 @@ static int mcux_lpadc_channel_setup(const struct device *dev,
 		}
 	} else if (channel_cfg->reference == ADC_REF_EXTERNAL0) {
 		LOG_DBG("ref external0");
+# if defined(FSL_FEATURE_LPADC_HAS_INTERNAL_TEMP_SENSOR)
+	} else if (channel_cfg->reference == ADC_REF_INTERNAL) {
+		/*
+		 * We are assuming that if the reference has been set to
+		 * ADC_REF_INTERNAL that the channel is being used to sample the
+		 * internal temperature sensor.
+		 */
+		LOG_DBG("ref internal");
+		cmd->loopCount = FSL_FEATURE_LPADC_TEMP_SENS_BUFFER_SIZE - 1U;
+#endif
 	} else {
 		LOG_DBG("ref not support");
 		return -EINVAL;
@@ -477,8 +487,12 @@ static int mcux_lpadc_init(const struct device *dev)
 	lpadc_config_t adc_config;
 	int err;
 
+	/*
+	 * pinctrl_apply_state() returns -ENOENT if pinctrl is not provided. This is
+	 * expected if only using the internal channels.
+	 */
 	err = pinctrl_apply_state(config->pincfg, PINCTRL_STATE_DEFAULT);
-	if (err) {
+	if (err && err != -ENOENT) {
 		return err;
 	}
 

drivers/sensor/nxp/CMakeLists.txt

@@ -13,4 +13,5 @@ add_subdirectory_ifdef(CONFIG_QDEC_NXP_S32 qdec_nxp_s32)
 add_subdirectory_ifdef(CONFIG_QDEC_TPM qdec_tpm)
 add_subdirectory_ifdef(CONFIG_SENSOR_MCUX_ACMP mcux_acmp)
 add_subdirectory_ifdef(CONFIG_TEMP_KINETIS nxp_kinetis_temp)
+add_subdirectory_ifdef(CONFIG_TEMP_LPC nxp_lpc_temp)
 # zephyr-keep-sorted-stop

drivers/sensor/nxp/Kconfig

@@ -8,6 +8,7 @@ source "drivers/sensor/nxp/fxos8700/Kconfig"
 source "drivers/sensor/nxp/mcux_acmp/Kconfig"
 source "drivers/sensor/nxp/mcux_lpcmp/Kconfig"
 source "drivers/sensor/nxp/nxp_kinetis_temp/Kconfig"
+source "drivers/sensor/nxp/nxp_lpc_temp/Kconfig"
 source "drivers/sensor/nxp/nxp_tempmon/Kconfig"
 source "drivers/sensor/nxp/p3t1755/Kconfig"
 source "drivers/sensor/nxp/qdec_mcux/Kconfig"

drivers/sensor/nxp/nxp_lpc_temp/CMakeLists.txt

@@ -0,0 +1,6 @@
+# Copyright (c) 2025 Nova Dynamics LLC
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources(temp_lpc.c)

drivers/sensor/nxp/nxp_lpc_temp/Kconfig

@@ -0,0 +1,9 @@
+# Copyright (c) 2025 Nova Dynamics LLC
+# SPDX-License-Identifier: Apache-2.0
+
+config TEMP_LPC
+	bool "NXP LPC Temperature Sensor"
+	default y
+	depends on ADC_MCUX_LPADC && DT_HAS_NXP_LPC_TEMPERATURE_ENABLED
+	help
+	  Enable driver for NXP LPC internal temperature sensor.

drivers/sensor/nxp/nxp_lpc_temp/temp_lpc.c

@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 2025 Nova Dynamics LLC
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT nxp_lpc_temperature
+
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/drivers/adc.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(temp_lpc, CONFIG_SENSOR_LOG_LEVEL);
+
+#include <fsl_lpadc.h>
+
+BUILD_ASSERT(DT_NUM_INST_STATUS_OKAY(DT_DRV_COMPAT) <= 1,
+		 "only one instance is supported");
+
+struct temp_lpc_config {
+	const struct device *adc;
+	uint8_t sensor_adc_ch;
+	struct adc_sequence adc_seq;
+	const struct adc_channel_cfg adc_ch_cfg[];
+};
+
+struct temp_lpc_data {
+	uint16_t buffer[FSL_FEATURE_LPADC_TEMP_SENS_BUFFER_SIZE];
+};
+
+static struct temp_lpc_data inst_data;
+
+static const struct temp_lpc_config inst_config = {
+	.adc = DEVICE_DT_GET(DT_INST_IO_CHANNELS_CTLR(0)),
+	.sensor_adc_ch = DT_INST_IO_CHANNELS_INPUT_BY_IDX(0, 0),
+	.adc_seq = {
+		.options = NULL,
+		.channels = BIT(DT_INST_IO_CHANNELS_INPUT_BY_IDX(0, 0)),
+		.buffer = &inst_data.buffer,
+		.buffer_size = sizeof(inst_data.buffer),
+		.resolution = 16,
+		.oversampling = 7,
+		.calibrate = false,
+	},
+	.adc_ch_cfg = {
+		DT_FOREACH_CHILD_SEP(DT_INST_IO_CHANNELS_CTLR(0), ADC_CHANNEL_CFG_DT, (,))
+	},
+};
+
+static int temp_lpc_sample_fetch(const struct device *dev,
+					enum sensor_channel chan)
+{
+	const struct temp_lpc_config *config = dev->config;
+
+	if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_DIE_TEMP) {
+		return -ENOTSUP;
+	}
+
+	return adc_read(config->adc, &config->adc_seq);
+}
+
+static int temp_lpc_channel_get(const struct device *dev,
+					enum sensor_channel chan, struct sensor_value *val)
+{
+	struct temp_lpc_data *data = dev->data;
+
+	uint16_t Vbe1;
+	uint16_t Vbe8;
+	float slope;
+	float offset;
+	float temperature;
+	uint32_t cal_slope;
+	uint32_t cal_offset;
+
+	const float alpha = FSL_FEATURE_LPADC_TEMP_PARAMETER_ALPHA;
+	const uintptr_t slope_addr = FSL_FEATURE_FLASH_NMPA_TEMP_SLOPE_ADDRS;
+	const uintptr_t offset_addr = FSL_FEATURE_FLASH_NMPA_TEMP_OFFSET_ADDRS;
+
+	if (chan != SENSOR_CHAN_VOLTAGE && chan != SENSOR_CHAN_DIE_TEMP) {
+		return -ENOTSUP;
+	}
+
+	/* Read the calibration from flash. */
+	cal_slope = (*((volatile uint32_t *)(slope_addr)));
+	cal_offset = (*((volatile uint32_t *)(offset_addr)));
+
+	if (((cal_slope & 0x1UL) != 0UL) && ((cal_offset & 0x1UL) != 0UL)) {
+		/* Re-justify based on the calibration values. */
+		slope = ((float)(uint32_t)(cal_slope >> 1UL) / 1024.0f);
+		offset = ((float)(uint32_t)(cal_offset >> 1UL) / 1024.0f);
+	} else {
+		/* Otherwise, use the default slope and offset value. */
+		slope = FSL_FEATURE_LPADC_TEMP_PARAMETER_A;
+		offset = FSL_FEATURE_LPADC_TEMP_PARAMETER_B;
+	}
+
+	/* Read the 2 temperature sensor result. */
+#if (FSL_FEATURE_LPADC_TEMP_SENS_BUFFER_SIZE == 4U)
+	Vbe1 = data->buffer[2];
+	Vbe8 = data->buffer[3];
+#else
+	Vbe1 = data->buffer[0];
+	Vbe8 = data->buffer[1];
+#endif
+
+	/* T = A*[alpha*(Vbe8-Vbe1)/(Vbe8 + alpha*(Vbe8-Vbe1))] - B. */
+	temperature = slope * (alpha * ((float)Vbe8 - (float)Vbe1) /
+			((float)Vbe8 + alpha * ((float)Vbe8 - (float)Vbe1))) - offset;
+
+	return sensor_value_from_float(val, temperature);
+}
+
+static DEVICE_API(sensor, temp_lpc_driver_api) = {
+	.sample_fetch = temp_lpc_sample_fetch,
+	.channel_get = temp_lpc_channel_get,
+};
+
+static int temp_lpc_init(const struct device *dev)
+{
+	const struct temp_lpc_config *config = dev->config;
+	const struct adc_channel_cfg *channels = config->adc_ch_cfg;
+	int ret;
+
+	if (!device_is_ready(config->adc)) {
+		LOG_ERR("ADC device is not ready");
+		return -EINVAL;
+	}
+
+	ret = adc_channel_setup(config->adc, &channels[config->sensor_adc_ch]);
+	if (ret) {
+		LOG_ERR("failed to configure ADC channel (%d)", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+SENSOR_DEVICE_DT_INST_DEFINE(0, temp_lpc_init, NULL, &inst_data,
+			&inst_config, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,
+			&temp_lpc_driver_api);

dts/arm/nxp/nxp_lpc55S1x_common.dtsi

@@ -5,6 +5,7 @@
  */
 
 #include <arm/armv8-m.dtsi>
+#include <zephyr/dt-bindings/adc/adc.h>
 #include <zephyr/dt-bindings/clock/mcux_lpc_syscon_clock.h>
 #include <zephyr/dt-bindings/gpio/gpio.h>
 #include <zephyr/dt-bindings/i2c/i2c.h>
@@ -319,6 +320,22 @@
 		status = "okay";
 	};
 
+	adc0: adc@a0000 {
+		compatible = "nxp,lpc-lpadc";
+		reg = <0xa0000 0x1000>;
+		interrupts = <22 0>;
+		status = "disabled";
+		clk-divider = <8>;
+		clk-source = <0>;
+		voltage-ref= <1>;
+		calibration-average = <128>;
+		power-level = <0>;
+		offset-value-a = <10>;
+		offset-value-b = <10>;
+		#io-channel-cells = <1>;
+		clocks = <&syscon MCUX_LPADC1_CLK>;
+	};
+
 	usbhs: usbhs@94000 {
 		compatible = "nxp,lpcip3511";
 		reg = <0x94000 0x1000>;

dts/bindings/sensor/nxp,lpc-temperature.yaml

@@ -0,0 +1,14 @@
+# Copyright (c) 2025 Nova Dynamics LLC
+# SPDX-License-Identifier: Apache-2.0
+
+description: NXP LPC temperature sensor
+
+compatible: "nxp,lpc-temperature"
+
+include: sensor-device.yaml
+
+properties:
+  io-channels:
+    required: true
+    description: This should point to an ADC channel (e.g., <&adc0 0>). That
+      will be used for reading from the internal temperature sensor.

samples/sensor/die_temp_polling/boards/lpcxpresso55s16.conf

@@ -0,0 +1 @@
+CONFIG_TEMP_LPC=y

samples/sensor/die_temp_polling/boards/lpcxpresso55s16.overlay

@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2025 Nova Dynamics LLC
+ */
+
+#include <zephyr/dt-bindings/adc/mcux-lpadc.h>
+
+/ {
+	aliases {
+		die-temp0 = &temp;
+	};
+
+	temp: temp {
+		status = "okay";
+		compatible = "nxp,lpc-temperature";
+		io-channels = <&adc0 0>;
+	};
+};
+
+&adc0 {
+	status = "okay";
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	channel@0 {
+		reg = <0>;
+		zephyr,gain = "ADC_GAIN_1";
+		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,acquisition-time = <ADC_ACQ_TIME(ADC_ACQ_TIME_TICKS, 131)>;
+		zephyr,vref-mv = <1000>;
+		zephyr,input-positive = <26>;
+		zephyr,input-negative = <26>;
+	};
+};