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drivers: sensors: Add support for RaspberryPi Pico CPU temperature
Support for the measuring the CPU die temperature for the RaspberryPi Pico. Signed-off-by: TOKITA Hiroshi <[email protected]>
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‎drivers/sensor/CMakeLists.txt

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@@ -114,6 +114,7 @@ add_subdirectory_ifdef(CONFIG_TACH_IT8XXX2 ite_tach_it8xxx2)
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add_subdirectory_ifdef(CONFIG_VCMP_IT8XXX2 ite_vcmp_it8xxx2)
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add_subdirectory_ifdef(CONFIG_PCNT_ESP32 pcnt_esp32)
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add_subdirectory_ifdef(CONFIG_ESP32_TEMP esp32_temp)
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add_subdirectory_ifdef(CONFIG_RPI_PICO_TEMP rpi_pico_temp)
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if(CONFIG_USERSPACE OR CONFIG_SENSOR_SHELL OR CONFIG_SENSOR_SHELL_BATTERY)
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# The above if() is needed or else CMake would complain about

‎drivers/sensor/Kconfig

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@@ -267,4 +267,6 @@ source "drivers/sensor/pcnt_esp32/Kconfig"
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source "drivers/sensor/esp32_temp/Kconfig"
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source "drivers/sensor/rpi_pico_temp/Kconfig"
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endif # SENSOR

‎drivers/sensor/rpi_pico_temp/CMakeLists.txt

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# Copyright (c) 2023 TOKITA Hiroshi
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# SPDX-License-Identifier: Apache-2.0
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zephyr_library()
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zephyr_library_sources(rpi_pico_temp.c)

‎drivers/sensor/rpi_pico_temp/Kconfig

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# Raspberry Pi Pico temperature sensor configuration options
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# Copyright (c) 2023 TOKITA Hiroshi
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# SPDX-License-Identifier: Apache-2.0
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config RPI_PICO_TEMP
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bool "Raspberry Pi Pico CPU Temperature Sensor"
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default y
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depends on DT_HAS_RASPBERRYPI_PICO_TEMP_ENABLED
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depends on ADC
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help
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Enable driver for Raspberry Pi Pico CPU temperature sensor.

‎drivers/sensor/rpi_pico_temp/rpi_pico_temp.c

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/*
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* Copyright (c) 2023 TOKITA Hiroshi
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/device.h>
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#include <zephyr/devicetree.h>
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#include <zephyr/drivers/sensor.h>
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#include <zephyr/drivers/adc.h>
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#include <zephyr/logging/log.h>
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#include <hardware/adc.h>
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LOG_MODULE_REGISTER(rpi_pico_temp, CONFIG_SENSOR_LOG_LEVEL);
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#define DT_DRV_COMPAT raspberrypi_pico_temp
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struct rpi_pico_temp_config {
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const struct device *adc;
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const struct adc_channel_cfg ch_cfg;
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const int32_t vbe;
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const int32_t vbe_slope;
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};
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struct rpi_pico_temp_data {
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struct adc_sequence adc_seq;
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int16_t sample;
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};
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static int rpi_pico_temp_sample_fetch(const struct device *dev, enum sensor_channel chan)
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{
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const struct rpi_pico_temp_config *cfg = dev->config;
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struct rpi_pico_temp_data *data = dev->data;
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int rc;
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if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_DIE_TEMP) {
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return -ENOTSUP;
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}
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rc = adc_channel_setup(cfg->adc, &cfg->ch_cfg);
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if (rc) {
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LOG_DBG("Setup ADC channel %u failed with %d", cfg->ch_cfg.channel_id, rc);
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return rc;
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}
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rc = adc_read(cfg->adc, &data->adc_seq);
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return rc;
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}
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static int rpi_pico_temp_channel_get(const struct device *dev, enum sensor_channel chan,
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struct sensor_value *val)
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{
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const struct rpi_pico_temp_config *cfg = dev->config;
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struct rpi_pico_temp_data *data = dev->data;
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int32_t mv = 0;
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int32_t work;
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int rc;
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if (chan != SENSOR_CHAN_DIE_TEMP) {
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return -ENOTSUP;
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}
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mv = data->sample;
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rc = adc_raw_to_millivolts(adc_ref_internal(cfg->adc), cfg->ch_cfg.gain,
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data->adc_seq.resolution, &mv);
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if (rc) {
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LOG_DBG("adc_raw_to_millivolts() failed %d", rc);
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return rc;
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}
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/*
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* Calculate CPU temperature from voltage by the equation:
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* T = 27 - (ADC_Voltage - 0.706)/0.001721
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*/
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work = ((27 * (-cfg->vbe_slope)) - (mv * 1000 - cfg->vbe));
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val->val1 = work / (-cfg->vbe_slope);
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work -= val->val1 * (-cfg->vbe_slope);
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val->val2 = work * 1000000 / (-cfg->vbe_slope);
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return 0;
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}
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static const struct sensor_driver_api rpi_pico_temp_driver_api = {
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.sample_fetch = rpi_pico_temp_sample_fetch,
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.channel_get = rpi_pico_temp_channel_get,
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};
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static int rpi_pico_temp_init(const struct device *dev)
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{
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const struct rpi_pico_temp_config *cfg = dev->config;
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if (!device_is_ready(cfg->adc)) {
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LOG_ERR("Device %s is not ready", cfg->adc->name);
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return -ENODEV;
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}
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adc_set_temp_sensor_enabled(true);
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return 0;
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}
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#define RPI_PICO_TEMP_DEFINE(inst) \
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static const struct rpi_pico_temp_config rpi_pico_temp_config_##inst = { \
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.adc = DEVICE_DT_GET(DT_INST_IO_CHANNELS_CTLR(inst)), \
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.vbe = DT_INST_PROP(inst, vbe), \
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.vbe_slope = DT_INST_PROP(inst, vbe_slope), \
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.ch_cfg = \
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{ \
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.gain = ADC_GAIN_1, \
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.reference = ADC_REF_INTERNAL, \
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.acquisition_time = ADC_ACQ_TIME_DEFAULT, \
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.channel_id = DT_INST_IO_CHANNELS_INPUT(inst), \
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.differential = 0, \
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}, \
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}; \
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static struct rpi_pico_temp_data rpi_pico_temp_dev_data_##inst = { \
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.adc_seq = \
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{ \
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.channels = BIT(DT_INST_IO_CHANNELS_INPUT(inst)), \
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.buffer = &rpi_pico_temp_dev_data_##inst.sample, \
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.buffer_size = sizeof(rpi_pico_temp_dev_data_##inst.sample), \
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.resolution = 12U, \
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}, \
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}; \
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\
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SENSOR_DEVICE_DT_INST_DEFINE(inst, rpi_pico_temp_init, NULL, \
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&rpi_pico_temp_dev_data_##inst, &rpi_pico_temp_config_##inst, \
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POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY, \
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&rpi_pico_temp_driver_api);
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DT_INST_FOREACH_STATUS_OKAY(RPI_PICO_TEMP_DEFINE)

‎dts/arm/rpi_pico/rp2040.dtsi

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@@ -12,6 +12,10 @@
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#include "rpi_pico_common.dtsi"
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/ {
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aliases {
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die-temp0 = &die_temp;
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};
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cpus {
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#address-cells = <1>;
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#size-cells = <0>;
@@ -185,6 +189,12 @@
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pinctrl: pin-controller {
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compatible = "raspberrypi,pico-pinctrl";
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};
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die_temp: dietemp {
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compatible = "raspberrypi,pico-temp";
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io-channels = <&adc 4>;
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status = "disabled";
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};
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};
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&nvic {

‎dts/bindings/sensor/raspberrrypi,pico-temp.yaml

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# Copyright (c) 2023 TOKITA Hiroshi
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# SPDX-License-Identifier: Apache-2.0
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description: RaspberryPi Pico family temperature sensor node
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compatible: "raspberrypi,pico-temp"
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include: sensor-device.yaml
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properties:
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io-channels:
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required: true
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description: ADC channel for CPU temperature sensor
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vbe:
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type: int
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default: 706000
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description: |
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Vbe voltage in microvolts at 27 degrees C. Vbe = 0.706V typically.
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The temperature sensor measures the Vbe voltage of a biased bipolar diode.
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The temperature calculates from the Vbe voltage measured by the sensor
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using the following equation typical case.
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T = 27 - (ADC_Voltage - 0.706)/0.001721
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See also the vbe-slope section.
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vbe-slope:
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type: int
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default: -1721
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description: |
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The slope of Vbe voltage in microvolts per degree C.
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Typically, a slope of -1.721mV per degree.
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See also the vbe section.

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