134 lines
3.3 KiB
C
134 lines
3.3 KiB
C
/*
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* Copyright (c) 2016 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT seeed_grove_temperature
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#include <zephyr/drivers/adc.h>
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#include <zephyr/device.h>
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#include <zephyr/devicetree.h>
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#include <math.h>
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#include <zephyr/drivers/sensor.h>
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#include <zephyr/kernel.h>
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#include <zephyr/logging/log.h>
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LOG_MODULE_REGISTER(grove_temp, CONFIG_SENSOR_LOG_LEVEL);
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/* The effect of gain and reference voltage must cancel. */
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#ifdef CONFIG_ADC_NRFX_SAADC
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#define GROVE_GAIN ADC_GAIN_1_4
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#define GROVE_REF ADC_REF_VDD_1_4
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#define GROVE_RESOLUTION 12
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#else
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#define GROVE_GAIN ADC_GAIN_1
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#define GROVE_REF ADC_REF_VDD_1
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#define GROVE_RESOLUTION 12
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#endif
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struct gts_data {
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struct adc_channel_cfg ch_cfg;
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uint16_t raw;
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};
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struct gts_config {
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const struct device *adc;
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int16_t b_const;
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uint8_t adc_channel;
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};
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static struct adc_sequence_options options = {
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.extra_samplings = 0,
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.interval_us = 15,
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};
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static struct adc_sequence adc_table = {
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.options = &options,
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};
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static int gts_sample_fetch(const struct device *dev,
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enum sensor_channel chan)
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{
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const struct gts_config *cfg = dev->config;
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return adc_read(cfg->adc, &adc_table);
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}
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static int gts_channel_get(const struct device *dev,
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enum sensor_channel chan,
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struct sensor_value *val)
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{
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struct gts_data *drv_data = dev->data;
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const struct gts_config *cfg = dev->config;
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double dval;
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/*
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* The formula for converting the analog value to degrees Celsius
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* is taken from the sensor reference page:
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* http://www.seeedstudio.com/wiki/Grove_-_Temperature_Sensor
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*/
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dval = (1 / (log((BIT(GROVE_RESOLUTION) - 1.0)
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/ drv_data->raw
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- 1.0)
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/ cfg->b_const
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+ (1 / 298.15)))
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- 273.15;
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val->val1 = (int32_t)dval;
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val->val2 = ((int32_t)(dval * 1000000)) % 1000000;
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return 0;
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}
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static const struct sensor_driver_api gts_api = {
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.sample_fetch = >s_sample_fetch,
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.channel_get = >s_channel_get,
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};
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static int gts_init(const struct device *dev)
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{
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struct gts_data *drv_data = dev->data;
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const struct gts_config *cfg = dev->config;
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if (!device_is_ready(cfg->adc)) {
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LOG_ERR("ADC device is not ready.");
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return -EINVAL;
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}
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/*Change following parameters according to board if necessary*/
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drv_data->ch_cfg = (struct adc_channel_cfg){
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.gain = GROVE_GAIN,
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.reference = GROVE_REF,
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.acquisition_time = ADC_ACQ_TIME_DEFAULT,
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.channel_id = cfg->adc_channel,
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#ifdef CONFIG_ADC_NRFX_SAADC
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.input_positive = SAADC_CH_PSELP_PSELP_AnalogInput0 + cfg->adc_channel,
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#endif
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};
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adc_table.buffer = &drv_data->raw;
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adc_table.buffer_size = sizeof(drv_data->raw);
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adc_table.resolution = GROVE_RESOLUTION;
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adc_table.channels = BIT(cfg->adc_channel);
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adc_channel_setup(cfg->adc, &drv_data->ch_cfg);
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return 0;
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}
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#define GTS_DEFINE(inst) \
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static struct gts_data gts_data_##inst; \
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\
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static const struct gts_config gts_cfg_##inst = { \
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.adc = DEVICE_DT_GET(DT_INST_IO_CHANNELS_CTLR(inst)), \
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.b_const = (IS_ENABLED(DT_INST_PROP(inst, v1p0)) \
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? 3975 \
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: 4250), \
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.adc_channel = DT_INST_IO_CHANNELS_INPUT(inst), \
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}; \
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\
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SENSOR_DEVICE_DT_INST_DEFINE(inst, >s_init, NULL, \
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>s_data_##inst, >s_cfg_##inst, POST_KERNEL, \
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CONFIG_SENSOR_INIT_PRIORITY, >s_api); \
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DT_INST_FOREACH_STATUS_OKAY(GTS_DEFINE)
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