128 lines
3.1 KiB
C
128 lines
3.1 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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#include <drivers/adc.h>
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#include <device.h>
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#include <math.h>
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#include <drivers/sensor.h>
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#include <zephyr.h>
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#include <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 device *adc;
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struct adc_channel_cfg ch_cfg;
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u16_t raw;
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};
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struct gts_config {
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const char *adc_label;
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s16_t b_const;
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u8_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(struct device *dev, enum sensor_channel chan)
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{
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struct gts_data *drv_data = dev->driver_data;
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return adc_read(drv_data->adc, &adc_table);
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}
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static int gts_channel_get(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->driver_data;
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const struct gts_config *cfg = dev->config->config_info;
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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 = (s32_t)dval;
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val->val2 = ((s32_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(struct device *dev)
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{
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struct gts_data *drv_data = dev->driver_data;
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const struct gts_config *cfg = dev->config->config_info;
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drv_data->adc = device_get_binding(cfg->adc_label);
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if (drv_data->adc == NULL) {
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LOG_ERR("Failed to get ADC device.");
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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(drv_data->adc, &drv_data->ch_cfg);
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return 0;
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}
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static struct gts_data gts_data;
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static const struct gts_config gts_cfg = {
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.adc_label = DT_INST_0_GROVE_TEMPERATURE_IO_CHANNELS_CONTROLLER,
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.b_const = (IS_ENABLED(DT_INST_0_GROVE_TEMPERATURE_V1P0)
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? 3975
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: 4250),
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.adc_channel = DT_INST_0_GROVE_TEMPERATURE_IO_CHANNELS_INPUT,
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};
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DEVICE_AND_API_INIT(gts_dev, DT_INST_0_GROVE_TEMPERATURE_LABEL, >s_init,
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>s_data, >s_cfg, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,
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>s_api);
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