141 lines
3.6 KiB
C
141 lines
3.6 KiB
C
/*
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* Copyright (c) 2023 FTP Technologies
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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 microchip_mcp970x
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#include <zephyr/drivers/adc.h>
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#include <zephyr/drivers/sensor.h>
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#include <zephyr/logging/log.h>
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LOG_MODULE_REGISTER(mcp970x, CONFIG_SENSOR_LOG_LEVEL);
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enum ic_family {
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FAMILY_MCP9700_9700A,
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FAMILY_MCP9701_9701A
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};
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/* Milli degrees C per degree C */
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#define MC_PER_C 1000
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#define MV_AT_0C_MCP9700_9700A 500
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#define MV_AT_0C_MCP9701_9701A 400
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#define T_COEFF_MCP9700_9700A 10
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#define T_COEFF_MCP9701_9701A 19.5
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struct mcp970x_config {
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struct adc_dt_spec adc;
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enum ic_family family;
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};
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struct mcp970x_data {
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struct adc_sequence sequence;
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int16_t raw;
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};
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static int fetch(const struct device *dev, enum sensor_channel chan)
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{
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const struct mcp970x_config *config = dev->config;
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struct mcp970x_data *data = dev->data;
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int ret;
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if ((chan != SENSOR_CHAN_AMBIENT_TEMP) && (chan != SENSOR_CHAN_ALL)) {
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return -ENOTSUP;
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}
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ret = adc_read(config->adc.dev, &data->sequence);
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if (ret != 0) {
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LOG_ERR("adc_read: %d", ret);
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}
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return ret;
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}
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static int get(const struct device *dev, enum sensor_channel chan, struct sensor_value *val)
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{
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const struct mcp970x_config *config = dev->config;
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struct mcp970x_data *data = dev->data;
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int32_t raw_val = data->raw;
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int32_t t;
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int ret;
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__ASSERT_NO_MSG(val != NULL);
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if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
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return -ENOTSUP;
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}
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ret = adc_raw_to_millivolts_dt(&config->adc, &raw_val);
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if (ret != 0) {
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LOG_ERR("to_mv: %d", ret);
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return ret;
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}
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if (config->family == FAMILY_MCP9700_9700A) {
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t = (MC_PER_C * (raw_val - MV_AT_0C_MCP9700_9700A)) / T_COEFF_MCP9700_9700A;
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} else {
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int32_t t_coeff = 10 * T_COEFF_MCP9701_9701A; /* float to int */
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t = (MC_PER_C * 10 * (raw_val - MV_AT_0C_MCP9701_9701A)) / t_coeff;
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}
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val->val1 = t / MC_PER_C;
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val->val2 = 1000 * (t % MC_PER_C);
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LOG_DBG("%d of %d, %dmV, %dmC", data->raw, (1 << data->sequence.resolution) - 1, raw_val,
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t);
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return 0;
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}
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static const struct sensor_driver_api mcp970x_api = {
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.sample_fetch = fetch,
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.channel_get = get,
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};
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static int init(const struct device *dev)
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{
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const struct mcp970x_config *config = dev->config;
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struct mcp970x_data *data = dev->data;
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int ret;
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if (!device_is_ready(config->adc.dev)) {
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LOG_ERR("ADC is not ready");
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return -ENODEV;
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}
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ret = adc_channel_setup_dt(&config->adc);
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if (ret != 0) {
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LOG_ERR("setup: %d", ret);
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return ret;
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}
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ret = adc_sequence_init_dt(&config->adc, &data->sequence);
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if (ret != 0) {
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LOG_ERR("sequence: %d", ret);
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return ret;
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}
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data->sequence.buffer = &data->raw;
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data->sequence.buffer_size = sizeof(data->raw);
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return 0;
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}
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#define MCP970X_INIT(inst) \
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static struct mcp970x_data mcp970x_##inst##_data = {0}; \
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\
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static const struct mcp970x_config mcp970x_##inst##_config = { \
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.adc = ADC_DT_SPEC_INST_GET(inst), \
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.family = DT_INST_ENUM_IDX(inst, family), \
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}; \
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\
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SENSOR_DEVICE_DT_INST_DEFINE(inst, &init, NULL, &mcp970x_##inst##_data, \
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&mcp970x_##inst##_config, POST_KERNEL, \
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CONFIG_SENSOR_INIT_PRIORITY, &mcp970x_api);
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DT_INST_FOREACH_STATUS_OKAY(MCP970X_INIT)
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