blob: 143dadc6671d9c96d812e023b0d0bff60f326643 [file] [log] [blame]
/*
* Copyright (c) 2023 FTP Technologies
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT microchip_mcp970x
#include <zephyr/drivers/adc.h>
#include <zephyr/drivers/sensor.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(mcp970x, CONFIG_SENSOR_LOG_LEVEL);
enum ic_family {
FAMILY_MCP9700_9700A,
FAMILY_MCP9701_9701A
};
/* Milli degrees C per degree C */
#define MC_PER_C 1000
#define MV_AT_0C_MCP9700_9700A 500
#define MV_AT_0C_MCP9701_9701A 400
#define T_COEFF_MCP9700_9700A 10
#define T_COEFF_MCP9701_9701A 19.5
struct mcp970x_config {
struct adc_dt_spec adc;
enum ic_family family;
};
struct mcp970x_data {
struct adc_sequence sequence;
int16_t raw;
};
static int fetch(const struct device *dev, enum sensor_channel chan)
{
const struct mcp970x_config *config = dev->config;
struct mcp970x_data *data = dev->data;
int ret;
if ((chan != SENSOR_CHAN_AMBIENT_TEMP) && (chan != SENSOR_CHAN_ALL)) {
return -ENOTSUP;
}
ret = adc_read(config->adc.dev, &data->sequence);
if (ret != 0) {
LOG_ERR("adc_read: %d", ret);
}
return ret;
}
static int get(const struct device *dev, enum sensor_channel chan, struct sensor_value *val)
{
const struct mcp970x_config *config = dev->config;
struct mcp970x_data *data = dev->data;
int32_t raw_val = data->raw;
int32_t t;
int ret;
__ASSERT_NO_MSG(val != NULL);
if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
LOG_ERR("chan %d not supported", chan);
return -ENOTSUP;
}
ret = adc_raw_to_millivolts_dt(&config->adc, &raw_val);
if (ret != 0) {
LOG_ERR("to_mv: %d", ret);
return ret;
}
if (config->family == FAMILY_MCP9700_9700A) {
t = (MC_PER_C * (raw_val - MV_AT_0C_MCP9700_9700A)) / T_COEFF_MCP9700_9700A;
} else {
int32_t t_coeff = 10 * T_COEFF_MCP9701_9701A; /* float to int */
t = (MC_PER_C * 10 * (raw_val - MV_AT_0C_MCP9701_9701A)) / t_coeff;
}
val->val1 = t / MC_PER_C;
val->val2 = t % (1000000 / MC_PER_C);
LOG_DBG("%d of %d, %dmV, %dmC", data->raw, (1 << data->sequence.resolution) - 1, raw_val,
t);
return 0;
}
static const struct sensor_driver_api mcp970x_api = {
.sample_fetch = fetch,
.channel_get = get,
};
static int init(const struct device *dev)
{
const struct mcp970x_config *config = dev->config;
struct mcp970x_data *data = dev->data;
int ret;
if (!device_is_ready(config->adc.dev)) {
LOG_ERR("ADC is not ready");
return -ENODEV;
}
ret = adc_channel_setup_dt(&config->adc);
if (ret != 0) {
LOG_ERR("setup: %d", ret);
return ret;
}
ret = adc_sequence_init_dt(&config->adc, &data->sequence);
if (ret != 0) {
LOG_ERR("sequence: %d", ret);
return ret;
}
data->sequence.buffer = &data->raw;
data->sequence.buffer_size = sizeof(data->raw);
return 0;
}
#define MCP970X_INIT(inst) \
static struct mcp970x_data mcp970x_##inst##_data = {0}; \
\
static const struct mcp970x_config mcp970x_##inst##_config = { \
.adc = ADC_DT_SPEC_INST_GET(inst), \
.family = DT_INST_ENUM_IDX(inst, family), \
}; \
\
SENSOR_DEVICE_DT_INST_DEFINE(inst, &init, NULL, &mcp970x_##inst##_data, \
&mcp970x_##inst##_config, POST_KERNEL, \
CONFIG_SENSOR_INIT_PRIORITY, &mcp970x_api);
DT_INST_FOREACH_STATUS_OKAY(MCP970X_INIT)