140 lines
3.8 KiB
C
140 lines
3.8 KiB
C
/*
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* Copyright (c) 2022, Maxmillion McLaughlin
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* Copyright (c) 2020, SER Consulting LLC / Steven Riedl
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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_mcp9600
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#include <zephyr/device.h>
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#include <zephyr/drivers/i2c.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(MCP9600, CONFIG_SENSOR_LOG_LEVEL);
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#define MCP9600_REG_TEMP_HOT 0x00
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#define MCP9600_REG_TEMP_DIFF 0x01
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#define MCP9600_REG_TEMP_COLD 0x02
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#define MCP9600_REG_RAW_ADC 0x03
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#define MCP9600_REG_STATUS 0x04
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#define MCP9600_REG_TC_CONFIG 0x05
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#define MCP9600_REG_DEV_CONFIG 0x06
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#define MCP9600_REG_A1_CONFIG 0x07
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#define MCP9600_REG_A2_CONFIG 0x08
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#define MCP9600_REG_A3_CONFIG 0x09
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#define MCP9600_REG_A4_CONFIG 0x0A
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#define MCP9600_A1_HYST 0x0B
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#define MCP9600_A2_HYST 0x0C
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#define MCP9600_A3_HYST 0x0D
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#define MCP9600_A4_HYST 0x0E
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#define MCP9600_A1_LIMIT 0x0F
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#define MCP9600_A2_LIMIT 0x10
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#define MCP9600_A3_LIMIT 0x11
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#define MCP9600_A4_LIMIT 0x12
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#define MCP9600_REG_ID_REVISION 0x13
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struct mcp9600_data {
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int32_t temp;
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};
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struct mcp9600_config {
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const struct i2c_dt_spec bus;
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};
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static int mcp9600_reg_read(const struct device *dev, uint8_t start, uint8_t *buf, int size)
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{
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const struct mcp9600_config *cfg = dev->config;
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return i2c_burst_read_dt(&cfg->bus, start, buf, size);
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}
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static int mcp9600_sample_fetch(const struct device *dev, enum sensor_channel chan)
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{
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struct mcp9600_data *data = dev->data;
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uint8_t buf[2];
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int ret;
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if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_AMBIENT_TEMP) {
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LOG_ERR("Unsupported sensor channel");
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return -ENOTSUP;
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}
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/* read signed 16 bit double-buffered register value */
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ret = mcp9600_reg_read(dev, MCP9600_REG_TEMP_HOT, buf, sizeof(buf));
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if (ret < 0) {
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data->temp = 1;
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return ret;
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}
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/* device's hot junction register is a signed int */
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data->temp = (int32_t)(int16_t)(buf[0] << 8) | buf[1];
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/* 0.0625C resolution per LSB */
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data->temp *= 62500;
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return 0;
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}
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static int mcp9600_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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struct mcp9600_data *data = dev->data;
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if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
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return -ENOTSUP;
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}
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if (data->temp == 1) {
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return -EINVAL;
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}
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val->val1 = data->temp / 1000000;
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val->val2 = data->temp % 1000000;
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return 0;
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}
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static const struct sensor_driver_api mcp9600_api = {
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.sample_fetch = mcp9600_sample_fetch,
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.channel_get = mcp9600_channel_get,
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};
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static int mcp9600_init(const struct device *dev)
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{
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const struct mcp9600_config *cfg = dev->config;
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uint8_t buf[2];
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int ret;
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if (!i2c_is_ready_dt(&cfg->bus)) {
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LOG_ERR("mcp9600 i2c bus %s not ready", cfg->bus.bus->name);
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return -ENODEV;
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}
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ret = mcp9600_reg_read(dev, MCP9600_REG_ID_REVISION, buf, sizeof(buf));
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LOG_DBG("id: 0x%02x version: 0x%02x", buf[0], buf[1]);
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return ret;
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}
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#define MCP9600_DEFINE(id) \
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static struct mcp9600_data mcp9600_data_##id; \
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\
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static const struct mcp9600_config mcp9600_config_##id = { \
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.bus = I2C_DT_SPEC_INST_GET(id), \
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}; \
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\
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SENSOR_DEVICE_DT_INST_DEFINE(id, mcp9600_init, NULL, &mcp9600_data_##id, \
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&mcp9600_config_##id, POST_KERNEL, \
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CONFIG_SENSOR_INIT_PRIORITY, &mcp9600_api);
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DT_INST_FOREACH_STATUS_OKAY(MCP9600_DEFINE)
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