drivers: sensor: mcp9600 add intial driver support

Implementation of MCP9600 i2c thermoouple amplifier - K, J, T, N, S, E, B
and R type T

Signed-off-by: Maxmillion McLaughlin <github@maxmclau.com>

drivers/sensor/CMakeLists.txt

@@ -79,6 +79,7 @@ add_subdirectory_ifdef(CONFIG_MAX31865		max31865)
 add_subdirectory_ifdef(CONFIG_MAX31875		max31875)
 add_subdirectory_ifdef(CONFIG_MAX44009		max44009)
 add_subdirectory_ifdef(CONFIG_MAX6675		max6675)
+add_subdirectory_ifdef(CONFIG_MCP9600		mcp9600)
 add_subdirectory_ifdef(CONFIG_MCP970X		mcp970x)
 add_subdirectory_ifdef(CONFIG_MCP9808		mcp9808)
 add_subdirectory_ifdef(CONFIG_MHZ19B		mhz19b)

drivers/sensor/Kconfig

@@ -201,6 +201,8 @@ source "drivers/sensor/max6675/Kconfig"
 
 source "drivers/sensor/mchp_tach_xec/Kconfig"
 
+source "drivers/sensor/mcp9600/Kconfig"
+
 source "drivers/sensor/mcp970x/Kconfig"
 
 source "drivers/sensor/mcp9808/Kconfig"

drivers/sensor/mcp9600/CMakeLists.txt

@@ -0,0 +1,8 @@
+# Copyright (c) 2022, Maxmillion McLaughlin
+# Copyright (c) 2020, SER Consulting LLC / Steven Riedl
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+zephyr_library()
+zephyr_library_sources(mcp9600.c)

drivers/sensor/mcp9600/Kconfig

@@ -0,0 +1,14 @@
+# I2C Compatible, Thermocouple EMF to Temperature Converter
+#
+# Copyright (c) 2022, Maxmillion McLaughlin
+# Copyright (c) 2020, SER Consulting LLC / Steven Riedl
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config MCP9600
+	bool "MCP9600 i2c thermocouple temperature sensor"
+	default y
+	depends on DT_HAS_MICROCHIP_MCP9600_ENABLED
+	select I2C
+	help
+	  Enable driver for MCP9600 i2c thermocouple temperature sensor.

drivers/sensor/mcp9600/mcp9600.c

@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2022, Maxmillion McLaughlin
+ * Copyright (c) 2020, SER Consulting LLC / Steven Riedl
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT microchip_mcp9600
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/sensor.h>
+#include <zephyr/kernel.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(MCP9600, CONFIG_SENSOR_LOG_LEVEL);
+
+#define MCP9600_REG_TEMP_HOT 0x00
+
+#define MCP9600_REG_TEMP_DIFF 0x01
+#define MCP9600_REG_TEMP_COLD 0x02
+#define MCP9600_REG_RAW_ADC   0x03
+
+#define MCP9600_REG_STATUS 0x04
+
+#define MCP9600_REG_TC_CONFIG  0x05
+#define MCP9600_REG_DEV_CONFIG 0x06
+#define MCP9600_REG_A1_CONFIG  0x07
+
+#define MCP9600_REG_A2_CONFIG 0x08
+#define MCP9600_REG_A3_CONFIG 0x09
+#define MCP9600_REG_A4_CONFIG 0x0A
+#define MCP9600_A1_HYST	      0x0B
+
+#define MCP9600_A2_HYST	 0x0C
+#define MCP9600_A3_HYST	 0x0D
+#define MCP9600_A4_HYST	 0x0E
+#define MCP9600_A1_LIMIT 0x0F
+
+#define MCP9600_A2_LIMIT	0x10
+#define MCP9600_A3_LIMIT	0x11
+#define MCP9600_A4_LIMIT	0x12
+#define MCP9600_REG_ID_REVISION 0x13
+
+struct mcp9600_data {
+	int32_t temp;
+};
+
+struct mcp9600_config {
+	const struct i2c_dt_spec bus;
+};
+
+static int mcp9600_reg_read(const struct device *dev, uint8_t start, uint8_t *buf, int size)
+{
+	const struct mcp9600_config *cfg = dev->config;
+
+	return i2c_burst_read_dt(&cfg->bus, start, buf, size);
+}
+
+static int mcp9600_sample_fetch(const struct device *dev, enum sensor_channel chan)
+{
+	struct mcp9600_data *data = dev->data;
+	uint8_t buf[2];
+	int ret;
+
+	if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_AMBIENT_TEMP) {
+		LOG_ERR("Unsupported sensor channel");
+		return -ENOTSUP;
+	}
+
+	/* read signed 16 bit double-buffered register value */
+	ret = mcp9600_reg_read(dev, MCP9600_REG_TEMP_HOT, buf, sizeof(buf));
+	if (ret < 0) {
+		data->temp = 1;
+		return ret;
+	}
+
+	/* device's hot junction register is a signed int */
+	data->temp = (int32_t)(int16_t)(buf[0] << 8) | buf[1];
+
+	/* 0.0625C resolution per LSB */
+	data->temp *= 62500;
+
+	return 0;
+}
+
+static int mcp9600_channel_get(const struct device *dev, enum sensor_channel chan,
+			       struct sensor_value *val)
+{
+	struct mcp9600_data *data = dev->data;
+
+	if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
+		return -ENOTSUP;
+	}
+
+	if (data->temp == 1) {
+		return -EINVAL;
+	}
+
+	val->val1 = data->temp / 1000000;
+	val->val2 = data->temp % 1000000;
+
+	return 0;
+}
+
+static const struct sensor_driver_api mcp9600_api = {
+	.sample_fetch = mcp9600_sample_fetch,
+	.channel_get = mcp9600_channel_get,
+};
+
+static int mcp9600_init(const struct device *dev)
+{
+	const struct mcp9600_config *cfg = dev->config;
+	uint8_t buf[2];
+	int ret;
+
+	if (!i2c_is_ready_dt(&cfg->bus)) {
+		LOG_ERR("mcp9600 i2c bus %s not ready", cfg->bus.bus->name);
+		return -ENODEV;
+	}
+
+	ret = mcp9600_reg_read(dev, MCP9600_REG_ID_REVISION, buf, sizeof(buf));
+	LOG_DBG("id: 0x%02x version: 0x%02x", buf[0], buf[1]);
+
+	return ret;
+}
+
+#define MCP9600_DEFINE(id)                                                                         \
+	static struct mcp9600_data mcp9600_data_##id;                                              \
+                                                                                                   \
+	static const struct mcp9600_config mcp9600_config_##id = {                                 \
+		.bus = I2C_DT_SPEC_INST_GET(id),                                                   \
+	};                                                                                         \
+                                                                                                   \
+	SENSOR_DEVICE_DT_INST_DEFINE(id, mcp9600_init, NULL, &mcp9600_data_##id,                   \
+				     &mcp9600_config_##id, POST_KERNEL,                            \
+				     CONFIG_SENSOR_INIT_PRIORITY, &mcp9600_api);
+
+DT_INST_FOREACH_STATUS_OKAY(MCP9600_DEFINE)

dts/bindings/sensor/microchip,mcp9600.yaml

@@ -0,0 +1,12 @@
+# Copyright (c) 2022, Maxmillion McLaughlin
+# Copyright (c) 2020, SER Consulting LLC / Steven Riedl
+#
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+  Microchip MCP9600 I2C Thermocouple EMF to Temperature Converter. See
+  https://www.microchip.com/wwwproducts/en/MCP9600.
+
+compatible: "microchip,mcp9600"
+
+include: [sensor-device.yaml, i2c-device.yaml]