Commit 3f6b9598 authored by Andrew Hepp's avatar Andrew Hepp Committed by Jonathan Cameron
Browse files

iio: temperature: Add MCP9600 thermocouple EMF converter 

Add support for the MCP9600 thermocouple electromotive force converter. The sensor has  integrated cold junction compensation and a typical accuracy of 0.5 degrees Celsius. The driver supports a resolution of 0.0625 degrees Celsius.

Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP960X-Data-Sheet-20005426.pdf


Signed-off-by: default avatarAndrew Hepp <andrew.hepp@ahepp.dev>
Link: https://lore.kernel.org/r/20231025233153.5454-2-andrew.hepp@ahepp.dev


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent d6f250b1

drivers/iio/temperature/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -158,4 +158,14 @@ config MAX31865 
	  This driver can also be build as a module. If so, the module

	  will be called max31865.



config MCP9600

	tristate "MCP9600 thermocouple EMF converter"

	depends on I2C

	help

	  If you say yes here you get support for MCP9600

	  thermocouple EMF converter connected via I2C.



	  This driver can also be built as a module. If so, the module

	  will be called mcp9600.



endmenu

drivers/iio/temperature/Makefile

+1 −0
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@@ -10,6 +10,7 @@ obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o 
obj-$(CONFIG_MAX30208) += max30208.o

obj-$(CONFIG_MAX31856) += max31856.o

obj-$(CONFIG_MAX31865) += max31865.o

obj-$(CONFIG_MCP9600) += mcp9600.o

obj-$(CONFIG_MLX90614) += mlx90614.o

obj-$(CONFIG_MLX90632) += mlx90632.o

obj-$(CONFIG_TMP006) += tmp006.o

drivers/iio/temperature/mcp9600.c

0 → 100644
+139 −0
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// SPDX-License-Identifier: GPL-2.0+

/*

 * mcp9600.c - Support for Microchip MCP9600 thermocouple EMF converter

 *

 * Copyright (c) 2022 Andrew Hepp

 * Author: <andrew.hepp@ahepp.dev>

 */



#include <linux/err.h>

#include <linux/i2c.h>

#include <linux/init.h>

#include <linux/mod_devicetable.h>

#include <linux/module.h>



#include <linux/iio/iio.h>



/* MCP9600 registers */

#define MCP9600_HOT_JUNCTION 0x0

#define MCP9600_COLD_JUNCTION 0x2

#define MCP9600_DEVICE_ID 0x20



/* MCP9600 device id value */

#define MCP9600_DEVICE_ID_MCP9600 0x40



static const struct iio_chan_spec mcp9600_channels[] = {

	{

		.type = IIO_TEMP,

		.address = MCP9600_HOT_JUNCTION,

		.info_mask_separate =

			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),

	},

	{

		.type = IIO_TEMP,

		.address = MCP9600_COLD_JUNCTION,

		.channel2 = IIO_MOD_TEMP_AMBIENT,

		.modified = 1,

		.info_mask_separate =

			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),

	},

};



struct mcp9600_data {

	struct i2c_client *client;

};



static int mcp9600_read(struct mcp9600_data *data,

			struct iio_chan_spec const *chan, int *val)

{

	int ret;



	ret = i2c_smbus_read_word_swapped(data->client, chan->address);



	if (ret < 0)

		return ret;

	*val = ret;



	return 0;

}



static int mcp9600_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan, int *val,

			    int *val2, long mask)

{

	struct mcp9600_data *data = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		ret = mcp9600_read(data, chan, val);

		if (ret)

			return ret;

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		*val = 62;

		*val2 = 500000;

		return IIO_VAL_INT_PLUS_MICRO;

	default:

		return -EINVAL;

	}

}



static const struct iio_info mcp9600_info = {

	.read_raw = mcp9600_read_raw,

};



static int mcp9600_probe(struct i2c_client *client)

{

	struct iio_dev *indio_dev;

	struct mcp9600_data *data;

	int ret;



	ret = i2c_smbus_read_byte_data(client, MCP9600_DEVICE_ID);

	if (ret < 0)

		return dev_err_probe(&client->dev, ret, "Failed to read device ID\n");

	if (ret != MCP9600_DEVICE_ID_MCP9600)

		dev_warn(&client->dev, "Expected ID %x, got %x\n",

				MCP9600_DEVICE_ID_MCP9600, ret);



	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));

	if (!indio_dev)

		return -ENOMEM;



	data = iio_priv(indio_dev);

	data->client = client;



	indio_dev->info = &mcp9600_info;

	indio_dev->name = "mcp9600";

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = mcp9600_channels;

	indio_dev->num_channels = ARRAY_SIZE(mcp9600_channels);



	return devm_iio_device_register(&client->dev, indio_dev);

}



static const struct i2c_device_id mcp9600_id[] = {

	{ "mcp9600" },

	{}

};

MODULE_DEVICE_TABLE(i2c, mcp9600_id);



static const struct of_device_id mcp9600_of_match[] = {

	{ .compatible = "microchip,mcp9600" },

	{}

};

MODULE_DEVICE_TABLE(of, mcp9600_of_match);



static struct i2c_driver mcp9600_driver = {

	.driver = {

		.name = "mcp9600",

		.of_match_table = mcp9600_of_match,

	},

	.probe = mcp9600_probe,

	.id_table = mcp9600_id

};

module_i2c_driver(mcp9600_driver);



MODULE_AUTHOR("Andrew Hepp <andrew.hepp@ahepp.dev>");

MODULE_DESCRIPTION("Microchip MCP9600 thermocouple EMF converter driver");

MODULE_LICENSE("GPL");