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: Andrew Hepp <andrew.hepp@xxxxxxxxx> --- Changes for v7: - remove unused buffer - remove unnecessary mutex - remove unusable timestamps - add error message if driver fails to read DEVICE_ID register - update probe callback Changes for v6: - read_word_swapped instead of block_data Changes for v5: - remove "driver" from subject Changes for v4: - none Changes for v3: - none Changes for v2: - remove unused sysfs include - remove unused scan fields from channel - warn rather than fail when probing unknown device - register device through devm - clean up style and prints --- drivers/iio/temperature/Kconfig | 10 +++ drivers/iio/temperature/Makefile | 1 + drivers/iio/temperature/mcp9600.c | 139 ++++++++++++++++++++++++++++++ 3 files changed, 150 insertions(+) create mode 100644 drivers/iio/temperature/mcp9600.c diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig index ed384f33e0c7..ea2ce364b2e9 100644 --- a/drivers/iio/temperature/Kconfig +++ b/drivers/iio/temperature/Kconfig @@ -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 diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile index dfec8c6d3019..9330d4a39598 100644 --- a/drivers/iio/temperature/Makefile +++ b/drivers/iio/temperature/Makefile @@ -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 diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c new file mode 100644 index 000000000000..46845804292b --- /dev/null +++ b/drivers/iio/temperature/mcp9600.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * mcp9600.c - Support for Microchip MCP9600 thermocouple EMF converter + * + * Copyright (c) 2022 Andrew Hepp + * Author: <andrew.hepp@xxxxxxxxx> + */ + +#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@xxxxxxxxx>"); +MODULE_DESCRIPTION("Microchip MCP9600 thermocouple EMF converter driver"); +MODULE_LICENSE("GPL"); -- 2.34.1
