iio: temperature: add driver support for ti tmp117

TMP117 is a Digital temperature sensor with integrated Non-Volatile memory.
Add support for tmp117 driver in iio subsystem.

Datasheet: https://www.ti.com/lit/gpn/tmp117
Signed-off-by: Puranjay Mohan <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Reviewed-by: Lars-Peter Clausen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

MAINTAINERS

···
 F:	Documentation/hwmon/tps23861.rst
 F:	drivers/hwmon/tps23861.c
 
+TEXAS INSTRUMENTS' TMP117 TEMPERATURE SENSOR DRIVER
+M:	Puranjay Mohan <[e-mail]>
+L:	[e-mail]
+S:	Supported
+F:	Documentation/devicetree/bindings/iio/temperature/ti,tmp117.yaml
+F:	drivers/iio/temperature/tmp117.c
+
 THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
 M:	Hans Verkuil <[e-mail]>
 L:	[e-mail]

drivers/iio/temperature/Kconfig

···
 	  This driver can also be built as a module. If so, the module will
 	  be called tmp007.
 
+config TMP117
+	tristate "TMP117 Digital temperature sensor with integrated NV memory"
+	depends on I2C
+	help
+	  If you say yes here you get support for the Texas Instruments
+	  TMP117 Digital temperature sensor with integrated NV memory.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called tmp117.
+
 config TSYS01
 	tristate "Measurement Specialties TSYS01 temperature sensor using I2C bus connection"
 	depends on I2C

drivers/iio/temperature/Makefile

···
 obj-$(CONFIG_MLX90632) += mlx90632.o
 obj-$(CONFIG_TMP006) += tmp006.o
 obj-$(CONFIG_TMP007) += tmp007.o
+obj-$(CONFIG_TMP117) += tmp117.o
 obj-$(CONFIG_TSYS01) += tsys01.o
 obj-$(CONFIG_TSYS02D) += tsys02d.o

drivers/iio/temperature/tmp117.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Digital temperature sensor with integrated Non-volatile memory
+ * Copyright (c) 2021 Puranjay Mohan <[e-mail]>
+ *
+ * Driver for the Texas Instruments TMP117 Temperature Sensor
+ * (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins)
+ *
+ * Note: This driver assumes that the sensor has been calibrated beforehand.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/limits.h>
+
+#include <linux/iio/iio.h>
+
+#define TMP117_REG_TEMP			0x0
+#define TMP117_REG_CFGR			0x1
+#define TMP117_REG_HIGH_LIM		0x2
+#define TMP117_REG_LOW_LIM		0x3
+#define TMP117_REG_EEPROM_UL		0x4
+#define TMP117_REG_EEPROM1		0x5
+#define TMP117_REG_EEPROM2		0x6
+#define TMP117_REG_TEMP_OFFSET		0x7
+#define TMP117_REG_EEPROM3		0x8
+#define TMP117_REG_DEVICE_ID		0xF
+
+#define TMP117_RESOLUTION_10UC		78125
+#define TMP117_DEVICE_ID		0x0117
+#define MICRODEGREE_PER_10MILLIDEGREE	10000
+
+struct tmp117_data {
+	struct i2c_client *client;
+	s16 calibbias;
+};
+
+static int tmp117_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *channel, int *val,
+		int *val2, long mask)
+{
+	struct tmp117_data *data = iio_priv(indio_dev);
+	s32 ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = i2c_smbus_read_word_swapped(data->client,
+						TMP117_REG_TEMP);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(ret, 15);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_CALIBBIAS:
+		ret = i2c_smbus_read_word_swapped(data->client,
+					TMP117_REG_TEMP_OFFSET);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(ret, 15);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		/*
+		 * Conversion from 10s of uC to mC
+		 * as IIO reports temperature in mC
+		 */
+		*val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
+		*val2 = (TMP117_RESOLUTION_10UC %
+					MICRODEGREE_PER_10MILLIDEGREE) * 100;
+
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int tmp117_write_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *channel, int val,
+		int val2, long mask)
+{
+	struct tmp117_data *data = iio_priv(indio_dev);
+	s16 off;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBBIAS:
+		off = clamp_t(int, val, S16_MIN, S16_MAX);
+		if (off == data->calibbias)
+			return 0;
+		data->calibbias = off;
+		return i2c_smbus_write_word_swapped(data->client,
+						TMP117_REG_TEMP_OFFSET, off);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec tmp117_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_SCALE),
+	},
+};
+
+static const struct iio_info tmp117_info = {
+	.read_raw = tmp117_read_raw,
+	.write_raw = tmp117_write_raw,
+};
+
+static int tmp117_identify(struct i2c_client *client)
+{
+	int dev_id;
+
+	dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
+	if (dev_id < 0)
+		return dev_id;
+	if (dev_id != TMP117_DEVICE_ID) {
+		dev_err(&client->dev, "TMP117 not found\n");
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static int tmp117_probe(struct i2c_client *client)
+{
+	struct tmp117_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	ret = tmp117_identify(client);
+	if (ret < 0)
+		return ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	data->calibbias = 0;
+
+	indio_dev->name = "tmp117";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &tmp117_info;
+
+	indio_dev->channels = tmp117_channels;
+	indio_dev->num_channels = ARRAY_SIZE(tmp117_channels);
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct of_device_id tmp117_of_match[] = {
+	{ .compatible = "ti,tmp117", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tmp117_of_match);
+
+static const struct i2c_device_id tmp117_id[] = {
+	{ "tmp117", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tmp117_id);
+
+static struct i2c_driver tmp117_driver = {
+	.driver = {
+		.name	= "tmp117",
+		.of_match_table = tmp117_of_match,
+	},
+	.probe_new	= tmp117_probe,
+	.id_table	= tmp117_id,
+};
+module_i2c_driver(tmp117_driver);
+
+MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
+MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
+MODULE_LICENSE("GPL");