tmp117.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Digital temperature sensor with integrated Non-volatile memory
  4 * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
  5 *
  6 * Driver for the Texas Instruments TMP117 Temperature Sensor
  7 * (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins)
  8 *
  9 * Note: This driver assumes that the sensor has been calibrated beforehand.
 10 */
 11
 12#include <linux/delay.h>
 13#include <linux/err.h>
 14#include <linux/i2c.h>
 15#include <linux/module.h>
 16#include <linux/bitops.h>
 17#include <linux/types.h>
 18#include <linux/kernel.h>
 19#include <linux/limits.h>
 20#include <linux/property.h>
 21#include <linux/regulator/consumer.h>
 22
 23#include <linux/iio/iio.h>
 24
 25#define TMP117_REG_TEMP			0x0
 26#define TMP117_REG_CFGR			0x1
 27#define TMP117_REG_HIGH_LIM		0x2
 28#define TMP117_REG_LOW_LIM		0x3
 29#define TMP117_REG_EEPROM_UL		0x4
 30#define TMP117_REG_EEPROM1		0x5
 31#define TMP117_REG_EEPROM2		0x6
 32#define TMP117_REG_TEMP_OFFSET		0x7
 33#define TMP117_REG_EEPROM3		0x8
 34#define TMP117_REG_DEVICE_ID		0xF
 35
 36#define TMP117_RESOLUTION_10UC		78125
 37#define MICRODEGREE_PER_10MILLIDEGREE	10000
 38
 39#define TMP116_DEVICE_ID		0x1116
 40#define TMP117_DEVICE_ID		0x0117
 41
 42struct tmp117_data {
 43	struct i2c_client *client;
 44	s16 calibbias;
 45};
 46
 47struct tmp11x_info {
 48	const char *name;
 49	struct iio_chan_spec const *channels;
 50	int num_channels;
 51};
 52
 53static int tmp117_read_raw(struct iio_dev *indio_dev,
 54			   struct iio_chan_spec const *channel, int *val,
 55			   int *val2, long mask)
 56{
 57	struct tmp117_data *data = iio_priv(indio_dev);
 58	s32 ret;
 59
 60	switch (mask) {
 61	case IIO_CHAN_INFO_RAW:
 62		ret = i2c_smbus_read_word_swapped(data->client,
 63						  TMP117_REG_TEMP);
 64		if (ret < 0)
 65			return ret;
 66		*val = sign_extend32(ret, 15);
 67		return IIO_VAL_INT;
 68
 69	case IIO_CHAN_INFO_CALIBBIAS:
 70		ret = i2c_smbus_read_word_swapped(data->client,
 71						  TMP117_REG_TEMP_OFFSET);
 72		if (ret < 0)
 73			return ret;
 74		*val = sign_extend32(ret, 15);
 75		return IIO_VAL_INT;
 76
 77	case IIO_CHAN_INFO_SCALE:
 78		/*
 79		 * Conversion from 10s of uC to mC
 80		 * as IIO reports temperature in mC
 81		 */
 82		*val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
 83		*val2 = (TMP117_RESOLUTION_10UC %
 84					MICRODEGREE_PER_10MILLIDEGREE) * 100;
 85
 86		return IIO_VAL_INT_PLUS_MICRO;
 87
 88	default:
 89		return -EINVAL;
 90	}
 91}
 92
 93static int tmp117_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec
 94			    const *channel, int val, int val2, long mask)
 95{
 96	struct tmp117_data *data = iio_priv(indio_dev);
 97	s16 off;
 98
 99	switch (mask) {
100	case IIO_CHAN_INFO_CALIBBIAS:
101		off = clamp_t(int, val, S16_MIN, S16_MAX);
102		if (off == data->calibbias)
103			return 0;
104		data->calibbias = off;
105		return i2c_smbus_write_word_swapped(data->client,
106						TMP117_REG_TEMP_OFFSET, off);
107
108	default:
109		return -EINVAL;
110	}
111}
112
113static const struct iio_chan_spec tmp117_channels[] = {
114	{
115		.type = IIO_TEMP,
116		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
117				      BIT(IIO_CHAN_INFO_CALIBBIAS) |
118				      BIT(IIO_CHAN_INFO_SCALE),
119	},
120};
121
122static const struct iio_chan_spec tmp116_channels[] = {
123	{
124		.type = IIO_TEMP,
125		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
126				      BIT(IIO_CHAN_INFO_SCALE),
127	},
128};
129
130static const struct tmp11x_info tmp116_channels_info = {
131	.name = "tmp116",
132	.channels = tmp116_channels,
133	.num_channels = ARRAY_SIZE(tmp116_channels)
134};
135
136static const struct tmp11x_info tmp117_channels_info = {
137	.name = "tmp117",
138	.channels = tmp117_channels,
139	.num_channels = ARRAY_SIZE(tmp117_channels)
140};
141
142static const struct iio_info tmp117_info = {
143	.read_raw = tmp117_read_raw,
144	.write_raw = tmp117_write_raw,
145};
146
147static int tmp117_probe(struct i2c_client *client)
148{
149	const struct tmp11x_info *match_data;
150	struct tmp117_data *data;
151	struct iio_dev *indio_dev;
152	int dev_id;
153	int ret;
154
155	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
156		return -EOPNOTSUPP;
157
158	ret = devm_regulator_get_enable(&client->dev, "vcc");
159	if (ret)
160		return ret;
161
162	fsleep(1500);
163
164	dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
165	if (dev_id < 0)
166		return dev_id;
167
168	switch (dev_id) {
169	case TMP116_DEVICE_ID:
170		match_data = &tmp116_channels_info;
171		break;
172	case TMP117_DEVICE_ID:
173		match_data = &tmp117_channels_info;
174		break;
175	default:
176		dev_info(&client->dev,
177			 "Unknown device id (0x%x), use fallback compatible\n",
178			 dev_id);
179		match_data = i2c_get_match_data(client);
180	}
181
182	if (!match_data)
183		return dev_err_probe(&client->dev, -ENODEV,
184				     "Failed to identify unsupported device\n");
185
186	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
187	if (!indio_dev)
188		return -ENOMEM;
189
190	data = iio_priv(indio_dev);
191	data->client = client;
192	data->calibbias = 0;
193
194	indio_dev->modes = INDIO_DIRECT_MODE;
195	indio_dev->info = &tmp117_info;
196	indio_dev->channels = match_data->channels;
197	indio_dev->num_channels = match_data->num_channels;
198	indio_dev->name = match_data->name;
199
200
201	return devm_iio_device_register(&client->dev, indio_dev);
202}
203
204static const struct of_device_id tmp117_of_match[] = {
205	{ .compatible = "ti,tmp116", .data = &tmp116_channels_info },
206	{ .compatible = "ti,tmp117", .data = &tmp117_channels_info },
207	{ }
208};
209MODULE_DEVICE_TABLE(of, tmp117_of_match);
210
211static const struct i2c_device_id tmp117_id[] = {
212	{ "tmp116", (kernel_ulong_t)&tmp116_channels_info },
213	{ "tmp117", (kernel_ulong_t)&tmp117_channels_info },
214	{ }
215};
216MODULE_DEVICE_TABLE(i2c, tmp117_id);
217
218static struct i2c_driver tmp117_driver = {
219	.driver = {
220		.name	= "tmp117",
221		.of_match_table = tmp117_of_match,
222	},
223	.probe		= tmp117_probe,
224	.id_table	= tmp117_id,
225};
226module_i2c_driver(tmp117_driver);
227
228MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
229MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
230MODULE_LICENSE("GPL");