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