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
20 #include <linux/iio/iio.h>
21
22 #define TMP117_REG_TEMP 0x0
23 #define TMP117_REG_CFGR 0x1
24 #define TMP117_REG_HIGH_LIM 0x2
25 #define TMP117_REG_LOW_LIM 0x3
26 #define TMP117_REG_EEPROM_UL 0x4
27 #define TMP117_REG_EEPROM1 0x5
28 #define TMP117_REG_EEPROM2 0x6
29 #define TMP117_REG_TEMP_OFFSET 0x7
30 #define TMP117_REG_EEPROM3 0x8
31 #define TMP117_REG_DEVICE_ID 0xF
32
33 #define TMP117_RESOLUTION_10UC 78125
34 #define TMP117_DEVICE_ID 0x0117
35 #define MICRODEGREE_PER_10MILLIDEGREE 10000
36
37 struct tmp117_data {
38 struct i2c_client *client;
39 s16 calibbias;
40 };
41
tmp117_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * channel,int * val,int * val2,long mask)42 static int tmp117_read_raw(struct iio_dev *indio_dev,
43 struct iio_chan_spec const *channel, int *val,
44 int *val2, long mask)
45 {
46 struct tmp117_data *data = iio_priv(indio_dev);
47 s32 ret;
48
49 switch (mask) {
50 case IIO_CHAN_INFO_RAW:
51 ret = i2c_smbus_read_word_swapped(data->client,
52 TMP117_REG_TEMP);
53 if (ret < 0)
54 return ret;
55 *val = sign_extend32(ret, 15);
56 return IIO_VAL_INT;
57
58 case IIO_CHAN_INFO_CALIBBIAS:
59 ret = i2c_smbus_read_word_swapped(data->client,
60 TMP117_REG_TEMP_OFFSET);
61 if (ret < 0)
62 return ret;
63 *val = sign_extend32(ret, 15);
64 return IIO_VAL_INT;
65
66 case IIO_CHAN_INFO_SCALE:
67 /*
68 * Conversion from 10s of uC to mC
69 * as IIO reports temperature in mC
70 */
71 *val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
72 *val2 = (TMP117_RESOLUTION_10UC %
73 MICRODEGREE_PER_10MILLIDEGREE) * 100;
74
75 return IIO_VAL_INT_PLUS_MICRO;
76
77 default:
78 return -EINVAL;
79 }
80 }
81
tmp117_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * channel,int val,int val2,long mask)82 static int tmp117_write_raw(struct iio_dev *indio_dev,
83 struct iio_chan_spec const *channel, int val,
84 int val2, long mask)
85 {
86 struct tmp117_data *data = iio_priv(indio_dev);
87 s16 off;
88
89 switch (mask) {
90 case IIO_CHAN_INFO_CALIBBIAS:
91 off = clamp_t(int, val, S16_MIN, S16_MAX);
92 if (off == data->calibbias)
93 return 0;
94 data->calibbias = off;
95 return i2c_smbus_write_word_swapped(data->client,
96 TMP117_REG_TEMP_OFFSET, off);
97
98 default:
99 return -EINVAL;
100 }
101 }
102
103 static const struct iio_chan_spec tmp117_channels[] = {
104 {
105 .type = IIO_TEMP,
106 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
107 BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_SCALE),
108 },
109 };
110
111 static const struct iio_info tmp117_info = {
112 .read_raw = tmp117_read_raw,
113 .write_raw = tmp117_write_raw,
114 };
115
tmp117_identify(struct i2c_client * client)116 static int tmp117_identify(struct i2c_client *client)
117 {
118 int dev_id;
119
120 dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
121 if (dev_id < 0)
122 return dev_id;
123 if (dev_id != TMP117_DEVICE_ID) {
124 dev_err(&client->dev, "TMP117 not found\n");
125 return -ENODEV;
126 }
127 return 0;
128 }
129
tmp117_probe(struct i2c_client * client)130 static int tmp117_probe(struct i2c_client *client)
131 {
132 struct tmp117_data *data;
133 struct iio_dev *indio_dev;
134 int ret;
135
136 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
137 return -EOPNOTSUPP;
138
139 ret = tmp117_identify(client);
140 if (ret < 0)
141 return ret;
142
143 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
144 if (!indio_dev)
145 return -ENOMEM;
146
147 data = iio_priv(indio_dev);
148 data->client = client;
149 data->calibbias = 0;
150
151 indio_dev->name = "tmp117";
152 indio_dev->modes = INDIO_DIRECT_MODE;
153 indio_dev->info = &tmp117_info;
154
155 indio_dev->channels = tmp117_channels;
156 indio_dev->num_channels = ARRAY_SIZE(tmp117_channels);
157
158 return devm_iio_device_register(&client->dev, indio_dev);
159 }
160
161 static const struct of_device_id tmp117_of_match[] = {
162 { .compatible = "ti,tmp117", },
163 { }
164 };
165 MODULE_DEVICE_TABLE(of, tmp117_of_match);
166
167 static const struct i2c_device_id tmp117_id[] = {
168 { "tmp117", 0 },
169 { }
170 };
171 MODULE_DEVICE_TABLE(i2c, tmp117_id);
172
173 static struct i2c_driver tmp117_driver = {
174 .driver = {
175 .name = "tmp117",
176 .of_match_table = tmp117_of_match,
177 },
178 .probe_new = tmp117_probe,
179 .id_table = tmp117_id,
180 };
181 module_i2c_driver(tmp117_driver);
182
183 MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
184 MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
185 MODULE_LICENSE("GPL");
186