1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * si7005.c - Support for Silabs Si7005 humidity and temperature sensor
4 *
5 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
6 *
7 * (7-bit I2C slave address 0x40)
8 *
9 * TODO: heater, fast mode, processed mode (temp. / linearity compensation)
10 */
11
12 #include <linux/err.h>
13 #include <linux/i2c.h>
14 #include <linux/delay.h>
15 #include <linux/module.h>
16 #include <linux/pm.h>
17
18 #include <linux/iio/iio.h>
19 #include <linux/iio/sysfs.h>
20
21 #define SI7005_STATUS 0x00
22 #define SI7005_DATA 0x01 /* 16-bit, MSB */
23 #define SI7005_CONFIG 0x03
24 #define SI7005_ID 0x11
25
26 #define SI7005_STATUS_NRDY BIT(0)
27 #define SI7005_CONFIG_TEMP BIT(4)
28 #define SI7005_CONFIG_START BIT(0)
29
30 #define SI7005_ID_7005 0x50
31 #define SI7005_ID_7015 0xf0
32
33 struct si7005_data {
34 struct i2c_client *client;
35 struct mutex lock;
36 u8 config;
37 };
38
si7005_read_measurement(struct si7005_data * data,bool temp)39 static int si7005_read_measurement(struct si7005_data *data, bool temp)
40 {
41 int tries = 50;
42 int ret;
43
44 mutex_lock(&data->lock);
45
46 ret = i2c_smbus_write_byte_data(data->client, SI7005_CONFIG,
47 data->config | SI7005_CONFIG_START |
48 (temp ? SI7005_CONFIG_TEMP : 0));
49 if (ret < 0)
50 goto done;
51
52 while (tries-- > 0) {
53 msleep(20);
54 ret = i2c_smbus_read_byte_data(data->client, SI7005_STATUS);
55 if (ret < 0)
56 goto done;
57 if (!(ret & SI7005_STATUS_NRDY))
58 break;
59 }
60 if (tries < 0) {
61 ret = -EIO;
62 goto done;
63 }
64
65 ret = i2c_smbus_read_word_swapped(data->client, SI7005_DATA);
66
67 done:
68 mutex_unlock(&data->lock);
69
70 return ret;
71 }
72
si7005_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)73 static int si7005_read_raw(struct iio_dev *indio_dev,
74 struct iio_chan_spec const *chan, int *val,
75 int *val2, long mask)
76 {
77 struct si7005_data *data = iio_priv(indio_dev);
78 int ret;
79
80 switch (mask) {
81 case IIO_CHAN_INFO_RAW:
82 ret = si7005_read_measurement(data, chan->type == IIO_TEMP);
83 if (ret < 0)
84 return ret;
85 *val = ret;
86 return IIO_VAL_INT;
87 case IIO_CHAN_INFO_SCALE:
88 if (chan->type == IIO_TEMP) {
89 *val = 7;
90 *val2 = 812500;
91 } else {
92 *val = 3;
93 *val2 = 906250;
94 }
95 return IIO_VAL_INT_PLUS_MICRO;
96 case IIO_CHAN_INFO_OFFSET:
97 if (chan->type == IIO_TEMP)
98 *val = -50 * 32 * 4;
99 else
100 *val = -24 * 16 * 16;
101 return IIO_VAL_INT;
102 default:
103 break;
104 }
105
106 return -EINVAL;
107 }
108
109 static const struct iio_chan_spec si7005_channels[] = {
110 {
111 .type = IIO_HUMIDITYRELATIVE,
112 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
113 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
114 },
115 {
116 .type = IIO_TEMP,
117 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
118 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
119 }
120 };
121
122 static const struct iio_info si7005_info = {
123 .read_raw = si7005_read_raw,
124 };
125
si7005_probe(struct i2c_client * client)126 static int si7005_probe(struct i2c_client *client)
127 {
128 struct iio_dev *indio_dev;
129 struct si7005_data *data;
130 int ret;
131
132 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
133 return -EOPNOTSUPP;
134
135 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
136 if (!indio_dev)
137 return -ENOMEM;
138
139 data = iio_priv(indio_dev);
140 i2c_set_clientdata(client, indio_dev);
141 data->client = client;
142 mutex_init(&data->lock);
143
144 indio_dev->name = dev_name(&client->dev);
145 indio_dev->modes = INDIO_DIRECT_MODE;
146 indio_dev->info = &si7005_info;
147
148 indio_dev->channels = si7005_channels;
149 indio_dev->num_channels = ARRAY_SIZE(si7005_channels);
150
151 ret = i2c_smbus_read_byte_data(client, SI7005_ID);
152 if (ret < 0)
153 return ret;
154 if (ret != SI7005_ID_7005 && ret != SI7005_ID_7015)
155 return -ENODEV;
156
157 ret = i2c_smbus_read_byte_data(client, SI7005_CONFIG);
158 if (ret < 0)
159 return ret;
160 data->config = ret;
161
162 return devm_iio_device_register(&client->dev, indio_dev);
163 }
164
165 static const struct i2c_device_id si7005_id[] = {
166 { "si7005", 0 },
167 { "th02", 0 },
168 { }
169 };
170 MODULE_DEVICE_TABLE(i2c, si7005_id);
171
172 static struct i2c_driver si7005_driver = {
173 .driver = {
174 .name = "si7005",
175 },
176 .probe_new = si7005_probe,
177 .id_table = si7005_id,
178 };
179 module_i2c_driver(si7005_driver);
180
181 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
182 MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");
183 MODULE_LICENSE("GPL");
184