1 /*
2 * si7005.c - Support for Silabs Si7005 humidity and temperature sensor
3 *
4 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
5 *
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
9 *
10 * (7-bit I2C slave address 0x40)
11 *
12 * TODO: heater, fast mode, processed mode (temp. / linearity compensation)
13 */
14
15 #include <linux/err.h>
16 #include <linux/i2c.h>
17 #include <linux/delay.h>
18 #include <linux/module.h>
19 #include <linux/pm.h>
20
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23
24 #define SI7005_STATUS 0x00
25 #define SI7005_DATA 0x01 /* 16-bit, MSB */
26 #define SI7005_CONFIG 0x03
27 #define SI7005_ID 0x11
28
29 #define SI7005_STATUS_NRDY BIT(0)
30 #define SI7005_CONFIG_TEMP BIT(4)
31 #define SI7005_CONFIG_START BIT(0)
32
33 #define SI7005_ID_7005 0x50
34 #define SI7005_ID_7015 0xf0
35
36 struct si7005_data {
37 struct i2c_client *client;
38 struct mutex lock;
39 u8 config;
40 };
41
si7005_read_measurement(struct si7005_data * data,bool temp)42 static int si7005_read_measurement(struct si7005_data *data, bool temp)
43 {
44 int tries = 50;
45 int ret;
46
47 mutex_lock(&data->lock);
48
49 ret = i2c_smbus_write_byte_data(data->client, SI7005_CONFIG,
50 data->config | SI7005_CONFIG_START |
51 (temp ? SI7005_CONFIG_TEMP : 0));
52 if (ret < 0)
53 goto done;
54
55 while (tries-- > 0) {
56 msleep(20);
57 ret = i2c_smbus_read_byte_data(data->client, SI7005_STATUS);
58 if (ret < 0)
59 goto done;
60 if (!(ret & SI7005_STATUS_NRDY))
61 break;
62 }
63 if (tries < 0) {
64 ret = -EIO;
65 goto done;
66 }
67
68 ret = i2c_smbus_read_word_swapped(data->client, SI7005_DATA);
69
70 done:
71 mutex_unlock(&data->lock);
72
73 return ret;
74 }
75
si7005_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)76 static int si7005_read_raw(struct iio_dev *indio_dev,
77 struct iio_chan_spec const *chan, int *val,
78 int *val2, long mask)
79 {
80 struct si7005_data *data = iio_priv(indio_dev);
81 int ret;
82
83 switch (mask) {
84 case IIO_CHAN_INFO_RAW:
85 ret = si7005_read_measurement(data, chan->type == IIO_TEMP);
86 if (ret < 0)
87 return ret;
88 *val = ret;
89 return IIO_VAL_INT;
90 case IIO_CHAN_INFO_SCALE:
91 if (chan->type == IIO_TEMP) {
92 *val = 7;
93 *val2 = 812500;
94 } else {
95 *val = 3;
96 *val2 = 906250;
97 }
98 return IIO_VAL_INT_PLUS_MICRO;
99 case IIO_CHAN_INFO_OFFSET:
100 if (chan->type == IIO_TEMP)
101 *val = -50 * 32 * 4;
102 else
103 *val = -24 * 16 * 16;
104 return IIO_VAL_INT;
105 default:
106 break;
107 }
108
109 return -EINVAL;
110 }
111
112 static const struct iio_chan_spec si7005_channels[] = {
113 {
114 .type = IIO_HUMIDITYRELATIVE,
115 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
116 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
117 },
118 {
119 .type = IIO_TEMP,
120 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
121 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
122 }
123 };
124
125 static const struct iio_info si7005_info = {
126 .read_raw = si7005_read_raw,
127 };
128
si7005_probe(struct i2c_client * client,const struct i2c_device_id * id)129 static int si7005_probe(struct i2c_client *client,
130 const struct i2c_device_id *id)
131 {
132 struct iio_dev *indio_dev;
133 struct si7005_data *data;
134 int ret;
135
136 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
137 return -EOPNOTSUPP;
138
139 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
140 if (!indio_dev)
141 return -ENOMEM;
142
143 data = iio_priv(indio_dev);
144 i2c_set_clientdata(client, indio_dev);
145 data->client = client;
146 mutex_init(&data->lock);
147
148 indio_dev->dev.parent = &client->dev;
149 indio_dev->name = dev_name(&client->dev);
150 indio_dev->modes = INDIO_DIRECT_MODE;
151 indio_dev->info = &si7005_info;
152
153 indio_dev->channels = si7005_channels;
154 indio_dev->num_channels = ARRAY_SIZE(si7005_channels);
155
156 ret = i2c_smbus_read_byte_data(client, SI7005_ID);
157 if (ret < 0)
158 return ret;
159 if (ret != SI7005_ID_7005 && ret != SI7005_ID_7015)
160 return -ENODEV;
161
162 ret = i2c_smbus_read_byte_data(client, SI7005_CONFIG);
163 if (ret < 0)
164 return ret;
165 data->config = ret;
166
167 return devm_iio_device_register(&client->dev, indio_dev);
168 }
169
170 static const struct i2c_device_id si7005_id[] = {
171 { "si7005", 0 },
172 { "th02", 0 },
173 { }
174 };
175 MODULE_DEVICE_TABLE(i2c, si7005_id);
176
177 static struct i2c_driver si7005_driver = {
178 .driver = {
179 .name = "si7005",
180 },
181 .probe = si7005_probe,
182 .id_table = si7005_id,
183 };
184 module_i2c_driver(si7005_driver);
185
186 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
187 MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");
188 MODULE_LICENSE("GPL");
189