summaryrefslogtreecommitdiffstats
path: root/drivers/iio/humidity/si7005.c
blob: 1fd19f035a5d9601e662d21ea3f42ce26a37d948 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
/*
 * si7005.c - Support for Silabs Si7005 humidity and temperature sensor
 *
 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * (7-bit I2C slave address 0x40)
 *
 * TODO: heater, fast mode, processed mode (temp. / linearity compensation)
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/pm.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define SI7005_STATUS 0x00
#define SI7005_DATA 0x01 /* 16-bit, MSB */
#define SI7005_CONFIG 0x03
#define SI7005_ID 0x11

#define SI7005_STATUS_NRDY BIT(0)
#define SI7005_CONFIG_TEMP BIT(4)
#define SI7005_CONFIG_START BIT(0)

#define SI7005_ID_7005 0x50
#define SI7005_ID_7015 0xf0

struct si7005_data {
	struct i2c_client *client;
	struct mutex lock;
	u8 config;
};

static int si7005_read_measurement(struct si7005_data *data, bool temp)
{
	int tries = 50;
	int ret;

	mutex_lock(&data->lock);

	ret = i2c_smbus_write_byte_data(data->client, SI7005_CONFIG,
		data->config | SI7005_CONFIG_START |
		(temp ? SI7005_CONFIG_TEMP : 0));
	if (ret < 0)
		goto done;

	while (tries-- > 0) {
		msleep(20);
		ret = i2c_smbus_read_byte_data(data->client, SI7005_STATUS);
		if (ret < 0)
			goto done;
		if (!(ret & SI7005_STATUS_NRDY))
			break;
	}
	if (tries < 0) {
		ret = -EIO;
		goto done;
	}

	ret = i2c_smbus_read_word_swapped(data->client, SI7005_DATA);

done:
	mutex_unlock(&data->lock);

	return ret;
}

static int si7005_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan, int *val,
			    int *val2, long mask)
{
	struct si7005_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = si7005_read_measurement(data, chan->type == IIO_TEMP);
		if (ret < 0)
			return ret;
		*val = ret;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		if (chan->type == IIO_TEMP) {
			*val = 7;
			*val2 = 812500;
		} else {
			*val = 3;
			*val2 = 906250;
		}
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_OFFSET:
		if (chan->type == IIO_TEMP)
			*val = -50 * 32 * 4;
		else
			*val = -24 * 16 * 16;
		return IIO_VAL_INT;
	default:
		break;
	}

	return -EINVAL;
}

static const struct iio_chan_spec si7005_channels[] = {
	{
		.type = IIO_HUMIDITYRELATIVE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
			BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
	},
	{
		.type = IIO_TEMP,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
			BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
	}
};

static const struct iio_info si7005_info = {
	.read_raw = si7005_read_raw,
};

static int si7005_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct iio_dev *indio_dev;
	struct si7005_data *data;
	int ret;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
		return -EOPNOTSUPP;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (!indio_dev)
		return -ENOMEM;

	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	data->client = client;
	mutex_init(&data->lock);

	indio_dev->dev.parent = &client->dev;
	indio_dev->name = dev_name(&client->dev);
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &si7005_info;

	indio_dev->channels = si7005_channels;
	indio_dev->num_channels = ARRAY_SIZE(si7005_channels);

	ret = i2c_smbus_read_byte_data(client, SI7005_ID);
	if (ret < 0)
		return ret;
	if (ret != SI7005_ID_7005 && ret != SI7005_ID_7015)
		return -ENODEV;

	ret = i2c_smbus_read_byte_data(client, SI7005_CONFIG);
	if (ret < 0)
		return ret;
	data->config = ret;

	return devm_iio_device_register(&client->dev, indio_dev);
}

static const struct i2c_device_id si7005_id[] = {
	{ "si7005", 0 },
	{ "th02", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, si7005_id);

static struct i2c_driver si7005_driver = {
	.driver = {
		.name	= "si7005",
	},
	.probe = si7005_probe,
	.id_table = si7005_id,
};
module_i2c_driver(si7005_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");
MODULE_LICENSE("GPL");