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
33struct si7005_data {
34	struct i2c_client *client;
35	struct mutex lock;
36	u8 config;
37};
38
39static 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
67done:
68	mutex_unlock(&data->lock);
69
70	return ret;
71}
72
73static 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
109static 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
122static const struct iio_info si7005_info = {
123	.read_raw = si7005_read_raw,
124};
125
126static 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
165static const struct i2c_device_id si7005_id[] = {
166	{ "si7005", 0 },
167	{ "th02", 0 },
168	{ }
169};
170MODULE_DEVICE_TABLE(i2c, si7005_id);
171
172static struct i2c_driver si7005_driver = {
173	.driver = {
174		.name	= "si7005",
175	},
176	.probe = si7005_probe,
177	.id_table = si7005_id,
178};
179module_i2c_driver(si7005_driver);
180
181MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
182MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");
183MODULE_LICENSE("GPL");
184