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" },
167	{ "th02" },
168	{ }
169};
170MODULE_DEVICE_TABLE(i2c, si7005_id);
171
172static const struct of_device_id si7005_dt_ids[] = {
173	{ .compatible = "silabs,si7005" },
174	{ }
175};
176MODULE_DEVICE_TABLE(of, si7005_dt_ids);
177
178static struct i2c_driver si7005_driver = {
179	.driver = {
180		.name	= "si7005",
181		.of_match_table = si7005_dt_ids,
182	},
183	.probe = si7005_probe,
184	.id_table = si7005_id,
185};
186module_i2c_driver(si7005_driver);
187
188MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
189MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");
190MODULE_LICENSE("GPL");