tjh.dev
Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * htu21.c - Support for Measurement-Specialties
4 * htu21 temperature & humidity sensor
5 * and humidity part of MS8607 sensor
6 *
7 * Copyright (c) 2014 Measurement-Specialties
8 *
9 * (7-bit I2C slave address 0x40)
10 *
11 * Datasheet:
12 * http://www.meas-spec.com/downloads/HTU21D.pdf
13 * Datasheet:
14 * http://www.meas-spec.com/downloads/MS8607-02BA01.pdf
15 */
16
17#include <linux/init.h>
18#include <linux/device.h>
19#include <linux/kernel.h>
20#include <linux/stat.h>
21#include <linux/module.h>
22#include <linux/iio/iio.h>
23#include <linux/iio/sysfs.h>
24
25#include "../common/ms_sensors/ms_sensors_i2c.h"
26
27#define HTU21_RESET 0xFE
28
29enum {
30 HTU21,
31 MS8607
32};
33
34static const int htu21_samp_freq[4] = { 20, 40, 70, 120 };
35/* String copy of the above const for readability purpose */
36static const char htu21_show_samp_freq[] = "20 40 70 120";
37
38static int htu21_read_raw(struct iio_dev *indio_dev,
39 struct iio_chan_spec const *channel, int *val,
40 int *val2, long mask)
41{
42 int ret, temperature;
43 unsigned int humidity;
44 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
45
46 switch (mask) {
47 case IIO_CHAN_INFO_PROCESSED:
48 switch (channel->type) {
49 case IIO_TEMP: /* in milli °C */
50 ret = ms_sensors_ht_read_temperature(dev_data,
51 &temperature);
52 if (ret)
53 return ret;
54 *val = temperature;
55
56 return IIO_VAL_INT;
57 case IIO_HUMIDITYRELATIVE: /* in milli %RH */
58 ret = ms_sensors_ht_read_humidity(dev_data,
59 &humidity);
60 if (ret)
61 return ret;
62 *val = humidity;
63
64 return IIO_VAL_INT;
65 default:
66 return -EINVAL;
67 }
68 case IIO_CHAN_INFO_SAMP_FREQ:
69 *val = htu21_samp_freq[dev_data->res_index];
70
71 return IIO_VAL_INT;
72 default:
73 return -EINVAL;
74 }
75}
76
77static int htu21_write_raw(struct iio_dev *indio_dev,
78 struct iio_chan_spec const *chan,
79 int val, int val2, long mask)
80{
81 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
82 int i, ret;
83
84 switch (mask) {
85 case IIO_CHAN_INFO_SAMP_FREQ:
86 i = ARRAY_SIZE(htu21_samp_freq);
87 while (i-- > 0)
88 if (val == htu21_samp_freq[i])
89 break;
90 if (i < 0)
91 return -EINVAL;
92 mutex_lock(&dev_data->lock);
93 dev_data->res_index = i;
94 ret = ms_sensors_write_resolution(dev_data, i);
95 mutex_unlock(&dev_data->lock);
96
97 return ret;
98 default:
99 return -EINVAL;
100 }
101}
102
103static const struct iio_chan_spec htu21_channels[] = {
104 {
105 .type = IIO_TEMP,
106 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
107 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
108 },
109 {
110 .type = IIO_HUMIDITYRELATIVE,
111 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
112 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
113 }
114};
115
116/*
117 * Meas Spec recommendation is to not read temperature
118 * on this driver part for MS8607
119 */
120static const struct iio_chan_spec ms8607_channels[] = {
121 {
122 .type = IIO_HUMIDITYRELATIVE,
123 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
124 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
125 }
126};
127
128static ssize_t htu21_show_battery_low(struct device *dev,
129 struct device_attribute *attr, char *buf)
130{
131 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
132 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
133
134 return ms_sensors_show_battery_low(dev_data, buf);
135}
136
137static ssize_t htu21_show_heater(struct device *dev,
138 struct device_attribute *attr, char *buf)
139{
140 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
141 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
142
143 return ms_sensors_show_heater(dev_data, buf);
144}
145
146static ssize_t htu21_write_heater(struct device *dev,
147 struct device_attribute *attr,
148 const char *buf, size_t len)
149{
150 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
151 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
152
153 return ms_sensors_write_heater(dev_data, buf, len);
154}
155
156static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(htu21_show_samp_freq);
157static IIO_DEVICE_ATTR(battery_low, S_IRUGO,
158 htu21_show_battery_low, NULL, 0);
159static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR,
160 htu21_show_heater, htu21_write_heater, 0);
161
162static struct attribute *htu21_attributes[] = {
163 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
164 &iio_dev_attr_battery_low.dev_attr.attr,
165 &iio_dev_attr_heater_enable.dev_attr.attr,
166 NULL,
167};
168
169static const struct attribute_group htu21_attribute_group = {
170 .attrs = htu21_attributes,
171};
172
173static const struct iio_info htu21_info = {
174 .read_raw = htu21_read_raw,
175 .write_raw = htu21_write_raw,
176 .attrs = &htu21_attribute_group,
177};
178
179static int htu21_probe(struct i2c_client *client,
180 const struct i2c_device_id *id)
181{
182 struct ms_ht_dev *dev_data;
183 struct iio_dev *indio_dev;
184 int ret;
185 u64 serial_number;
186
187 if (!i2c_check_functionality(client->adapter,
188 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
189 I2C_FUNC_SMBUS_WRITE_BYTE |
190 I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
191 dev_err(&client->dev,
192 "Adapter does not support some i2c transaction\n");
193 return -EOPNOTSUPP;
194 }
195
196 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
197 if (!indio_dev)
198 return -ENOMEM;
199
200 dev_data = iio_priv(indio_dev);
201 dev_data->client = client;
202 dev_data->res_index = 0;
203 mutex_init(&dev_data->lock);
204
205 indio_dev->info = &htu21_info;
206 indio_dev->name = id->name;
207 indio_dev->dev.parent = &client->dev;
208 indio_dev->modes = INDIO_DIRECT_MODE;
209
210 if (id->driver_data == MS8607) {
211 indio_dev->channels = ms8607_channels;
212 indio_dev->num_channels = ARRAY_SIZE(ms8607_channels);
213 } else {
214 indio_dev->channels = htu21_channels;
215 indio_dev->num_channels = ARRAY_SIZE(htu21_channels);
216 }
217
218 i2c_set_clientdata(client, indio_dev);
219
220 ret = ms_sensors_reset(client, HTU21_RESET, 15000);
221 if (ret)
222 return ret;
223
224 ret = ms_sensors_read_serial(client, &serial_number);
225 if (ret)
226 return ret;
227 dev_info(&client->dev, "Serial number : %llx", serial_number);
228
229 return devm_iio_device_register(&client->dev, indio_dev);
230}
231
232static const struct i2c_device_id htu21_id[] = {
233 {"htu21", HTU21},
234 {"ms8607-humidity", MS8607},
235 {}
236};
237MODULE_DEVICE_TABLE(i2c, htu21_id);
238
239static const struct of_device_id htu21_of_match[] = {
240 { .compatible = "meas,htu21", },
241 { .compatible = "meas,ms8607-humidity", },
242 { },
243};
244MODULE_DEVICE_TABLE(of, htu21_of_match);
245
246static struct i2c_driver htu21_driver = {
247 .probe = htu21_probe,
248 .id_table = htu21_id,
249 .driver = {
250 .name = "htu21",
251 .of_match_table = of_match_ptr(htu21_of_match),
252 },
253};
254
255module_i2c_driver(htu21_driver);
256
257MODULE_DESCRIPTION("Measurement-Specialties htu21 temperature and humidity driver");
258MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
259MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
260MODULE_LICENSE("GPL v2");