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/mod_devicetable.h>
23 #include <linux/iio/iio.h>
24 #include <linux/iio/sysfs.h>
25
26 #include "../common/ms_sensors/ms_sensors_i2c.h"
27
28 #define HTU21_RESET 0xFE
29
30 enum {
31 HTU21,
32 MS8607
33 };
34
35 static const int htu21_samp_freq[4] = { 20, 40, 70, 120 };
36 /* String copy of the above const for readability purpose */
37 static const char htu21_show_samp_freq[] = "20 40 70 120";
38
htu21_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * channel,int * val,int * val2,long mask)39 static int htu21_read_raw(struct iio_dev *indio_dev,
40 struct iio_chan_spec const *channel, int *val,
41 int *val2, long mask)
42 {
43 int ret, temperature;
44 unsigned int humidity;
45 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
46
47 switch (mask) {
48 case IIO_CHAN_INFO_PROCESSED:
49 switch (channel->type) {
50 case IIO_TEMP: /* in milli °C */
51 ret = ms_sensors_ht_read_temperature(dev_data,
52 &temperature);
53 if (ret)
54 return ret;
55 *val = temperature;
56
57 return IIO_VAL_INT;
58 case IIO_HUMIDITYRELATIVE: /* in milli %RH */
59 ret = ms_sensors_ht_read_humidity(dev_data,
60 &humidity);
61 if (ret)
62 return ret;
63 *val = humidity;
64
65 return IIO_VAL_INT;
66 default:
67 return -EINVAL;
68 }
69 case IIO_CHAN_INFO_SAMP_FREQ:
70 *val = htu21_samp_freq[dev_data->res_index];
71
72 return IIO_VAL_INT;
73 default:
74 return -EINVAL;
75 }
76 }
77
htu21_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)78 static int htu21_write_raw(struct iio_dev *indio_dev,
79 struct iio_chan_spec const *chan,
80 int val, int val2, long mask)
81 {
82 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
83 int i, ret;
84
85 switch (mask) {
86 case IIO_CHAN_INFO_SAMP_FREQ:
87 i = ARRAY_SIZE(htu21_samp_freq);
88 while (i-- > 0)
89 if (val == htu21_samp_freq[i])
90 break;
91 if (i < 0)
92 return -EINVAL;
93 mutex_lock(&dev_data->lock);
94 dev_data->res_index = i;
95 ret = ms_sensors_write_resolution(dev_data, i);
96 mutex_unlock(&dev_data->lock);
97
98 return ret;
99 default:
100 return -EINVAL;
101 }
102 }
103
104 static const struct iio_chan_spec htu21_channels[] = {
105 {
106 .type = IIO_TEMP,
107 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
108 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
109 },
110 {
111 .type = IIO_HUMIDITYRELATIVE,
112 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
113 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
114 }
115 };
116
117 /*
118 * Meas Spec recommendation is to not read temperature
119 * on this driver part for MS8607
120 */
121 static const struct iio_chan_spec ms8607_channels[] = {
122 {
123 .type = IIO_HUMIDITYRELATIVE,
124 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
125 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
126 }
127 };
128
htu21_show_battery_low(struct device * dev,struct device_attribute * attr,char * buf)129 static ssize_t htu21_show_battery_low(struct device *dev,
130 struct device_attribute *attr, char *buf)
131 {
132 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
133 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
134
135 return ms_sensors_show_battery_low(dev_data, buf);
136 }
137
htu21_show_heater(struct device * dev,struct device_attribute * attr,char * buf)138 static ssize_t htu21_show_heater(struct device *dev,
139 struct device_attribute *attr, char *buf)
140 {
141 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
142 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
143
144 return ms_sensors_show_heater(dev_data, buf);
145 }
146
htu21_write_heater(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)147 static ssize_t htu21_write_heater(struct device *dev,
148 struct device_attribute *attr,
149 const char *buf, size_t len)
150 {
151 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
152 struct ms_ht_dev *dev_data = iio_priv(indio_dev);
153
154 return ms_sensors_write_heater(dev_data, buf, len);
155 }
156
157 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(htu21_show_samp_freq);
158 static IIO_DEVICE_ATTR(battery_low, S_IRUGO,
159 htu21_show_battery_low, NULL, 0);
160 static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR,
161 htu21_show_heater, htu21_write_heater, 0);
162
163 static struct attribute *htu21_attributes[] = {
164 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
165 &iio_dev_attr_battery_low.dev_attr.attr,
166 &iio_dev_attr_heater_enable.dev_attr.attr,
167 NULL,
168 };
169
170 static const struct attribute_group htu21_attribute_group = {
171 .attrs = htu21_attributes,
172 };
173
174 static const struct iio_info htu21_info = {
175 .read_raw = htu21_read_raw,
176 .write_raw = htu21_write_raw,
177 .attrs = &htu21_attribute_group,
178 };
179
htu21_probe(struct i2c_client * client,const struct i2c_device_id * id)180 static int htu21_probe(struct i2c_client *client,
181 const struct i2c_device_id *id)
182 {
183 struct ms_ht_dev *dev_data;
184 struct iio_dev *indio_dev;
185 int ret;
186 u64 serial_number;
187
188 if (!i2c_check_functionality(client->adapter,
189 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
190 I2C_FUNC_SMBUS_WRITE_BYTE |
191 I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
192 dev_err(&client->dev,
193 "Adapter does not support some i2c transaction\n");
194 return -EOPNOTSUPP;
195 }
196
197 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
198 if (!indio_dev)
199 return -ENOMEM;
200
201 dev_data = iio_priv(indio_dev);
202 dev_data->client = client;
203 dev_data->res_index = 0;
204 mutex_init(&dev_data->lock);
205
206 indio_dev->info = &htu21_info;
207 indio_dev->name = id->name;
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
232 static const struct i2c_device_id htu21_id[] = {
233 {"htu21", HTU21},
234 {"ms8607-humidity", MS8607},
235 {}
236 };
237 MODULE_DEVICE_TABLE(i2c, htu21_id);
238
239 static const struct of_device_id htu21_of_match[] = {
240 { .compatible = "meas,htu21", },
241 { .compatible = "meas,ms8607-humidity", },
242 { },
243 };
244 MODULE_DEVICE_TABLE(of, htu21_of_match);
245
246 static struct i2c_driver htu21_driver = {
247 .probe = htu21_probe,
248 .id_table = htu21_id,
249 .driver = {
250 .name = "htu21",
251 .of_match_table = htu21_of_match,
252 },
253 };
254
255 module_i2c_driver(htu21_driver);
256
257 MODULE_DESCRIPTION("Measurement-Specialties htu21 temperature and humidity driver");
258 MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
259 MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
260 MODULE_LICENSE("GPL v2");
261