diff options
author | Iain Paton <ipaton0@gmail.com> | 2012-06-27 04:55:11 -0400 |
---|---|---|
committer | Guenter Roeck <linux@roeck-us.net> | 2012-07-22 00:48:44 -0400 |
commit | 27f8b1355504744e7cfbb5756f120734d58644a8 (patch) | |
tree | 3f30ded2736a1692a8ff3ff92406775a11b8d7fb /drivers/hwmon/hih6130.c | |
parent | edf48f3a73b027a99c92edab2b07d78fe77523cc (diff) |
hwmon: Honeywell Humidicon HIH-6130/HIH-6131 humidity and temperature sensor driver
This is a new driver for the Honeywell Humidicon HIH-6130/HIH-6131 humidity sensor.
The driver is based on the existing Sensiron sht21 driver with the necessary changes
to the probe, update_measurements and conversion functions necessary to use the
Honeywell sensors.
There's no difference between the 6130 & 6131 other than the 6131 having an external
condensation filter attached.
Signed-off-by: Iain Paton <ipaton0@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/hih6130.c')
-rw-r--r-- | drivers/hwmon/hih6130.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/drivers/hwmon/hih6130.c b/drivers/hwmon/hih6130.c new file mode 100644 index 000000000000..e8ee75f55472 --- /dev/null +++ b/drivers/hwmon/hih6130.c | |||
@@ -0,0 +1,293 @@ | |||
1 | /* Honeywell HIH-6130/HIH-6131 humidity and temperature sensor driver | ||
2 | * | ||
3 | * Copyright (C) 2012 Iain Paton <ipaton0@gmail.com> | ||
4 | * | ||
5 | * heavily based on the sht21 driver | ||
6 | * Copyright (C) 2010 Urs Fleisch <urs.fleisch@sensirion.com> | ||
7 | * | ||
8 | * This program is free software; you can redistribute it and/or modify | ||
9 | * it under the terms of the GNU General Public License as published by | ||
10 | * the Free Software Foundation; either version 2 of the License, or | ||
11 | * (at your option) any later version. | ||
12 | * | ||
13 | * This program is distributed in the hope that it will be useful, | ||
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
16 | * GNU General Public License for more details. | ||
17 | * | ||
18 | * You should have received a copy of the GNU General Public License | ||
19 | * along with this program; if not, write to the Free Software | ||
20 | * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA | ||
21 | * | ||
22 | * Data sheets available (2012-06-22) at | ||
23 | * http://sensing.honeywell.com/index.php?ci_id=3106&la_id=1&defId=44872 | ||
24 | */ | ||
25 | |||
26 | #include <linux/module.h> | ||
27 | #include <linux/init.h> | ||
28 | #include <linux/slab.h> | ||
29 | #include <linux/i2c.h> | ||
30 | #include <linux/hwmon.h> | ||
31 | #include <linux/hwmon-sysfs.h> | ||
32 | #include <linux/err.h> | ||
33 | #include <linux/mutex.h> | ||
34 | #include <linux/device.h> | ||
35 | #include <linux/delay.h> | ||
36 | |||
37 | /** | ||
38 | * struct hih6130 - HIH-6130 device specific data | ||
39 | * @hwmon_dev: device registered with hwmon | ||
40 | * @lock: mutex to protect measurement values | ||
41 | * @valid: only false before first measurement is taken | ||
42 | * @last_update: time of last update (jiffies) | ||
43 | * @temperature: cached temperature measurement value | ||
44 | * @humidity: cached humidity measurement value | ||
45 | */ | ||
46 | struct hih6130 { | ||
47 | struct device *hwmon_dev; | ||
48 | struct mutex lock; | ||
49 | bool valid; | ||
50 | unsigned long last_update; | ||
51 | int temperature; | ||
52 | int humidity; | ||
53 | }; | ||
54 | |||
55 | /** | ||
56 | * hih6130_temp_ticks_to_millicelsius() - convert raw temperature ticks to | ||
57 | * milli celsius | ||
58 | * @ticks: temperature ticks value received from sensor | ||
59 | */ | ||
60 | static inline int hih6130_temp_ticks_to_millicelsius(int ticks) | ||
61 | { | ||
62 | |||
63 | ticks = ticks >> 2; | ||
64 | /* | ||
65 | * from data sheet section 5.0 | ||
66 | * Formula T = ( ticks / ( 2^14 - 2 ) ) * 165 -40 | ||
67 | */ | ||
68 | return (DIV_ROUND_CLOSEST(ticks * 1650, 16382) - 400) * 100; | ||
69 | } | ||
70 | |||
71 | /** | ||
72 | * hih6130_rh_ticks_to_per_cent_mille() - convert raw humidity ticks to | ||
73 | * one-thousandths of a percent relative humidity | ||
74 | * @ticks: humidity ticks value received from sensor | ||
75 | */ | ||
76 | static inline int hih6130_rh_ticks_to_per_cent_mille(int ticks) | ||
77 | { | ||
78 | |||
79 | ticks &= ~0xC000; /* clear status bits */ | ||
80 | /* | ||
81 | * from data sheet section 4.0 | ||
82 | * Formula RH = ( ticks / ( 2^14 -2 ) ) * 100 | ||
83 | */ | ||
84 | return DIV_ROUND_CLOSEST(ticks * 1000, 16382) * 100; | ||
85 | } | ||
86 | |||
87 | /** | ||
88 | * hih6130_update_measurements() - get updated measurements from device | ||
89 | * @client: I2C client device | ||
90 | * | ||
91 | * Returns 0 on success, else negative errno. | ||
92 | */ | ||
93 | static int hih6130_update_measurements(struct i2c_client *client) | ||
94 | { | ||
95 | int ret = 0; | ||
96 | int t; | ||
97 | struct hih6130 *hih6130 = i2c_get_clientdata(client); | ||
98 | unsigned char tmp[4]; | ||
99 | struct i2c_msg msgs[1] = { | ||
100 | { | ||
101 | .addr = client->addr, | ||
102 | .flags = I2C_M_RD, | ||
103 | .len = 4, | ||
104 | .buf = tmp, | ||
105 | } | ||
106 | }; | ||
107 | |||
108 | mutex_lock(&hih6130->lock); | ||
109 | |||
110 | /* | ||
111 | * While the measurement can be completed in ~40ms the sensor takes | ||
112 | * much longer to react to a change in external conditions. How quickly | ||
113 | * it reacts depends on airflow and other factors outwith our control. | ||
114 | * The datasheet specifies maximum 'Response time' for humidity at 8s | ||
115 | * and temperature at 30s under specified conditions. | ||
116 | * We therefore choose to only read the sensor at most once per second. | ||
117 | * This trades off pointless activity polling the sensor much faster | ||
118 | * than it can react against better response times in conditions more | ||
119 | * favourable than specified in the datasheet. | ||
120 | */ | ||
121 | if (time_after(jiffies, hih6130->last_update + HZ) || !hih6130->valid) { | ||
122 | |||
123 | /* write to slave address, no data, to request a measurement */ | ||
124 | ret = i2c_master_send(client, tmp, 0); | ||
125 | if (ret < 0) | ||
126 | goto out; | ||
127 | |||
128 | /* measurement cycle time is ~36.65msec */ | ||
129 | msleep(40); | ||
130 | |||
131 | ret = i2c_transfer(client->adapter, msgs, 1); | ||
132 | if (ret < 0) | ||
133 | goto out; | ||
134 | |||
135 | if ((tmp[0] & 0xC0) != 0) { | ||
136 | dev_err(&client->dev, "Error while reading measurement result\n"); | ||
137 | ret = -EIO; | ||
138 | goto out; | ||
139 | } | ||
140 | |||
141 | t = (tmp[0] << 8) + tmp[1]; | ||
142 | hih6130->humidity = hih6130_rh_ticks_to_per_cent_mille(t); | ||
143 | |||
144 | t = (tmp[2] << 8) + tmp[3]; | ||
145 | hih6130->temperature = hih6130_temp_ticks_to_millicelsius(t); | ||
146 | |||
147 | hih6130->last_update = jiffies; | ||
148 | hih6130->valid = true; | ||
149 | } | ||
150 | out: | ||
151 | mutex_unlock(&hih6130->lock); | ||
152 | |||
153 | return ret >= 0 ? 0 : ret; | ||
154 | } | ||
155 | |||
156 | /** | ||
157 | * hih6130_show_temperature() - show temperature measurement value in sysfs | ||
158 | * @dev: device | ||
159 | * @attr: device attribute | ||
160 | * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to | ||
161 | * | ||
162 | * Will be called on read access to temp1_input sysfs attribute. | ||
163 | * Returns number of bytes written into buffer, negative errno on error. | ||
164 | */ | ||
165 | static ssize_t hih6130_show_temperature(struct device *dev, | ||
166 | struct device_attribute *attr, | ||
167 | char *buf) | ||
168 | { | ||
169 | struct i2c_client *client = to_i2c_client(dev); | ||
170 | struct hih6130 *hih6130 = i2c_get_clientdata(client); | ||
171 | int ret = hih6130_update_measurements(client); | ||
172 | if (ret < 0) | ||
173 | return ret; | ||
174 | return sprintf(buf, "%d\n", hih6130->temperature); | ||
175 | } | ||
176 | |||
177 | /** | ||
178 | * hih6130_show_humidity() - show humidity measurement value in sysfs | ||
179 | * @dev: device | ||
180 | * @attr: device attribute | ||
181 | * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to | ||
182 | * | ||
183 | * Will be called on read access to humidity1_input sysfs attribute. | ||
184 | * Returns number of bytes written into buffer, negative errno on error. | ||
185 | */ | ||
186 | static ssize_t hih6130_show_humidity(struct device *dev, | ||
187 | struct device_attribute *attr, char *buf) | ||
188 | { | ||
189 | struct i2c_client *client = to_i2c_client(dev); | ||
190 | struct hih6130 *hih6130 = i2c_get_clientdata(client); | ||
191 | int ret = hih6130_update_measurements(client); | ||
192 | if (ret < 0) | ||
193 | return ret; | ||
194 | return sprintf(buf, "%d\n", hih6130->humidity); | ||
195 | } | ||
196 | |||
197 | /* sysfs attributes */ | ||
198 | static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, hih6130_show_temperature, | ||
199 | NULL, 0); | ||
200 | static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO, hih6130_show_humidity, | ||
201 | NULL, 0); | ||
202 | |||
203 | static struct attribute *hih6130_attributes[] = { | ||
204 | &sensor_dev_attr_temp1_input.dev_attr.attr, | ||
205 | &sensor_dev_attr_humidity1_input.dev_attr.attr, | ||
206 | NULL | ||
207 | }; | ||
208 | |||
209 | static const struct attribute_group hih6130_attr_group = { | ||
210 | .attrs = hih6130_attributes, | ||
211 | }; | ||
212 | |||
213 | /** | ||
214 | * hih6130_probe() - probe device | ||
215 | * @client: I2C client device | ||
216 | * @id: device ID | ||
217 | * | ||
218 | * Called by the I2C core when an entry in the ID table matches a | ||
219 | * device's name. | ||
220 | * Returns 0 on success. | ||
221 | */ | ||
222 | static int __devinit hih6130_probe(struct i2c_client *client, | ||
223 | const struct i2c_device_id *id) | ||
224 | { | ||
225 | struct hih6130 *hih6130; | ||
226 | int err; | ||
227 | |||
228 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { | ||
229 | dev_err(&client->dev, "adapter does not support true I2C\n"); | ||
230 | return -ENODEV; | ||
231 | } | ||
232 | |||
233 | hih6130 = devm_kzalloc(&client->dev, sizeof(*hih6130), GFP_KERNEL); | ||
234 | if (!hih6130) | ||
235 | return -ENOMEM; | ||
236 | |||
237 | i2c_set_clientdata(client, hih6130); | ||
238 | |||
239 | mutex_init(&hih6130->lock); | ||
240 | |||
241 | err = sysfs_create_group(&client->dev.kobj, &hih6130_attr_group); | ||
242 | if (err) { | ||
243 | dev_dbg(&client->dev, "could not create sysfs files\n"); | ||
244 | return err; | ||
245 | } | ||
246 | |||
247 | hih6130->hwmon_dev = hwmon_device_register(&client->dev); | ||
248 | if (IS_ERR(hih6130->hwmon_dev)) { | ||
249 | dev_dbg(&client->dev, "unable to register hwmon device\n"); | ||
250 | err = PTR_ERR(hih6130->hwmon_dev); | ||
251 | goto fail_remove_sysfs; | ||
252 | } | ||
253 | |||
254 | return 0; | ||
255 | |||
256 | fail_remove_sysfs: | ||
257 | sysfs_remove_group(&client->dev.kobj, &hih6130_attr_group); | ||
258 | return err; | ||
259 | } | ||
260 | |||
261 | /** | ||
262 | * hih6130_remove() - remove device | ||
263 | * @client: I2C client device | ||
264 | */ | ||
265 | static int __devexit hih6130_remove(struct i2c_client *client) | ||
266 | { | ||
267 | struct hih6130 *hih6130 = i2c_get_clientdata(client); | ||
268 | |||
269 | hwmon_device_unregister(hih6130->hwmon_dev); | ||
270 | sysfs_remove_group(&client->dev.kobj, &hih6130_attr_group); | ||
271 | |||
272 | return 0; | ||
273 | } | ||
274 | |||
275 | /* Device ID table */ | ||
276 | static const struct i2c_device_id hih6130_id[] = { | ||
277 | { "hih6130", 0 }, | ||
278 | { } | ||
279 | }; | ||
280 | MODULE_DEVICE_TABLE(i2c, hih6130_id); | ||
281 | |||
282 | static struct i2c_driver hih6130_driver = { | ||
283 | .driver.name = "hih6130", | ||
284 | .probe = hih6130_probe, | ||
285 | .remove = __devexit_p(hih6130_remove), | ||
286 | .id_table = hih6130_id, | ||
287 | }; | ||
288 | |||
289 | module_i2c_driver(hih6130_driver); | ||
290 | |||
291 | MODULE_AUTHOR("Iain Paton <ipaton0@gmail.com>"); | ||
292 | MODULE_DESCRIPTION("Honeywell HIH-6130 humidity and temperature sensor driver"); | ||
293 | MODULE_LICENSE("GPL"); | ||