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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1a539d37 TP |
2 | /* Sensirion SHTC1 humidity and temperature sensor driver |
3 | * | |
4 | * Copyright (C) 2014 Sensirion AG, Switzerland | |
5 | * Author: Johannes Winkelmann <johannes.winkelmann@sensirion.com> | |
1a539d37 TP |
6 | */ |
7 | ||
8 | #include <linux/module.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/slab.h> | |
11 | #include <linux/i2c.h> | |
12 | #include <linux/hwmon.h> | |
13 | #include <linux/hwmon-sysfs.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/delay.h> | |
16 | #include <linux/platform_data/shtc1.h> | |
be7373b6 | 17 | #include <linux/of.h> |
1a539d37 TP |
18 | |
19 | /* commands (high precision mode) */ | |
20 | static const unsigned char shtc1_cmd_measure_blocking_hpm[] = { 0x7C, 0xA2 }; | |
21 | static const unsigned char shtc1_cmd_measure_nonblocking_hpm[] = { 0x78, 0x66 }; | |
22 | ||
23 | /* commands (low precision mode) */ | |
24 | static const unsigned char shtc1_cmd_measure_blocking_lpm[] = { 0x64, 0x58 }; | |
25 | static const unsigned char shtc1_cmd_measure_nonblocking_lpm[] = { 0x60, 0x9c }; | |
26 | ||
27 | /* command for reading the ID register */ | |
ffd96868 | 28 | static const unsigned char shtc1_cmd_read_id_reg[] = { 0xef, 0xc8 }; |
1a539d37 | 29 | |
ffd96868 DR |
30 | /* |
31 | * constants for reading the ID register | |
32 | * SHTC1: 0x0007 with mask 0x003f | |
33 | * SHTW1: 0x0007 with mask 0x003f | |
34 | * SHTC3: 0x0807 with mask 0x083f | |
35 | */ | |
36 | #define SHTC3_ID 0x0807 | |
37 | #define SHTC3_ID_MASK 0x083f | |
38 | #define SHTC1_ID 0x0007 | |
39 | #define SHTC1_ID_MASK 0x003f | |
1a539d37 TP |
40 | |
41 | /* delays for non-blocking i2c commands, both in us */ | |
42 | #define SHTC1_NONBLOCKING_WAIT_TIME_HPM 14400 | |
43 | #define SHTC1_NONBLOCKING_WAIT_TIME_LPM 1000 | |
ffd96868 DR |
44 | #define SHTC3_NONBLOCKING_WAIT_TIME_HPM 12100 |
45 | #define SHTC3_NONBLOCKING_WAIT_TIME_LPM 800 | |
1a539d37 TP |
46 | |
47 | #define SHTC1_CMD_LENGTH 2 | |
48 | #define SHTC1_RESPONSE_LENGTH 6 | |
49 | ||
ffd96868 DR |
50 | enum shtcx_chips { |
51 | shtc1, | |
52 | shtc3, | |
53 | }; | |
54 | ||
1a539d37 TP |
55 | struct shtc1_data { |
56 | struct i2c_client *client; | |
57 | struct mutex update_lock; | |
58 | bool valid; | |
59 | unsigned long last_updated; /* in jiffies */ | |
60 | ||
61 | const unsigned char *command; | |
62 | unsigned int nonblocking_wait_time; /* in us */ | |
63 | ||
64 | struct shtc1_platform_data setup; | |
ffd96868 | 65 | enum shtcx_chips chip; |
1a539d37 TP |
66 | |
67 | int temperature; /* 1000 * temperature in dgr C */ | |
68 | int humidity; /* 1000 * relative humidity in %RH */ | |
69 | }; | |
70 | ||
71 | static int shtc1_update_values(struct i2c_client *client, | |
72 | struct shtc1_data *data, | |
73 | char *buf, int bufsize) | |
74 | { | |
75 | int ret = i2c_master_send(client, data->command, SHTC1_CMD_LENGTH); | |
76 | if (ret != SHTC1_CMD_LENGTH) { | |
77 | dev_err(&client->dev, "failed to send command: %d\n", ret); | |
78 | return ret < 0 ? ret : -EIO; | |
79 | } | |
80 | ||
81 | /* | |
82 | * In blocking mode (clock stretching mode) the I2C bus | |
83 | * is blocked for other traffic, thus the call to i2c_master_recv() | |
84 | * will wait until the data is ready. For non blocking mode, we | |
85 | * have to wait ourselves. | |
86 | */ | |
87 | if (!data->setup.blocking_io) | |
88 | usleep_range(data->nonblocking_wait_time, | |
89 | data->nonblocking_wait_time + 1000); | |
90 | ||
91 | ret = i2c_master_recv(client, buf, bufsize); | |
92 | if (ret != bufsize) { | |
93 | dev_err(&client->dev, "failed to read values: %d\n", ret); | |
94 | return ret < 0 ? ret : -EIO; | |
95 | } | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | /* sysfs attributes */ | |
101 | static struct shtc1_data *shtc1_update_client(struct device *dev) | |
102 | { | |
103 | struct shtc1_data *data = dev_get_drvdata(dev); | |
104 | struct i2c_client *client = data->client; | |
105 | unsigned char buf[SHTC1_RESPONSE_LENGTH]; | |
106 | int val; | |
107 | int ret = 0; | |
108 | ||
109 | mutex_lock(&data->update_lock); | |
110 | ||
111 | if (time_after(jiffies, data->last_updated + HZ / 10) || !data->valid) { | |
112 | ret = shtc1_update_values(client, data, buf, sizeof(buf)); | |
113 | if (ret) | |
114 | goto out; | |
115 | ||
116 | /* | |
117 | * From datasheet: | |
118 | * T = -45 + 175 * ST / 2^16 | |
119 | * RH = 100 * SRH / 2^16 | |
120 | * | |
121 | * Adapted for integer fixed point (3 digit) arithmetic. | |
122 | */ | |
123 | val = be16_to_cpup((__be16 *)buf); | |
124 | data->temperature = ((21875 * val) >> 13) - 45000; | |
125 | val = be16_to_cpup((__be16 *)(buf + 3)); | |
126 | data->humidity = ((12500 * val) >> 13); | |
127 | ||
128 | data->last_updated = jiffies; | |
129 | data->valid = true; | |
130 | } | |
131 | ||
132 | out: | |
133 | mutex_unlock(&data->update_lock); | |
134 | ||
135 | return ret == 0 ? data : ERR_PTR(ret); | |
136 | } | |
137 | ||
138 | static ssize_t temp1_input_show(struct device *dev, | |
139 | struct device_attribute *attr, | |
140 | char *buf) | |
141 | { | |
142 | struct shtc1_data *data = shtc1_update_client(dev); | |
143 | if (IS_ERR(data)) | |
144 | return PTR_ERR(data); | |
145 | ||
146 | return sprintf(buf, "%d\n", data->temperature); | |
147 | } | |
148 | ||
149 | static ssize_t humidity1_input_show(struct device *dev, | |
150 | struct device_attribute *attr, char *buf) | |
151 | { | |
152 | struct shtc1_data *data = shtc1_update_client(dev); | |
153 | if (IS_ERR(data)) | |
154 | return PTR_ERR(data); | |
155 | ||
156 | return sprintf(buf, "%d\n", data->humidity); | |
157 | } | |
158 | ||
159 | static DEVICE_ATTR_RO(temp1_input); | |
160 | static DEVICE_ATTR_RO(humidity1_input); | |
161 | ||
162 | static struct attribute *shtc1_attrs[] = { | |
163 | &dev_attr_temp1_input.attr, | |
164 | &dev_attr_humidity1_input.attr, | |
165 | NULL | |
166 | }; | |
167 | ||
168 | ATTRIBUTE_GROUPS(shtc1); | |
169 | ||
170 | static void shtc1_select_command(struct shtc1_data *data) | |
171 | { | |
172 | if (data->setup.high_precision) { | |
173 | data->command = data->setup.blocking_io ? | |
174 | shtc1_cmd_measure_blocking_hpm : | |
175 | shtc1_cmd_measure_nonblocking_hpm; | |
ffd96868 DR |
176 | data->nonblocking_wait_time = (data->chip == shtc1) ? |
177 | SHTC1_NONBLOCKING_WAIT_TIME_HPM : | |
178 | SHTC3_NONBLOCKING_WAIT_TIME_HPM; | |
1a539d37 TP |
179 | } else { |
180 | data->command = data->setup.blocking_io ? | |
181 | shtc1_cmd_measure_blocking_lpm : | |
182 | shtc1_cmd_measure_nonblocking_lpm; | |
ffd96868 DR |
183 | data->nonblocking_wait_time = (data->chip == shtc1) ? |
184 | SHTC1_NONBLOCKING_WAIT_TIME_LPM : | |
185 | SHTC3_NONBLOCKING_WAIT_TIME_LPM; | |
1a539d37 TP |
186 | } |
187 | } | |
188 | ||
67487038 SK |
189 | static const struct i2c_device_id shtc1_id[]; |
190 | ||
191 | static int shtc1_probe(struct i2c_client *client) | |
1a539d37 TP |
192 | { |
193 | int ret; | |
ffd96868 DR |
194 | u16 id_reg; |
195 | char id_reg_buf[2]; | |
1a539d37 TP |
196 | struct shtc1_data *data; |
197 | struct device *hwmon_dev; | |
67487038 | 198 | enum shtcx_chips chip = i2c_match_id(shtc1_id, client)->driver_data; |
1a539d37 TP |
199 | struct i2c_adapter *adap = client->adapter; |
200 | struct device *dev = &client->dev; | |
be7373b6 | 201 | struct device_node *np = dev->of_node; |
1a539d37 TP |
202 | |
203 | if (!i2c_check_functionality(adap, I2C_FUNC_I2C)) { | |
204 | dev_err(dev, "plain i2c transactions not supported\n"); | |
205 | return -ENODEV; | |
206 | } | |
207 | ||
208 | ret = i2c_master_send(client, shtc1_cmd_read_id_reg, SHTC1_CMD_LENGTH); | |
209 | if (ret != SHTC1_CMD_LENGTH) { | |
210 | dev_err(dev, "could not send read_id_reg command: %d\n", ret); | |
211 | return ret < 0 ? ret : -ENODEV; | |
212 | } | |
ffd96868 DR |
213 | ret = i2c_master_recv(client, id_reg_buf, sizeof(id_reg_buf)); |
214 | if (ret != sizeof(id_reg_buf)) { | |
1a539d37 TP |
215 | dev_err(dev, "could not read ID register: %d\n", ret); |
216 | return -ENODEV; | |
217 | } | |
ffd96868 DR |
218 | |
219 | id_reg = be16_to_cpup((__be16 *)id_reg_buf); | |
220 | if (chip == shtc3) { | |
221 | if ((id_reg & SHTC3_ID_MASK) != SHTC3_ID) { | |
222 | dev_err(dev, "SHTC3 ID register does not match\n"); | |
223 | return -ENODEV; | |
224 | } | |
225 | } else if ((id_reg & SHTC1_ID_MASK) != SHTC1_ID) { | |
226 | dev_err(dev, "SHTC1 ID register does not match\n"); | |
1a539d37 TP |
227 | return -ENODEV; |
228 | } | |
229 | ||
230 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); | |
231 | if (!data) | |
232 | return -ENOMEM; | |
233 | ||
234 | data->setup.blocking_io = false; | |
235 | data->setup.high_precision = true; | |
236 | data->client = client; | |
ffd96868 | 237 | data->chip = chip; |
1a539d37 | 238 | |
be7373b6 CR |
239 | if (np) { |
240 | data->setup.blocking_io = of_property_read_bool(np, "sensirion,blocking-io"); | |
241 | data->setup.high_precision = !of_property_read_bool(np, "sensicon,low-precision"); | |
242 | } else { | |
243 | if (client->dev.platform_data) | |
244 | data->setup = *(struct shtc1_platform_data *)dev->platform_data; | |
245 | } | |
246 | ||
1a539d37 TP |
247 | shtc1_select_command(data); |
248 | mutex_init(&data->update_lock); | |
249 | ||
250 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, | |
251 | client->name, | |
252 | data, | |
253 | shtc1_groups); | |
254 | if (IS_ERR(hwmon_dev)) | |
255 | dev_dbg(dev, "unable to register hwmon device\n"); | |
256 | ||
257 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
258 | } | |
259 | ||
260 | /* device ID table */ | |
261 | static const struct i2c_device_id shtc1_id[] = { | |
ffd96868 DR |
262 | { "shtc1", shtc1 }, |
263 | { "shtw1", shtc1 }, | |
264 | { "shtc3", shtc3 }, | |
1a539d37 TP |
265 | { } |
266 | }; | |
267 | MODULE_DEVICE_TABLE(i2c, shtc1_id); | |
268 | ||
be7373b6 CR |
269 | static const struct of_device_id shtc1_of_match[] = { |
270 | { .compatible = "sensirion,shtc1" }, | |
271 | { .compatible = "sensirion,shtw1" }, | |
272 | { .compatible = "sensirion,shtc3" }, | |
273 | { } | |
274 | }; | |
275 | MODULE_DEVICE_TABLE(of, shtc1_of_match); | |
276 | ||
1a539d37 | 277 | static struct i2c_driver shtc1_i2c_driver = { |
be7373b6 CR |
278 | .driver = { |
279 | .name = "shtc1", | |
280 | .of_match_table = shtc1_of_match, | |
281 | }, | |
1975d167 | 282 | .probe = shtc1_probe, |
1a539d37 TP |
283 | .id_table = shtc1_id, |
284 | }; | |
285 | ||
286 | module_i2c_driver(shtc1_i2c_driver); | |
287 | ||
288 | MODULE_AUTHOR("Johannes Winkelmann <johannes.winkelmann@sensirion.com>"); | |
289 | MODULE_DESCRIPTION("Sensirion SHTC1 humidity and temperature sensor driver"); | |
290 | MODULE_LICENSE("GPL"); |