1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * This is a non-complete driver implementation for the
4 * HS3001 humidity and temperature sensor and compatibles. It does not include
5 * the configuration possibilities, where it needs to be set to 'programming mode'
6 * during power-up.
7 *
8 *
9 * Copyright (C) 2023 SYS TEC electronic AG
10 * Author: Andre Werner <andre.werner@systec-electronic.com>
11 */
12
13 #include <linux/bitfield.h>
14 #include <linux/delay.h>
15 #include <linux/err.h>
16 #include <linux/hwmon.h>
17 #include <linux/i2c.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/of_device.h>
22 #include <linux/slab.h>
23 #include <linux/types.h>
24
25 /* Measurement times */
26 #define HS3001_WAKEUP_TIME 100 /* us */
27 #define HS3001_8BIT_RESOLUTION 550 /* us */
28 #define HS3001_10BIT_RESOLUTION 1310 /* us */
29 #define HS3001_12BIT_RESOLUTION 4500 /* us */
30 #define HS3001_14BIT_RESOLUTION 16900 /* us */
31
32 #define HS3001_RESPONSE_LENGTH 4
33
34 #define HS3001_FIXPOINT_ARITH 1000U
35
36 #define HS3001_MASK_HUMIDITY_0X3FFF GENMASK(13, 0)
37 #define HS3001_MASK_STATUS_0XC0 GENMASK(7, 6)
38
39 /* Definitions for Status Bits of A/D Data */
40 #define HS3001_DATA_VALID 0x00 /* Valid Data */
41 #define HS3001_DATA_STALE 0x01 /* Stale Data */
42
43 struct hs3001_data {
44 struct i2c_client *client;
45 struct mutex i2c_lock; /* lock for sending i2c commands */
46 u32 wait_time; /* in us */
47 int temperature; /* in milli degree */
48 u32 humidity; /* in milli % */
49 };
50
hs3001_extract_temperature(u16 raw)51 static int hs3001_extract_temperature(u16 raw)
52 {
53 /* fixpoint arithmetic 1 digit */
54 u32 temp = (raw >> 2) * HS3001_FIXPOINT_ARITH * 165;
55
56 temp /= (1 << 14) - 1;
57
58 return (int)temp - 40 * HS3001_FIXPOINT_ARITH;
59 }
60
hs3001_extract_humidity(u16 raw)61 static u32 hs3001_extract_humidity(u16 raw)
62 {
63 u32 hum = (raw & HS3001_MASK_HUMIDITY_0X3FFF) * HS3001_FIXPOINT_ARITH * 100;
64
65 return hum /= (1 << 14) - 1;
66 }
67
hs3001_data_fetch_command(struct i2c_client * client,struct hs3001_data * data)68 static int hs3001_data_fetch_command(struct i2c_client *client,
69 struct hs3001_data *data)
70 {
71 int ret;
72 u8 buf[HS3001_RESPONSE_LENGTH];
73 u8 hs3001_status;
74
75 ret = i2c_master_recv(client, buf, HS3001_RESPONSE_LENGTH);
76 if (ret != HS3001_RESPONSE_LENGTH) {
77 ret = ret < 0 ? ret : -EIO;
78 dev_dbg(&client->dev,
79 "Error in i2c communication. Error code: %d.\n", ret);
80 return ret;
81 }
82
83 hs3001_status = FIELD_GET(HS3001_MASK_STATUS_0XC0, buf[0]);
84 if (hs3001_status == HS3001_DATA_STALE) {
85 dev_dbg(&client->dev, "Sensor busy.\n");
86 return -EBUSY;
87 }
88 if (hs3001_status != HS3001_DATA_VALID) {
89 dev_dbg(&client->dev, "Data invalid.\n");
90 return -EIO;
91 }
92
93 data->humidity =
94 hs3001_extract_humidity(be16_to_cpup((__be16 *)&buf[0]));
95 data->temperature =
96 hs3001_extract_temperature(be16_to_cpup((__be16 *)&buf[2]));
97
98 return 0;
99 }
100
hs3001_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)101 static umode_t hs3001_is_visible(const void *data, enum hwmon_sensor_types type,
102 u32 attr, int channel)
103 {
104 /* Both, humidity and temperature can only be read. */
105 return 0444;
106 }
107
hs3001_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)108 static int hs3001_read(struct device *dev, enum hwmon_sensor_types type,
109 u32 attr, int channel, long *val)
110 {
111 struct hs3001_data *data = dev_get_drvdata(dev);
112 struct i2c_client *client = data->client;
113 int ret;
114
115 mutex_lock(&data->i2c_lock);
116 ret = i2c_master_send(client, NULL, 0);
117 if (ret < 0) {
118 mutex_unlock(&data->i2c_lock);
119 return ret;
120 }
121
122 /*
123 * Sensor needs some time to process measurement depending on
124 * resolution (ref. datasheet)
125 */
126 fsleep(data->wait_time);
127
128 ret = hs3001_data_fetch_command(client, data);
129 mutex_unlock(&data->i2c_lock);
130
131 if (ret < 0)
132 return ret;
133
134 switch (type) {
135 case hwmon_temp:
136 switch (attr) {
137 case hwmon_temp_input:
138 *val = data->temperature;
139 break;
140 default:
141 return -EINVAL;
142 }
143 break;
144 case hwmon_humidity:
145 switch (attr) {
146 case hwmon_humidity_input:
147 *val = data->humidity;
148 break;
149 default:
150 return -EINVAL;
151 }
152 break;
153 default:
154 return -EINVAL;
155 }
156
157 return 0;
158 }
159
160 static const struct hwmon_channel_info *hs3001_info[] = {
161 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
162 HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT),
163 NULL
164 };
165
166 static const struct hwmon_ops hs3001_hwmon_ops = {
167 .is_visible = hs3001_is_visible,
168 .read = hs3001_read,
169 };
170
171 static const struct hwmon_chip_info hs3001_chip_info = {
172 .ops = &hs3001_hwmon_ops,
173 .info = hs3001_info,
174 };
175
176 /* device ID table */
177 static const struct i2c_device_id hs3001_ids[] = {
178 { "hs3001", 0 },
179 { },
180 };
181
182 MODULE_DEVICE_TABLE(i2c, hs3001_ids);
183
184 static const struct of_device_id hs3001_of_match[] = {
185 {.compatible = "renesas,hs3001"},
186 { },
187 };
188
189 MODULE_DEVICE_TABLE(of, hs3001_of_match);
190
hs3001_probe(struct i2c_client * client)191 static int hs3001_probe(struct i2c_client *client)
192 {
193 struct hs3001_data *data;
194 struct device *hwmon_dev;
195 struct device *dev = &client->dev;
196
197 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
198 return -EOPNOTSUPP;
199
200 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
201 if (!data)
202 return -ENOMEM;
203
204 data->client = client;
205
206 /*
207 * Measurement time = wake-up time + measurement time temperature
208 * + measurement time humidity. This is currently static, because
209 * enabling programming mode is not supported, yet.
210 */
211 data->wait_time = (HS3001_WAKEUP_TIME + HS3001_14BIT_RESOLUTION +
212 HS3001_14BIT_RESOLUTION);
213
214 mutex_init(&data->i2c_lock);
215
216 hwmon_dev = devm_hwmon_device_register_with_info(dev,
217 client->name,
218 data,
219 &hs3001_chip_info,
220 NULL);
221
222 if (IS_ERR(hwmon_dev))
223 return dev_err_probe(dev, PTR_ERR(hwmon_dev),
224 "Unable to register hwmon device.\n");
225
226 return 0;
227 }
228
229 static struct i2c_driver hs3001_i2c_driver = {
230 .driver = {
231 .name = "hs3001",
232 .of_match_table = hs3001_of_match,
233 },
234 .probe = hs3001_probe,
235 .id_table = hs3001_ids,
236 };
237
238 module_i2c_driver(hs3001_i2c_driver);
239
240 MODULE_AUTHOR("Andre Werner <andre.werner@systec-electronic.com>");
241 MODULE_DESCRIPTION("HS3001 humidity and temperature sensor base driver");
242 MODULE_LICENSE("GPL");
243
