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234 lines · 5.5 KiB

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 <[email protected]>
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
43struct hs3001_data {
44 struct i2c_client *client;
45 u32 wait_time; /* in us */
46 int temperature; /* in milli degree */
47 u32 humidity; /* in milli % */
48};
49
50static int hs3001_extract_temperature(u16 raw)
51{
52 /* fixpoint arithmetic 1 digit */
53 u32 temp = (raw >> 2) * HS3001_FIXPOINT_ARITH * 165;
54
55 temp /= (1 << 14) - 1;
56
57 return (int)temp - 40 * HS3001_FIXPOINT_ARITH;
58}
59
60static u32 hs3001_extract_humidity(u16 raw)
61{
62 u32 hum = (raw & HS3001_MASK_HUMIDITY_0X3FFF) * HS3001_FIXPOINT_ARITH * 100;
63
64 return hum / (1 << 14) - 1;
65}
66
67static int hs3001_data_fetch_command(struct i2c_client *client,
68 struct hs3001_data *data)
69{
70 int ret;
71 u8 buf[HS3001_RESPONSE_LENGTH];
72 u8 hs3001_status;
73
74 ret = i2c_master_recv(client, buf, HS3001_RESPONSE_LENGTH);
75 if (ret != HS3001_RESPONSE_LENGTH) {
76 ret = ret < 0 ? ret : -EIO;
77 dev_dbg(&client->dev,
78 "Error in i2c communication. Error code: %d.\n", ret);
79 return ret;
80 }
81
82 hs3001_status = FIELD_GET(HS3001_MASK_STATUS_0XC0, buf[0]);
83 if (hs3001_status == HS3001_DATA_STALE) {
84 dev_dbg(&client->dev, "Sensor busy.\n");
85 return -EBUSY;
86 }
87 if (hs3001_status != HS3001_DATA_VALID) {
88 dev_dbg(&client->dev, "Data invalid.\n");
89 return -EIO;
90 }
91
92 data->humidity =
93 hs3001_extract_humidity(be16_to_cpup((__be16 *)&buf[0]));
94 data->temperature =
95 hs3001_extract_temperature(be16_to_cpup((__be16 *)&buf[2]));
96
97 return 0;
98}
99
100static umode_t hs3001_is_visible(const void *data, enum hwmon_sensor_types type,
101 u32 attr, int channel)
102{
103 /* Both, humidity and temperature can only be read. */
104 return 0444;
105}
106
107static int hs3001_read(struct device *dev, enum hwmon_sensor_types type,
108 u32 attr, int channel, long *val)
109{
110 struct hs3001_data *data = dev_get_drvdata(dev);
111 struct i2c_client *client = data->client;
112 int ret;
113
114 ret = i2c_master_send(client, NULL, 0);
115 if (ret < 0)
116 return ret;
117
118 /*
119 * Sensor needs some time to process measurement depending on
120 * resolution (ref. datasheet)
121 */
122 fsleep(data->wait_time);
123
124 ret = hs3001_data_fetch_command(client, data);
125 if (ret < 0)
126 return ret;
127
128 switch (type) {
129 case hwmon_temp:
130 switch (attr) {
131 case hwmon_temp_input:
132 *val = data->temperature;
133 break;
134 default:
135 return -EINVAL;
136 }
137 break;
138 case hwmon_humidity:
139 switch (attr) {
140 case hwmon_humidity_input:
141 *val = data->humidity;
142 break;
143 default:
144 return -EINVAL;
145 }
146 break;
147 default:
148 return -EINVAL;
149 }
150
151 return 0;
152}
153
154static const struct hwmon_channel_info *hs3001_info[] = {
155 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
156 HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT),
157 NULL
158};
159
160static const struct hwmon_ops hs3001_hwmon_ops = {
161 .is_visible = hs3001_is_visible,
162 .read = hs3001_read,
163};
164
165static const struct hwmon_chip_info hs3001_chip_info = {
166 .ops = &hs3001_hwmon_ops,
167 .info = hs3001_info,
168};
169
170/* device ID table */
171static const struct i2c_device_id hs3001_ids[] = {
172 { .name = "hs3001" },
173 { }
174};
175
176MODULE_DEVICE_TABLE(i2c, hs3001_ids);
177
178static const struct of_device_id hs3001_of_match[] = {
179 {.compatible = "renesas,hs3001"},
180 { },
181};
182
183MODULE_DEVICE_TABLE(of, hs3001_of_match);
184
185static int hs3001_probe(struct i2c_client *client)
186{
187 struct hs3001_data *data;
188 struct device *hwmon_dev;
189 struct device *dev = &client->dev;
190
191 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
192 return -EOPNOTSUPP;
193
194 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
195 if (!data)
196 return -ENOMEM;
197
198 data->client = client;
199
200 /*
201 * Measurement time = wake-up time + measurement time temperature
202 * + measurement time humidity. This is currently static, because
203 * enabling programming mode is not supported, yet.
204 */
205 data->wait_time = (HS3001_WAKEUP_TIME + HS3001_14BIT_RESOLUTION +
206 HS3001_14BIT_RESOLUTION);
207
208 hwmon_dev = devm_hwmon_device_register_with_info(dev,
209 client->name,
210 data,
211 &hs3001_chip_info,
212 NULL);
213
214 if (IS_ERR(hwmon_dev))
215 return dev_err_probe(dev, PTR_ERR(hwmon_dev),
216 "Unable to register hwmon device.\n");
217
218 return 0;
219}
220
221static struct i2c_driver hs3001_i2c_driver = {
222 .driver = {
223 .name = "hs3001",
224 .of_match_table = hs3001_of_match,
225 },
226 .probe = hs3001_probe,
227 .id_table = hs3001_ids,
228};
229
230module_i2c_driver(hs3001_i2c_driver);
231
232MODULE_AUTHOR("Andre Werner <[email protected]>");
233MODULE_DESCRIPTION("HS3001 humidity and temperature sensor base driver");
234MODULE_LICENSE("GPL");