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 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 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 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 } 100 101 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 } 107 108 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" }, 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); 190 191 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