drivers/hwmon/hs3001.c

   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", 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
 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");