drivers/iio/humidity/htu21.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * htu21.c - Support for Measurement-Specialties
   4  *           htu21 temperature & humidity sensor
   5  *           and humidity part of MS8607 sensor
   6  *
   7  * Copyright (c) 2014 Measurement-Specialties
   8  *
   9  * (7-bit I2C slave address 0x40)
  10  *
  11  * Datasheet:
  12  *  http://www.meas-spec.com/downloads/HTU21D.pdf
  13  * Datasheet:
  14  *  http://www.meas-spec.com/downloads/MS8607-02BA01.pdf
  15  */
  16
  17 #include <linux/init.h>
  18 #include <linux/device.h>
  19 #include <linux/kernel.h>
  20 #include <linux/stat.h>
  21 #include <linux/module.h>
  22 #include <linux/iio/iio.h>
  23 #include <linux/iio/sysfs.h>
  24
  25 #include "../common/ms_sensors/ms_sensors_i2c.h"
  26
  27 #define HTU21_RESET                             0xFE
  28
  29 enum {
  30         HTU21,
  31         MS8607
  32 };
  33
  34 static const int htu21_samp_freq[4] = { 20, 40, 70, 120 };
  35 /* String copy of the above const for readability purpose */
  36 static const char htu21_show_samp_freq[] = "20 40 70 120";
  37
  38 static int htu21_read_raw(struct iio_dev *indio_dev,
  39                           struct iio_chan_spec const *channel, int *val,
  40                           int *val2, long mask)
  41 {
  42         int ret, temperature;
  43         unsigned int humidity;
  44         struct ms_ht_dev *dev_data = iio_priv(indio_dev);
  45
  46         switch (mask) {
  47         case IIO_CHAN_INFO_PROCESSED:
  48                 switch (channel->type) {
  49                 case IIO_TEMP:  /* in milli °C */
  50                         ret = ms_sensors_ht_read_temperature(dev_data,
  51                                                              &temperature);
  52                         if (ret)
  53                                 return ret;
  54                         *val = temperature;
  55
  56                         return IIO_VAL_INT;
  57                 case IIO_HUMIDITYRELATIVE:      /* in milli %RH */
  58                         ret = ms_sensors_ht_read_humidity(dev_data,
  59                                                           &humidity);
  60                         if (ret)
  61                                 return ret;
  62                         *val = humidity;
  63
  64                         return IIO_VAL_INT;
  65                 default:
  66                         return -EINVAL;
  67                 }
  68         case IIO_CHAN_INFO_SAMP_FREQ:
  69                 *val = htu21_samp_freq[dev_data->res_index];
  70
  71                 return IIO_VAL_INT;
  72         default:
  73                 return -EINVAL;
  74         }
  75 }
  76
  77 static int htu21_write_raw(struct iio_dev *indio_dev,
  78                            struct iio_chan_spec const *chan,
  79                            int val, int val2, long mask)
  80 {
  81         struct ms_ht_dev *dev_data = iio_priv(indio_dev);
  82         int i, ret;
  83
  84         switch (mask) {
  85         case IIO_CHAN_INFO_SAMP_FREQ:
  86                 i = ARRAY_SIZE(htu21_samp_freq);
  87                 while (i-- > 0)
  88                         if (val == htu21_samp_freq[i])
  89                                 break;
  90                 if (i < 0)
  91                         return -EINVAL;
  92                 mutex_lock(&dev_data->lock);
  93                 dev_data->res_index = i;
  94                 ret = ms_sensors_write_resolution(dev_data, i);
  95                 mutex_unlock(&dev_data->lock);
  96
  97                 return ret;
  98         default:
  99                 return -EINVAL;
 100         }
 101 }
 102
 103 static const struct iio_chan_spec htu21_channels[] = {
 104         {
 105                 .type = IIO_TEMP,
 106                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
 107                 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 108          },
 109         {
 110                 .type = IIO_HUMIDITYRELATIVE,
 111                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
 112                 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 113          }
 114 };
 115
 116 /*
 117  * Meas Spec recommendation is to not read temperature
 118  * on this driver part for MS8607
 119  */
 120 static const struct iio_chan_spec ms8607_channels[] = {
 121         {
 122                 .type = IIO_HUMIDITYRELATIVE,
 123                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
 124                 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
 125          }
 126 };
 127
 128 static ssize_t htu21_show_battery_low(struct device *dev,
 129                                       struct device_attribute *attr, char *buf)
 130 {
 131         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 132         struct ms_ht_dev *dev_data = iio_priv(indio_dev);
 133
 134         return ms_sensors_show_battery_low(dev_data, buf);
 135 }
 136
 137 static ssize_t htu21_show_heater(struct device *dev,
 138                                  struct device_attribute *attr, char *buf)
 139 {
 140         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 141         struct ms_ht_dev *dev_data = iio_priv(indio_dev);
 142
 143         return ms_sensors_show_heater(dev_data, buf);
 144 }
 145
 146 static ssize_t htu21_write_heater(struct device *dev,
 147                                   struct device_attribute *attr,
 148                                   const char *buf, size_t len)
 149 {
 150         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 151         struct ms_ht_dev *dev_data = iio_priv(indio_dev);
 152
 153         return ms_sensors_write_heater(dev_data, buf, len);
 154 }
 155
 156 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(htu21_show_samp_freq);
 157 static IIO_DEVICE_ATTR(battery_low, S_IRUGO,
 158                        htu21_show_battery_low, NULL, 0);
 159 static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR,
 160                        htu21_show_heater, htu21_write_heater, 0);
 161
 162 static struct attribute *htu21_attributes[] = {
 163         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 164         &iio_dev_attr_battery_low.dev_attr.attr,
 165         &iio_dev_attr_heater_enable.dev_attr.attr,
 166         NULL,
 167 };
 168
 169 static const struct attribute_group htu21_attribute_group = {
 170         .attrs = htu21_attributes,
 171 };
 172
 173 static const struct iio_info htu21_info = {
 174         .read_raw = htu21_read_raw,
 175         .write_raw = htu21_write_raw,
 176         .attrs = &htu21_attribute_group,
 177 };
 178
 179 static int htu21_probe(struct i2c_client *client,
 180                        const struct i2c_device_id *id)
 181 {
 182         struct ms_ht_dev *dev_data;
 183         struct iio_dev *indio_dev;
 184         int ret;
 185         u64 serial_number;
 186
 187         if (!i2c_check_functionality(client->adapter,
 188                                      I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 189                                      I2C_FUNC_SMBUS_WRITE_BYTE |
 190                                      I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
 191                 dev_err(&client->dev,
 192                         "Adapter does not support some i2c transaction\n");
 193                 return -EOPNOTSUPP;
 194         }
 195
 196         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
 197         if (!indio_dev)
 198                 return -ENOMEM;
 199
 200         dev_data = iio_priv(indio_dev);
 201         dev_data->client = client;
 202         dev_data->res_index = 0;
 203         mutex_init(&dev_data->lock);
 204
 205         indio_dev->info = &htu21_info;
 206         indio_dev->name = id->name;
 207         indio_dev->dev.parent = &client->dev;
 208         indio_dev->modes = INDIO_DIRECT_MODE;
 209
 210         if (id->driver_data == MS8607) {
 211                 indio_dev->channels = ms8607_channels;
 212                 indio_dev->num_channels = ARRAY_SIZE(ms8607_channels);
 213         } else {
 214                 indio_dev->channels = htu21_channels;
 215                 indio_dev->num_channels = ARRAY_SIZE(htu21_channels);
 216         }
 217
 218         i2c_set_clientdata(client, indio_dev);
 219
 220         ret = ms_sensors_reset(client, HTU21_RESET, 15000);
 221         if (ret)
 222                 return ret;
 223
 224         ret = ms_sensors_read_serial(client, &serial_number);
 225         if (ret)
 226                 return ret;
 227         dev_info(&client->dev, "Serial number : %llx", serial_number);
 228
 229         return devm_iio_device_register(&client->dev, indio_dev);
 230 }
 231
 232 static const struct i2c_device_id htu21_id[] = {
 233         {"htu21", HTU21},
 234         {"ms8607-humidity", MS8607},
 235         {}
 236 };
 237 MODULE_DEVICE_TABLE(i2c, htu21_id);
 238
 239 static const struct of_device_id htu21_of_match[] = {
 240         { .compatible = "meas,htu21", },
 241         { .compatible = "meas,ms8607-humidity", },
 242         { },
 243 };
 244 MODULE_DEVICE_TABLE(of, htu21_of_match);
 245
 246 static struct i2c_driver htu21_driver = {
 247         .probe = htu21_probe,
 248         .id_table = htu21_id,
 249         .driver = {
 250                    .name = "htu21",
 251                    .of_match_table = of_match_ptr(htu21_of_match),
 252                    },
 253 };
 254
 255 module_i2c_driver(htu21_driver);
 256
 257 MODULE_DESCRIPTION("Measurement-Specialties htu21 temperature and humidity driver");
 258 MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
 259 MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
 260 MODULE_LICENSE("GPL v2");