drivers/iio/humidity/htu21.c

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