kernel/drivers/iio/humidity/htu21.c

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