drivers/iio/temperature/mlx90614.c

   1 /*
   2  * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
   3  *
   4  * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License.  See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
  11  *
  12  * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
  13  *
  14  * TODO: sleep mode, configuration EEPROM
  15  */
  16
  17 #include <linux/err.h>
  18 #include <linux/i2c.h>
  19 #include <linux/module.h>
  20
  21 #include <linux/iio/iio.h>
  22
  23 #define MLX90614_OP_RAM 0x00
  24
  25 /* RAM offsets with 16-bit data, MSB first */
  26 #define MLX90614_TA 0x06 /* ambient temperature */
  27 #define MLX90614_TOBJ1 0x07 /* object temperature */
  28
  29 struct mlx90614_data {
  30         struct i2c_client *client;
  31 };
  32
  33 static int mlx90614_read_raw(struct iio_dev *indio_dev,
  34                             struct iio_chan_spec const *channel, int *val,
  35                             int *val2, long mask)
  36 {
  37         struct mlx90614_data *data = iio_priv(indio_dev);
  38         s32 ret;
  39
  40         switch (mask) {
  41         case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
  42                 switch (channel->channel2) {
  43                 case IIO_MOD_TEMP_AMBIENT:
  44                         ret = i2c_smbus_read_word_data(data->client,
  45                             MLX90614_OP_RAM | MLX90614_TA);
  46                         if (ret < 0)
  47                                 return ret;
  48                         break;
  49                 case IIO_MOD_TEMP_OBJECT:
  50                         ret = i2c_smbus_read_word_data(data->client,
  51                             MLX90614_OP_RAM | MLX90614_TOBJ1);
  52                         if (ret < 0)
  53                                 return ret;
  54                         break;
  55                 default:
  56                         return -EINVAL;
  57                 }
  58                 *val = ret;
  59                 return IIO_VAL_INT;
  60         case IIO_CHAN_INFO_OFFSET:
  61                 *val = 13657;
  62                 *val2 = 500000;
  63                 return IIO_VAL_INT_PLUS_MICRO;
  64         case IIO_CHAN_INFO_SCALE:
  65                 *val = 20;
  66                 return IIO_VAL_INT;
  67         default:
  68                 return -EINVAL;
  69         }
  70 }
  71
  72 static const struct iio_chan_spec mlx90614_channels[] = {
  73         {
  74                 .type = IIO_TEMP,
  75                 .modified = 1,
  76                 .channel2 = IIO_MOD_TEMP_AMBIENT,
  77                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  78                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
  79                     BIT(IIO_CHAN_INFO_SCALE),
  80         },
  81         {
  82                 .type = IIO_TEMP,
  83                 .modified = 1,
  84                 .channel2 = IIO_MOD_TEMP_OBJECT,
  85                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  86                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
  87                     BIT(IIO_CHAN_INFO_SCALE),
  88         },
  89 };
  90
  91 static const struct iio_info mlx90614_info = {
  92         .read_raw = mlx90614_read_raw,
  93         .driver_module = THIS_MODULE,
  94 };
  95
  96 static int mlx90614_probe(struct i2c_client *client,
  97                          const struct i2c_device_id *id)
  98 {
  99         struct iio_dev *indio_dev;
 100         struct mlx90614_data *data;
 101
 102         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 103                 return -ENODEV;
 104
 105         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 106         if (!indio_dev)
 107                 return -ENOMEM;
 108
 109         data = iio_priv(indio_dev);
 110         i2c_set_clientdata(client, indio_dev);
 111         data->client = client;
 112
 113         indio_dev->dev.parent = &client->dev;
 114         indio_dev->name = id->name;
 115         indio_dev->modes = INDIO_DIRECT_MODE;
 116         indio_dev->info = &mlx90614_info;
 117
 118         indio_dev->channels = mlx90614_channels;
 119         indio_dev->num_channels = ARRAY_SIZE(mlx90614_channels);
 120
 121         return iio_device_register(indio_dev);
 122 }
 123
 124 static int mlx90614_remove(struct i2c_client *client)
 125 {
 126         iio_device_unregister(i2c_get_clientdata(client));
 127
 128         return 0;
 129 }
 130
 131 static const struct i2c_device_id mlx90614_id[] = {
 132         { "mlx90614", 0 },
 133         { }
 134 };
 135 MODULE_DEVICE_TABLE(i2c, mlx90614_id);
 136
 137 static struct i2c_driver mlx90614_driver = {
 138         .driver = {
 139                 .name   = "mlx90614",
 140                 .owner  = THIS_MODULE,
 141         },
 142         .probe = mlx90614_probe,
 143         .remove = mlx90614_remove,
 144         .id_table = mlx90614_id,
 145 };
 146 module_i2c_driver(mlx90614_driver);
 147
 148 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 149 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
 150 MODULE_LICENSE("GPL");