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  * Copyright (c) 2015 Essensium NV
   6  *
   7  * This file is subject to the terms and conditions of version 2 of
   8  * the GNU General Public License.  See the file COPYING in the main
   9  * directory of this archive for more details.
  10  *
  11  * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
  12  *
  13  * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
  14  *
  15  * TODO: sleep mode, configuration EEPROM
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/i2c.h>
  20 #include <linux/module.h>
  21
  22 #include <linux/iio/iio.h>
  23
  24 #define MLX90614_OP_RAM         0x00
  25 #define MLX90614_OP_EEPROM      0x20
  26 #define MLX90614_OP_SLEEP       0xff
  27
  28 /* RAM offsets with 16-bit data, MSB first */
  29 #define MLX90614_RAW1   (MLX90614_OP_RAM | 0x04) /* raw data IR channel 1 */
  30 #define MLX90614_RAW2   (MLX90614_OP_RAM | 0x05) /* raw data IR channel 2 */
  31 #define MLX90614_TA     (MLX90614_OP_RAM | 0x06) /* ambient temperature */
  32 #define MLX90614_TOBJ1  (MLX90614_OP_RAM | 0x07) /* object 1 temperature */
  33 #define MLX90614_TOBJ2  (MLX90614_OP_RAM | 0x08) /* object 2 temperature */
  34
  35 /* EEPROM offsets with 16-bit data, MSB first */
  36 #define MLX90614_EMISSIVITY     (MLX90614_OP_EEPROM | 0x04) /* emissivity correction coefficient */
  37 #define MLX90614_CONFIG         (MLX90614_OP_EEPROM | 0x05) /* configuration register */
  38
  39 /* Control bits in configuration register */
  40 #define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */
  41 #define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT)
  42 #define MLX90614_CONFIG_DUAL_SHIFT 6 /* single (0) or dual (1) IR sensor */
  43 #define MLX90614_CONFIG_DUAL_MASK (1 << MLX90614_CONFIG_DUAL_SHIFT)
  44 #define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */
  45 #define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT)
  46 #define MLX90614_CONFIG_GAIN_SHIFT 11 /* gain */
  47 #define MLX90614_CONFIG_GAIN_MASK (0x7 << MLX90614_CONFIG_GAIN_SHIFT)
  48
  49 /* Timings (in ms) */
  50 #define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */
  51 #define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
  52 #define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
  53
  54 struct mlx90614_data {
  55         struct i2c_client *client;
  56 };
  57
  58 static int mlx90614_read_raw(struct iio_dev *indio_dev,
  59                             struct iio_chan_spec const *channel, int *val,
  60                             int *val2, long mask)
  61 {
  62         struct mlx90614_data *data = iio_priv(indio_dev);
  63         u8 cmd;
  64         s32 ret;
  65
  66         switch (mask) {
  67         case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
  68                 switch (channel->channel2) {
  69                 case IIO_MOD_TEMP_AMBIENT:
  70                         cmd = MLX90614_TA;
  71                         break;
  72                 case IIO_MOD_TEMP_OBJECT:
  73                         switch (channel->channel) {
  74                         case 0:
  75                                 cmd = MLX90614_TOBJ1;
  76                                 break;
  77                         case 1:
  78                                 cmd = MLX90614_TOBJ2;
  79                                 break;
  80                         default:
  81                                 return -EINVAL;
  82                         }
  83                         break;
  84                 default:
  85                         return -EINVAL;
  86                 }
  87
  88                 ret = i2c_smbus_read_word_data(data->client, cmd);
  89                 if (ret < 0)
  90                         return ret;
  91                 *val = ret;
  92                 return IIO_VAL_INT;
  93         case IIO_CHAN_INFO_OFFSET:
  94                 *val = 13657;
  95                 *val2 = 500000;
  96                 return IIO_VAL_INT_PLUS_MICRO;
  97         case IIO_CHAN_INFO_SCALE:
  98                 *val = 20;
  99                 return IIO_VAL_INT;
 100         default:
 101                 return -EINVAL;
 102         }
 103 }
 104
 105 static const struct iio_chan_spec mlx90614_channels[] = {
 106         {
 107                 .type = IIO_TEMP,
 108                 .modified = 1,
 109                 .channel2 = IIO_MOD_TEMP_AMBIENT,
 110                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 111                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 112                     BIT(IIO_CHAN_INFO_SCALE),
 113         },
 114         {
 115                 .type = IIO_TEMP,
 116                 .modified = 1,
 117                 .channel2 = IIO_MOD_TEMP_OBJECT,
 118                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 119                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 120                     BIT(IIO_CHAN_INFO_SCALE),
 121         },
 122         {
 123                 .type = IIO_TEMP,
 124                 .indexed = 1,
 125                 .modified = 1,
 126                 .channel = 1,
 127                 .channel2 = IIO_MOD_TEMP_OBJECT,
 128                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 129                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
 130                     BIT(IIO_CHAN_INFO_SCALE),
 131         },
 132 };
 133
 134 static const struct iio_info mlx90614_info = {
 135         .read_raw = mlx90614_read_raw,
 136         .driver_module = THIS_MODULE,
 137 };
 138
 139 /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
 140 static int mlx90614_probe_num_ir_sensors(struct i2c_client *client)
 141 {
 142         s32 ret;
 143
 144         ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
 145
 146         if (ret < 0)
 147                 return ret;
 148
 149         return (ret & MLX90614_CONFIG_DUAL_MASK) ? 1 : 0;
 150 }
 151
 152 static int mlx90614_probe(struct i2c_client *client,
 153                          const struct i2c_device_id *id)
 154 {
 155         struct iio_dev *indio_dev;
 156         struct mlx90614_data *data;
 157         int ret;
 158
 159         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 160                 return -ENODEV;
 161
 162         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 163         if (!indio_dev)
 164                 return -ENOMEM;
 165
 166         data = iio_priv(indio_dev);
 167         i2c_set_clientdata(client, indio_dev);
 168         data->client = client;
 169
 170         indio_dev->dev.parent = &client->dev;
 171         indio_dev->name = id->name;
 172         indio_dev->modes = INDIO_DIRECT_MODE;
 173         indio_dev->info = &mlx90614_info;
 174
 175         ret = mlx90614_probe_num_ir_sensors(client);
 176         switch (ret) {
 177         case 0:
 178                 dev_dbg(&client->dev, "Found single sensor");
 179                 indio_dev->channels = mlx90614_channels;
 180                 indio_dev->num_channels = 2;
 181                 break;
 182         case 1:
 183                 dev_dbg(&client->dev, "Found dual sensor");
 184                 indio_dev->channels = mlx90614_channels;
 185                 indio_dev->num_channels = 3;
 186                 break;
 187         default:
 188                 return ret;
 189         }
 190
 191         return iio_device_register(indio_dev);
 192 }
 193
 194 static int mlx90614_remove(struct i2c_client *client)
 195 {
 196         iio_device_unregister(i2c_get_clientdata(client));
 197
 198         return 0;
 199 }
 200
 201 static const struct i2c_device_id mlx90614_id[] = {
 202         { "mlx90614", 0 },
 203         { }
 204 };
 205 MODULE_DEVICE_TABLE(i2c, mlx90614_id);
 206
 207 static struct i2c_driver mlx90614_driver = {
 208         .driver = {
 209                 .name   = "mlx90614",
 210                 .owner  = THIS_MODULE,
 211         },
 212         .probe = mlx90614_probe,
 213         .remove = mlx90614_remove,
 214         .id_table = mlx90614_id,
 215 };
 216 module_i2c_driver(mlx90614_driver);
 217
 218 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 219 MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
 220 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
 221 MODULE_LICENSE("GPL");