drivers/iio/temperature/tmp117.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Digital temperature sensor with integrated Non-volatile memory
   4  * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
   5  *
   6  * Driver for the Texas Instruments TMP117 Temperature Sensor
   7  * (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins)
   8  *
   9  * Note: This driver assumes that the sensor has been calibrated beforehand.
  10  */
  11
  12 #include <linux/err.h>
  13 #include <linux/i2c.h>
  14 #include <linux/module.h>
  15 #include <linux/bitops.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/limits.h>
  19 #include <linux/property.h>
  20
  21 #include <linux/iio/iio.h>
  22
  23 #define TMP117_REG_TEMP                 0x0
  24 #define TMP117_REG_CFGR                 0x1
  25 #define TMP117_REG_HIGH_LIM             0x2
  26 #define TMP117_REG_LOW_LIM              0x3
  27 #define TMP117_REG_EEPROM_UL            0x4
  28 #define TMP117_REG_EEPROM1              0x5
  29 #define TMP117_REG_EEPROM2              0x6
  30 #define TMP117_REG_TEMP_OFFSET          0x7
  31 #define TMP117_REG_EEPROM3              0x8
  32 #define TMP117_REG_DEVICE_ID            0xF
  33
  34 #define TMP117_RESOLUTION_10UC          78125
  35 #define MICRODEGREE_PER_10MILLIDEGREE   10000
  36
  37 #define TMP116_DEVICE_ID                0x1116
  38 #define TMP117_DEVICE_ID                0x0117
  39
  40 struct tmp117_data {
  41         struct i2c_client *client;
  42         s16 calibbias;
  43 };
  44
  45 static int tmp117_read_raw(struct iio_dev *indio_dev,
  46                            struct iio_chan_spec const *channel, int *val,
  47                            int *val2, long mask)
  48 {
  49         struct tmp117_data *data = iio_priv(indio_dev);
  50         s32 ret;
  51
  52         switch (mask) {
  53         case IIO_CHAN_INFO_RAW:
  54                 ret = i2c_smbus_read_word_swapped(data->client,
  55                                                   TMP117_REG_TEMP);
  56                 if (ret < 0)
  57                         return ret;
  58                 *val = sign_extend32(ret, 15);
  59                 return IIO_VAL_INT;
  60
  61         case IIO_CHAN_INFO_CALIBBIAS:
  62                 ret = i2c_smbus_read_word_swapped(data->client,
  63                                                   TMP117_REG_TEMP_OFFSET);
  64                 if (ret < 0)
  65                         return ret;
  66                 *val = sign_extend32(ret, 15);
  67                 return IIO_VAL_INT;
  68
  69         case IIO_CHAN_INFO_SCALE:
  70                 /*
  71                  * Conversion from 10s of uC to mC
  72                  * as IIO reports temperature in mC
  73                  */
  74                 *val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
  75                 *val2 = (TMP117_RESOLUTION_10UC %
  76                                         MICRODEGREE_PER_10MILLIDEGREE) * 100;
  77
  78                 return IIO_VAL_INT_PLUS_MICRO;
  79
  80         default:
  81                 return -EINVAL;
  82         }
  83 }
  84
  85 static int tmp117_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec
  86                             const *channel, int val, int val2, long mask)
  87 {
  88         struct tmp117_data *data = iio_priv(indio_dev);
  89         s16 off;
  90
  91         switch (mask) {
  92         case IIO_CHAN_INFO_CALIBBIAS:
  93                 off = clamp_t(int, val, S16_MIN, S16_MAX);
  94                 if (off == data->calibbias)
  95                         return 0;
  96                 data->calibbias = off;
  97                 return i2c_smbus_write_word_swapped(data->client,
  98                                                 TMP117_REG_TEMP_OFFSET, off);
  99
 100         default:
 101                 return -EINVAL;
 102         }
 103 }
 104
 105 static const struct iio_chan_spec tmp117_channels[] = {
 106         {
 107                 .type = IIO_TEMP,
 108                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 109                                       BIT(IIO_CHAN_INFO_CALIBBIAS) |
 110                                       BIT(IIO_CHAN_INFO_SCALE),
 111         },
 112 };
 113
 114 static const struct iio_chan_spec tmp116_channels[] = {
 115         {
 116                 .type = IIO_TEMP,
 117                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 118                                       BIT(IIO_CHAN_INFO_SCALE),
 119         },
 120 };
 121
 122 static const struct iio_info tmp117_info = {
 123         .read_raw = tmp117_read_raw,
 124         .write_raw = tmp117_write_raw,
 125 };
 126
 127 static int tmp117_identify(struct i2c_client *client)
 128 {
 129         const struct i2c_device_id *id;
 130         unsigned long match_data;
 131         int dev_id;
 132
 133         dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
 134         if (dev_id < 0)
 135                 return dev_id;
 136
 137         switch (dev_id) {
 138         case TMP116_DEVICE_ID:
 139         case TMP117_DEVICE_ID:
 140                 return dev_id;
 141         }
 142
 143         dev_info(&client->dev, "Unknown device id (0x%x), use fallback compatible\n",
 144                  dev_id);
 145
 146         match_data = (uintptr_t)device_get_match_data(&client->dev);
 147         if (match_data)
 148                 return match_data;
 149
 150         id = i2c_client_get_device_id(client);
 151         if (id)
 152                 return id->driver_data;
 153
 154         dev_err(&client->dev, "Failed to identify unsupported device\n");
 155
 156         return -ENODEV;
 157 }
 158
 159 static int tmp117_probe(struct i2c_client *client)
 160 {
 161         struct tmp117_data *data;
 162         struct iio_dev *indio_dev;
 163         int ret, dev_id;
 164
 165         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 166                 return -EOPNOTSUPP;
 167
 168         ret = tmp117_identify(client);
 169         if (ret < 0)
 170                 return ret;
 171
 172         dev_id = ret;
 173
 174         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 175         if (!indio_dev)
 176                 return -ENOMEM;
 177
 178         data = iio_priv(indio_dev);
 179         data->client = client;
 180         data->calibbias = 0;
 181
 182         indio_dev->modes = INDIO_DIRECT_MODE;
 183         indio_dev->info = &tmp117_info;
 184
 185         switch (dev_id) {
 186         case TMP116_DEVICE_ID:
 187                 indio_dev->channels = tmp116_channels;
 188                 indio_dev->num_channels = ARRAY_SIZE(tmp116_channels);
 189                 indio_dev->name = "tmp116";
 190                 break;
 191         case TMP117_DEVICE_ID:
 192                 indio_dev->channels = tmp117_channels;
 193                 indio_dev->num_channels = ARRAY_SIZE(tmp117_channels);
 194                 indio_dev->name = "tmp117";
 195                 break;
 196         }
 197
 198         return devm_iio_device_register(&client->dev, indio_dev);
 199 }
 200
 201 static const struct of_device_id tmp117_of_match[] = {
 202         { .compatible = "ti,tmp116", .data = (void *)TMP116_DEVICE_ID },
 203         { .compatible = "ti,tmp117", .data = (void *)TMP117_DEVICE_ID },
 204         { }
 205 };
 206 MODULE_DEVICE_TABLE(of, tmp117_of_match);
 207
 208 static const struct i2c_device_id tmp117_id[] = {
 209         { "tmp116", TMP116_DEVICE_ID },
 210         { "tmp117", TMP117_DEVICE_ID },
 211         { }
 212 };
 213 MODULE_DEVICE_TABLE(i2c, tmp117_id);
 214
 215 static struct i2c_driver tmp117_driver = {
 216         .driver = {
 217                 .name   = "tmp117",
 218                 .of_match_table = tmp117_of_match,
 219         },
 220         .probe_new      = tmp117_probe,
 221         .id_table       = tmp117_id,
 222 };
 223 module_i2c_driver(tmp117_driver);
 224
 225 MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
 226 MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
 227 MODULE_LICENSE("GPL");