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
  20 #include <linux/iio/iio.h>
  21
  22 #define TMP117_REG_TEMP                 0x0
  23 #define TMP117_REG_CFGR                 0x1
  24 #define TMP117_REG_HIGH_LIM             0x2
  25 #define TMP117_REG_LOW_LIM              0x3
  26 #define TMP117_REG_EEPROM_UL            0x4
  27 #define TMP117_REG_EEPROM1              0x5
  28 #define TMP117_REG_EEPROM2              0x6
  29 #define TMP117_REG_TEMP_OFFSET          0x7
  30 #define TMP117_REG_EEPROM3              0x8
  31 #define TMP117_REG_DEVICE_ID            0xF
  32
  33 #define TMP117_RESOLUTION_10UC          78125
  34 #define TMP117_DEVICE_ID                0x0117
  35 #define MICRODEGREE_PER_10MILLIDEGREE   10000
  36
  37 struct tmp117_data {
  38         struct i2c_client *client;
  39         s16 calibbias;
  40 };
  41
  42 static int tmp117_read_raw(struct iio_dev *indio_dev,
  43                 struct iio_chan_spec const *channel, int *val,
  44                 int *val2, long mask)
  45 {
  46         struct tmp117_data *data = iio_priv(indio_dev);
  47         s32 ret;
  48
  49         switch (mask) {
  50         case IIO_CHAN_INFO_RAW:
  51                 ret = i2c_smbus_read_word_swapped(data->client,
  52                                                 TMP117_REG_TEMP);
  53                 if (ret < 0)
  54                         return ret;
  55                 *val = sign_extend32(ret, 15);
  56                 return IIO_VAL_INT;
  57
  58         case IIO_CHAN_INFO_CALIBBIAS:
  59                 ret = i2c_smbus_read_word_swapped(data->client,
  60                                         TMP117_REG_TEMP_OFFSET);
  61                 if (ret < 0)
  62                         return ret;
  63                 *val = sign_extend32(ret, 15);
  64                 return IIO_VAL_INT;
  65
  66         case IIO_CHAN_INFO_SCALE:
  67                 /*
  68                  * Conversion from 10s of uC to mC
  69                  * as IIO reports temperature in mC
  70                  */
  71                 *val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
  72                 *val2 = (TMP117_RESOLUTION_10UC %
  73                                         MICRODEGREE_PER_10MILLIDEGREE) * 100;
  74
  75                 return IIO_VAL_INT_PLUS_MICRO;
  76
  77         default:
  78                 return -EINVAL;
  79         }
  80 }
  81
  82 static int tmp117_write_raw(struct iio_dev *indio_dev,
  83                 struct iio_chan_spec const *channel, int val,
  84                 int val2, long mask)
  85 {
  86         struct tmp117_data *data = iio_priv(indio_dev);
  87         s16 off;
  88
  89         switch (mask) {
  90         case IIO_CHAN_INFO_CALIBBIAS:
  91                 off = clamp_t(int, val, S16_MIN, S16_MAX);
  92                 if (off == data->calibbias)
  93                         return 0;
  94                 data->calibbias = off;
  95                 return i2c_smbus_write_word_swapped(data->client,
  96                                                 TMP117_REG_TEMP_OFFSET, off);
  97
  98         default:
  99                 return -EINVAL;
 100         }
 101 }
 102
 103 static const struct iio_chan_spec tmp117_channels[] = {
 104         {
 105                 .type = IIO_TEMP,
 106                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 107                         BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_SCALE),
 108         },
 109 };
 110
 111 static const struct iio_info tmp117_info = {
 112         .read_raw = tmp117_read_raw,
 113         .write_raw = tmp117_write_raw,
 114 };
 115
 116 static int tmp117_identify(struct i2c_client *client)
 117 {
 118         int dev_id;
 119
 120         dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
 121         if (dev_id < 0)
 122                 return dev_id;
 123         if (dev_id != TMP117_DEVICE_ID) {
 124                 dev_err(&client->dev, "TMP117 not found\n");
 125                 return -ENODEV;
 126         }
 127         return 0;
 128 }
 129
 130 static int tmp117_probe(struct i2c_client *client)
 131 {
 132         struct tmp117_data *data;
 133         struct iio_dev *indio_dev;
 134         int ret;
 135
 136         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 137                 return -EOPNOTSUPP;
 138
 139         ret = tmp117_identify(client);
 140         if (ret < 0)
 141                 return ret;
 142
 143         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 144         if (!indio_dev)
 145                 return -ENOMEM;
 146
 147         data = iio_priv(indio_dev);
 148         data->client = client;
 149         data->calibbias = 0;
 150
 151         indio_dev->name = "tmp117";
 152         indio_dev->modes = INDIO_DIRECT_MODE;
 153         indio_dev->info = &tmp117_info;
 154
 155         indio_dev->channels = tmp117_channels;
 156         indio_dev->num_channels = ARRAY_SIZE(tmp117_channels);
 157
 158         return devm_iio_device_register(&client->dev, indio_dev);
 159 }
 160
 161 static const struct of_device_id tmp117_of_match[] = {
 162         { .compatible = "ti,tmp117", },
 163         { }
 164 };
 165 MODULE_DEVICE_TABLE(of, tmp117_of_match);
 166
 167 static const struct i2c_device_id tmp117_id[] = {
 168         { "tmp117", 0 },
 169         { }
 170 };
 171 MODULE_DEVICE_TABLE(i2c, tmp117_id);
 172
 173 static struct i2c_driver tmp117_driver = {
 174         .driver = {
 175                 .name   = "tmp117",
 176                 .of_match_table = tmp117_of_match,
 177         },
 178         .probe_new      = tmp117_probe,
 179         .id_table       = tmp117_id,
 180 };
 181 module_i2c_driver(tmp117_driver);
 182
 183 MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
 184 MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
 185 MODULE_LICENSE("GPL");