drivers/iio/temperature/tsys01.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * tsys01.c - Support for Measurement-Specialties tsys01 temperature sensor
   4  *
   5  * Copyright (c) 2015 Measurement-Specialties
   6  *
   7  * Datasheet:
   8  *  http://www.meas-spec.com/downloads/TSYS01_Digital_Temperature_Sensor.pdf
   9  */
  10
  11 #include <linux/iio/iio.h>
  12 #include <linux/iio/sysfs.h>
  13 #include <linux/device.h>
  14 #include <linux/mutex.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/kernel.h>
  18 #include <linux/stat.h>
  19 #include "../common/ms_sensors/ms_sensors_i2c.h"
  20
  21 /* TSYS01 Commands */
  22 #define TSYS01_RESET                            0x1E
  23 #define TSYS01_CONVERSION_START                 0x48
  24 #define TSYS01_ADC_READ                         0x00
  25 #define TSYS01_PROM_READ                        0xA0
  26
  27 #define TSYS01_PROM_WORDS_NB                    8
  28
  29 struct tsys01_dev {
  30         void *client;
  31         struct mutex lock; /* lock during conversion */
  32
  33         int (*reset)(void *cli, u8 cmd, unsigned int delay);
  34         int (*convert_and_read)(void *cli, u8 conv, u8 rd,
  35                                 unsigned int delay, u32 *adc);
  36         int (*read_prom_word)(void *cli, int cmd, u16 *word);
  37
  38         u16 prom[TSYS01_PROM_WORDS_NB];
  39 };
  40
  41 /* Multiplication coefficients for temperature computation */
  42 static const int coeff_mul[] = { -1500000, 1000000, -2000000,
  43                                  4000000, -2000000 };
  44
  45 static int tsys01_read_temperature(struct iio_dev *indio_dev,
  46                                    s32 *temperature)
  47 {
  48         int ret, i;
  49         u32 adc;
  50         s64 temp = 0;
  51         struct tsys01_dev *dev_data = iio_priv(indio_dev);
  52
  53         mutex_lock(&dev_data->lock);
  54         ret = dev_data->convert_and_read(dev_data->client,
  55                                          TSYS01_CONVERSION_START,
  56                                          TSYS01_ADC_READ, 9000, &adc);
  57         mutex_unlock(&dev_data->lock);
  58         if (ret)
  59                 return ret;
  60
  61         adc >>= 8;
  62
  63         /* Temperature algorithm */
  64         for (i = 4; i > 0; i--) {
  65                 temp += coeff_mul[i] *
  66                         (s64)dev_data->prom[5 - i];
  67                 temp *= (s64)adc;
  68                 temp = div64_s64(temp, 100000);
  69         }
  70         temp *= 10;
  71         temp += coeff_mul[0] * (s64)dev_data->prom[5];
  72         temp = div64_s64(temp, 100000);
  73
  74         *temperature = temp;
  75
  76         return 0;
  77 }
  78
  79 static int tsys01_read_raw(struct iio_dev *indio_dev,
  80                            struct iio_chan_spec const *channel, int *val,
  81                            int *val2, long mask)
  82 {
  83         int ret;
  84         s32 temperature;
  85
  86         switch (mask) {
  87         case IIO_CHAN_INFO_PROCESSED:
  88                 switch (channel->type) {
  89                 case IIO_TEMP:  /* in milli °C */
  90                         ret = tsys01_read_temperature(indio_dev, &temperature);
  91                         if (ret)
  92                                 return ret;
  93                         *val = temperature;
  94
  95                         return IIO_VAL_INT;
  96                 default:
  97                         return -EINVAL;
  98                 }
  99         default:
 100                 return -EINVAL;
 101         }
 102 }
 103
 104 static const struct iio_chan_spec tsys01_channels[] = {
 105         {
 106                 .type = IIO_TEMP,
 107                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
 108         }
 109 };
 110
 111 static const struct iio_info tsys01_info = {
 112         .read_raw = tsys01_read_raw,
 113 };
 114
 115 static bool tsys01_crc_valid(u16 *n_prom)
 116 {
 117         u8 cnt;
 118         u8 sum = 0;
 119
 120         for (cnt = 0; cnt < TSYS01_PROM_WORDS_NB; cnt++)
 121                 sum += ((n_prom[0] >> 8) + (n_prom[0] & 0xFF));
 122
 123         return (sum == 0);
 124 }
 125
 126 static int tsys01_read_prom(struct iio_dev *indio_dev)
 127 {
 128         int i, ret;
 129         struct tsys01_dev *dev_data = iio_priv(indio_dev);
 130         char buf[7 * TSYS01_PROM_WORDS_NB + 1];
 131         char *ptr = buf;
 132
 133         for (i = 0; i < TSYS01_PROM_WORDS_NB; i++) {
 134                 ret = dev_data->read_prom_word(dev_data->client,
 135                                                TSYS01_PROM_READ + (i << 1),
 136                                                &dev_data->prom[i]);
 137                 if (ret)
 138                         return ret;
 139
 140                 ret = sprintf(ptr, "0x%04x ", dev_data->prom[i]);
 141                 ptr += ret;
 142         }
 143
 144         if (!tsys01_crc_valid(dev_data->prom)) {
 145                 dev_err(&indio_dev->dev, "prom crc check error\n");
 146                 return -ENODEV;
 147         }
 148         *ptr = 0;
 149         dev_info(&indio_dev->dev, "PROM coefficients : %s\n", buf);
 150
 151         return 0;
 152 }
 153
 154 static int tsys01_probe(struct iio_dev *indio_dev, struct device *dev)
 155 {
 156         int ret;
 157         struct tsys01_dev *dev_data = iio_priv(indio_dev);
 158
 159         mutex_init(&dev_data->lock);
 160
 161         indio_dev->info = &tsys01_info;
 162         indio_dev->name = dev->driver->name;
 163         indio_dev->dev.parent = dev;
 164         indio_dev->modes = INDIO_DIRECT_MODE;
 165         indio_dev->channels = tsys01_channels;
 166         indio_dev->num_channels = ARRAY_SIZE(tsys01_channels);
 167
 168         ret = dev_data->reset(dev_data->client, TSYS01_RESET, 3000);
 169         if (ret)
 170                 return ret;
 171
 172         ret = tsys01_read_prom(indio_dev);
 173         if (ret)
 174                 return ret;
 175
 176         return devm_iio_device_register(dev, indio_dev);
 177 }
 178
 179 static int tsys01_i2c_probe(struct i2c_client *client,
 180                             const struct i2c_device_id *id)
 181 {
 182         struct tsys01_dev *dev_data;
 183         struct iio_dev *indio_dev;
 184
 185         if (!i2c_check_functionality(client->adapter,
 186                                      I2C_FUNC_SMBUS_WORD_DATA |
 187                                      I2C_FUNC_SMBUS_WRITE_BYTE |
 188                                      I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
 189                 dev_err(&client->dev,
 190                         "Adapter does not support some i2c transaction\n");
 191                 return -EOPNOTSUPP;
 192         }
 193
 194         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
 195         if (!indio_dev)
 196                 return -ENOMEM;
 197
 198         dev_data = iio_priv(indio_dev);
 199         dev_data->client = client;
 200         dev_data->reset = ms_sensors_reset;
 201         dev_data->read_prom_word = ms_sensors_read_prom_word;
 202         dev_data->convert_and_read = ms_sensors_convert_and_read;
 203
 204         i2c_set_clientdata(client, indio_dev);
 205
 206         return tsys01_probe(indio_dev, &client->dev);
 207 }
 208
 209 static const struct i2c_device_id tsys01_id[] = {
 210         {"tsys01", 0},
 211         {}
 212 };
 213 MODULE_DEVICE_TABLE(i2c, tsys01_id);
 214
 215 static const struct of_device_id tsys01_of_match[] = {
 216         { .compatible = "meas,tsys01", },
 217         { },
 218 };
 219 MODULE_DEVICE_TABLE(of, tsys01_of_match);
 220
 221 static struct i2c_driver tsys01_driver = {
 222         .probe = tsys01_i2c_probe,
 223         .id_table = tsys01_id,
 224         .driver = {
 225                    .name = "tsys01",
 226                    .of_match_table = of_match_ptr(tsys01_of_match),
 227                    },
 228 };
 229
 230 module_i2c_driver(tsys01_driver);
 231
 232 MODULE_DESCRIPTION("Measurement-Specialties tsys01 temperature driver");
 233 MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
 234 MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
 235 MODULE_LICENSE("GPL v2");