drivers/iio/temperature/tsys01.c

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