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         .driver_module = THIS_MODULE,
 115 };
 116
 117 static bool tsys01_crc_valid(u16 *n_prom)
 118 {
 119         u8 cnt;
 120         u8 sum = 0;
 121
 122         for (cnt = 0; cnt < TSYS01_PROM_WORDS_NB; cnt++)
 123                 sum += ((n_prom[0] >> 8) + (n_prom[0] & 0xFF));
 124
 125         return (sum == 0);
 126 }
 127
 128 static int tsys01_read_prom(struct iio_dev *indio_dev)
 129 {
 130         int i, ret;
 131         struct tsys01_dev *dev_data = iio_priv(indio_dev);
 132         char buf[7 * TSYS01_PROM_WORDS_NB + 1];
 133         char *ptr = buf;
 134
 135         for (i = 0; i < TSYS01_PROM_WORDS_NB; i++) {
 136                 ret = dev_data->read_prom_word(dev_data->client,
 137                                                TSYS01_PROM_READ + (i << 1),
 138                                                &dev_data->prom[i]);
 139                 if (ret)
 140                         return ret;
 141
 142                 ret = sprintf(ptr, "0x%04x ", dev_data->prom[i]);
 143                 ptr += ret;
 144         }
 145
 146         if (!tsys01_crc_valid(dev_data->prom)) {
 147                 dev_err(&indio_dev->dev, "prom crc check error\n");
 148                 return -ENODEV;
 149         }
 150         *ptr = 0;
 151         dev_info(&indio_dev->dev, "PROM coefficients : %s\n", buf);
 152
 153         return 0;
 154 }
 155
 156 static int tsys01_probe(struct iio_dev *indio_dev, struct device *dev)
 157 {
 158         int ret;
 159         struct tsys01_dev *dev_data = iio_priv(indio_dev);
 160
 161         mutex_init(&dev_data->lock);
 162
 163         indio_dev->info = &tsys01_info;
 164         indio_dev->name = dev->driver->name;
 165         indio_dev->dev.parent = dev;
 166         indio_dev->modes = INDIO_DIRECT_MODE;
 167         indio_dev->channels = tsys01_channels;
 168         indio_dev->num_channels = ARRAY_SIZE(tsys01_channels);
 169
 170         ret = dev_data->reset(dev_data->client, TSYS01_RESET, 3000);
 171         if (ret)
 172                 return ret;
 173
 174         ret = tsys01_read_prom(indio_dev);
 175         if (ret)
 176                 return ret;
 177
 178         return devm_iio_device_register(dev, indio_dev);
 179 }
 180
 181 static int tsys01_i2c_probe(struct i2c_client *client,
 182                             const struct i2c_device_id *id)
 183 {
 184         struct tsys01_dev *dev_data;
 185         struct iio_dev *indio_dev;
 186
 187         if (!i2c_check_functionality(client->adapter,
 188                                      I2C_FUNC_SMBUS_WORD_DATA |
 189                                      I2C_FUNC_SMBUS_WRITE_BYTE |
 190                                      I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
 191                 dev_err(&client->dev,
 192                         "Adapter does not support some i2c transaction\n");
 193                 return -ENODEV;
 194         }
 195
 196         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
 197         if (!indio_dev)
 198                 return -ENOMEM;
 199
 200         dev_data = iio_priv(indio_dev);
 201         dev_data->client = client;
 202         dev_data->reset = ms_sensors_reset;
 203         dev_data->read_prom_word = ms_sensors_read_prom_word;
 204         dev_data->convert_and_read = ms_sensors_convert_and_read;
 205
 206         i2c_set_clientdata(client, indio_dev);
 207
 208         return tsys01_probe(indio_dev, &client->dev);
 209 }
 210
 211 static const struct i2c_device_id tsys01_id[] = {
 212         {"tsys01", 0},
 213         {}
 214 };
 215 MODULE_DEVICE_TABLE(i2c, tsys01_id);
 216
 217 static struct i2c_driver tsys01_driver = {
 218         .probe = tsys01_i2c_probe,
 219         .id_table = tsys01_id,
 220         .driver = {
 221                    .name = "tsys01",
 222                    },
 223 };
 224
 225 module_i2c_driver(tsys01_driver);
 226
 227 MODULE_DESCRIPTION("Measurement-Specialties tsys01 temperature driver");
 228 MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
 229 MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
 230 MODULE_LICENSE("GPL v2");