drivers/iio/pressure/ms5611_core.c

   1 /*
   2  * MS5611 pressure and temperature sensor driver
   3  *
   4  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Data sheet:
  11  *  http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
  12  *  http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/iio/iio.h>
  18 #include <linux/delay.h>
  19 #include <linux/regulator/consumer.h>
  20
  21 #include <linux/iio/buffer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23 #include <linux/iio/trigger_consumer.h>
  24 #include "ms5611.h"
  25
  26 static bool ms5611_prom_is_valid(u16 *prom, size_t len)
  27 {
  28         int i, j;
  29         uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
  30
  31         prom[7] &= 0xFF00;
  32
  33         for (i = 0; i < len * 2; i++) {
  34                 if (i % 2 == 1)
  35                         crc ^= prom[i >> 1] & 0x00FF;
  36                 else
  37                         crc ^= prom[i >> 1] >> 8;
  38
  39                 for (j = 0; j < 8; j++) {
  40                         if (crc & 0x8000)
  41                                 crc = (crc << 1) ^ 0x3000;
  42                         else
  43                                 crc <<= 1;
  44                 }
  45         }
  46
  47         crc = (crc >> 12) & 0x000F;
  48
  49         return crc_orig != 0x0000 && crc == crc_orig;
  50 }
  51
  52 static int ms5611_read_prom(struct iio_dev *indio_dev)
  53 {
  54         int ret, i;
  55         struct ms5611_state *st = iio_priv(indio_dev);
  56
  57         for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
  58                 ret = st->read_prom_word(&indio_dev->dev,
  59                                          i, &st->chip_info->prom[i]);
  60                 if (ret < 0) {
  61                         dev_err(&indio_dev->dev,
  62                                 "failed to read prom at %d\n", i);
  63                         return ret;
  64                 }
  65         }
  66
  67         if (!ms5611_prom_is_valid(st->chip_info->prom, MS5611_PROM_WORDS_NB)) {
  68                 dev_err(&indio_dev->dev, "PROM integrity check failed\n");
  69                 return -ENODEV;
  70         }
  71
  72         return 0;
  73 }
  74
  75 static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
  76                                          s32 *temp, s32 *pressure)
  77 {
  78         int ret;
  79         struct ms5611_state *st = iio_priv(indio_dev);
  80
  81         ret = st->read_adc_temp_and_pressure(&indio_dev->dev, temp, pressure);
  82         if (ret < 0) {
  83                 dev_err(&indio_dev->dev,
  84                         "failed to read temperature and pressure\n");
  85                 return ret;
  86         }
  87
  88         return st->chip_info->temp_and_pressure_compensate(st->chip_info,
  89                                                            temp, pressure);
  90 }
  91
  92 static int ms5611_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
  93                                                s32 *temp, s32 *pressure)
  94 {
  95         s32 t = *temp, p = *pressure;
  96         s64 off, sens, dt;
  97
  98         dt = t - (chip_info->prom[5] << 8);
  99         off = ((s64)chip_info->prom[2] << 16) + ((chip_info->prom[4] * dt) >> 7);
 100         sens = ((s64)chip_info->prom[1] << 15) + ((chip_info->prom[3] * dt) >> 8);
 101
 102         t = 2000 + ((chip_info->prom[6] * dt) >> 23);
 103         if (t < 2000) {
 104                 s64 off2, sens2, t2;
 105
 106                 t2 = (dt * dt) >> 31;
 107                 off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
 108                 sens2 = off2 >> 1;
 109
 110                 if (t < -1500) {
 111                         s64 tmp = (t + 1500) * (t + 1500);
 112
 113                         off2 += 7 * tmp;
 114                         sens2 += (11 * tmp) >> 1;
 115                 }
 116
 117                 t -= t2;
 118                 off -= off2;
 119                 sens -= sens2;
 120         }
 121
 122         *temp = t;
 123         *pressure = (((p * sens) >> 21) - off) >> 15;
 124
 125         return 0;
 126 }
 127
 128 static int ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
 129                                                s32 *temp, s32 *pressure)
 130 {
 131         s32 t = *temp, p = *pressure;
 132         s64 off, sens, dt;
 133
 134         dt = t - (chip_info->prom[5] << 8);
 135         off = ((s64)chip_info->prom[2] << 17) + ((chip_info->prom[4] * dt) >> 6);
 136         sens = ((s64)chip_info->prom[1] << 16) + ((chip_info->prom[3] * dt) >> 7);
 137
 138         t = 2000 + ((chip_info->prom[6] * dt) >> 23);
 139         if (t < 2000) {
 140                 s64 off2, sens2, t2, tmp;
 141
 142                 t2 = (dt * dt) >> 31;
 143                 tmp = (t - 2000) * (t - 2000);
 144                 off2 = (61 * tmp) >> 4;
 145                 sens2 = tmp << 1;
 146
 147                 if (t < -1500) {
 148                         tmp = (t + 1500) * (t + 1500);
 149                         off2 += 15 * tmp;
 150                         sens2 += 8 * tmp;
 151                 }
 152
 153                 t -= t2;
 154                 off -= off2;
 155                 sens -= sens2;
 156         }
 157
 158         *temp = t;
 159         *pressure = (((p * sens) >> 21) - off) >> 15;
 160
 161         return 0;
 162 }
 163
 164 static int ms5611_reset(struct iio_dev *indio_dev)
 165 {
 166         int ret;
 167         struct ms5611_state *st = iio_priv(indio_dev);
 168
 169         ret = st->reset(&indio_dev->dev);
 170         if (ret < 0) {
 171                 dev_err(&indio_dev->dev, "failed to reset device\n");
 172                 return ret;
 173         }
 174
 175         usleep_range(3000, 4000);
 176
 177         return 0;
 178 }
 179
 180 static irqreturn_t ms5611_trigger_handler(int irq, void *p)
 181 {
 182         struct iio_poll_func *pf = p;
 183         struct iio_dev *indio_dev = pf->indio_dev;
 184         struct ms5611_state *st = iio_priv(indio_dev);
 185         s32 buf[4]; /* s32 (pressure) + s32 (temp) + 2 * s32 (timestamp) */
 186         int ret;
 187
 188         mutex_lock(&st->lock);
 189         ret = ms5611_read_temp_and_pressure(indio_dev, &buf[1], &buf[0]);
 190         mutex_unlock(&st->lock);
 191         if (ret < 0)
 192                 goto err;
 193
 194         iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
 195
 196 err:
 197         iio_trigger_notify_done(indio_dev->trig);
 198
 199         return IRQ_HANDLED;
 200 }
 201
 202 static int ms5611_read_raw(struct iio_dev *indio_dev,
 203                            struct iio_chan_spec const *chan,
 204                            int *val, int *val2, long mask)
 205 {
 206         int ret;
 207         s32 temp, pressure;
 208         struct ms5611_state *st = iio_priv(indio_dev);
 209
 210         switch (mask) {
 211         case IIO_CHAN_INFO_PROCESSED:
 212                 mutex_lock(&st->lock);
 213                 ret = ms5611_read_temp_and_pressure(indio_dev,
 214                                                     &temp, &pressure);
 215                 mutex_unlock(&st->lock);
 216                 if (ret < 0)
 217                         return ret;
 218
 219                 switch (chan->type) {
 220                 case IIO_TEMP:
 221                         *val = temp * 10;
 222                         return IIO_VAL_INT;
 223                 case IIO_PRESSURE:
 224                         *val = pressure / 1000;
 225                         *val2 = (pressure % 1000) * 1000;
 226                         return IIO_VAL_INT_PLUS_MICRO;
 227                 default:
 228                         return -EINVAL;
 229                 }
 230         case IIO_CHAN_INFO_SCALE:
 231                 switch (chan->type) {
 232                 case IIO_TEMP:
 233                         *val = 10;
 234                         return IIO_VAL_INT;
 235                 case IIO_PRESSURE:
 236                         *val = 0;
 237                         *val2 = 1000;
 238                         return IIO_VAL_INT_PLUS_MICRO;
 239                 default:
 240                         return -EINVAL;
 241                 }
 242         }
 243
 244         return -EINVAL;
 245 }
 246
 247 static const unsigned long ms5611_scan_masks[] = {0x3, 0};
 248
 249 static struct ms5611_chip_info chip_info_tbl[] = {
 250         [MS5611] = {
 251                 .temp_and_pressure_compensate = ms5611_temp_and_pressure_compensate,
 252         },
 253         [MS5607] = {
 254                 .temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate,
 255         }
 256 };
 257
 258 static const struct iio_chan_spec ms5611_channels[] = {
 259         {
 260                 .type = IIO_PRESSURE,
 261                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 262                         BIT(IIO_CHAN_INFO_SCALE),
 263                 .scan_index = 0,
 264                 .scan_type = {
 265                         .sign = 's',
 266                         .realbits = 32,
 267                         .storagebits = 32,
 268                         .endianness = IIO_CPU,
 269                 },
 270         },
 271         {
 272                 .type = IIO_TEMP,
 273                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 274                         BIT(IIO_CHAN_INFO_SCALE),
 275                 .scan_index = 1,
 276                 .scan_type = {
 277                         .sign = 's',
 278                         .realbits = 32,
 279                         .storagebits = 32,
 280                         .endianness = IIO_CPU,
 281                 },
 282         },
 283         IIO_CHAN_SOFT_TIMESTAMP(2),
 284 };
 285
 286 static const struct iio_info ms5611_info = {
 287         .read_raw = &ms5611_read_raw,
 288         .driver_module = THIS_MODULE,
 289 };
 290
 291 static int ms5611_init(struct iio_dev *indio_dev)
 292 {
 293         int ret;
 294         struct regulator *vdd = devm_regulator_get(indio_dev->dev.parent,
 295                                                    "vdd");
 296
 297         /* Enable attached regulator if any. */
 298         if (!IS_ERR(vdd)) {
 299                 ret = regulator_enable(vdd);
 300                 if (ret) {
 301                         dev_err(indio_dev->dev.parent,
 302                                 "failed to enable Vdd supply: %d\n", ret);
 303                         return ret;
 304                 }
 305         }
 306
 307         ret = ms5611_reset(indio_dev);
 308         if (ret < 0)
 309                 return ret;
 310
 311         return ms5611_read_prom(indio_dev);
 312 }
 313
 314 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
 315                  const char *name, int type)
 316 {
 317         int ret;
 318         struct ms5611_state *st = iio_priv(indio_dev);
 319
 320         mutex_init(&st->lock);
 321         st->chip_info = &chip_info_tbl[type];
 322         indio_dev->dev.parent = dev;
 323         indio_dev->name = name;
 324         indio_dev->info = &ms5611_info;
 325         indio_dev->channels = ms5611_channels;
 326         indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
 327         indio_dev->modes = INDIO_DIRECT_MODE;
 328         indio_dev->available_scan_masks = ms5611_scan_masks;
 329
 330         ret = ms5611_init(indio_dev);
 331         if (ret < 0)
 332                 return ret;
 333
 334         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 335                                          ms5611_trigger_handler, NULL);
 336         if (ret < 0) {
 337                 dev_err(dev, "iio triggered buffer setup failed\n");
 338                 return ret;
 339         }
 340
 341         ret = iio_device_register(indio_dev);
 342         if (ret < 0) {
 343                 dev_err(dev, "unable to register iio device\n");
 344                 goto err_buffer_cleanup;
 345         }
 346
 347         return 0;
 348
 349 err_buffer_cleanup:
 350         iio_triggered_buffer_cleanup(indio_dev);
 351
 352         return ret;
 353 }
 354 EXPORT_SYMBOL(ms5611_probe);
 355
 356 int ms5611_remove(struct iio_dev *indio_dev)
 357 {
 358         iio_device_unregister(indio_dev);
 359         iio_triggered_buffer_cleanup(indio_dev);
 360
 361         return 0;
 362 }
 363 EXPORT_SYMBOL(ms5611_remove);
 364
 365 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 366 MODULE_DESCRIPTION("MS5611 core driver");
 367 MODULE_LICENSE("GPL v2");