drivers/staging/iio/magnetometer/hmc5843.c

   1 /*  Copyright (C) 2010 Texas Instruments
   2     Author: Shubhrajyoti Datta <shubhrajyoti@ti.com>
   3     Acknowledgement: Jonathan Cameron <jic23@cam.ac.uk> for valuable inputs.
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/i2c.h>
  23 #include <linux/slab.h>
  24 #include <linux/types.h>
  25 #include "../iio.h"
  26 #include "../sysfs.h"
  27
  28 #define HMC5843_I2C_ADDRESS                     0x1E
  29
  30 #define HMC5843_CONFIG_REG_A                    0x00
  31 #define HMC5843_CONFIG_REG_B                    0x01
  32 #define HMC5843_MODE_REG                        0x02
  33 #define HMC5843_DATA_OUT_X_MSB_REG              0x03
  34 #define HMC5843_DATA_OUT_X_LSB_REG              0x04
  35 #define HMC5843_DATA_OUT_Y_MSB_REG              0x05
  36 #define HMC5843_DATA_OUT_Y_LSB_REG              0x06
  37 #define HMC5843_DATA_OUT_Z_MSB_REG              0x07
  38 #define HMC5843_DATA_OUT_Z_LSB_REG              0x08
  39 #define HMC5843_STATUS_REG                      0x09
  40 #define HMC5843_ID_REG_A                        0x0A
  41 #define HMC5843_ID_REG_B                        0x0B
  42 #define HMC5843_ID_REG_C                        0x0C
  43
  44 #define HMC5843_ID_REG_LENGTH                   0x03
  45 #define HMC5843_ID_STRING                       "H43"
  46
  47 /*
  48  * Range settings in  (+-)Ga
  49  * */
  50 #define RANGE_GAIN_OFFSET                       0x05
  51
  52 #define RANGE_0_7                               0x00
  53 #define RANGE_1_0                               0x01 /* default */
  54 #define RANGE_1_5                               0x02
  55 #define RANGE_2_0                               0x03
  56 #define RANGE_3_2                               0x04
  57 #define RANGE_3_8                               0x05
  58 #define RANGE_4_5                               0x06
  59 #define RANGE_6_5                               0x07 /* Not recommended */
  60
  61 /*
  62  * Device status
  63  */
  64 #define DATA_READY                              0x01
  65 #define DATA_OUTPUT_LOCK                        0x02
  66 #define VOLTAGE_REGULATOR_ENABLED               0x04
  67
  68 /*
  69  * Mode register configuration
  70  */
  71 #define MODE_CONVERSION_CONTINUOUS              0x00
  72 #define MODE_CONVERSION_SINGLE                  0x01
  73 #define MODE_IDLE                               0x02
  74 #define MODE_SLEEP                              0x03
  75
  76 /* Minimum Data Output Rate in 1/10 Hz  */
  77 #define RATE_OFFSET                             0x02
  78 #define RATE_BITMASK                            0x1C
  79 #define RATE_5                                  0x00
  80 #define RATE_10                                 0x01
  81 #define RATE_20                                 0x02
  82 #define RATE_50                                 0x03
  83 #define RATE_100                                0x04
  84 #define RATE_200                                0x05
  85 #define RATE_500                                0x06
  86 #define RATE_NOT_USED                           0x07
  87
  88 /*
  89  * Device Configutration
  90  */
  91 #define CONF_NORMAL                             0x00
  92 #define CONF_POSITIVE_BIAS                      0x01
  93 #define CONF_NEGATIVE_BIAS                      0x02
  94 #define CONF_NOT_USED                           0x03
  95 #define MEAS_CONF_MASK                          0x03
  96
  97 static int hmc5843_regval_to_nanoscale[] = {
  98         6173, 7692, 10309, 12821, 18868, 21739, 25641, 35714
  99 };
 100
 101 static const int regval_to_input_field_mg[] = {
 102         700,
 103         1000,
 104         1500,
 105         2000,
 106         3200,
 107         3800,
 108         4500,
 109         6500
 110 };
 111 static const char * const regval_to_samp_freq[] = {
 112         "0.5",
 113         "1",
 114         "2",
 115         "5",
 116         "10",
 117         "20",
 118         "50",
 119 };
 120
 121 /* Addresses to scan: 0x1E */
 122 static const unsigned short normal_i2c[] = { HMC5843_I2C_ADDRESS,
 123                                                         I2C_CLIENT_END };
 124
 125 /* Each client has this additional data */
 126 struct hmc5843_data {
 127         struct mutex lock;
 128         u8              rate;
 129         u8              meas_conf;
 130         u8              operating_mode;
 131         u8              range;
 132 };
 133
 134 static void hmc5843_init_client(struct i2c_client *client);
 135
 136 static s32 hmc5843_configure(struct i2c_client *client,
 137                                        u8 operating_mode)
 138 {
 139         /* The lower two bits contain the current conversion mode */
 140         return i2c_smbus_write_byte_data(client,
 141                                         HMC5843_MODE_REG,
 142                                         (operating_mode & 0x03));
 143 }
 144
 145 /* Return the measurement value from the  specified channel */
 146 static int hmc5843_read_measurement(struct iio_dev *indio_dev,
 147                                     int address,
 148                                     int *val)
 149 {
 150         struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
 151         struct hmc5843_data *data = iio_priv(indio_dev);
 152         s32 result;
 153
 154         mutex_lock(&data->lock);
 155         result = i2c_smbus_read_byte_data(client, HMC5843_STATUS_REG);
 156         while (!(result & DATA_READY))
 157                 result = i2c_smbus_read_byte_data(client, HMC5843_STATUS_REG);
 158
 159         result = i2c_smbus_read_word_data(client, address);
 160         mutex_unlock(&data->lock);
 161         if (result < 0)
 162                 return -EINVAL;
 163
 164         *val    = (s16)swab16((u16)result);
 165         return IIO_VAL_INT;
 166 }
 167
 168
 169 /*
 170  * From the datasheet
 171  * 0 - Continuous-Conversion Mode: In continuous-conversion mode, the
 172  * device continuously performs conversions an places the result in the
 173  * data register.
 174  *
 175  * 1 - Single-Conversion Mode : device performs a single measurement,
 176  *  sets RDY high and returned to sleep mode
 177  *
 178  * 2 - Idle Mode :  Device is placed in idle mode.
 179  *
 180  * 3 - Sleep Mode. Device is placed in sleep mode.
 181  *
 182  */
 183 static ssize_t hmc5843_show_operating_mode(struct device *dev,
 184                                         struct device_attribute *attr,
 185                                         char *buf)
 186 {
 187         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 188         struct hmc5843_data *data = iio_priv(indio_dev);
 189         return sprintf(buf, "%d\n", data->operating_mode);
 190 }
 191
 192 static ssize_t hmc5843_set_operating_mode(struct device *dev,
 193                                 struct device_attribute *attr,
 194                                 const char *buf,
 195                                 size_t count)
 196 {
 197         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 198         struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
 199         struct hmc5843_data *data = iio_priv(indio_dev);
 200         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 201         unsigned long operating_mode = 0;
 202         s32 status;
 203         int error;
 204         mutex_lock(&data->lock);
 205         error = strict_strtoul(buf, 10, &operating_mode);
 206         if (error) {
 207                 count = error;
 208                 goto exit;
 209         }
 210         dev_dbg(dev, "set Conversion mode to %lu\n", operating_mode);
 211         if (operating_mode > MODE_SLEEP) {
 212                 count = -EINVAL;
 213                 goto exit;
 214         }
 215
 216         status = i2c_smbus_write_byte_data(client, this_attr->address,
 217                                         operating_mode);
 218         if (status) {
 219                 count = -EINVAL;
 220                 goto exit;
 221         }
 222         data->operating_mode = operating_mode;
 223
 224 exit:
 225         mutex_unlock(&data->lock);
 226         return count;
 227 }
 228 static IIO_DEVICE_ATTR(operating_mode,
 229                         S_IWUSR | S_IRUGO,
 230                         hmc5843_show_operating_mode,
 231                         hmc5843_set_operating_mode,
 232                         HMC5843_MODE_REG);
 233
 234 /*
 235  * API for setting the measurement configuration to
 236  * Normal, Positive bias and Negative bias
 237  * From the datasheet
 238  *
 239  * Normal measurement configuration (default): In normal measurement
 240  * configuration the device follows normal measurement flow. Pins BP and BN
 241  * are left floating and high impedance.
 242  *
 243  * Positive bias configuration: In positive bias configuration, a positive
 244  * current is forced across the resistive load on pins BP and BN.
 245  *
 246  * Negative bias configuration. In negative bias configuration, a negative
 247  * current is forced across the resistive load on pins BP and BN.
 248  *
 249  */
 250 static s32 hmc5843_set_meas_conf(struct i2c_client *client,
 251                                       u8 meas_conf)
 252 {
 253         struct hmc5843_data *data = i2c_get_clientdata(client);
 254         u8 reg_val;
 255         reg_val = (meas_conf & MEAS_CONF_MASK) |  (data->rate << RATE_OFFSET);
 256         return i2c_smbus_write_byte_data(client, HMC5843_CONFIG_REG_A, reg_val);
 257 }
 258
 259 static ssize_t hmc5843_show_measurement_configuration(struct device *dev,
 260                                                 struct device_attribute *attr,
 261                                                 char *buf)
 262 {
 263         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 264         struct hmc5843_data *data = iio_priv(indio_dev);
 265         return sprintf(buf, "%d\n", data->meas_conf);
 266 }
 267
 268 static ssize_t hmc5843_set_measurement_configuration(struct device *dev,
 269                                                 struct device_attribute *attr,
 270                                                 const char *buf,
 271                                                 size_t count)
 272 {
 273         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 274         struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
 275         struct hmc5843_data *data = i2c_get_clientdata(client);
 276         unsigned long meas_conf = 0;
 277         int error = strict_strtoul(buf, 10, &meas_conf);
 278         if (error)
 279                 return error;
 280         mutex_lock(&data->lock);
 281
 282         dev_dbg(dev, "set mode to %lu\n", meas_conf);
 283         if (hmc5843_set_meas_conf(client, meas_conf)) {
 284                 count = -EINVAL;
 285                 goto exit;
 286         }
 287         data->meas_conf = meas_conf;
 288
 289 exit:
 290         mutex_unlock(&data->lock);
 291         return count;
 292 }
 293 static IIO_DEVICE_ATTR(meas_conf,
 294                         S_IWUSR | S_IRUGO,
 295                         hmc5843_show_measurement_configuration,
 296                         hmc5843_set_measurement_configuration,
 297                         0);
 298
 299 /*
 300  * From Datasheet
 301  * The table shows the minimum data output
 302  * Value        | Minimum data output rate(Hz)
 303  * 0            | 0.5
 304  * 1            | 1
 305  * 2            | 2
 306  * 3            | 5
 307  * 4            | 10 (default)
 308  * 5            | 20
 309  * 6            | 50
 310  * 7            | Not used
 311  */
 312 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("0.5 1 2 5 10 20 50");
 313
 314 static s32 hmc5843_set_rate(struct i2c_client *client,
 315                                 u8 rate)
 316 {
 317         struct hmc5843_data *data = i2c_get_clientdata(client);
 318         u8 reg_val;
 319
 320         reg_val = (data->meas_conf) |  (rate << RATE_OFFSET);
 321         if (rate >= RATE_NOT_USED) {
 322                 dev_err(&client->dev,
 323                         "This data output rate is not supported\n");
 324                 return -EINVAL;
 325         }
 326         return i2c_smbus_write_byte_data(client, HMC5843_CONFIG_REG_A, reg_val);
 327 }
 328
 329 static ssize_t set_sampling_frequency(struct device *dev,
 330                                         struct device_attribute *attr,
 331                                         const char *buf, size_t count)
 332 {
 333
 334         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 335         struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
 336         struct hmc5843_data *data = iio_priv(indio_dev);
 337         unsigned long rate = 0;
 338
 339         if (strncmp(buf, "0.5" , 3) == 0)
 340                 rate = RATE_5;
 341         else if (strncmp(buf, "1" , 1) == 0)
 342                 rate = RATE_10;
 343         else if (strncmp(buf, "2", 1) == 0)
 344                 rate = RATE_20;
 345         else if (strncmp(buf, "5", 1) == 0)
 346                 rate = RATE_50;
 347         else if (strncmp(buf, "10", 2) == 0)
 348                 rate = RATE_100;
 349         else if (strncmp(buf, "20" , 2) == 0)
 350                 rate = RATE_200;
 351         else if (strncmp(buf, "50" , 2) == 0)
 352                 rate = RATE_500;
 353         else
 354                 return -EINVAL;
 355
 356         mutex_lock(&data->lock);
 357         dev_dbg(dev, "set rate to %lu\n", rate);
 358         if (hmc5843_set_rate(client, rate)) {
 359                 count = -EINVAL;
 360                 goto exit;
 361         }
 362         data->rate = rate;
 363
 364 exit:
 365         mutex_unlock(&data->lock);
 366         return count;
 367 }
 368
 369 static ssize_t show_sampling_frequency(struct device *dev,
 370                         struct device_attribute *attr, char *buf)
 371 {
 372         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 373         struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
 374         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 375         s32 rate;
 376
 377         rate = i2c_smbus_read_byte_data(client,  this_attr->address);
 378         if (rate < 0)
 379                 return rate;
 380         rate = (rate & RATE_BITMASK) >> RATE_OFFSET;
 381         return sprintf(buf, "%s\n", regval_to_samp_freq[rate]);
 382 }
 383 static IIO_DEVICE_ATTR(sampling_frequency,
 384                         S_IWUSR | S_IRUGO,
 385                         show_sampling_frequency,
 386                         set_sampling_frequency,
 387                         HMC5843_CONFIG_REG_A);
 388
 389 /*
 390  * From Datasheet
 391  *      Nominal gain settings
 392  * Value        | Sensor Input Field Range(Ga)  | Gain(counts/ milli-gauss)
 393  *0             |(+-)0.7                        |1620
 394  *1             |(+-)1.0                        |1300
 395  *2             |(+-)1.5                        |970
 396  *3             |(+-)2.0                        |780
 397  *4             |(+-)3.2                        |530
 398  *5             |(+-)3.8                        |460
 399  *6             |(+-)4.5                        |390
 400  *7             |(+-)6.5                        |280
 401  */
 402 static ssize_t show_range(struct device *dev,
 403                                 struct device_attribute *attr,
 404                                 char *buf)
 405 {
 406         u8 range;
 407         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 408         struct hmc5843_data *data = iio_priv(indio_dev);
 409
 410         range = data->range;
 411         return sprintf(buf, "%d\n", regval_to_input_field_mg[range]);
 412 }
 413
 414 static ssize_t set_range(struct device *dev,
 415                         struct device_attribute *attr,
 416                         const char *buf,
 417                         size_t count)
 418 {
 419         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 420         struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
 421         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 422         struct hmc5843_data *data = iio_priv(indio_dev);
 423         unsigned long range = 0;
 424         int error;
 425         mutex_lock(&data->lock);
 426         error = strict_strtoul(buf, 10, &range);
 427         if (error) {
 428                 count = error;
 429                 goto exit;
 430         }
 431         dev_dbg(dev, "set range to %lu\n", range);
 432
 433         if (range > RANGE_6_5) {
 434                 count = -EINVAL;
 435                 goto exit;
 436         }
 437
 438         data->range = range;
 439         range = range << RANGE_GAIN_OFFSET;
 440         if (i2c_smbus_write_byte_data(client, this_attr->address, range))
 441                 count = -EINVAL;
 442
 443 exit:
 444         mutex_unlock(&data->lock);
 445         return count;
 446
 447 }
 448 static IIO_DEVICE_ATTR(in_magn_range,
 449                         S_IWUSR | S_IRUGO,
 450                         show_range,
 451                         set_range,
 452                         HMC5843_CONFIG_REG_B);
 453
 454 static int hmc5843_read_raw(struct iio_dev *indio_dev,
 455                             struct iio_chan_spec const *chan,
 456                             int *val, int *val2,
 457                             long mask)
 458 {
 459         struct hmc5843_data *data = iio_priv(indio_dev);
 460
 461         switch (mask) {
 462         case 0:
 463                 return hmc5843_read_measurement(indio_dev,
 464                                                 chan->address,
 465                                                 val);
 466         case (1 << IIO_CHAN_INFO_SCALE_SHARED):
 467                 *val = 0;
 468                 *val2 = hmc5843_regval_to_nanoscale[data->range];
 469                 return IIO_VAL_INT_PLUS_NANO;
 470         };
 471         return -EINVAL;
 472 }
 473
 474 #define HMC5843_CHANNEL(axis, add)                                      \
 475         {                                                               \
 476                 .type = IIO_MAGN,                                       \
 477                 .modified = 1,                                          \
 478                 .channel2 = IIO_MOD_##axis,                             \
 479                 .info_mask = (1 << IIO_CHAN_INFO_SCALE_SHARED),         \
 480                 .address = add                                          \
 481         }
 482
 483 static const struct iio_chan_spec hmc5843_channels[] = {
 484         HMC5843_CHANNEL(X, HMC5843_DATA_OUT_X_MSB_REG),
 485         HMC5843_CHANNEL(Y, HMC5843_DATA_OUT_Y_MSB_REG),
 486         HMC5843_CHANNEL(Z, HMC5843_DATA_OUT_Z_MSB_REG),
 487 };
 488
 489 static struct attribute *hmc5843_attributes[] = {
 490         &iio_dev_attr_meas_conf.dev_attr.attr,
 491         &iio_dev_attr_operating_mode.dev_attr.attr,
 492         &iio_dev_attr_sampling_frequency.dev_attr.attr,
 493         &iio_dev_attr_in_magn_range.dev_attr.attr,
 494         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 495         NULL
 496 };
 497
 498 static const struct attribute_group hmc5843_group = {
 499         .attrs = hmc5843_attributes,
 500 };
 501
 502 static int hmc5843_detect(struct i2c_client *client,
 503                           struct i2c_board_info *info)
 504 {
 505         unsigned char id_str[HMC5843_ID_REG_LENGTH];
 506
 507         if (client->addr != HMC5843_I2C_ADDRESS)
 508                 return -ENODEV;
 509
 510         if (i2c_smbus_read_i2c_block_data(client, HMC5843_ID_REG_A,
 511                                 HMC5843_ID_REG_LENGTH, id_str)
 512                         != HMC5843_ID_REG_LENGTH)
 513                 return -ENODEV;
 514
 515         if (0 != strncmp(id_str, HMC5843_ID_STRING, HMC5843_ID_REG_LENGTH))
 516                 return -ENODEV;
 517
 518         return 0;
 519 }
 520
 521 /* Called when we have found a new HMC5843. */
 522 static void hmc5843_init_client(struct i2c_client *client)
 523 {
 524         struct hmc5843_data *data = i2c_get_clientdata(client);
 525         hmc5843_set_meas_conf(client, data->meas_conf);
 526         hmc5843_set_rate(client, data->rate);
 527         hmc5843_configure(client, data->operating_mode);
 528         i2c_smbus_write_byte_data(client, HMC5843_CONFIG_REG_B, data->range);
 529         mutex_init(&data->lock);
 530         pr_info("HMC5843 initialized\n");
 531 }
 532
 533 static const struct iio_info hmc5843_info = {
 534         .attrs = &hmc5843_group,
 535         .read_raw = &hmc5843_read_raw,
 536         .driver_module = THIS_MODULE,
 537 };
 538
 539 static int hmc5843_probe(struct i2c_client *client,
 540                          const struct i2c_device_id *id)
 541 {
 542         struct hmc5843_data *data;
 543         struct iio_dev *indio_dev;
 544         int err = 0;
 545
 546         indio_dev = iio_allocate_device(sizeof(*data));
 547         if (indio_dev == NULL) {
 548                 err = -ENOMEM;
 549                 goto exit;
 550         }
 551         data = iio_priv(indio_dev);
 552         /* default settings at probe */
 553
 554         data->meas_conf = CONF_NORMAL;
 555         data->range = RANGE_1_0;
 556         data->operating_mode = MODE_CONVERSION_CONTINUOUS;
 557
 558         i2c_set_clientdata(client, indio_dev);
 559
 560         /* Initialize the HMC5843 chip */
 561         hmc5843_init_client(client);
 562
 563         indio_dev->info = &hmc5843_info;
 564         indio_dev->name = id->name;
 565         indio_dev->channels = hmc5843_channels;
 566         indio_dev->num_channels = ARRAY_SIZE(hmc5843_channels);
 567         indio_dev->dev.parent = &client->dev;
 568         indio_dev->modes = INDIO_DIRECT_MODE;
 569         err = iio_device_register(indio_dev);
 570         if (err)
 571                 goto exit_free2;
 572         return 0;
 573 exit_free2:
 574         iio_free_device(indio_dev);
 575 exit:
 576         return err;
 577 }
 578
 579 static int hmc5843_remove(struct i2c_client *client)
 580 {
 581         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 582
 583         iio_device_unregister(indio_dev);
 584          /*  sleep mode to save power */
 585         hmc5843_configure(client, MODE_SLEEP);
 586         iio_free_device(indio_dev);
 587
 588         return 0;
 589 }
 590
 591 static int hmc5843_suspend(struct i2c_client *client, pm_message_t mesg)
 592 {
 593         hmc5843_configure(client, MODE_SLEEP);
 594         return 0;
 595 }
 596
 597 static int hmc5843_resume(struct i2c_client *client)
 598 {
 599         struct hmc5843_data *data = i2c_get_clientdata(client);
 600         hmc5843_configure(client, data->operating_mode);
 601         return 0;
 602 }
 603
 604 static const struct i2c_device_id hmc5843_id[] = {
 605         { "hmc5843", 0 },
 606         { }
 607 };
 608
 609 static struct i2c_driver hmc5843_driver = {
 610         .driver = {
 611                 .name   = "hmc5843",
 612         },
 613         .id_table       = hmc5843_id,
 614         .probe          = hmc5843_probe,
 615         .remove         = hmc5843_remove,
 616         .detect         = hmc5843_detect,
 617         .address_list   = normal_i2c,
 618         .suspend        = hmc5843_suspend,
 619         .resume         = hmc5843_resume,
 620 };
 621
 622 static int __init hmc5843_init(void)
 623 {
 624         return i2c_add_driver(&hmc5843_driver);
 625 }
 626
 627 static void __exit hmc5843_exit(void)
 628 {
 629         i2c_del_driver(&hmc5843_driver);
 630 }
 631
 632 MODULE_AUTHOR("Shubhrajyoti Datta <shubhrajyoti@ti.com");
 633 MODULE_DESCRIPTION("HMC5843 driver");
 634 MODULE_LICENSE("GPL");
 635
 636 module_init(hmc5843_init);
 637 module_exit(hmc5843_exit);