drivers/iio/magnetometer/mag3110.c

   1 /*
   2  * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
   3  *
   4  * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License.  See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * (7-bit I2C slave address 0x0e)
  11  *
  12  * TODO: irq, user offset, oversampling, continuous mode
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/i2c.h>
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/sysfs.h>
  19 #include <linux/iio/trigger_consumer.h>
  20 #include <linux/iio/buffer.h>
  21 #include <linux/iio/triggered_buffer.h>
  22 #include <linux/delay.h>
  23
  24 #define MAG3110_STATUS 0x00
  25 #define MAG3110_OUT_X 0x01 /* MSB first */
  26 #define MAG3110_OUT_Y 0x03
  27 #define MAG3110_OUT_Z 0x05
  28 #define MAG3110_WHO_AM_I 0x07
  29 #define MAG3110_OFF_X 0x09 /* MSB first */
  30 #define MAG3110_OFF_Y 0x0b
  31 #define MAG3110_OFF_Z 0x0d
  32 #define MAG3110_DIE_TEMP 0x0f
  33 #define MAG3110_CTRL_REG1 0x10
  34 #define MAG3110_CTRL_REG2 0x11
  35
  36 #define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
  37
  38 #define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
  39 #define MAG3110_CTRL_DR_SHIFT 5
  40 #define MAG3110_CTRL_DR_DEFAULT 0
  41
  42 #define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
  43 #define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
  44
  45 #define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
  46 #define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
  47
  48 #define MAG3110_DEVICE_ID 0xc4
  49
  50 /* Each client has this additional data */
  51 struct mag3110_data {
  52         struct i2c_client *client;
  53         struct mutex lock;
  54         u8 ctrl_reg1;
  55 };
  56
  57 static int mag3110_request(struct mag3110_data *data)
  58 {
  59         int ret, tries = 150;
  60
  61         /* trigger measurement */
  62         ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
  63                 data->ctrl_reg1 | MAG3110_CTRL_TM);
  64         if (ret < 0)
  65                 return ret;
  66
  67         while (tries-- > 0) {
  68                 ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
  69                 if (ret < 0)
  70                         return ret;
  71                 /* wait for data ready */
  72                 if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
  73                         break;
  74                 msleep(20);
  75         }
  76
  77         if (tries < 0) {
  78                 dev_err(&data->client->dev, "data not ready\n");
  79                 return -EIO;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
  86 {
  87         int ret;
  88
  89         mutex_lock(&data->lock);
  90         ret = mag3110_request(data);
  91         if (ret < 0) {
  92                 mutex_unlock(&data->lock);
  93                 return ret;
  94         }
  95         ret = i2c_smbus_read_i2c_block_data(data->client,
  96                 MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
  97         mutex_unlock(&data->lock);
  98
  99         return ret;
 100 }
 101
 102 static ssize_t mag3110_show_int_plus_micros(char *buf,
 103         const int (*vals)[2], int n)
 104 {
 105         size_t len = 0;
 106
 107         while (n-- > 0)
 108                 len += scnprintf(buf + len, PAGE_SIZE - len,
 109                         "%d.%06d ", vals[n][0], vals[n][1]);
 110
 111         /* replace trailing space by newline */
 112         buf[len - 1] = '\n';
 113
 114         return len;
 115 }
 116
 117 static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
 118                                         int val, int val2)
 119 {
 120         while (n-- > 0)
 121                 if (val == vals[n][0] && val2 == vals[n][1])
 122                         return n;
 123
 124         return -EINVAL;
 125 }
 126
 127 static const int mag3110_samp_freq[8][2] = {
 128         {80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
 129         {1, 250000}, {0, 625000}
 130 };
 131
 132 static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
 133                                 struct device_attribute *attr, char *buf)
 134 {
 135         return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
 136 }
 137
 138 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
 139
 140 static int mag3110_get_samp_freq_index(struct mag3110_data *data,
 141         int val, int val2)
 142 {
 143         return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
 144                 val2);
 145 }
 146
 147 static int mag3110_read_raw(struct iio_dev *indio_dev,
 148                             struct iio_chan_spec const *chan,
 149                             int *val, int *val2, long mask)
 150 {
 151         struct mag3110_data *data = iio_priv(indio_dev);
 152         __be16 buffer[3];
 153         int i, ret;
 154
 155         switch (mask) {
 156         case IIO_CHAN_INFO_RAW:
 157                 ret = iio_device_claim_direct_mode(indio_dev);
 158                 if (ret)
 159                         return ret;
 160
 161                 switch (chan->type) {
 162                 case IIO_MAGN: /* in 0.1 uT / LSB */
 163                         ret = mag3110_read(data, buffer);
 164                         if (ret < 0)
 165                                 goto release;
 166                         *val = sign_extend32(
 167                                 be16_to_cpu(buffer[chan->scan_index]), 15);
 168                         ret = IIO_VAL_INT;
 169                         break;
 170                 case IIO_TEMP: /* in 1 C / LSB */
 171                         mutex_lock(&data->lock);
 172                         ret = mag3110_request(data);
 173                         if (ret < 0) {
 174                                 mutex_unlock(&data->lock);
 175                                 goto release;
 176                         }
 177                         ret = i2c_smbus_read_byte_data(data->client,
 178                                 MAG3110_DIE_TEMP);
 179                         mutex_unlock(&data->lock);
 180                         if (ret < 0)
 181                                 goto release;
 182                         *val = sign_extend32(ret, 7);
 183                         ret = IIO_VAL_INT;
 184                         break;
 185                 default:
 186                         ret = -EINVAL;
 187                 }
 188 release:
 189                 iio_device_release_direct_mode(indio_dev);
 190                 return ret;
 191
 192         case IIO_CHAN_INFO_SCALE:
 193                 switch (chan->type) {
 194                 case IIO_MAGN:
 195                         *val = 0;
 196                         *val2 = 1000;
 197                         return IIO_VAL_INT_PLUS_MICRO;
 198                 case IIO_TEMP:
 199                         *val = 1000;
 200                         return IIO_VAL_INT;
 201                 default:
 202                         return -EINVAL;
 203                 }
 204         case IIO_CHAN_INFO_SAMP_FREQ:
 205                 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 206                 *val = mag3110_samp_freq[i][0];
 207                 *val2 = mag3110_samp_freq[i][1];
 208                 return IIO_VAL_INT_PLUS_MICRO;
 209         case IIO_CHAN_INFO_CALIBBIAS:
 210                 ret = i2c_smbus_read_word_swapped(data->client,
 211                         MAG3110_OFF_X + 2 * chan->scan_index);
 212                 if (ret < 0)
 213                         return ret;
 214                 *val = sign_extend32(ret >> 1, 14);
 215                 return IIO_VAL_INT;
 216         }
 217         return -EINVAL;
 218 }
 219
 220 static int mag3110_write_raw(struct iio_dev *indio_dev,
 221                              struct iio_chan_spec const *chan,
 222                              int val, int val2, long mask)
 223 {
 224         struct mag3110_data *data = iio_priv(indio_dev);
 225         int rate, ret;
 226
 227         ret = iio_device_claim_direct_mode(indio_dev);
 228         if (ret)
 229                 return ret;
 230
 231         switch (mask) {
 232         case IIO_CHAN_INFO_SAMP_FREQ:
 233                 rate = mag3110_get_samp_freq_index(data, val, val2);
 234                 if (rate < 0) {
 235                         ret = -EINVAL;
 236                         break;
 237                 }
 238
 239                 data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
 240                 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
 241                 ret = i2c_smbus_write_byte_data(data->client,
 242                         MAG3110_CTRL_REG1, data->ctrl_reg1);
 243                 break;
 244         case IIO_CHAN_INFO_CALIBBIAS:
 245                 if (val < -10000 || val > 10000) {
 246                         ret = -EINVAL;
 247                         break;
 248                 }
 249                 ret = i2c_smbus_write_word_swapped(data->client,
 250                         MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
 251                 break;
 252         default:
 253                 ret = -EINVAL;
 254                 break;
 255         }
 256         iio_device_release_direct_mode(indio_dev);
 257         return ret;
 258 }
 259
 260 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
 261 {
 262         struct iio_poll_func *pf = p;
 263         struct iio_dev *indio_dev = pf->indio_dev;
 264         struct mag3110_data *data = iio_priv(indio_dev);
 265         u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
 266         int ret;
 267
 268         ret = mag3110_read(data, (__be16 *) buffer);
 269         if (ret < 0)
 270                 goto done;
 271
 272         if (test_bit(3, indio_dev->active_scan_mask)) {
 273                 ret = i2c_smbus_read_byte_data(data->client,
 274                         MAG3110_DIE_TEMP);
 275                 if (ret < 0)
 276                         goto done;
 277                 buffer[6] = ret;
 278         }
 279
 280         iio_push_to_buffers_with_timestamp(indio_dev, buffer,
 281                 iio_get_time_ns(indio_dev));
 282
 283 done:
 284         iio_trigger_notify_done(indio_dev->trig);
 285         return IRQ_HANDLED;
 286 }
 287
 288 #define MAG3110_CHANNEL(axis, idx) { \
 289         .type = IIO_MAGN, \
 290         .modified = 1, \
 291         .channel2 = IIO_MOD_##axis, \
 292         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 293                 BIT(IIO_CHAN_INFO_CALIBBIAS), \
 294         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 295                 BIT(IIO_CHAN_INFO_SCALE), \
 296         .scan_index = idx, \
 297         .scan_type = { \
 298                 .sign = 's', \
 299                 .realbits = 16, \
 300                 .storagebits = 16, \
 301                 .endianness = IIO_BE, \
 302         }, \
 303 }
 304
 305 static const struct iio_chan_spec mag3110_channels[] = {
 306         MAG3110_CHANNEL(X, 0),
 307         MAG3110_CHANNEL(Y, 1),
 308         MAG3110_CHANNEL(Z, 2),
 309         {
 310                 .type = IIO_TEMP,
 311                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 312                         BIT(IIO_CHAN_INFO_SCALE),
 313                 .scan_index = 3,
 314                 .scan_type = {
 315                         .sign = 's',
 316                         .realbits = 8,
 317                         .storagebits = 8,
 318                         },
 319         },
 320         IIO_CHAN_SOFT_TIMESTAMP(4),
 321 };
 322
 323 static struct attribute *mag3110_attributes[] = {
 324         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 325         NULL
 326 };
 327
 328 static const struct attribute_group mag3110_group = {
 329         .attrs = mag3110_attributes,
 330 };
 331
 332 static const struct iio_info mag3110_info = {
 333         .attrs = &mag3110_group,
 334         .read_raw = &mag3110_read_raw,
 335         .write_raw = &mag3110_write_raw,
 336         .driver_module = THIS_MODULE,
 337 };
 338
 339 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
 340
 341 static int mag3110_standby(struct mag3110_data *data)
 342 {
 343         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 344                 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
 345 }
 346
 347 static int mag3110_probe(struct i2c_client *client,
 348                          const struct i2c_device_id *id)
 349 {
 350         struct mag3110_data *data;
 351         struct iio_dev *indio_dev;
 352         int ret;
 353
 354         ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
 355         if (ret < 0)
 356                 return ret;
 357         if (ret != MAG3110_DEVICE_ID)
 358                 return -ENODEV;
 359
 360         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 361         if (!indio_dev)
 362                 return -ENOMEM;
 363
 364         data = iio_priv(indio_dev);
 365         data->client = client;
 366         mutex_init(&data->lock);
 367
 368         i2c_set_clientdata(client, indio_dev);
 369         indio_dev->info = &mag3110_info;
 370         indio_dev->name = id->name;
 371         indio_dev->dev.parent = &client->dev;
 372         indio_dev->modes = INDIO_DIRECT_MODE;
 373         indio_dev->channels = mag3110_channels;
 374         indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
 375         indio_dev->available_scan_masks = mag3110_scan_masks;
 376
 377         data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
 378         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
 379                 data->ctrl_reg1);
 380         if (ret < 0)
 381                 return ret;
 382
 383         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
 384                 MAG3110_CTRL_AUTO_MRST_EN);
 385         if (ret < 0)
 386                 goto standby_on_error;
 387
 388         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 389                 mag3110_trigger_handler, NULL);
 390         if (ret < 0)
 391                 goto standby_on_error;
 392
 393         ret = iio_device_register(indio_dev);
 394         if (ret < 0)
 395                 goto buffer_cleanup;
 396         return 0;
 397
 398 buffer_cleanup:
 399         iio_triggered_buffer_cleanup(indio_dev);
 400 standby_on_error:
 401         mag3110_standby(iio_priv(indio_dev));
 402         return ret;
 403 }
 404
 405 static int mag3110_remove(struct i2c_client *client)
 406 {
 407         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 408
 409         iio_device_unregister(indio_dev);
 410         iio_triggered_buffer_cleanup(indio_dev);
 411         mag3110_standby(iio_priv(indio_dev));
 412
 413         return 0;
 414 }
 415
 416 #ifdef CONFIG_PM_SLEEP
 417 static int mag3110_suspend(struct device *dev)
 418 {
 419         return mag3110_standby(iio_priv(i2c_get_clientdata(
 420                 to_i2c_client(dev))));
 421 }
 422
 423 static int mag3110_resume(struct device *dev)
 424 {
 425         struct mag3110_data *data = iio_priv(i2c_get_clientdata(
 426                 to_i2c_client(dev)));
 427
 428         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 429                 data->ctrl_reg1);
 430 }
 431
 432 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
 433 #define MAG3110_PM_OPS (&mag3110_pm_ops)
 434 #else
 435 #define MAG3110_PM_OPS NULL
 436 #endif
 437
 438 static const struct i2c_device_id mag3110_id[] = {
 439         { "mag3110", 0 },
 440         { }
 441 };
 442 MODULE_DEVICE_TABLE(i2c, mag3110_id);
 443
 444 static const struct of_device_id mag3110_of_match[] = {
 445         { .compatible = "fsl,mag3110" },
 446         { }
 447 };
 448 MODULE_DEVICE_TABLE(of, mag3110_of_match);
 449
 450 static struct i2c_driver mag3110_driver = {
 451         .driver = {
 452                 .name   = "mag3110",
 453                 .of_match_table = mag3110_of_match,
 454                 .pm     = MAG3110_PM_OPS,
 455         },
 456         .probe = mag3110_probe,
 457         .remove = mag3110_remove,
 458         .id_table = mag3110_id,
 459 };
 460 module_i2c_driver(mag3110_driver);
 461
 462 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 463 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
 464 MODULE_LICENSE("GPL");