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                 if (iio_buffer_enabled(indio_dev))
 158                         return -EBUSY;
 159
 160                 switch (chan->type) {
 161                 case IIO_MAGN: /* in 0.1 uT / LSB */
 162                         ret = mag3110_read(data, buffer);
 163                         if (ret < 0)
 164                                 return ret;
 165                         *val = sign_extend32(
 166                                 be16_to_cpu(buffer[chan->scan_index]), 15);
 167                         return IIO_VAL_INT;
 168                 case IIO_TEMP: /* in 1 C / LSB */
 169                         mutex_lock(&data->lock);
 170                         ret = mag3110_request(data);
 171                         if (ret < 0) {
 172                                 mutex_unlock(&data->lock);
 173                                 return ret;
 174                         }
 175                         ret = i2c_smbus_read_byte_data(data->client,
 176                                 MAG3110_DIE_TEMP);
 177                         mutex_unlock(&data->lock);
 178                         if (ret < 0)
 179                                 return ret;
 180                         *val = sign_extend32(ret, 7);
 181                         return IIO_VAL_INT;
 182                 default:
 183                         return -EINVAL;
 184                 }
 185         case IIO_CHAN_INFO_SCALE:
 186                 switch (chan->type) {
 187                 case IIO_MAGN:
 188                         *val = 0;
 189                         *val2 = 1000;
 190                         return IIO_VAL_INT_PLUS_MICRO;
 191                 case IIO_TEMP:
 192                         *val = 1000;
 193                         return IIO_VAL_INT;
 194                 default:
 195                         return -EINVAL;
 196                 }
 197         case IIO_CHAN_INFO_SAMP_FREQ:
 198                 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 199                 *val = mag3110_samp_freq[i][0];
 200                 *val2 = mag3110_samp_freq[i][1];
 201                 return IIO_VAL_INT_PLUS_MICRO;
 202         case IIO_CHAN_INFO_CALIBBIAS:
 203                 ret = i2c_smbus_read_word_swapped(data->client,
 204                         MAG3110_OFF_X + 2 * chan->scan_index);
 205                 if (ret < 0)
 206                         return ret;
 207                 *val = sign_extend32(ret >> 1, 14);
 208                 return IIO_VAL_INT;
 209         }
 210         return -EINVAL;
 211 }
 212
 213 static int mag3110_write_raw(struct iio_dev *indio_dev,
 214                              struct iio_chan_spec const *chan,
 215                              int val, int val2, long mask)
 216 {
 217         struct mag3110_data *data = iio_priv(indio_dev);
 218         int rate;
 219
 220         if (iio_buffer_enabled(indio_dev))
 221                 return -EBUSY;
 222
 223         switch (mask) {
 224         case IIO_CHAN_INFO_SAMP_FREQ:
 225                 rate = mag3110_get_samp_freq_index(data, val, val2);
 226                 if (rate < 0)
 227                         return -EINVAL;
 228
 229                 data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
 230                 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
 231                 return i2c_smbus_write_byte_data(data->client,
 232                         MAG3110_CTRL_REG1, data->ctrl_reg1);
 233         case IIO_CHAN_INFO_CALIBBIAS:
 234                 if (val < -10000 || val > 10000)
 235                         return -EINVAL;
 236                 return i2c_smbus_write_word_swapped(data->client,
 237                         MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
 238         default:
 239                 return -EINVAL;
 240         }
 241 }
 242
 243 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
 244 {
 245         struct iio_poll_func *pf = p;
 246         struct iio_dev *indio_dev = pf->indio_dev;
 247         struct mag3110_data *data = iio_priv(indio_dev);
 248         u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
 249         int ret;
 250
 251         ret = mag3110_read(data, (__be16 *) buffer);
 252         if (ret < 0)
 253                 goto done;
 254
 255         if (test_bit(3, indio_dev->active_scan_mask)) {
 256                 ret = i2c_smbus_read_byte_data(data->client,
 257                         MAG3110_DIE_TEMP);
 258                 if (ret < 0)
 259                         goto done;
 260                 buffer[6] = ret;
 261         }
 262
 263         iio_push_to_buffers_with_timestamp(indio_dev, buffer,
 264                 iio_get_time_ns(indio_dev));
 265
 266 done:
 267         iio_trigger_notify_done(indio_dev->trig);
 268         return IRQ_HANDLED;
 269 }
 270
 271 #define MAG3110_CHANNEL(axis, idx) { \
 272         .type = IIO_MAGN, \
 273         .modified = 1, \
 274         .channel2 = IIO_MOD_##axis, \
 275         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 276                 BIT(IIO_CHAN_INFO_CALIBBIAS), \
 277         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 278                 BIT(IIO_CHAN_INFO_SCALE), \
 279         .scan_index = idx, \
 280         .scan_type = { \
 281                 .sign = 's', \
 282                 .realbits = 16, \
 283                 .storagebits = 16, \
 284                 .endianness = IIO_BE, \
 285         }, \
 286 }
 287
 288 static const struct iio_chan_spec mag3110_channels[] = {
 289         MAG3110_CHANNEL(X, 0),
 290         MAG3110_CHANNEL(Y, 1),
 291         MAG3110_CHANNEL(Z, 2),
 292         {
 293                 .type = IIO_TEMP,
 294                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 295                         BIT(IIO_CHAN_INFO_SCALE),
 296                 .scan_index = 3,
 297                 .scan_type = {
 298                         .sign = 's',
 299                         .realbits = 8,
 300                         .storagebits = 8,
 301                         },
 302         },
 303         IIO_CHAN_SOFT_TIMESTAMP(4),
 304 };
 305
 306 static struct attribute *mag3110_attributes[] = {
 307         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 308         NULL
 309 };
 310
 311 static const struct attribute_group mag3110_group = {
 312         .attrs = mag3110_attributes,
 313 };
 314
 315 static const struct iio_info mag3110_info = {
 316         .attrs = &mag3110_group,
 317         .read_raw = &mag3110_read_raw,
 318         .write_raw = &mag3110_write_raw,
 319         .driver_module = THIS_MODULE,
 320 };
 321
 322 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
 323
 324 static int mag3110_standby(struct mag3110_data *data)
 325 {
 326         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 327                 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
 328 }
 329
 330 static int mag3110_probe(struct i2c_client *client,
 331                          const struct i2c_device_id *id)
 332 {
 333         struct mag3110_data *data;
 334         struct iio_dev *indio_dev;
 335         int ret;
 336
 337         ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
 338         if (ret < 0)
 339                 return ret;
 340         if (ret != MAG3110_DEVICE_ID)
 341                 return -ENODEV;
 342
 343         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 344         if (!indio_dev)
 345                 return -ENOMEM;
 346
 347         data = iio_priv(indio_dev);
 348         data->client = client;
 349         mutex_init(&data->lock);
 350
 351         i2c_set_clientdata(client, indio_dev);
 352         indio_dev->info = &mag3110_info;
 353         indio_dev->name = id->name;
 354         indio_dev->dev.parent = &client->dev;
 355         indio_dev->modes = INDIO_DIRECT_MODE;
 356         indio_dev->channels = mag3110_channels;
 357         indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
 358         indio_dev->available_scan_masks = mag3110_scan_masks;
 359
 360         data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
 361         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
 362                 data->ctrl_reg1);
 363         if (ret < 0)
 364                 return ret;
 365
 366         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
 367                 MAG3110_CTRL_AUTO_MRST_EN);
 368         if (ret < 0)
 369                 goto standby_on_error;
 370
 371         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 372                 mag3110_trigger_handler, NULL);
 373         if (ret < 0)
 374                 goto standby_on_error;
 375
 376         ret = iio_device_register(indio_dev);
 377         if (ret < 0)
 378                 goto buffer_cleanup;
 379         return 0;
 380
 381 buffer_cleanup:
 382         iio_triggered_buffer_cleanup(indio_dev);
 383 standby_on_error:
 384         mag3110_standby(iio_priv(indio_dev));
 385         return ret;
 386 }
 387
 388 static int mag3110_remove(struct i2c_client *client)
 389 {
 390         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 391
 392         iio_device_unregister(indio_dev);
 393         iio_triggered_buffer_cleanup(indio_dev);
 394         mag3110_standby(iio_priv(indio_dev));
 395
 396         return 0;
 397 }
 398
 399 #ifdef CONFIG_PM_SLEEP
 400 static int mag3110_suspend(struct device *dev)
 401 {
 402         return mag3110_standby(iio_priv(i2c_get_clientdata(
 403                 to_i2c_client(dev))));
 404 }
 405
 406 static int mag3110_resume(struct device *dev)
 407 {
 408         struct mag3110_data *data = iio_priv(i2c_get_clientdata(
 409                 to_i2c_client(dev)));
 410
 411         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 412                 data->ctrl_reg1);
 413 }
 414
 415 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
 416 #define MAG3110_PM_OPS (&mag3110_pm_ops)
 417 #else
 418 #define MAG3110_PM_OPS NULL
 419 #endif
 420
 421 static const struct i2c_device_id mag3110_id[] = {
 422         { "mag3110", 0 },
 423         { }
 424 };
 425 MODULE_DEVICE_TABLE(i2c, mag3110_id);
 426
 427 static struct i2c_driver mag3110_driver = {
 428         .driver = {
 429                 .name   = "mag3110",
 430                 .pm     = MAG3110_PM_OPS,
 431         },
 432         .probe = mag3110_probe,
 433         .remove = mag3110_remove,
 434         .id_table = mag3110_id,
 435 };
 436 module_i2c_driver(mag3110_driver);
 437
 438 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 439 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
 440 MODULE_LICENSE("GPL");