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                 *val = 0;
 187                 *val2 = 1000;
 188                 return IIO_VAL_INT_PLUS_MICRO;
 189         case IIO_CHAN_INFO_SAMP_FREQ:
 190                 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 191                 *val = mag3110_samp_freq[i][0];
 192                 *val2 = mag3110_samp_freq[i][1];
 193                 return IIO_VAL_INT_PLUS_MICRO;
 194         }
 195         return -EINVAL;
 196 }
 197
 198 static int mag3110_write_raw(struct iio_dev *indio_dev,
 199                              struct iio_chan_spec const *chan,
 200                              int val, int val2, long mask)
 201 {
 202         struct mag3110_data *data = iio_priv(indio_dev);
 203         int rate;
 204
 205         if (iio_buffer_enabled(indio_dev))
 206                 return -EBUSY;
 207
 208         switch (mask) {
 209         case IIO_CHAN_INFO_SAMP_FREQ:
 210                 rate = mag3110_get_samp_freq_index(data, val, val2);
 211                 if (rate < 0)
 212                         return -EINVAL;
 213
 214                 data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
 215                 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
 216                 return i2c_smbus_write_byte_data(data->client,
 217                         MAG3110_CTRL_REG1, data->ctrl_reg1);
 218         default:
 219                 return -EINVAL;
 220         }
 221 }
 222
 223 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
 224 {
 225         struct iio_poll_func *pf = p;
 226         struct iio_dev *indio_dev = pf->indio_dev;
 227         struct mag3110_data *data = iio_priv(indio_dev);
 228         u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
 229         int ret;
 230
 231         ret = mag3110_read(data, (__be16 *) buffer);
 232         if (ret < 0)
 233                 goto done;
 234
 235         if (test_bit(3, indio_dev->active_scan_mask)) {
 236                 ret = i2c_smbus_read_byte_data(data->client,
 237                         MAG3110_DIE_TEMP);
 238                 if (ret < 0)
 239                         goto done;
 240                 buffer[6] = ret;
 241         }
 242
 243         iio_push_to_buffers_with_timestamp(indio_dev, buffer,
 244                 iio_get_time_ns());
 245
 246 done:
 247         iio_trigger_notify_done(indio_dev->trig);
 248         return IRQ_HANDLED;
 249 }
 250
 251 #define MAG3110_CHANNEL(axis, idx) { \
 252         .type = IIO_MAGN, \
 253         .modified = 1, \
 254         .channel2 = IIO_MOD_##axis, \
 255         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 256         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 257                 BIT(IIO_CHAN_INFO_SCALE), \
 258         .scan_index = idx, \
 259         .scan_type = { \
 260                 .sign = 's', \
 261                 .realbits = 16, \
 262                 .storagebits = 16, \
 263                 .endianness = IIO_BE, \
 264         }, \
 265 }
 266
 267 static const struct iio_chan_spec mag3110_channels[] = {
 268         MAG3110_CHANNEL(X, 0),
 269         MAG3110_CHANNEL(Y, 1),
 270         MAG3110_CHANNEL(Z, 2),
 271         {
 272                 .type = IIO_TEMP,
 273                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 274                 .scan_index = 3,
 275                 .scan_type = {
 276                         .sign = 's',
 277                         .realbits = 8,
 278                         .storagebits = 8,
 279                         },
 280         },
 281         IIO_CHAN_SOFT_TIMESTAMP(4),
 282 };
 283
 284 static struct attribute *mag3110_attributes[] = {
 285         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 286         NULL
 287 };
 288
 289 static const struct attribute_group mag3110_group = {
 290         .attrs = mag3110_attributes,
 291 };
 292
 293 static const struct iio_info mag3110_info = {
 294         .attrs = &mag3110_group,
 295         .read_raw = &mag3110_read_raw,
 296         .write_raw = &mag3110_write_raw,
 297         .driver_module = THIS_MODULE,
 298 };
 299
 300 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
 301
 302 static int mag3110_probe(struct i2c_client *client,
 303                          const struct i2c_device_id *id)
 304 {
 305         struct mag3110_data *data;
 306         struct iio_dev *indio_dev;
 307         int ret;
 308
 309         ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
 310         if (ret < 0)
 311                 return ret;
 312         if (ret != MAG3110_DEVICE_ID)
 313                 return -ENODEV;
 314
 315         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 316         if (!indio_dev)
 317                 return -ENOMEM;
 318
 319         data = iio_priv(indio_dev);
 320         data->client = client;
 321         mutex_init(&data->lock);
 322
 323         i2c_set_clientdata(client, indio_dev);
 324         indio_dev->info = &mag3110_info;
 325         indio_dev->name = id->name;
 326         indio_dev->dev.parent = &client->dev;
 327         indio_dev->modes = INDIO_DIRECT_MODE;
 328         indio_dev->channels = mag3110_channels;
 329         indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
 330         indio_dev->available_scan_masks = mag3110_scan_masks;
 331
 332         data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT;
 333         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
 334                 data->ctrl_reg1);
 335         if (ret < 0)
 336                 return ret;
 337
 338         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
 339                 MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);
 340         if (ret < 0)
 341                 return ret;
 342
 343         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 344                 mag3110_trigger_handler, NULL);
 345         if (ret < 0)
 346                 return ret;
 347
 348         ret = iio_device_register(indio_dev);
 349         if (ret < 0)
 350                 goto buffer_cleanup;
 351         return 0;
 352
 353 buffer_cleanup:
 354         iio_triggered_buffer_cleanup(indio_dev);
 355         return ret;
 356 }
 357
 358 static int mag3110_standby(struct mag3110_data *data)
 359 {
 360         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 361                 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
 362 }
 363
 364 static int mag3110_remove(struct i2c_client *client)
 365 {
 366         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 367
 368         iio_device_unregister(indio_dev);
 369         iio_triggered_buffer_cleanup(indio_dev);
 370         mag3110_standby(iio_priv(indio_dev));
 371
 372         return 0;
 373 }
 374
 375 #ifdef CONFIG_PM_SLEEP
 376 static int mag3110_suspend(struct device *dev)
 377 {
 378         return mag3110_standby(iio_priv(i2c_get_clientdata(
 379                 to_i2c_client(dev))));
 380 }
 381
 382 static int mag3110_resume(struct device *dev)
 383 {
 384         struct mag3110_data *data = iio_priv(i2c_get_clientdata(
 385                 to_i2c_client(dev)));
 386
 387         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 388                 data->ctrl_reg1);
 389 }
 390
 391 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
 392 #define MAG3110_PM_OPS (&mag3110_pm_ops)
 393 #else
 394 #define MAG3110_PM_OPS NULL
 395 #endif
 396
 397 static const struct i2c_device_id mag3110_id[] = {
 398         { "mag3110", 0 },
 399         { }
 400 };
 401 MODULE_DEVICE_TABLE(i2c, mag3110_id);
 402
 403 static struct i2c_driver mag3110_driver = {
 404         .driver = {
 405                 .name   = "mag3110",
 406                 .pm     = MAG3110_PM_OPS,
 407         },
 408         .probe = mag3110_probe,
 409         .remove = mag3110_remove,
 410         .id_table = mag3110_id,
 411 };
 412 module_i2c_driver(mag3110_driver);
 413
 414 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 415 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
 416 MODULE_LICENSE("GPL");