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.%d ", 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                 switch (chan->type) {
 158                 case IIO_MAGN: /* in 0.1 uT / LSB */
 159                         ret = mag3110_read(data, buffer);
 160                         if (ret < 0)
 161                                 return ret;
 162                         *val = sign_extend32(
 163                                 be16_to_cpu(buffer[chan->scan_index]), 15);
 164                         return IIO_VAL_INT;
 165                 case IIO_TEMP: /* in 1 C / LSB */
 166                         mutex_lock(&data->lock);
 167                         ret = mag3110_request(data);
 168                         if (ret < 0) {
 169                                 mutex_unlock(&data->lock);
 170                                 return ret;
 171                         }
 172                         ret = i2c_smbus_read_byte_data(data->client,
 173                                 MAG3110_DIE_TEMP);
 174                         mutex_unlock(&data->lock);
 175                         if (ret < 0)
 176                                 return ret;
 177                         *val = sign_extend32(ret, 7);
 178                         return IIO_VAL_INT;
 179                 default:
 180                         return -EINVAL;
 181                 }
 182         case IIO_CHAN_INFO_SCALE:
 183                 *val = 0;
 184                 *val2 = 1000;
 185                 return IIO_VAL_INT_PLUS_MICRO;
 186         case IIO_CHAN_INFO_SAMP_FREQ:
 187                 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
 188                 *val = mag3110_samp_freq[i][0];
 189                 *val2 = mag3110_samp_freq[i][1];
 190                 return IIO_VAL_INT_PLUS_MICRO;
 191         }
 192         return -EINVAL;
 193 }
 194
 195 static int mag3110_write_raw(struct iio_dev *indio_dev,
 196                              struct iio_chan_spec const *chan,
 197                              int val, int val2, long mask)
 198 {
 199         struct mag3110_data *data = iio_priv(indio_dev);
 200         int rate;
 201
 202         switch (mask) {
 203         case IIO_CHAN_INFO_SAMP_FREQ:
 204                 rate = mag3110_get_samp_freq_index(data, val, val2);
 205                 if (rate < 0)
 206                         return -EINVAL;
 207
 208                 data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
 209                 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
 210                 return i2c_smbus_write_byte_data(data->client,
 211                         MAG3110_CTRL_REG1, data->ctrl_reg1);
 212         default:
 213                 return -EINVAL;
 214         }
 215 }
 216
 217 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
 218 {
 219         struct iio_poll_func *pf = p;
 220         struct iio_dev *indio_dev = pf->indio_dev;
 221         struct mag3110_data *data = iio_priv(indio_dev);
 222         u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
 223         int ret;
 224
 225         ret = mag3110_read(data, (__be16 *) buffer);
 226         if (ret < 0)
 227                 goto done;
 228
 229         if (test_bit(3, indio_dev->active_scan_mask)) {
 230                 ret = i2c_smbus_read_byte_data(data->client,
 231                         MAG3110_DIE_TEMP);
 232                 if (ret < 0)
 233                         goto done;
 234                 buffer[6] = ret;
 235         }
 236
 237         iio_push_to_buffers_with_timestamp(indio_dev, buffer,
 238                 iio_get_time_ns());
 239
 240 done:
 241         iio_trigger_notify_done(indio_dev->trig);
 242         return IRQ_HANDLED;
 243 }
 244
 245 #define MAG3110_CHANNEL(axis, idx) { \
 246         .type = IIO_MAGN, \
 247         .modified = 1, \
 248         .channel2 = IIO_MOD_##axis, \
 249         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 250         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 251                 BIT(IIO_CHAN_INFO_SCALE), \
 252         .scan_index = idx, \
 253         .scan_type = { \
 254                 .sign = 's', \
 255                 .realbits = 16, \
 256                 .storagebits = 16, \
 257                 .endianness = IIO_BE, \
 258         }, \
 259 }
 260
 261 static const struct iio_chan_spec mag3110_channels[] = {
 262         MAG3110_CHANNEL(X, 0),
 263         MAG3110_CHANNEL(Y, 1),
 264         MAG3110_CHANNEL(Z, 2),
 265         {
 266                 .type = IIO_TEMP,
 267                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 268                 .scan_index = 3,
 269                 .scan_type = IIO_ST('s', 8, 8, 0),
 270         },
 271         IIO_CHAN_SOFT_TIMESTAMP(4),
 272 };
 273
 274 static struct attribute *mag3110_attributes[] = {
 275         &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 276         NULL
 277 };
 278
 279 static const struct attribute_group mag3110_group = {
 280         .attrs = mag3110_attributes,
 281 };
 282
 283 static const struct iio_info mag3110_info = {
 284         .attrs = &mag3110_group,
 285         .read_raw = &mag3110_read_raw,
 286         .write_raw = &mag3110_write_raw,
 287         .driver_module = THIS_MODULE,
 288 };
 289
 290 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
 291
 292 static int mag3110_probe(struct i2c_client *client,
 293                          const struct i2c_device_id *id)
 294 {
 295         struct mag3110_data *data;
 296         struct iio_dev *indio_dev;
 297         int ret;
 298
 299         ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
 300         if (ret < 0)
 301                 return ret;
 302         if (ret != MAG3110_DEVICE_ID)
 303                 return -ENODEV;
 304
 305         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 306         if (!indio_dev)
 307                 return -ENOMEM;
 308
 309         data = iio_priv(indio_dev);
 310         data->client = client;
 311         mutex_init(&data->lock);
 312
 313         i2c_set_clientdata(client, indio_dev);
 314         indio_dev->info = &mag3110_info;
 315         indio_dev->name = id->name;
 316         indio_dev->dev.parent = &client->dev;
 317         indio_dev->modes = INDIO_DIRECT_MODE;
 318         indio_dev->channels = mag3110_channels;
 319         indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
 320         indio_dev->available_scan_masks = mag3110_scan_masks;
 321
 322         data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT;
 323         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
 324                 data->ctrl_reg1);
 325         if (ret < 0)
 326                 return ret;
 327
 328         ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
 329                 MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);
 330         if (ret < 0)
 331                 return ret;
 332
 333         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 334                 mag3110_trigger_handler, NULL);
 335         if (ret < 0)
 336                 return ret;
 337
 338         ret = iio_device_register(indio_dev);
 339         if (ret < 0)
 340                 goto buffer_cleanup;
 341         return 0;
 342
 343 buffer_cleanup:
 344         iio_triggered_buffer_cleanup(indio_dev);
 345         return ret;
 346 }
 347
 348 static int mag3110_standby(struct mag3110_data *data)
 349 {
 350         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 351                 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
 352 }
 353
 354 static int mag3110_remove(struct i2c_client *client)
 355 {
 356         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 357
 358         iio_device_unregister(indio_dev);
 359         iio_triggered_buffer_cleanup(indio_dev);
 360         mag3110_standby(iio_priv(indio_dev));
 361
 362         return 0;
 363 }
 364
 365 #ifdef CONFIG_PM_SLEEP
 366 static int mag3110_suspend(struct device *dev)
 367 {
 368         return mag3110_standby(iio_priv(i2c_get_clientdata(
 369                 to_i2c_client(dev))));
 370 }
 371
 372 static int mag3110_resume(struct device *dev)
 373 {
 374         struct mag3110_data *data = iio_priv(i2c_get_clientdata(
 375                 to_i2c_client(dev)));
 376
 377         return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
 378                 data->ctrl_reg1);
 379 }
 380
 381 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
 382 #define MAG3110_PM_OPS (&mag3110_pm_ops)
 383 #else
 384 #define MAG3110_PM_OPS NULL
 385 #endif
 386
 387 static const struct i2c_device_id mag3110_id[] = {
 388         { "mag3110", 0 },
 389         { }
 390 };
 391 MODULE_DEVICE_TABLE(i2c, mag3110_id);
 392
 393 static struct i2c_driver mag3110_driver = {
 394         .driver = {
 395                 .name   = "mag3110",
 396                 .pm     = MAG3110_PM_OPS,
 397         },
 398         .probe = mag3110_probe,
 399         .remove = mag3110_remove,
 400         .id_table = mag3110_id,
 401 };
 402 module_i2c_driver(mag3110_driver);
 403
 404 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 405 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
 406 MODULE_LICENSE("GPL");