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; 226 227 if (iio_buffer_enabled(indio_dev)) 228 return -EBUSY; 229 230 switch (mask) { 231 case IIO_CHAN_INFO_SAMP_FREQ: 232 rate = mag3110_get_samp_freq_index(data, val, val2); 233 if (rate < 0) 234 return -EINVAL; 235 236 data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK; 237 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT; 238 return i2c_smbus_write_byte_data(data->client, 239 MAG3110_CTRL_REG1, data->ctrl_reg1); 240 case IIO_CHAN_INFO_CALIBBIAS: 241 if (val < -10000 || val > 10000) 242 return -EINVAL; 243 return i2c_smbus_write_word_swapped(data->client, 244 MAG3110_OFF_X + 2 * chan->scan_index, val << 1); 245 default: 246 return -EINVAL; 247 } 248 } 249 250 static irqreturn_t mag3110_trigger_handler(int irq, void *p) 251 { 252 struct iio_poll_func *pf = p; 253 struct iio_dev *indio_dev = pf->indio_dev; 254 struct mag3110_data *data = iio_priv(indio_dev); 255 u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */ 256 int ret; 257 258 ret = mag3110_read(data, (__be16 *) buffer); 259 if (ret < 0) 260 goto done; 261 262 if (test_bit(3, indio_dev->active_scan_mask)) { 263 ret = i2c_smbus_read_byte_data(data->client, 264 MAG3110_DIE_TEMP); 265 if (ret < 0) 266 goto done; 267 buffer[6] = ret; 268 } 269 270 iio_push_to_buffers_with_timestamp(indio_dev, buffer, 271 iio_get_time_ns(indio_dev)); 272 273 done: 274 iio_trigger_notify_done(indio_dev->trig); 275 return IRQ_HANDLED; 276 } 277 278 #define MAG3110_CHANNEL(axis, idx) { \ 279 .type = IIO_MAGN, \ 280 .modified = 1, \ 281 .channel2 = IIO_MOD_##axis, \ 282 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 283 BIT(IIO_CHAN_INFO_CALIBBIAS), \ 284 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ 285 BIT(IIO_CHAN_INFO_SCALE), \ 286 .scan_index = idx, \ 287 .scan_type = { \ 288 .sign = 's', \ 289 .realbits = 16, \ 290 .storagebits = 16, \ 291 .endianness = IIO_BE, \ 292 }, \ 293 } 294 295 static const struct iio_chan_spec mag3110_channels[] = { 296 MAG3110_CHANNEL(X, 0), 297 MAG3110_CHANNEL(Y, 1), 298 MAG3110_CHANNEL(Z, 2), 299 { 300 .type = IIO_TEMP, 301 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 302 BIT(IIO_CHAN_INFO_SCALE), 303 .scan_index = 3, 304 .scan_type = { 305 .sign = 's', 306 .realbits = 8, 307 .storagebits = 8, 308 }, 309 }, 310 IIO_CHAN_SOFT_TIMESTAMP(4), 311 }; 312 313 static struct attribute *mag3110_attributes[] = { 314 &iio_dev_attr_sampling_frequency_available.dev_attr.attr, 315 NULL 316 }; 317 318 static const struct attribute_group mag3110_group = { 319 .attrs = mag3110_attributes, 320 }; 321 322 static const struct iio_info mag3110_info = { 323 .attrs = &mag3110_group, 324 .read_raw = &mag3110_read_raw, 325 .write_raw = &mag3110_write_raw, 326 .driver_module = THIS_MODULE, 327 }; 328 329 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0}; 330 331 static int mag3110_standby(struct mag3110_data *data) 332 { 333 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, 334 data->ctrl_reg1 & ~MAG3110_CTRL_AC); 335 } 336 337 static int mag3110_probe(struct i2c_client *client, 338 const struct i2c_device_id *id) 339 { 340 struct mag3110_data *data; 341 struct iio_dev *indio_dev; 342 int ret; 343 344 ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I); 345 if (ret < 0) 346 return ret; 347 if (ret != MAG3110_DEVICE_ID) 348 return -ENODEV; 349 350 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 351 if (!indio_dev) 352 return -ENOMEM; 353 354 data = iio_priv(indio_dev); 355 data->client = client; 356 mutex_init(&data->lock); 357 358 i2c_set_clientdata(client, indio_dev); 359 indio_dev->info = &mag3110_info; 360 indio_dev->name = id->name; 361 indio_dev->dev.parent = &client->dev; 362 indio_dev->modes = INDIO_DIRECT_MODE; 363 indio_dev->channels = mag3110_channels; 364 indio_dev->num_channels = ARRAY_SIZE(mag3110_channels); 365 indio_dev->available_scan_masks = mag3110_scan_masks; 366 367 data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT; 368 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1, 369 data->ctrl_reg1); 370 if (ret < 0) 371 return ret; 372 373 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2, 374 MAG3110_CTRL_AUTO_MRST_EN); 375 if (ret < 0) 376 goto standby_on_error; 377 378 ret = iio_triggered_buffer_setup(indio_dev, NULL, 379 mag3110_trigger_handler, NULL); 380 if (ret < 0) 381 goto standby_on_error; 382 383 ret = iio_device_register(indio_dev); 384 if (ret < 0) 385 goto buffer_cleanup; 386 return 0; 387 388 buffer_cleanup: 389 iio_triggered_buffer_cleanup(indio_dev); 390 standby_on_error: 391 mag3110_standby(iio_priv(indio_dev)); 392 return ret; 393 } 394 395 static int mag3110_remove(struct i2c_client *client) 396 { 397 struct iio_dev *indio_dev = i2c_get_clientdata(client); 398 399 iio_device_unregister(indio_dev); 400 iio_triggered_buffer_cleanup(indio_dev); 401 mag3110_standby(iio_priv(indio_dev)); 402 403 return 0; 404 } 405 406 #ifdef CONFIG_PM_SLEEP 407 static int mag3110_suspend(struct device *dev) 408 { 409 return mag3110_standby(iio_priv(i2c_get_clientdata( 410 to_i2c_client(dev)))); 411 } 412 413 static int mag3110_resume(struct device *dev) 414 { 415 struct mag3110_data *data = iio_priv(i2c_get_clientdata( 416 to_i2c_client(dev))); 417 418 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, 419 data->ctrl_reg1); 420 } 421 422 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume); 423 #define MAG3110_PM_OPS (&mag3110_pm_ops) 424 #else 425 #define MAG3110_PM_OPS NULL 426 #endif 427 428 static const struct i2c_device_id mag3110_id[] = { 429 { "mag3110", 0 }, 430 { } 431 }; 432 MODULE_DEVICE_TABLE(i2c, mag3110_id); 433 434 static struct i2c_driver mag3110_driver = { 435 .driver = { 436 .name = "mag3110", 437 .pm = MAG3110_PM_OPS, 438 }, 439 .probe = mag3110_probe, 440 .remove = mag3110_remove, 441 .id_table = mag3110_id, 442 }; 443 module_i2c_driver(mag3110_driver); 444 445 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); 446 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver"); 447 MODULE_LICENSE("GPL"); 448