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 } 203 return -EINVAL; 204 } 205 206 static int mag3110_write_raw(struct iio_dev *indio_dev, 207 struct iio_chan_spec const *chan, 208 int val, int val2, long mask) 209 { 210 struct mag3110_data *data = iio_priv(indio_dev); 211 int rate; 212 213 if (iio_buffer_enabled(indio_dev)) 214 return -EBUSY; 215 216 switch (mask) { 217 case IIO_CHAN_INFO_SAMP_FREQ: 218 rate = mag3110_get_samp_freq_index(data, val, val2); 219 if (rate < 0) 220 return -EINVAL; 221 222 data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK; 223 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT; 224 return i2c_smbus_write_byte_data(data->client, 225 MAG3110_CTRL_REG1, data->ctrl_reg1); 226 default: 227 return -EINVAL; 228 } 229 } 230 231 static irqreturn_t mag3110_trigger_handler(int irq, void *p) 232 { 233 struct iio_poll_func *pf = p; 234 struct iio_dev *indio_dev = pf->indio_dev; 235 struct mag3110_data *data = iio_priv(indio_dev); 236 u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */ 237 int ret; 238 239 ret = mag3110_read(data, (__be16 *) buffer); 240 if (ret < 0) 241 goto done; 242 243 if (test_bit(3, indio_dev->active_scan_mask)) { 244 ret = i2c_smbus_read_byte_data(data->client, 245 MAG3110_DIE_TEMP); 246 if (ret < 0) 247 goto done; 248 buffer[6] = ret; 249 } 250 251 iio_push_to_buffers_with_timestamp(indio_dev, buffer, 252 iio_get_time_ns()); 253 254 done: 255 iio_trigger_notify_done(indio_dev->trig); 256 return IRQ_HANDLED; 257 } 258 259 #define MAG3110_CHANNEL(axis, idx) { \ 260 .type = IIO_MAGN, \ 261 .modified = 1, \ 262 .channel2 = IIO_MOD_##axis, \ 263 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 264 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ 265 BIT(IIO_CHAN_INFO_SCALE), \ 266 .scan_index = idx, \ 267 .scan_type = { \ 268 .sign = 's', \ 269 .realbits = 16, \ 270 .storagebits = 16, \ 271 .endianness = IIO_BE, \ 272 }, \ 273 } 274 275 static const struct iio_chan_spec mag3110_channels[] = { 276 MAG3110_CHANNEL(X, 0), 277 MAG3110_CHANNEL(Y, 1), 278 MAG3110_CHANNEL(Z, 2), 279 { 280 .type = IIO_TEMP, 281 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 282 BIT(IIO_CHAN_INFO_SCALE), 283 .scan_index = 3, 284 .scan_type = { 285 .sign = 's', 286 .realbits = 8, 287 .storagebits = 8, 288 }, 289 }, 290 IIO_CHAN_SOFT_TIMESTAMP(4), 291 }; 292 293 static struct attribute *mag3110_attributes[] = { 294 &iio_dev_attr_sampling_frequency_available.dev_attr.attr, 295 NULL 296 }; 297 298 static const struct attribute_group mag3110_group = { 299 .attrs = mag3110_attributes, 300 }; 301 302 static const struct iio_info mag3110_info = { 303 .attrs = &mag3110_group, 304 .read_raw = &mag3110_read_raw, 305 .write_raw = &mag3110_write_raw, 306 .driver_module = THIS_MODULE, 307 }; 308 309 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0}; 310 311 static int mag3110_probe(struct i2c_client *client, 312 const struct i2c_device_id *id) 313 { 314 struct mag3110_data *data; 315 struct iio_dev *indio_dev; 316 int ret; 317 318 ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I); 319 if (ret < 0) 320 return ret; 321 if (ret != MAG3110_DEVICE_ID) 322 return -ENODEV; 323 324 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 325 if (!indio_dev) 326 return -ENOMEM; 327 328 data = iio_priv(indio_dev); 329 data->client = client; 330 mutex_init(&data->lock); 331 332 i2c_set_clientdata(client, indio_dev); 333 indio_dev->info = &mag3110_info; 334 indio_dev->name = id->name; 335 indio_dev->dev.parent = &client->dev; 336 indio_dev->modes = INDIO_DIRECT_MODE; 337 indio_dev->channels = mag3110_channels; 338 indio_dev->num_channels = ARRAY_SIZE(mag3110_channels); 339 indio_dev->available_scan_masks = mag3110_scan_masks; 340 341 data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT; 342 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1, 343 data->ctrl_reg1); 344 if (ret < 0) 345 return ret; 346 347 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2, 348 MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW); 349 if (ret < 0) 350 return ret; 351 352 ret = iio_triggered_buffer_setup(indio_dev, NULL, 353 mag3110_trigger_handler, NULL); 354 if (ret < 0) 355 return ret; 356 357 ret = iio_device_register(indio_dev); 358 if (ret < 0) 359 goto buffer_cleanup; 360 return 0; 361 362 buffer_cleanup: 363 iio_triggered_buffer_cleanup(indio_dev); 364 return ret; 365 } 366 367 static int mag3110_standby(struct mag3110_data *data) 368 { 369 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, 370 data->ctrl_reg1 & ~MAG3110_CTRL_AC); 371 } 372 373 static int mag3110_remove(struct i2c_client *client) 374 { 375 struct iio_dev *indio_dev = i2c_get_clientdata(client); 376 377 iio_device_unregister(indio_dev); 378 iio_triggered_buffer_cleanup(indio_dev); 379 mag3110_standby(iio_priv(indio_dev)); 380 381 return 0; 382 } 383 384 #ifdef CONFIG_PM_SLEEP 385 static int mag3110_suspend(struct device *dev) 386 { 387 return mag3110_standby(iio_priv(i2c_get_clientdata( 388 to_i2c_client(dev)))); 389 } 390 391 static int mag3110_resume(struct device *dev) 392 { 393 struct mag3110_data *data = iio_priv(i2c_get_clientdata( 394 to_i2c_client(dev))); 395 396 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, 397 data->ctrl_reg1); 398 } 399 400 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume); 401 #define MAG3110_PM_OPS (&mag3110_pm_ops) 402 #else 403 #define MAG3110_PM_OPS NULL 404 #endif 405 406 static const struct i2c_device_id mag3110_id[] = { 407 { "mag3110", 0 }, 408 { } 409 }; 410 MODULE_DEVICE_TABLE(i2c, mag3110_id); 411 412 static struct i2c_driver mag3110_driver = { 413 .driver = { 414 .name = "mag3110", 415 .pm = MAG3110_PM_OPS, 416 }, 417 .probe = mag3110_probe, 418 .remove = mag3110_remove, 419 .id_table = mag3110_id, 420 }; 421 module_i2c_driver(mag3110_driver); 422 423 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); 424 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver"); 425 MODULE_LICENSE("GPL"); 426