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"); 417