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 = IIO_ST('s', 16, 16, IIO_BE), \ 254 } 255 256 static const struct iio_chan_spec mag3110_channels[] = { 257 MAG3110_CHANNEL(X, 0), 258 MAG3110_CHANNEL(Y, 1), 259 MAG3110_CHANNEL(Z, 2), 260 { 261 .type = IIO_TEMP, 262 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 263 .scan_index = 3, 264 .scan_type = IIO_ST('s', 8, 8, 0), 265 }, 266 IIO_CHAN_SOFT_TIMESTAMP(4), 267 }; 268 269 static struct attribute *mag3110_attributes[] = { 270 &iio_dev_attr_sampling_frequency_available.dev_attr.attr, 271 NULL 272 }; 273 274 static const struct attribute_group mag3110_group = { 275 .attrs = mag3110_attributes, 276 }; 277 278 static const struct iio_info mag3110_info = { 279 .attrs = &mag3110_group, 280 .read_raw = &mag3110_read_raw, 281 .write_raw = &mag3110_write_raw, 282 .driver_module = THIS_MODULE, 283 }; 284 285 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0}; 286 287 static int mag3110_probe(struct i2c_client *client, 288 const struct i2c_device_id *id) 289 { 290 struct mag3110_data *data; 291 struct iio_dev *indio_dev; 292 int ret; 293 294 ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I); 295 if (ret < 0) 296 return ret; 297 if (ret != MAG3110_DEVICE_ID) 298 return -ENODEV; 299 300 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 301 if (!indio_dev) 302 return -ENOMEM; 303 304 data = iio_priv(indio_dev); 305 data->client = client; 306 mutex_init(&data->lock); 307 308 i2c_set_clientdata(client, indio_dev); 309 indio_dev->info = &mag3110_info; 310 indio_dev->name = id->name; 311 indio_dev->dev.parent = &client->dev; 312 indio_dev->modes = INDIO_DIRECT_MODE; 313 indio_dev->channels = mag3110_channels; 314 indio_dev->num_channels = ARRAY_SIZE(mag3110_channels); 315 indio_dev->available_scan_masks = mag3110_scan_masks; 316 317 data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT; 318 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1, 319 data->ctrl_reg1); 320 if (ret < 0) 321 return ret; 322 323 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2, 324 MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW); 325 if (ret < 0) 326 return ret; 327 328 ret = iio_triggered_buffer_setup(indio_dev, NULL, 329 mag3110_trigger_handler, NULL); 330 if (ret < 0) 331 return ret; 332 333 ret = iio_device_register(indio_dev); 334 if (ret < 0) 335 goto buffer_cleanup; 336 return 0; 337 338 buffer_cleanup: 339 iio_triggered_buffer_cleanup(indio_dev); 340 return ret; 341 } 342 343 static int mag3110_standby(struct mag3110_data *data) 344 { 345 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, 346 data->ctrl_reg1 & ~MAG3110_CTRL_AC); 347 } 348 349 static int mag3110_remove(struct i2c_client *client) 350 { 351 struct iio_dev *indio_dev = i2c_get_clientdata(client); 352 353 iio_device_unregister(indio_dev); 354 iio_triggered_buffer_cleanup(indio_dev); 355 mag3110_standby(iio_priv(indio_dev)); 356 357 return 0; 358 } 359 360 #ifdef CONFIG_PM_SLEEP 361 static int mag3110_suspend(struct device *dev) 362 { 363 return mag3110_standby(iio_priv(i2c_get_clientdata( 364 to_i2c_client(dev)))); 365 } 366 367 static int mag3110_resume(struct device *dev) 368 { 369 struct mag3110_data *data = iio_priv(i2c_get_clientdata( 370 to_i2c_client(dev))); 371 372 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1, 373 data->ctrl_reg1); 374 } 375 376 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume); 377 #define MAG3110_PM_OPS (&mag3110_pm_ops) 378 #else 379 #define MAG3110_PM_OPS NULL 380 #endif 381 382 static const struct i2c_device_id mag3110_id[] = { 383 { "mag3110", 0 }, 384 { } 385 }; 386 MODULE_DEVICE_TABLE(i2c, mag3110_id); 387 388 static struct i2c_driver mag3110_driver = { 389 .driver = { 390 .name = "mag3110", 391 .pm = MAG3110_PM_OPS, 392 }, 393 .probe = mag3110_probe, 394 .remove = mag3110_remove, 395 .id_table = mag3110_id, 396 }; 397 module_i2c_driver(mag3110_driver); 398 399 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); 400 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver"); 401 MODULE_LICENSE("GPL"); 402