1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * MMC35240 - MEMSIC 3-axis Magnetic Sensor 4 * 5 * Copyright (c) 2015, Intel Corporation. 6 * 7 * IIO driver for MMC35240 (7-bit I2C slave address 0x30). 8 * 9 * TODO: offset, ACPI, continuous measurement mode, PM 10 */ 11 12 #include <linux/module.h> 13 #include <linux/mod_devicetable.h> 14 #include <linux/init.h> 15 #include <linux/i2c.h> 16 #include <linux/delay.h> 17 #include <linux/regmap.h> 18 #include <linux/pm.h> 19 20 #include <linux/iio/iio.h> 21 #include <linux/iio/sysfs.h> 22 23 #define MMC35240_DRV_NAME "mmc35240" 24 25 #define MMC35240_REG_XOUT_L 0x00 26 #define MMC35240_REG_XOUT_H 0x01 27 #define MMC35240_REG_YOUT_L 0x02 28 #define MMC35240_REG_YOUT_H 0x03 29 #define MMC35240_REG_ZOUT_L 0x04 30 #define MMC35240_REG_ZOUT_H 0x05 31 32 #define MMC35240_REG_STATUS 0x06 33 #define MMC35240_REG_CTRL0 0x07 34 #define MMC35240_REG_CTRL1 0x08 35 36 #define MMC35240_REG_ID 0x20 37 38 #define MMC35240_STATUS_MEAS_DONE_BIT BIT(0) 39 40 #define MMC35240_CTRL0_REFILL_BIT BIT(7) 41 #define MMC35240_CTRL0_RESET_BIT BIT(6) 42 #define MMC35240_CTRL0_SET_BIT BIT(5) 43 #define MMC35240_CTRL0_CMM_BIT BIT(1) 44 #define MMC35240_CTRL0_TM_BIT BIT(0) 45 46 /* output resolution bits */ 47 #define MMC35240_CTRL1_BW0_BIT BIT(0) 48 #define MMC35240_CTRL1_BW1_BIT BIT(1) 49 50 #define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \ 51 MMC35240_CTRL1_BW1_BIT) 52 #define MMC35240_CTRL1_BW_SHIFT 0 53 54 #define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */ 55 #define MMC35240_WAIT_SET_RESET 1000 /* us */ 56 57 /* 58 * Memsic OTP process code piece is put here for reference: 59 * 60 * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006 61 * 1) For X axis, the COEFFICIENT is always 1. 62 * 2) For Y axis, the COEFFICIENT is as below: 63 * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) | 64 * (reg_data[2] >> 4)) + 1.0; 65 * 3) For Z axis, the COEFFICIENT is as below: 66 * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35; 67 * We implemented the OTP logic into driver. 68 */ 69 70 /* scale = 1000 here for Y otp */ 71 #define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6) 72 73 /* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */ 74 #define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81) 75 76 #define MMC35240_X_COEFF(x) (x) 77 #define MMC35240_Y_COEFF(y) (y + 1000) 78 #define MMC35240_Z_COEFF(z) (z + 13500) 79 80 #define MMC35240_OTP_START_ADDR 0x1B 81 82 enum mmc35240_resolution { 83 MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */ 84 MMC35240_16_BITS_FAST, /* 4.08 ms */ 85 MMC35240_14_BITS, /* 2.16 ms */ 86 MMC35240_12_BITS, /* 1.20 ms */ 87 }; 88 89 enum mmc35240_axis { 90 AXIS_X = 0, 91 AXIS_Y, 92 AXIS_Z, 93 }; 94 95 static const struct { 96 int sens[3]; /* sensitivity per X, Y, Z axis */ 97 int nfo; /* null field output */ 98 } mmc35240_props_table[] = { 99 /* 16 bits, 125Hz ODR */ 100 { 101 {1024, 1024, 1024}, 102 32768, 103 }, 104 /* 16 bits, 250Hz ODR */ 105 { 106 {1024, 1024, 770}, 107 32768, 108 }, 109 /* 14 bits, 450Hz ODR */ 110 { 111 {256, 256, 193}, 112 8192, 113 }, 114 /* 12 bits, 800Hz ODR */ 115 { 116 {64, 64, 48}, 117 2048, 118 }, 119 }; 120 121 struct mmc35240_data { 122 struct i2c_client *client; 123 struct mutex mutex; 124 struct regmap *regmap; 125 enum mmc35240_resolution res; 126 127 /* OTP compensation */ 128 int axis_coef[3]; 129 int axis_scale[3]; 130 }; 131 132 static const struct { 133 int val; 134 int val2; 135 } mmc35240_samp_freq[] = { {1, 500000}, 136 {13, 0}, 137 {25, 0}, 138 {50, 0} }; 139 140 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50"); 141 142 #define MMC35240_CHANNEL(_axis) { \ 143 .type = IIO_MAGN, \ 144 .modified = 1, \ 145 .channel2 = IIO_MOD_ ## _axis, \ 146 .address = AXIS_ ## _axis, \ 147 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 148 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ 149 BIT(IIO_CHAN_INFO_SCALE), \ 150 } 151 152 static const struct iio_chan_spec mmc35240_channels[] = { 153 MMC35240_CHANNEL(X), 154 MMC35240_CHANNEL(Y), 155 MMC35240_CHANNEL(Z), 156 }; 157 158 static struct attribute *mmc35240_attributes[] = { 159 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 160 NULL 161 }; 162 163 static const struct attribute_group mmc35240_attribute_group = { 164 .attrs = mmc35240_attributes, 165 }; 166 167 static int mmc35240_get_samp_freq_index(struct mmc35240_data *data, 168 int val, int val2) 169 { 170 int i; 171 172 for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++) 173 if (mmc35240_samp_freq[i].val == val && 174 mmc35240_samp_freq[i].val2 == val2) 175 return i; 176 return -EINVAL; 177 } 178 179 static int mmc35240_hw_set(struct mmc35240_data *data, bool set) 180 { 181 int ret; 182 u8 coil_bit; 183 184 /* 185 * Recharge the capacitor at VCAP pin, requested to be issued 186 * before a SET/RESET command. 187 */ 188 ret = regmap_set_bits(data->regmap, MMC35240_REG_CTRL0, 189 MMC35240_CTRL0_REFILL_BIT); 190 if (ret < 0) 191 return ret; 192 usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1); 193 194 if (set) 195 coil_bit = MMC35240_CTRL0_SET_BIT; 196 else 197 coil_bit = MMC35240_CTRL0_RESET_BIT; 198 199 return regmap_set_bits(data->regmap, MMC35240_REG_CTRL0, coil_bit); 200 201 } 202 203 static int mmc35240_init(struct mmc35240_data *data) 204 { 205 int ret, y_convert, z_convert; 206 unsigned int reg_id; 207 u8 otp_data[6]; 208 209 ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id); 210 if (ret < 0) { 211 dev_err(&data->client->dev, "Error reading product id\n"); 212 return ret; 213 } 214 215 dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id); 216 217 /* 218 * make sure we restore sensor characteristics, by doing 219 * a SET/RESET sequence, the axis polarity being naturally 220 * aligned after RESET 221 */ 222 ret = mmc35240_hw_set(data, true); 223 if (ret < 0) 224 return ret; 225 usleep_range(MMC35240_WAIT_SET_RESET, MMC35240_WAIT_SET_RESET + 1); 226 227 ret = mmc35240_hw_set(data, false); 228 if (ret < 0) 229 return ret; 230 231 /* set default sampling frequency */ 232 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, 233 MMC35240_CTRL1_BW_MASK, 234 data->res << MMC35240_CTRL1_BW_SHIFT); 235 if (ret < 0) 236 return ret; 237 238 ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR, 239 otp_data, sizeof(otp_data)); 240 if (ret < 0) 241 return ret; 242 243 y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) | 244 (otp_data[2] >> 4)); 245 z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f); 246 247 data->axis_coef[0] = MMC35240_X_COEFF(1); 248 data->axis_coef[1] = MMC35240_Y_COEFF(y_convert); 249 data->axis_coef[2] = MMC35240_Z_COEFF(z_convert); 250 251 data->axis_scale[0] = 1; 252 data->axis_scale[1] = 1000; 253 data->axis_scale[2] = 10000; 254 255 return 0; 256 } 257 258 static int mmc35240_take_measurement(struct mmc35240_data *data) 259 { 260 int ret, tries = 100; 261 unsigned int reg_status; 262 263 ret = regmap_write(data->regmap, MMC35240_REG_CTRL0, 264 MMC35240_CTRL0_TM_BIT); 265 if (ret < 0) 266 return ret; 267 268 while (tries-- > 0) { 269 ret = regmap_read(data->regmap, MMC35240_REG_STATUS, 270 ®_status); 271 if (ret < 0) 272 return ret; 273 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT) 274 break; 275 /* minimum wait time to complete measurement is 10 ms */ 276 usleep_range(10000, 11000); 277 } 278 279 if (tries < 0) { 280 dev_err(&data->client->dev, "data not ready\n"); 281 return -EIO; 282 } 283 284 return 0; 285 } 286 287 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3]) 288 { 289 int ret; 290 291 ret = mmc35240_take_measurement(data); 292 if (ret < 0) 293 return ret; 294 295 return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, buf, 296 3 * sizeof(__le16)); 297 } 298 299 /** 300 * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply 301 * compensation for output value. 302 * 303 * @data: device private data 304 * @index: axis index for which we want the conversion 305 * @buf: raw data to be converted, 2 bytes in little endian format 306 * @val: compensated output reading (unit is milli gauss) 307 * 308 * Returns: 0 in case of success, -EINVAL when @index is not valid 309 */ 310 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index, 311 __le16 buf[], int *val) 312 { 313 int raw[3]; 314 int sens[3]; 315 int nfo; 316 317 raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]); 318 raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]); 319 raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]); 320 321 sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X]; 322 sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y]; 323 sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z]; 324 325 nfo = mmc35240_props_table[data->res].nfo; 326 327 switch (index) { 328 case AXIS_X: 329 *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X]; 330 break; 331 case AXIS_Y: 332 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] - 333 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z]; 334 break; 335 case AXIS_Z: 336 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] + 337 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z]; 338 break; 339 default: 340 return -EINVAL; 341 } 342 /* apply OTP compensation */ 343 *val = (*val) * data->axis_coef[index] / data->axis_scale[index]; 344 345 return 0; 346 } 347 348 static int mmc35240_read_raw(struct iio_dev *indio_dev, 349 struct iio_chan_spec const *chan, int *val, 350 int *val2, long mask) 351 { 352 struct mmc35240_data *data = iio_priv(indio_dev); 353 int ret, i; 354 unsigned int reg; 355 __le16 buf[3]; 356 357 switch (mask) { 358 case IIO_CHAN_INFO_RAW: 359 mutex_lock(&data->mutex); 360 ret = mmc35240_read_measurement(data, buf); 361 mutex_unlock(&data->mutex); 362 if (ret < 0) 363 return ret; 364 ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val); 365 if (ret < 0) 366 return ret; 367 return IIO_VAL_INT; 368 case IIO_CHAN_INFO_SCALE: 369 *val = 0; 370 *val2 = 1000; 371 return IIO_VAL_INT_PLUS_MICRO; 372 case IIO_CHAN_INFO_SAMP_FREQ: 373 mutex_lock(&data->mutex); 374 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®); 375 mutex_unlock(&data->mutex); 376 if (ret < 0) 377 return ret; 378 379 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT; 380 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq)) 381 return -EINVAL; 382 383 *val = mmc35240_samp_freq[i].val; 384 *val2 = mmc35240_samp_freq[i].val2; 385 return IIO_VAL_INT_PLUS_MICRO; 386 default: 387 return -EINVAL; 388 } 389 } 390 391 static int mmc35240_write_raw(struct iio_dev *indio_dev, 392 struct iio_chan_spec const *chan, int val, 393 int val2, long mask) 394 { 395 struct mmc35240_data *data = iio_priv(indio_dev); 396 int i, ret; 397 398 switch (mask) { 399 case IIO_CHAN_INFO_SAMP_FREQ: 400 i = mmc35240_get_samp_freq_index(data, val, val2); 401 if (i < 0) 402 return -EINVAL; 403 mutex_lock(&data->mutex); 404 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, 405 MMC35240_CTRL1_BW_MASK, 406 i << MMC35240_CTRL1_BW_SHIFT); 407 mutex_unlock(&data->mutex); 408 return ret; 409 default: 410 return -EINVAL; 411 } 412 } 413 414 static const struct iio_info mmc35240_info = { 415 .read_raw = mmc35240_read_raw, 416 .write_raw = mmc35240_write_raw, 417 .attrs = &mmc35240_attribute_group, 418 }; 419 420 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg) 421 { 422 switch (reg) { 423 case MMC35240_REG_CTRL0: 424 case MMC35240_REG_CTRL1: 425 return true; 426 default: 427 return false; 428 } 429 } 430 431 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg) 432 { 433 switch (reg) { 434 case MMC35240_REG_XOUT_L: 435 case MMC35240_REG_XOUT_H: 436 case MMC35240_REG_YOUT_L: 437 case MMC35240_REG_YOUT_H: 438 case MMC35240_REG_ZOUT_L: 439 case MMC35240_REG_ZOUT_H: 440 case MMC35240_REG_STATUS: 441 case MMC35240_REG_ID: 442 return true; 443 default: 444 return false; 445 } 446 } 447 448 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg) 449 { 450 switch (reg) { 451 case MMC35240_REG_CTRL0: 452 case MMC35240_REG_CTRL1: 453 return false; 454 default: 455 return true; 456 } 457 } 458 459 static const struct reg_default mmc35240_reg_defaults[] = { 460 { MMC35240_REG_CTRL0, 0x00 }, 461 { MMC35240_REG_CTRL1, 0x00 }, 462 }; 463 464 static const struct regmap_config mmc35240_regmap_config = { 465 .name = "mmc35240_regmap", 466 467 .reg_bits = 8, 468 .val_bits = 8, 469 470 .max_register = MMC35240_REG_ID, 471 .cache_type = REGCACHE_FLAT, 472 473 .writeable_reg = mmc35240_is_writeable_reg, 474 .readable_reg = mmc35240_is_readable_reg, 475 .volatile_reg = mmc35240_is_volatile_reg, 476 477 .reg_defaults = mmc35240_reg_defaults, 478 .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults), 479 }; 480 481 static int mmc35240_probe(struct i2c_client *client) 482 { 483 struct mmc35240_data *data; 484 struct iio_dev *indio_dev; 485 struct regmap *regmap; 486 int ret; 487 488 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 489 if (!indio_dev) 490 return -ENOMEM; 491 492 regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config); 493 if (IS_ERR(regmap)) { 494 dev_err(&client->dev, "regmap initialization failed\n"); 495 return PTR_ERR(regmap); 496 } 497 498 data = iio_priv(indio_dev); 499 i2c_set_clientdata(client, indio_dev); 500 data->client = client; 501 data->regmap = regmap; 502 data->res = MMC35240_16_BITS_SLOW; 503 504 mutex_init(&data->mutex); 505 506 indio_dev->info = &mmc35240_info; 507 indio_dev->name = MMC35240_DRV_NAME; 508 indio_dev->channels = mmc35240_channels; 509 indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels); 510 indio_dev->modes = INDIO_DIRECT_MODE; 511 512 ret = mmc35240_init(data); 513 if (ret < 0) { 514 dev_err(&client->dev, "mmc35240 chip init failed\n"); 515 return ret; 516 } 517 return devm_iio_device_register(&client->dev, indio_dev); 518 } 519 520 static int mmc35240_suspend(struct device *dev) 521 { 522 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); 523 struct mmc35240_data *data = iio_priv(indio_dev); 524 525 regcache_cache_only(data->regmap, true); 526 527 return 0; 528 } 529 530 static int mmc35240_resume(struct device *dev) 531 { 532 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); 533 struct mmc35240_data *data = iio_priv(indio_dev); 534 int ret; 535 536 regcache_mark_dirty(data->regmap); 537 ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0, 538 MMC35240_REG_CTRL1); 539 if (ret < 0) 540 dev_err(dev, "Failed to restore control registers\n"); 541 542 regcache_cache_only(data->regmap, false); 543 544 return 0; 545 } 546 547 static DEFINE_SIMPLE_DEV_PM_OPS(mmc35240_pm_ops, mmc35240_suspend, 548 mmc35240_resume); 549 550 static const struct of_device_id mmc35240_of_match[] = { 551 { .compatible = "memsic,mmc35240", }, 552 { } 553 }; 554 MODULE_DEVICE_TABLE(of, mmc35240_of_match); 555 556 static const struct acpi_device_id mmc35240_acpi_match[] = { 557 {"MMC35240", 0}, 558 { } 559 }; 560 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match); 561 562 static const struct i2c_device_id mmc35240_id[] = { 563 { "mmc35240" }, 564 { } 565 }; 566 MODULE_DEVICE_TABLE(i2c, mmc35240_id); 567 568 static struct i2c_driver mmc35240_driver = { 569 .driver = { 570 .name = MMC35240_DRV_NAME, 571 .of_match_table = mmc35240_of_match, 572 .pm = pm_sleep_ptr(&mmc35240_pm_ops), 573 .acpi_match_table = mmc35240_acpi_match, 574 }, 575 .probe = mmc35240_probe, 576 .id_table = mmc35240_id, 577 }; 578 579 module_i2c_driver(mmc35240_driver); 580 581 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); 582 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver"); 583 MODULE_LICENSE("GPL v2"); 584