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/init.h> 14 #include <linux/i2c.h> 15 #include <linux/delay.h> 16 #include <linux/regmap.h> 17 #include <linux/acpi.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 #define MMC35240_REGMAP_NAME "mmc35240_regmap" 25 26 #define MMC35240_REG_XOUT_L 0x00 27 #define MMC35240_REG_XOUT_H 0x01 28 #define MMC35240_REG_YOUT_L 0x02 29 #define MMC35240_REG_YOUT_H 0x03 30 #define MMC35240_REG_ZOUT_L 0x04 31 #define MMC35240_REG_ZOUT_H 0x05 32 33 #define MMC35240_REG_STATUS 0x06 34 #define MMC35240_REG_CTRL0 0x07 35 #define MMC35240_REG_CTRL1 0x08 36 37 #define MMC35240_REG_ID 0x20 38 39 #define MMC35240_STATUS_MEAS_DONE_BIT BIT(0) 40 41 #define MMC35240_CTRL0_REFILL_BIT BIT(7) 42 #define MMC35240_CTRL0_RESET_BIT BIT(6) 43 #define MMC35240_CTRL0_SET_BIT BIT(5) 44 #define MMC35240_CTRL0_CMM_BIT BIT(1) 45 #define MMC35240_CTRL0_TM_BIT BIT(0) 46 47 /* output resolution bits */ 48 #define MMC35240_CTRL1_BW0_BIT BIT(0) 49 #define MMC35240_CTRL1_BW1_BIT BIT(1) 50 51 #define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \ 52 MMC35240_CTRL1_BW1_BIT) 53 #define MMC35240_CTRL1_BW_SHIFT 0 54 55 #define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */ 56 #define MMC35240_WAIT_SET_RESET 1000 /* us */ 57 58 /* 59 * Memsic OTP process code piece is put here for reference: 60 * 61 * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006 62 * 1) For X axis, the COEFFICIENT is always 1. 63 * 2) For Y axis, the COEFFICIENT is as below: 64 * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) | 65 * (reg_data[2] >> 4)) + 1.0; 66 * 3) For Z axis, the COEFFICIENT is as below: 67 * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35; 68 * We implemented the OTP logic into driver. 69 */ 70 71 /* scale = 1000 here for Y otp */ 72 #define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6) 73 74 /* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */ 75 #define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81) 76 77 #define MMC35240_X_COEFF(x) (x) 78 #define MMC35240_Y_COEFF(y) (y + 1000) 79 #define MMC35240_Z_COEFF(z) (z + 13500) 80 81 #define MMC35240_OTP_START_ADDR 0x1B 82 83 enum mmc35240_resolution { 84 MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */ 85 MMC35240_16_BITS_FAST, /* 4.08 ms */ 86 MMC35240_14_BITS, /* 2.16 ms */ 87 MMC35240_12_BITS, /* 1.20 ms */ 88 }; 89 90 enum mmc35240_axis { 91 AXIS_X = 0, 92 AXIS_Y, 93 AXIS_Z, 94 }; 95 96 static const struct { 97 int sens[3]; /* sensitivity per X, Y, Z axis */ 98 int nfo; /* null field output */ 99 } mmc35240_props_table[] = { 100 /* 16 bits, 125Hz ODR */ 101 { 102 {1024, 1024, 1024}, 103 32768, 104 }, 105 /* 16 bits, 250Hz ODR */ 106 { 107 {1024, 1024, 770}, 108 32768, 109 }, 110 /* 14 bits, 450Hz ODR */ 111 { 112 {256, 256, 193}, 113 8192, 114 }, 115 /* 12 bits, 800Hz ODR */ 116 { 117 {64, 64, 48}, 118 2048, 119 }, 120 }; 121 122 struct mmc35240_data { 123 struct i2c_client *client; 124 struct mutex mutex; 125 struct regmap *regmap; 126 enum mmc35240_resolution res; 127 128 /* OTP compensation */ 129 int axis_coef[3]; 130 int axis_scale[3]; 131 }; 132 133 static const struct { 134 int val; 135 int val2; 136 } mmc35240_samp_freq[] = { {1, 500000}, 137 {13, 0}, 138 {25, 0}, 139 {50, 0} }; 140 141 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50"); 142 143 #define MMC35240_CHANNEL(_axis) { \ 144 .type = IIO_MAGN, \ 145 .modified = 1, \ 146 .channel2 = IIO_MOD_ ## _axis, \ 147 .address = AXIS_ ## _axis, \ 148 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 149 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ 150 BIT(IIO_CHAN_INFO_SCALE), \ 151 } 152 153 static const struct iio_chan_spec mmc35240_channels[] = { 154 MMC35240_CHANNEL(X), 155 MMC35240_CHANNEL(Y), 156 MMC35240_CHANNEL(Z), 157 }; 158 159 static struct attribute *mmc35240_attributes[] = { 160 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 161 NULL 162 }; 163 164 static const struct attribute_group mmc35240_attribute_group = { 165 .attrs = mmc35240_attributes, 166 }; 167 168 static int mmc35240_get_samp_freq_index(struct mmc35240_data *data, 169 int val, int val2) 170 { 171 int i; 172 173 for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++) 174 if (mmc35240_samp_freq[i].val == val && 175 mmc35240_samp_freq[i].val2 == val2) 176 return i; 177 return -EINVAL; 178 } 179 180 static int mmc35240_hw_set(struct mmc35240_data *data, bool set) 181 { 182 int ret; 183 u8 coil_bit; 184 185 /* 186 * Recharge the capacitor at VCAP pin, requested to be issued 187 * before a SET/RESET command. 188 */ 189 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0, 190 MMC35240_CTRL0_REFILL_BIT, 191 MMC35240_CTRL0_REFILL_BIT); 192 if (ret < 0) 193 return ret; 194 usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1); 195 196 if (set) 197 coil_bit = MMC35240_CTRL0_SET_BIT; 198 else 199 coil_bit = MMC35240_CTRL0_RESET_BIT; 200 201 return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0, 202 coil_bit, coil_bit); 203 204 } 205 206 static int mmc35240_init(struct mmc35240_data *data) 207 { 208 int ret, y_convert, z_convert; 209 unsigned int reg_id; 210 u8 otp_data[6]; 211 212 ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id); 213 if (ret < 0) { 214 dev_err(&data->client->dev, "Error reading product id\n"); 215 return ret; 216 } 217 218 dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id); 219 220 /* 221 * make sure we restore sensor characteristics, by doing 222 * a SET/RESET sequence, the axis polarity being naturally 223 * aligned after RESET 224 */ 225 ret = mmc35240_hw_set(data, true); 226 if (ret < 0) 227 return ret; 228 usleep_range(MMC35240_WAIT_SET_RESET, MMC35240_WAIT_SET_RESET + 1); 229 230 ret = mmc35240_hw_set(data, false); 231 if (ret < 0) 232 return ret; 233 234 /* set default sampling frequency */ 235 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, 236 MMC35240_CTRL1_BW_MASK, 237 data->res << MMC35240_CTRL1_BW_SHIFT); 238 if (ret < 0) 239 return ret; 240 241 ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR, 242 otp_data, sizeof(otp_data)); 243 if (ret < 0) 244 return ret; 245 246 y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) | 247 (otp_data[2] >> 4)); 248 z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f); 249 250 data->axis_coef[0] = MMC35240_X_COEFF(1); 251 data->axis_coef[1] = MMC35240_Y_COEFF(y_convert); 252 data->axis_coef[2] = MMC35240_Z_COEFF(z_convert); 253 254 data->axis_scale[0] = 1; 255 data->axis_scale[1] = 1000; 256 data->axis_scale[2] = 10000; 257 258 return 0; 259 } 260 261 static int mmc35240_take_measurement(struct mmc35240_data *data) 262 { 263 int ret, tries = 100; 264 unsigned int reg_status; 265 266 ret = regmap_write(data->regmap, MMC35240_REG_CTRL0, 267 MMC35240_CTRL0_TM_BIT); 268 if (ret < 0) 269 return ret; 270 271 while (tries-- > 0) { 272 ret = regmap_read(data->regmap, MMC35240_REG_STATUS, 273 ®_status); 274 if (ret < 0) 275 return ret; 276 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT) 277 break; 278 /* minimum wait time to complete measurement is 10 ms */ 279 usleep_range(10000, 11000); 280 } 281 282 if (tries < 0) { 283 dev_err(&data->client->dev, "data not ready\n"); 284 return -EIO; 285 } 286 287 return 0; 288 } 289 290 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3]) 291 { 292 int ret; 293 294 ret = mmc35240_take_measurement(data); 295 if (ret < 0) 296 return ret; 297 298 return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, buf, 299 3 * sizeof(__le16)); 300 } 301 302 /** 303 * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply 304 * compensation for output value. 305 * 306 * @data: device private data 307 * @index: axis index for which we want the conversion 308 * @buf: raw data to be converted, 2 bytes in little endian format 309 * @val: compensated output reading (unit is milli gauss) 310 * 311 * Returns: 0 in case of success, -EINVAL when @index is not valid 312 */ 313 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index, 314 __le16 buf[], int *val) 315 { 316 int raw[3]; 317 int sens[3]; 318 int nfo; 319 320 raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]); 321 raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]); 322 raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]); 323 324 sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X]; 325 sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y]; 326 sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z]; 327 328 nfo = mmc35240_props_table[data->res].nfo; 329 330 switch (index) { 331 case AXIS_X: 332 *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X]; 333 break; 334 case AXIS_Y: 335 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] - 336 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z]; 337 break; 338 case AXIS_Z: 339 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] + 340 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z]; 341 break; 342 default: 343 return -EINVAL; 344 } 345 /* apply OTP compensation */ 346 *val = (*val) * data->axis_coef[index] / data->axis_scale[index]; 347 348 return 0; 349 } 350 351 static int mmc35240_read_raw(struct iio_dev *indio_dev, 352 struct iio_chan_spec const *chan, int *val, 353 int *val2, long mask) 354 { 355 struct mmc35240_data *data = iio_priv(indio_dev); 356 int ret, i; 357 unsigned int reg; 358 __le16 buf[3]; 359 360 switch (mask) { 361 case IIO_CHAN_INFO_RAW: 362 mutex_lock(&data->mutex); 363 ret = mmc35240_read_measurement(data, buf); 364 mutex_unlock(&data->mutex); 365 if (ret < 0) 366 return ret; 367 ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val); 368 if (ret < 0) 369 return ret; 370 return IIO_VAL_INT; 371 case IIO_CHAN_INFO_SCALE: 372 *val = 0; 373 *val2 = 1000; 374 return IIO_VAL_INT_PLUS_MICRO; 375 case IIO_CHAN_INFO_SAMP_FREQ: 376 mutex_lock(&data->mutex); 377 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®); 378 mutex_unlock(&data->mutex); 379 if (ret < 0) 380 return ret; 381 382 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT; 383 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq)) 384 return -EINVAL; 385 386 *val = mmc35240_samp_freq[i].val; 387 *val2 = mmc35240_samp_freq[i].val2; 388 return IIO_VAL_INT_PLUS_MICRO; 389 default: 390 return -EINVAL; 391 } 392 } 393 394 static int mmc35240_write_raw(struct iio_dev *indio_dev, 395 struct iio_chan_spec const *chan, int val, 396 int val2, long mask) 397 { 398 struct mmc35240_data *data = iio_priv(indio_dev); 399 int i, ret; 400 401 switch (mask) { 402 case IIO_CHAN_INFO_SAMP_FREQ: 403 i = mmc35240_get_samp_freq_index(data, val, val2); 404 if (i < 0) 405 return -EINVAL; 406 mutex_lock(&data->mutex); 407 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, 408 MMC35240_CTRL1_BW_MASK, 409 i << MMC35240_CTRL1_BW_SHIFT); 410 mutex_unlock(&data->mutex); 411 return ret; 412 default: 413 return -EINVAL; 414 } 415 } 416 417 static const struct iio_info mmc35240_info = { 418 .read_raw = mmc35240_read_raw, 419 .write_raw = mmc35240_write_raw, 420 .attrs = &mmc35240_attribute_group, 421 }; 422 423 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg) 424 { 425 switch (reg) { 426 case MMC35240_REG_CTRL0: 427 case MMC35240_REG_CTRL1: 428 return true; 429 default: 430 return false; 431 } 432 } 433 434 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg) 435 { 436 switch (reg) { 437 case MMC35240_REG_XOUT_L: 438 case MMC35240_REG_XOUT_H: 439 case MMC35240_REG_YOUT_L: 440 case MMC35240_REG_YOUT_H: 441 case MMC35240_REG_ZOUT_L: 442 case MMC35240_REG_ZOUT_H: 443 case MMC35240_REG_STATUS: 444 case MMC35240_REG_ID: 445 return true; 446 default: 447 return false; 448 } 449 } 450 451 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg) 452 { 453 switch (reg) { 454 case MMC35240_REG_CTRL0: 455 case MMC35240_REG_CTRL1: 456 return false; 457 default: 458 return true; 459 } 460 } 461 462 static const struct reg_default mmc35240_reg_defaults[] = { 463 { MMC35240_REG_CTRL0, 0x00 }, 464 { MMC35240_REG_CTRL1, 0x00 }, 465 }; 466 467 static const struct regmap_config mmc35240_regmap_config = { 468 .name = MMC35240_REGMAP_NAME, 469 470 .reg_bits = 8, 471 .val_bits = 8, 472 473 .max_register = MMC35240_REG_ID, 474 .cache_type = REGCACHE_FLAT, 475 476 .writeable_reg = mmc35240_is_writeable_reg, 477 .readable_reg = mmc35240_is_readable_reg, 478 .volatile_reg = mmc35240_is_volatile_reg, 479 480 .reg_defaults = mmc35240_reg_defaults, 481 .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults), 482 }; 483 484 static int mmc35240_probe(struct i2c_client *client) 485 { 486 struct mmc35240_data *data; 487 struct iio_dev *indio_dev; 488 struct regmap *regmap; 489 int ret; 490 491 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 492 if (!indio_dev) 493 return -ENOMEM; 494 495 regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config); 496 if (IS_ERR(regmap)) { 497 dev_err(&client->dev, "regmap initialization failed\n"); 498 return PTR_ERR(regmap); 499 } 500 501 data = iio_priv(indio_dev); 502 i2c_set_clientdata(client, indio_dev); 503 data->client = client; 504 data->regmap = regmap; 505 data->res = MMC35240_16_BITS_SLOW; 506 507 mutex_init(&data->mutex); 508 509 indio_dev->info = &mmc35240_info; 510 indio_dev->name = MMC35240_DRV_NAME; 511 indio_dev->channels = mmc35240_channels; 512 indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels); 513 indio_dev->modes = INDIO_DIRECT_MODE; 514 515 ret = mmc35240_init(data); 516 if (ret < 0) { 517 dev_err(&client->dev, "mmc35240 chip init failed\n"); 518 return ret; 519 } 520 return devm_iio_device_register(&client->dev, indio_dev); 521 } 522 523 static int mmc35240_suspend(struct device *dev) 524 { 525 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); 526 struct mmc35240_data *data = iio_priv(indio_dev); 527 528 regcache_cache_only(data->regmap, true); 529 530 return 0; 531 } 532 533 static int mmc35240_resume(struct device *dev) 534 { 535 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); 536 struct mmc35240_data *data = iio_priv(indio_dev); 537 int ret; 538 539 regcache_mark_dirty(data->regmap); 540 ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0, 541 MMC35240_REG_CTRL1); 542 if (ret < 0) 543 dev_err(dev, "Failed to restore control registers\n"); 544 545 regcache_cache_only(data->regmap, false); 546 547 return 0; 548 } 549 550 static DEFINE_SIMPLE_DEV_PM_OPS(mmc35240_pm_ops, mmc35240_suspend, 551 mmc35240_resume); 552 553 static const struct of_device_id mmc35240_of_match[] = { 554 { .compatible = "memsic,mmc35240", }, 555 { } 556 }; 557 MODULE_DEVICE_TABLE(of, mmc35240_of_match); 558 559 static const struct acpi_device_id mmc35240_acpi_match[] = { 560 {"MMC35240", 0}, 561 { }, 562 }; 563 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match); 564 565 static const struct i2c_device_id mmc35240_id[] = { 566 {"mmc35240", 0}, 567 {} 568 }; 569 MODULE_DEVICE_TABLE(i2c, mmc35240_id); 570 571 static struct i2c_driver mmc35240_driver = { 572 .driver = { 573 .name = MMC35240_DRV_NAME, 574 .of_match_table = mmc35240_of_match, 575 .pm = pm_sleep_ptr(&mmc35240_pm_ops), 576 .acpi_match_table = ACPI_PTR(mmc35240_acpi_match), 577 }, 578 .probe = mmc35240_probe, 579 .id_table = mmc35240_id, 580 }; 581 582 module_i2c_driver(mmc35240_driver); 583 584 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); 585 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver"); 586 MODULE_LICENSE("GPL v2"); 587