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 #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_set_bits(data->regmap, MMC35240_REG_CTRL0, 190 MMC35240_CTRL0_REFILL_BIT); 191 if (ret < 0) 192 return ret; 193 usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1); 194 195 if (set) 196 coil_bit = MMC35240_CTRL0_SET_BIT; 197 else 198 coil_bit = MMC35240_CTRL0_RESET_BIT; 199 200 return regmap_set_bits(data->regmap, MMC35240_REG_CTRL0, coil_bit); 201 202 } 203 204 static int mmc35240_init(struct mmc35240_data *data) 205 { 206 int ret, y_convert, z_convert; 207 unsigned int reg_id; 208 u8 otp_data[6]; 209 210 ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id); 211 if (ret < 0) { 212 dev_err(&data->client->dev, "Error reading product id\n"); 213 return ret; 214 } 215 216 dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id); 217 218 /* 219 * make sure we restore sensor characteristics, by doing 220 * a SET/RESET sequence, the axis polarity being naturally 221 * aligned after RESET 222 */ 223 ret = mmc35240_hw_set(data, true); 224 if (ret < 0) 225 return ret; 226 usleep_range(MMC35240_WAIT_SET_RESET, MMC35240_WAIT_SET_RESET + 1); 227 228 ret = mmc35240_hw_set(data, false); 229 if (ret < 0) 230 return ret; 231 232 /* set default sampling frequency */ 233 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, 234 MMC35240_CTRL1_BW_MASK, 235 data->res << MMC35240_CTRL1_BW_SHIFT); 236 if (ret < 0) 237 return ret; 238 239 ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR, 240 otp_data, sizeof(otp_data)); 241 if (ret < 0) 242 return ret; 243 244 y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) | 245 (otp_data[2] >> 4)); 246 z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f); 247 248 data->axis_coef[0] = MMC35240_X_COEFF(1); 249 data->axis_coef[1] = MMC35240_Y_COEFF(y_convert); 250 data->axis_coef[2] = MMC35240_Z_COEFF(z_convert); 251 252 data->axis_scale[0] = 1; 253 data->axis_scale[1] = 1000; 254 data->axis_scale[2] = 10000; 255 256 return 0; 257 } 258 259 static int mmc35240_take_measurement(struct mmc35240_data *data) 260 { 261 int ret, tries = 100; 262 unsigned int reg_status; 263 264 ret = regmap_write(data->regmap, MMC35240_REG_CTRL0, 265 MMC35240_CTRL0_TM_BIT); 266 if (ret < 0) 267 return ret; 268 269 while (tries-- > 0) { 270 ret = regmap_read(data->regmap, MMC35240_REG_STATUS, 271 ®_status); 272 if (ret < 0) 273 return ret; 274 if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT) 275 break; 276 /* minimum wait time to complete measurement is 10 ms */ 277 usleep_range(10000, 11000); 278 } 279 280 if (tries < 0) { 281 dev_err(&data->client->dev, "data not ready\n"); 282 return -EIO; 283 } 284 285 return 0; 286 } 287 288 static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3]) 289 { 290 int ret; 291 292 ret = mmc35240_take_measurement(data); 293 if (ret < 0) 294 return ret; 295 296 return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, buf, 297 3 * sizeof(__le16)); 298 } 299 300 /** 301 * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply 302 * compensation for output value. 303 * 304 * @data: device private data 305 * @index: axis index for which we want the conversion 306 * @buf: raw data to be converted, 2 bytes in little endian format 307 * @val: compensated output reading (unit is milli gauss) 308 * 309 * Returns: 0 in case of success, -EINVAL when @index is not valid 310 */ 311 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index, 312 __le16 buf[], int *val) 313 { 314 int raw[3]; 315 int sens[3]; 316 int nfo; 317 318 raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]); 319 raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]); 320 raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]); 321 322 sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X]; 323 sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y]; 324 sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z]; 325 326 nfo = mmc35240_props_table[data->res].nfo; 327 328 switch (index) { 329 case AXIS_X: 330 *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X]; 331 break; 332 case AXIS_Y: 333 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] - 334 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z]; 335 break; 336 case AXIS_Z: 337 *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] + 338 (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z]; 339 break; 340 default: 341 return -EINVAL; 342 } 343 /* apply OTP compensation */ 344 *val = (*val) * data->axis_coef[index] / data->axis_scale[index]; 345 346 return 0; 347 } 348 349 static int mmc35240_read_raw(struct iio_dev *indio_dev, 350 struct iio_chan_spec const *chan, int *val, 351 int *val2, long mask) 352 { 353 struct mmc35240_data *data = iio_priv(indio_dev); 354 int ret, i; 355 unsigned int reg; 356 __le16 buf[3]; 357 358 switch (mask) { 359 case IIO_CHAN_INFO_RAW: 360 mutex_lock(&data->mutex); 361 ret = mmc35240_read_measurement(data, buf); 362 mutex_unlock(&data->mutex); 363 if (ret < 0) 364 return ret; 365 ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val); 366 if (ret < 0) 367 return ret; 368 return IIO_VAL_INT; 369 case IIO_CHAN_INFO_SCALE: 370 *val = 0; 371 *val2 = 1000; 372 return IIO_VAL_INT_PLUS_MICRO; 373 case IIO_CHAN_INFO_SAMP_FREQ: 374 mutex_lock(&data->mutex); 375 ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®); 376 mutex_unlock(&data->mutex); 377 if (ret < 0) 378 return ret; 379 380 i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT; 381 if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq)) 382 return -EINVAL; 383 384 *val = mmc35240_samp_freq[i].val; 385 *val2 = mmc35240_samp_freq[i].val2; 386 return IIO_VAL_INT_PLUS_MICRO; 387 default: 388 return -EINVAL; 389 } 390 } 391 392 static int mmc35240_write_raw(struct iio_dev *indio_dev, 393 struct iio_chan_spec const *chan, int val, 394 int val2, long mask) 395 { 396 struct mmc35240_data *data = iio_priv(indio_dev); 397 int i, ret; 398 399 switch (mask) { 400 case IIO_CHAN_INFO_SAMP_FREQ: 401 i = mmc35240_get_samp_freq_index(data, val, val2); 402 if (i < 0) 403 return -EINVAL; 404 mutex_lock(&data->mutex); 405 ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, 406 MMC35240_CTRL1_BW_MASK, 407 i << MMC35240_CTRL1_BW_SHIFT); 408 mutex_unlock(&data->mutex); 409 return ret; 410 default: 411 return -EINVAL; 412 } 413 } 414 415 static const struct iio_info mmc35240_info = { 416 .read_raw = mmc35240_read_raw, 417 .write_raw = mmc35240_write_raw, 418 .attrs = &mmc35240_attribute_group, 419 }; 420 421 static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg) 422 { 423 switch (reg) { 424 case MMC35240_REG_CTRL0: 425 case MMC35240_REG_CTRL1: 426 return true; 427 default: 428 return false; 429 } 430 } 431 432 static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg) 433 { 434 switch (reg) { 435 case MMC35240_REG_XOUT_L: 436 case MMC35240_REG_XOUT_H: 437 case MMC35240_REG_YOUT_L: 438 case MMC35240_REG_YOUT_H: 439 case MMC35240_REG_ZOUT_L: 440 case MMC35240_REG_ZOUT_H: 441 case MMC35240_REG_STATUS: 442 case MMC35240_REG_ID: 443 return true; 444 default: 445 return false; 446 } 447 } 448 449 static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg) 450 { 451 switch (reg) { 452 case MMC35240_REG_CTRL0: 453 case MMC35240_REG_CTRL1: 454 return false; 455 default: 456 return true; 457 } 458 } 459 460 static const struct reg_default mmc35240_reg_defaults[] = { 461 { MMC35240_REG_CTRL0, 0x00 }, 462 { MMC35240_REG_CTRL1, 0x00 }, 463 }; 464 465 static const struct regmap_config mmc35240_regmap_config = { 466 .name = MMC35240_REGMAP_NAME, 467 468 .reg_bits = 8, 469 .val_bits = 8, 470 471 .max_register = MMC35240_REG_ID, 472 .cache_type = REGCACHE_FLAT, 473 474 .writeable_reg = mmc35240_is_writeable_reg, 475 .readable_reg = mmc35240_is_readable_reg, 476 .volatile_reg = mmc35240_is_volatile_reg, 477 478 .reg_defaults = mmc35240_reg_defaults, 479 .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults), 480 }; 481 482 static int mmc35240_probe(struct i2c_client *client) 483 { 484 struct mmc35240_data *data; 485 struct iio_dev *indio_dev; 486 struct regmap *regmap; 487 int ret; 488 489 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 490 if (!indio_dev) 491 return -ENOMEM; 492 493 regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config); 494 if (IS_ERR(regmap)) { 495 dev_err(&client->dev, "regmap initialization failed\n"); 496 return PTR_ERR(regmap); 497 } 498 499 data = iio_priv(indio_dev); 500 i2c_set_clientdata(client, indio_dev); 501 data->client = client; 502 data->regmap = regmap; 503 data->res = MMC35240_16_BITS_SLOW; 504 505 mutex_init(&data->mutex); 506 507 indio_dev->info = &mmc35240_info; 508 indio_dev->name = MMC35240_DRV_NAME; 509 indio_dev->channels = mmc35240_channels; 510 indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels); 511 indio_dev->modes = INDIO_DIRECT_MODE; 512 513 ret = mmc35240_init(data); 514 if (ret < 0) { 515 dev_err(&client->dev, "mmc35240 chip init failed\n"); 516 return ret; 517 } 518 return devm_iio_device_register(&client->dev, indio_dev); 519 } 520 521 static int mmc35240_suspend(struct device *dev) 522 { 523 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); 524 struct mmc35240_data *data = iio_priv(indio_dev); 525 526 regcache_cache_only(data->regmap, true); 527 528 return 0; 529 } 530 531 static int mmc35240_resume(struct device *dev) 532 { 533 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); 534 struct mmc35240_data *data = iio_priv(indio_dev); 535 int ret; 536 537 regcache_mark_dirty(data->regmap); 538 ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0, 539 MMC35240_REG_CTRL1); 540 if (ret < 0) 541 dev_err(dev, "Failed to restore control registers\n"); 542 543 regcache_cache_only(data->regmap, false); 544 545 return 0; 546 } 547 548 static DEFINE_SIMPLE_DEV_PM_OPS(mmc35240_pm_ops, mmc35240_suspend, 549 mmc35240_resume); 550 551 static const struct of_device_id mmc35240_of_match[] = { 552 { .compatible = "memsic,mmc35240", }, 553 { } 554 }; 555 MODULE_DEVICE_TABLE(of, mmc35240_of_match); 556 557 static const struct acpi_device_id mmc35240_acpi_match[] = { 558 {"MMC35240", 0}, 559 { }, 560 }; 561 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match); 562 563 static const struct i2c_device_id mmc35240_id[] = { 564 { "mmc35240" }, 565 {} 566 }; 567 MODULE_DEVICE_TABLE(i2c, mmc35240_id); 568 569 static struct i2c_driver mmc35240_driver = { 570 .driver = { 571 .name = MMC35240_DRV_NAME, 572 .of_match_table = mmc35240_of_match, 573 .pm = pm_sleep_ptr(&mmc35240_pm_ops), 574 .acpi_match_table = mmc35240_acpi_match, 575 }, 576 .probe = mmc35240_probe, 577 .id_table = mmc35240_id, 578 }; 579 580 module_i2c_driver(mmc35240_driver); 581 582 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); 583 MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver"); 584 MODULE_LICENSE("GPL v2"); 585