| 1 | /* |
| 2 | * MMC35240 - MEMSIC 3-axis Magnetic Sensor |
| 3 | * |
| 4 | * Copyright (c) 2015, Intel Corporation. |
| 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 | * IIO driver for MMC35240 (7-bit I2C slave address 0x30). |
| 11 | * |
| 12 | * TODO: offset, ACPI, continuous measurement mode, PM |
| 13 | */ |
| 14 | |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/i2c.h> |
| 18 | #include <linux/delay.h> |
| 19 | #include <linux/regmap.h> |
| 20 | #include <linux/acpi.h> |
| 21 | #include <linux/pm.h> |
| 22 | |
| 23 | #include <linux/iio/iio.h> |
| 24 | #include <linux/iio/sysfs.h> |
| 25 | |
| 26 | #define MMC35240_DRV_NAME "mmc35240" |
| 27 | #define MMC35240_REGMAP_NAME "mmc35240_regmap" |
| 28 | |
| 29 | #define MMC35240_REG_XOUT_L 0x00 |
| 30 | #define MMC35240_REG_XOUT_H 0x01 |
| 31 | #define MMC35240_REG_YOUT_L 0x02 |
| 32 | #define MMC35240_REG_YOUT_H 0x03 |
| 33 | #define MMC35240_REG_ZOUT_L 0x04 |
| 34 | #define MMC35240_REG_ZOUT_H 0x05 |
| 35 | |
| 36 | #define MMC35240_REG_STATUS 0x06 |
| 37 | #define MMC35240_REG_CTRL0 0x07 |
| 38 | #define MMC35240_REG_CTRL1 0x08 |
| 39 | |
| 40 | #define MMC35240_REG_ID 0x20 |
| 41 | |
| 42 | #define MMC35240_STATUS_MEAS_DONE_BIT BIT(0) |
| 43 | |
| 44 | #define MMC35240_CTRL0_REFILL_BIT BIT(7) |
| 45 | #define MMC35240_CTRL0_RESET_BIT BIT(6) |
| 46 | #define MMC35240_CTRL0_SET_BIT BIT(5) |
| 47 | #define MMC35240_CTRL0_CMM_BIT BIT(1) |
| 48 | #define MMC35240_CTRL0_TM_BIT BIT(0) |
| 49 | |
| 50 | /* output resolution bits */ |
| 51 | #define MMC35240_CTRL1_BW0_BIT BIT(0) |
| 52 | #define MMC35240_CTRL1_BW1_BIT BIT(1) |
| 53 | |
| 54 | #define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \ |
| 55 | MMC35240_CTRL1_BW1_BIT) |
| 56 | #define MMC35240_CTRL1_BW_SHIFT 0 |
| 57 | |
| 58 | #define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */ |
| 59 | #define MMC53240_WAIT_SET_RESET 1000 /* us */ |
| 60 | |
| 61 | enum mmc35240_resolution { |
| 62 | MMC35240_16_BITS_SLOW = 0, /* 100 Hz */ |
| 63 | MMC35240_16_BITS_FAST, /* 200 Hz */ |
| 64 | MMC35240_14_BITS, /* 333 Hz */ |
| 65 | MMC35240_12_BITS, /* 666 Hz */ |
| 66 | }; |
| 67 | |
| 68 | enum mmc35240_axis { |
| 69 | AXIS_X = 0, |
| 70 | AXIS_Y, |
| 71 | AXIS_Z, |
| 72 | }; |
| 73 | |
| 74 | static const struct { |
| 75 | int sens[3]; /* sensitivity per X, Y, Z axis */ |
| 76 | int nfo; /* null field output */ |
| 77 | } mmc35240_props_table[] = { |
| 78 | /* 16 bits, 100Hz ODR */ |
| 79 | { |
| 80 | {1024, 1024, 770}, |
| 81 | 32768, |
| 82 | }, |
| 83 | /* 16 bits, 200Hz ODR */ |
| 84 | { |
| 85 | {1024, 1024, 770}, |
| 86 | 32768, |
| 87 | }, |
| 88 | /* 14 bits, 333Hz ODR */ |
| 89 | { |
| 90 | {256, 256, 193}, |
| 91 | 8192, |
| 92 | }, |
| 93 | /* 12 bits, 666Hz ODR */ |
| 94 | { |
| 95 | {64, 64, 48}, |
| 96 | 2048, |
| 97 | }, |
| 98 | }; |
| 99 | |
| 100 | struct mmc35240_data { |
| 101 | struct i2c_client *client; |
| 102 | struct mutex mutex; |
| 103 | struct regmap *regmap; |
| 104 | enum mmc35240_resolution res; |
| 105 | }; |
| 106 | |
| 107 | static const int mmc35240_samp_freq[] = {100, 200, 333, 666}; |
| 108 | |
| 109 | static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666"); |
| 110 | |
| 111 | #define MMC35240_CHANNEL(_axis) { \ |
| 112 | .type = IIO_MAGN, \ |
| 113 | .modified = 1, \ |
| 114 | .channel2 = IIO_MOD_ ## _axis, \ |
| 115 | .address = AXIS_ ## _axis, \ |
| 116 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| 117 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ |
| 118 | BIT(IIO_CHAN_INFO_SCALE), \ |
| 119 | } |
| 120 | |
| 121 | static const struct iio_chan_spec mmc35240_channels[] = { |
| 122 | MMC35240_CHANNEL(X), |
| 123 | MMC35240_CHANNEL(Y), |
| 124 | MMC35240_CHANNEL(Z), |
| 125 | }; |
| 126 | |
| 127 | static struct attribute *mmc35240_attributes[] = { |
| 128 | &iio_const_attr_sampling_frequency_available.dev_attr.attr, |
| 129 | NULL |
| 130 | }; |
| 131 | |
| 132 | static const struct attribute_group mmc35240_attribute_group = { |
| 133 | .attrs = mmc35240_attributes, |
| 134 | }; |
| 135 | |
| 136 | static int mmc35240_get_samp_freq_index(struct mmc35240_data *data, |
| 137 | int val, int val2) |
| 138 | { |
| 139 | int i; |
| 140 | |
| 141 | for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++) |
| 142 | if (mmc35240_samp_freq[i] == val) |
| 143 | return i; |
| 144 | return -EINVAL; |
| 145 | } |
| 146 | |
| 147 | static int mmc35240_hw_set(struct mmc35240_data *data, bool set) |
| 148 | { |
| 149 | int ret; |
| 150 | u8 coil_bit; |
| 151 | |
| 152 | /* |
| 153 | * Recharge the capacitor at VCAP pin, requested to be issued |
| 154 | * before a SET/RESET command. |
| 155 | */ |
| 156 | ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0, |
| 157 | MMC35240_CTRL0_REFILL_BIT, |
| 158 | MMC35240_CTRL0_REFILL_BIT); |
| 159 | if (ret < 0) |
| 160 | return ret; |
| 161 | usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1); |
| 162 | |
| 163 | if (set) |
| 164 | coil_bit = MMC35240_CTRL0_SET_BIT; |
| 165 | else |
| 166 | coil_bit = MMC35240_CTRL0_RESET_BIT; |
| 167 | |
| 168 | return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0, |
| 169 | MMC35240_CTRL0_REFILL_BIT, |
| 170 | coil_bit); |
| 171 | } |
| 172 | |
| 173 | static int mmc35240_init(struct mmc35240_data *data) |
| 174 | { |
| 175 | int ret; |
| 176 | unsigned int reg_id; |
| 177 | |
| 178 | ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id); |
| 179 | if (ret < 0) { |
| 180 | dev_err(&data->client->dev, "Error reading product id\n"); |
| 181 | return ret; |
| 182 | } |
| 183 | |
| 184 | dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id); |
| 185 | |
| 186 | /* |
| 187 | * make sure we restore sensor characteristics, by doing |
| 188 | * a RESET/SET sequence |
| 189 | */ |
| 190 | ret = mmc35240_hw_set(data, false); |
| 191 | if (ret < 0) |
| 192 | return ret; |
| 193 | usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1); |
| 194 | |
| 195 | ret = mmc35240_hw_set(data, true); |
| 196 | if (ret < 0) |
| 197 | return ret; |
| 198 | |
| 199 | /* set default sampling frequency */ |
| 200 | return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, |
| 201 | MMC35240_CTRL1_BW_MASK, |
| 202 | data->res << MMC35240_CTRL1_BW_SHIFT); |
| 203 | } |
| 204 | |
| 205 | static int mmc35240_take_measurement(struct mmc35240_data *data) |
| 206 | { |
| 207 | int ret, tries = 100; |
| 208 | unsigned int reg_status; |
| 209 | |
| 210 | ret = regmap_write(data->regmap, MMC35240_REG_CTRL0, |
| 211 | MMC35240_CTRL0_TM_BIT); |
| 212 | if (ret < 0) |
| 213 | return ret; |
| 214 | |
| 215 | while (tries-- > 0) { |
| 216 | ret = regmap_read(data->regmap, MMC35240_REG_STATUS, |
| 217 | ®_status); |
| 218 | if (ret < 0) |
| 219 | return ret; |
| 220 | if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT) |
| 221 | break; |
| 222 | /* minimum wait time to complete measurement is 10 ms */ |
| 223 | usleep_range(10000, 11000); |
| 224 | } |
| 225 | |
| 226 | if (tries < 0) { |
| 227 | dev_err(&data->client->dev, "data not ready\n"); |
| 228 | return -EIO; |
| 229 | } |
| 230 | |
| 231 | return 0; |
| 232 | } |
| 233 | |
| 234 | static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3]) |
| 235 | { |
| 236 | int ret; |
| 237 | |
| 238 | ret = mmc35240_take_measurement(data); |
| 239 | if (ret < 0) |
| 240 | return ret; |
| 241 | |
| 242 | return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf, |
| 243 | 3 * sizeof(__le16)); |
| 244 | } |
| 245 | |
| 246 | /** |
| 247 | * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply |
| 248 | compensation for output value. |
| 249 | * |
| 250 | * @data: device private data |
| 251 | * @index: axis index for which we want the conversion |
| 252 | * @buf: raw data to be converted, 2 bytes in little endian format |
| 253 | * @val: compensated output reading (unit is milli gauss) |
| 254 | * |
| 255 | * Returns: 0 in case of success, -EINVAL when @index is not valid |
| 256 | */ |
| 257 | static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index, |
| 258 | __le16 buf[], int *val) |
| 259 | { |
| 260 | int raw_x, raw_y, raw_z; |
| 261 | int sens_x, sens_y, sens_z; |
| 262 | int nfo; |
| 263 | |
| 264 | raw_x = le16_to_cpu(buf[AXIS_X]); |
| 265 | raw_y = le16_to_cpu(buf[AXIS_Y]); |
| 266 | raw_z = le16_to_cpu(buf[AXIS_Z]); |
| 267 | |
| 268 | sens_x = mmc35240_props_table[data->res].sens[AXIS_X]; |
| 269 | sens_y = mmc35240_props_table[data->res].sens[AXIS_Y]; |
| 270 | sens_z = mmc35240_props_table[data->res].sens[AXIS_Z]; |
| 271 | |
| 272 | nfo = mmc35240_props_table[data->res].nfo; |
| 273 | |
| 274 | switch (index) { |
| 275 | case AXIS_X: |
| 276 | *val = (raw_x - nfo) * 1000 / sens_x; |
| 277 | break; |
| 278 | case AXIS_Y: |
| 279 | *val = (raw_y - nfo) * 1000 / sens_y - |
| 280 | (raw_z - nfo) * 1000 / sens_z; |
| 281 | break; |
| 282 | case AXIS_Z: |
| 283 | *val = (raw_y - nfo) * 1000 / sens_y + |
| 284 | (raw_z - nfo) * 1000 / sens_z; |
| 285 | break; |
| 286 | default: |
| 287 | return -EINVAL; |
| 288 | } |
| 289 | return 0; |
| 290 | } |
| 291 | |
| 292 | static int mmc35240_read_raw(struct iio_dev *indio_dev, |
| 293 | struct iio_chan_spec const *chan, int *val, |
| 294 | int *val2, long mask) |
| 295 | { |
| 296 | struct mmc35240_data *data = iio_priv(indio_dev); |
| 297 | int ret, i; |
| 298 | unsigned int reg; |
| 299 | __le16 buf[3]; |
| 300 | |
| 301 | switch (mask) { |
| 302 | case IIO_CHAN_INFO_RAW: |
| 303 | mutex_lock(&data->mutex); |
| 304 | ret = mmc35240_read_measurement(data, buf); |
| 305 | mutex_unlock(&data->mutex); |
| 306 | if (ret < 0) |
| 307 | return ret; |
| 308 | ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val); |
| 309 | if (ret < 0) |
| 310 | return ret; |
| 311 | return IIO_VAL_INT; |
| 312 | case IIO_CHAN_INFO_SCALE: |
| 313 | *val = 0; |
| 314 | *val2 = 1000; |
| 315 | return IIO_VAL_INT_PLUS_MICRO; |
| 316 | case IIO_CHAN_INFO_SAMP_FREQ: |
| 317 | mutex_lock(&data->mutex); |
| 318 | ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®); |
| 319 | mutex_unlock(&data->mutex); |
| 320 | if (ret < 0) |
| 321 | return ret; |
| 322 | |
| 323 | i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT; |
| 324 | if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq)) |
| 325 | return -EINVAL; |
| 326 | |
| 327 | *val = mmc35240_samp_freq[i]; |
| 328 | *val2 = 0; |
| 329 | return IIO_VAL_INT; |
| 330 | default: |
| 331 | return -EINVAL; |
| 332 | } |
| 333 | } |
| 334 | |
| 335 | static int mmc35240_write_raw(struct iio_dev *indio_dev, |
| 336 | struct iio_chan_spec const *chan, int val, |
| 337 | int val2, long mask) |
| 338 | { |
| 339 | struct mmc35240_data *data = iio_priv(indio_dev); |
| 340 | int i, ret; |
| 341 | |
| 342 | switch (mask) { |
| 343 | case IIO_CHAN_INFO_SAMP_FREQ: |
| 344 | i = mmc35240_get_samp_freq_index(data, val, val2); |
| 345 | if (i < 0) |
| 346 | return -EINVAL; |
| 347 | mutex_lock(&data->mutex); |
| 348 | ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, |
| 349 | MMC35240_CTRL1_BW_MASK, |
| 350 | i << MMC35240_CTRL1_BW_SHIFT); |
| 351 | mutex_unlock(&data->mutex); |
| 352 | return ret; |
| 353 | default: |
| 354 | return -EINVAL; |
| 355 | } |
| 356 | } |
| 357 | |
| 358 | static const struct iio_info mmc35240_info = { |
| 359 | .driver_module = THIS_MODULE, |
| 360 | .read_raw = mmc35240_read_raw, |
| 361 | .write_raw = mmc35240_write_raw, |
| 362 | .attrs = &mmc35240_attribute_group, |
| 363 | }; |
| 364 | |
| 365 | static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg) |
| 366 | { |
| 367 | switch (reg) { |
| 368 | case MMC35240_REG_CTRL0: |
| 369 | case MMC35240_REG_CTRL1: |
| 370 | return true; |
| 371 | default: |
| 372 | return false; |
| 373 | } |
| 374 | } |
| 375 | |
| 376 | static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg) |
| 377 | { |
| 378 | switch (reg) { |
| 379 | case MMC35240_REG_XOUT_L: |
| 380 | case MMC35240_REG_XOUT_H: |
| 381 | case MMC35240_REG_YOUT_L: |
| 382 | case MMC35240_REG_YOUT_H: |
| 383 | case MMC35240_REG_ZOUT_L: |
| 384 | case MMC35240_REG_ZOUT_H: |
| 385 | case MMC35240_REG_STATUS: |
| 386 | case MMC35240_REG_ID: |
| 387 | return true; |
| 388 | default: |
| 389 | return false; |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg) |
| 394 | { |
| 395 | switch (reg) { |
| 396 | case MMC35240_REG_CTRL0: |
| 397 | case MMC35240_REG_CTRL1: |
| 398 | return false; |
| 399 | default: |
| 400 | return true; |
| 401 | } |
| 402 | } |
| 403 | |
| 404 | static struct reg_default mmc35240_reg_defaults[] = { |
| 405 | { MMC35240_REG_CTRL0, 0x00 }, |
| 406 | { MMC35240_REG_CTRL1, 0x00 }, |
| 407 | }; |
| 408 | |
| 409 | static const struct regmap_config mmc35240_regmap_config = { |
| 410 | .name = MMC35240_REGMAP_NAME, |
| 411 | |
| 412 | .reg_bits = 8, |
| 413 | .val_bits = 8, |
| 414 | |
| 415 | .max_register = MMC35240_REG_ID, |
| 416 | .cache_type = REGCACHE_FLAT, |
| 417 | |
| 418 | .writeable_reg = mmc35240_is_writeable_reg, |
| 419 | .readable_reg = mmc35240_is_readable_reg, |
| 420 | .volatile_reg = mmc35240_is_volatile_reg, |
| 421 | |
| 422 | .reg_defaults = mmc35240_reg_defaults, |
| 423 | .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults), |
| 424 | }; |
| 425 | |
| 426 | static int mmc35240_probe(struct i2c_client *client, |
| 427 | const struct i2c_device_id *id) |
| 428 | { |
| 429 | struct mmc35240_data *data; |
| 430 | struct iio_dev *indio_dev; |
| 431 | struct regmap *regmap; |
| 432 | int ret; |
| 433 | |
| 434 | indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); |
| 435 | if (!indio_dev) |
| 436 | return -ENOMEM; |
| 437 | |
| 438 | regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config); |
| 439 | if (IS_ERR(regmap)) { |
| 440 | dev_err(&client->dev, "regmap initialization failed\n"); |
| 441 | return PTR_ERR(regmap); |
| 442 | } |
| 443 | |
| 444 | data = iio_priv(indio_dev); |
| 445 | data->client = client; |
| 446 | data->regmap = regmap; |
| 447 | data->res = MMC35240_16_BITS_SLOW; |
| 448 | |
| 449 | mutex_init(&data->mutex); |
| 450 | |
| 451 | indio_dev->dev.parent = &client->dev; |
| 452 | indio_dev->info = &mmc35240_info; |
| 453 | indio_dev->name = MMC35240_DRV_NAME; |
| 454 | indio_dev->channels = mmc35240_channels; |
| 455 | indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels); |
| 456 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 457 | |
| 458 | ret = mmc35240_init(data); |
| 459 | if (ret < 0) { |
| 460 | dev_err(&client->dev, "mmc35240 chip init failed\n"); |
| 461 | return ret; |
| 462 | } |
| 463 | return devm_iio_device_register(&client->dev, indio_dev); |
| 464 | } |
| 465 | |
| 466 | #ifdef CONFIG_PM_SLEEP |
| 467 | static int mmc35240_suspend(struct device *dev) |
| 468 | { |
| 469 | struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); |
| 470 | struct mmc35240_data *data = iio_priv(indio_dev); |
| 471 | |
| 472 | regcache_cache_only(data->regmap, true); |
| 473 | |
| 474 | return 0; |
| 475 | } |
| 476 | |
| 477 | static int mmc35240_resume(struct device *dev) |
| 478 | { |
| 479 | struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); |
| 480 | struct mmc35240_data *data = iio_priv(indio_dev); |
| 481 | int ret; |
| 482 | |
| 483 | regcache_mark_dirty(data->regmap); |
| 484 | ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0, |
| 485 | MMC35240_REG_CTRL1); |
| 486 | if (ret < 0) |
| 487 | dev_err(dev, "Failed to restore control registers\n"); |
| 488 | |
| 489 | regcache_cache_only(data->regmap, false); |
| 490 | |
| 491 | return 0; |
| 492 | } |
| 493 | #endif |
| 494 | |
| 495 | static const struct dev_pm_ops mmc35240_pm_ops = { |
| 496 | SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume) |
| 497 | }; |
| 498 | |
| 499 | static const struct acpi_device_id mmc35240_acpi_match[] = { |
| 500 | {"MMC35240", 0}, |
| 501 | { }, |
| 502 | }; |
| 503 | MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match); |
| 504 | |
| 505 | static const struct i2c_device_id mmc35240_id[] = { |
| 506 | {"mmc35240", 0}, |
| 507 | {} |
| 508 | }; |
| 509 | MODULE_DEVICE_TABLE(i2c, mmc35240_id); |
| 510 | |
| 511 | static struct i2c_driver mmc35240_driver = { |
| 512 | .driver = { |
| 513 | .name = MMC35240_DRV_NAME, |
| 514 | .pm = &mmc35240_pm_ops, |
| 515 | .acpi_match_table = ACPI_PTR(mmc35240_acpi_match), |
| 516 | }, |
| 517 | .probe = mmc35240_probe, |
| 518 | .id_table = mmc35240_id, |
| 519 | }; |
| 520 | |
| 521 | module_i2c_driver(mmc35240_driver); |
| 522 | |
| 523 | MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); |
| 524 | MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver"); |
| 525 | MODULE_LICENSE("GPL v2"); |