drivers/iio/magnetometer/ak8975.c

   1 /*
   2  * A sensor driver for the magnetometer AK8975.
   3  *
   4  * Magnetic compass sensor driver for monitoring magnetic flux information.
   5  *
   6  * Copyright (c) 2010, NVIDIA Corporation.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16  * more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/slab.h>
  26 #include <linux/i2c.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/err.h>
  29 #include <linux/mutex.h>
  30 #include <linux/delay.h>
  31 #include <linux/bitops.h>
  32 #include <linux/gpio.h>
  33 #include <linux/of_gpio.h>
  34 #include <linux/acpi.h>
  35
  36 #include <linux/iio/iio.h>
  37 #include <linux/iio/sysfs.h>
  38 /*
  39  * Register definitions, as well as various shifts and masks to get at the
  40  * individual fields of the registers.
  41  */
  42 #define AK8975_REG_WIA                  0x00
  43 #define AK8975_DEVICE_ID                0x48
  44
  45 #define AK8975_REG_INFO                 0x01
  46
  47 #define AK8975_REG_ST1                  0x02
  48 #define AK8975_REG_ST1_DRDY_SHIFT       0
  49 #define AK8975_REG_ST1_DRDY_MASK        (1 << AK8975_REG_ST1_DRDY_SHIFT)
  50
  51 #define AK8975_REG_HXL                  0x03
  52 #define AK8975_REG_HXH                  0x04
  53 #define AK8975_REG_HYL                  0x05
  54 #define AK8975_REG_HYH                  0x06
  55 #define AK8975_REG_HZL                  0x07
  56 #define AK8975_REG_HZH                  0x08
  57 #define AK8975_REG_ST2                  0x09
  58 #define AK8975_REG_ST2_DERR_SHIFT       2
  59 #define AK8975_REG_ST2_DERR_MASK        (1 << AK8975_REG_ST2_DERR_SHIFT)
  60
  61 #define AK8975_REG_ST2_HOFL_SHIFT       3
  62 #define AK8975_REG_ST2_HOFL_MASK        (1 << AK8975_REG_ST2_HOFL_SHIFT)
  63
  64 #define AK8975_REG_CNTL                 0x0A
  65 #define AK8975_REG_CNTL_MODE_SHIFT      0
  66 #define AK8975_REG_CNTL_MODE_MASK       (0xF << AK8975_REG_CNTL_MODE_SHIFT)
  67 #define AK8975_REG_CNTL_MODE_POWER_DOWN 0x00
  68 #define AK8975_REG_CNTL_MODE_ONCE       0x01
  69 #define AK8975_REG_CNTL_MODE_SELF_TEST  0x08
  70 #define AK8975_REG_CNTL_MODE_FUSE_ROM   0x0F
  71
  72 #define AK8975_REG_RSVC                 0x0B
  73 #define AK8975_REG_ASTC                 0x0C
  74 #define AK8975_REG_TS1                  0x0D
  75 #define AK8975_REG_TS2                  0x0E
  76 #define AK8975_REG_I2CDIS               0x0F
  77 #define AK8975_REG_ASAX                 0x10
  78 #define AK8975_REG_ASAY                 0x11
  79 #define AK8975_REG_ASAZ                 0x12
  80
  81 #define AK8975_MAX_REGS                 AK8975_REG_ASAZ
  82
  83 /*
  84  * AK09912 Register definitions
  85  */
  86 #define AK09912_REG_WIA1                0x00
  87 #define AK09912_REG_WIA2                0x01
  88 #define AK09912_DEVICE_ID               0x04
  89 #define AK09911_DEVICE_ID               0x05
  90
  91 #define AK09911_REG_INFO1               0x02
  92 #define AK09911_REG_INFO2               0x03
  93
  94 #define AK09912_REG_ST1                 0x10
  95
  96 #define AK09912_REG_ST1_DRDY_SHIFT      0
  97 #define AK09912_REG_ST1_DRDY_MASK       (1 << AK09912_REG_ST1_DRDY_SHIFT)
  98
  99 #define AK09912_REG_HXL                 0x11
 100 #define AK09912_REG_HXH                 0x12
 101 #define AK09912_REG_HYL                 0x13
 102 #define AK09912_REG_HYH                 0x14
 103 #define AK09912_REG_HZL                 0x15
 104 #define AK09912_REG_HZH                 0x16
 105 #define AK09912_REG_TMPS                0x17
 106
 107 #define AK09912_REG_ST2                 0x18
 108 #define AK09912_REG_ST2_HOFL_SHIFT      3
 109 #define AK09912_REG_ST2_HOFL_MASK       (1 << AK09912_REG_ST2_HOFL_SHIFT)
 110
 111 #define AK09912_REG_CNTL1               0x30
 112
 113 #define AK09912_REG_CNTL2               0x31
 114 #define AK09912_REG_CNTL_MODE_POWER_DOWN        0x00
 115 #define AK09912_REG_CNTL_MODE_ONCE      0x01
 116 #define AK09912_REG_CNTL_MODE_SELF_TEST 0x10
 117 #define AK09912_REG_CNTL_MODE_FUSE_ROM  0x1F
 118 #define AK09912_REG_CNTL2_MODE_SHIFT    0
 119 #define AK09912_REG_CNTL2_MODE_MASK     (0x1F << AK09912_REG_CNTL2_MODE_SHIFT)
 120
 121 #define AK09912_REG_CNTL3               0x32
 122
 123 #define AK09912_REG_TS1                 0x33
 124 #define AK09912_REG_TS2                 0x34
 125 #define AK09912_REG_TS3                 0x35
 126 #define AK09912_REG_I2CDIS              0x36
 127 #define AK09912_REG_TS4                 0x37
 128
 129 #define AK09912_REG_ASAX                0x60
 130 #define AK09912_REG_ASAY                0x61
 131 #define AK09912_REG_ASAZ                0x62
 132
 133 #define AK09912_MAX_REGS                AK09912_REG_ASAZ
 134
 135 /*
 136  * Miscellaneous values.
 137  */
 138 #define AK8975_MAX_CONVERSION_TIMEOUT   500
 139 #define AK8975_CONVERSION_DONE_POLL_TIME 10
 140 #define AK8975_DATA_READY_TIMEOUT       ((100*HZ)/1000)
 141
 142 /*
 143  * Precalculate scale factor (in Gauss units) for each axis and
 144  * store in the device data.
 145  *
 146  * This scale factor is axis-dependent, and is derived from 3 calibration
 147  * factors ASA(x), ASA(y), and ASA(z).
 148  *
 149  * These ASA values are read from the sensor device at start of day, and
 150  * cached in the device context struct.
 151  *
 152  * Adjusting the flux value with the sensitivity adjustment value should be
 153  * done via the following formula:
 154  *
 155  * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
 156  * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
 157  * is the resultant adjusted value.
 158  *
 159  * We reduce the formula to:
 160  *
 161  * Hadj = H * (ASA + 128) / 256
 162  *
 163  * H is in the range of -4096 to 4095.  The magnetometer has a range of
 164  * +-1229uT.  To go from the raw value to uT is:
 165  *
 166  * HuT = H * 1229/4096, or roughly, 3/10.
 167  *
 168  * Since 1uT = 0.01 gauss, our final scale factor becomes:
 169  *
 170  * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100
 171  * Hadj = H * ((ASA + 128) * 0.003) / 256
 172  *
 173  * Since ASA doesn't change, we cache the resultant scale factor into the
 174  * device context in ak8975_setup().
 175  *
 176  * Given we use IIO_VAL_INT_PLUS_MICRO bit when displaying the scale, we
 177  * multiply the stored scale value by 1e6.
 178  */
 179 static long ak8975_raw_to_gauss(u16 data)
 180 {
 181         return (((long)data + 128) * 3000) / 256;
 182 }
 183
 184 /*
 185  * For AK8963 and AK09911, same calculation, but the device is less sensitive:
 186  *
 187  * H is in the range of +-8190.  The magnetometer has a range of
 188  * +-4912uT.  To go from the raw value to uT is:
 189  *
 190  * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10.
 191  */
 192
 193 static long ak8963_09911_raw_to_gauss(u16 data)
 194 {
 195         return (((long)data + 128) * 6000) / 256;
 196 }
 197
 198 /*
 199  * For AK09912, same calculation, except the device is more sensitive:
 200  *
 201  * H is in the range of -32752 to 32752.  The magnetometer has a range of
 202  * +-4912uT.  To go from the raw value to uT is:
 203  *
 204  * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10.
 205  */
 206 static long ak09912_raw_to_gauss(u16 data)
 207 {
 208         return (((long)data + 128) * 1500) / 256;
 209 }
 210
 211 /* Compatible Asahi Kasei Compass parts */
 212 enum asahi_compass_chipset {
 213         AK8975,
 214         AK8963,
 215         AK09911,
 216         AK09912,
 217         AK_MAX_TYPE
 218 };
 219
 220 enum ak_ctrl_reg_addr {
 221         ST1,
 222         ST2,
 223         CNTL,
 224         ASA_BASE,
 225         MAX_REGS,
 226         REGS_END,
 227 };
 228
 229 enum ak_ctrl_reg_mask {
 230         ST1_DRDY,
 231         ST2_HOFL,
 232         ST2_DERR,
 233         CNTL_MODE,
 234         MASK_END,
 235 };
 236
 237 enum ak_ctrl_mode {
 238         POWER_DOWN,
 239         MODE_ONCE,
 240         SELF_TEST,
 241         FUSE_ROM,
 242         MODE_END,
 243 };
 244
 245 struct ak_def {
 246         enum asahi_compass_chipset type;
 247         long (*raw_to_gauss)(u16 data);
 248         u16 range;
 249         u8 ctrl_regs[REGS_END];
 250         u8 ctrl_masks[MASK_END];
 251         u8 ctrl_modes[MODE_END];
 252         u8 data_regs[3];
 253 };
 254
 255 static struct ak_def ak_def_array[AK_MAX_TYPE] = {
 256         {
 257                 .type = AK8975,
 258                 .raw_to_gauss = ak8975_raw_to_gauss,
 259                 .range = 4096,
 260                 .ctrl_regs = {
 261                         AK8975_REG_ST1,
 262                         AK8975_REG_ST2,
 263                         AK8975_REG_CNTL,
 264                         AK8975_REG_ASAX,
 265                         AK8975_MAX_REGS},
 266                 .ctrl_masks = {
 267                         AK8975_REG_ST1_DRDY_MASK,
 268                         AK8975_REG_ST2_HOFL_MASK,
 269                         AK8975_REG_ST2_DERR_MASK,
 270                         AK8975_REG_CNTL_MODE_MASK},
 271                 .ctrl_modes = {
 272                         AK8975_REG_CNTL_MODE_POWER_DOWN,
 273                         AK8975_REG_CNTL_MODE_ONCE,
 274                         AK8975_REG_CNTL_MODE_SELF_TEST,
 275                         AK8975_REG_CNTL_MODE_FUSE_ROM},
 276                 .data_regs = {
 277                         AK8975_REG_HXL,
 278                         AK8975_REG_HYL,
 279                         AK8975_REG_HZL},
 280         },
 281         {
 282                 .type = AK8963,
 283                 .raw_to_gauss = ak8963_09911_raw_to_gauss,
 284                 .range = 8190,
 285                 .ctrl_regs = {
 286                         AK8975_REG_ST1,
 287                         AK8975_REG_ST2,
 288                         AK8975_REG_CNTL,
 289                         AK8975_REG_ASAX,
 290                         AK8975_MAX_REGS},
 291                 .ctrl_masks = {
 292                         AK8975_REG_ST1_DRDY_MASK,
 293                         AK8975_REG_ST2_HOFL_MASK,
 294                         0,
 295                         AK8975_REG_CNTL_MODE_MASK},
 296                 .ctrl_modes = {
 297                         AK8975_REG_CNTL_MODE_POWER_DOWN,
 298                         AK8975_REG_CNTL_MODE_ONCE,
 299                         AK8975_REG_CNTL_MODE_SELF_TEST,
 300                         AK8975_REG_CNTL_MODE_FUSE_ROM},
 301                 .data_regs = {
 302                         AK8975_REG_HXL,
 303                         AK8975_REG_HYL,
 304                         AK8975_REG_HZL},
 305         },
 306         {
 307                 .type = AK09911,
 308                 .raw_to_gauss = ak8963_09911_raw_to_gauss,
 309                 .range = 8192,
 310                 .ctrl_regs = {
 311                         AK09912_REG_ST1,
 312                         AK09912_REG_ST2,
 313                         AK09912_REG_CNTL2,
 314                         AK09912_REG_ASAX,
 315                         AK09912_MAX_REGS},
 316                 .ctrl_masks = {
 317                         AK09912_REG_ST1_DRDY_MASK,
 318                         AK09912_REG_ST2_HOFL_MASK,
 319                         0,
 320                         AK09912_REG_CNTL2_MODE_MASK},
 321                 .ctrl_modes = {
 322                         AK09912_REG_CNTL_MODE_POWER_DOWN,
 323                         AK09912_REG_CNTL_MODE_ONCE,
 324                         AK09912_REG_CNTL_MODE_SELF_TEST,
 325                         AK09912_REG_CNTL_MODE_FUSE_ROM},
 326                 .data_regs = {
 327                         AK09912_REG_HXL,
 328                         AK09912_REG_HYL,
 329                         AK09912_REG_HZL},
 330         },
 331         {
 332                 .type = AK09912,
 333                 .raw_to_gauss = ak09912_raw_to_gauss,
 334                 .range = 32752,
 335                 .ctrl_regs = {
 336                         AK09912_REG_ST1,
 337                         AK09912_REG_ST2,
 338                         AK09912_REG_CNTL2,
 339                         AK09912_REG_ASAX,
 340                         AK09912_MAX_REGS},
 341                 .ctrl_masks = {
 342                         AK09912_REG_ST1_DRDY_MASK,
 343                         AK09912_REG_ST2_HOFL_MASK,
 344                         0,
 345                         AK09912_REG_CNTL2_MODE_MASK},
 346                 .ctrl_modes = {
 347                         AK09912_REG_CNTL_MODE_POWER_DOWN,
 348                         AK09912_REG_CNTL_MODE_ONCE,
 349                         AK09912_REG_CNTL_MODE_SELF_TEST,
 350                         AK09912_REG_CNTL_MODE_FUSE_ROM},
 351                 .data_regs = {
 352                         AK09912_REG_HXL,
 353                         AK09912_REG_HYL,
 354                         AK09912_REG_HZL},
 355         }
 356 };
 357
 358 /*
 359  * Per-instance context data for the device.
 360  */
 361 struct ak8975_data {
 362         struct i2c_client       *client;
 363         struct ak_def           *def;
 364         struct attribute_group  attrs;
 365         struct mutex            lock;
 366         u8                      asa[3];
 367         long                    raw_to_gauss[3];
 368         int                     eoc_gpio;
 369         int                     eoc_irq;
 370         wait_queue_head_t       data_ready_queue;
 371         unsigned long           flags;
 372         u8                      cntl_cache;
 373 };
 374
 375 /*
 376  * Return 0 if the i2c device is the one we expect.
 377  * return a negative error number otherwise
 378  */
 379 static int ak8975_who_i_am(struct i2c_client *client,
 380                            enum asahi_compass_chipset type)
 381 {
 382         u8 wia_val[2];
 383         int ret;
 384
 385         /*
 386          * Signature for each device:
 387          * Device   |  WIA1      |  WIA2
 388          * AK09912  |  DEVICE_ID |  AK09912_DEVICE_ID
 389          * AK09911  |  DEVICE_ID |  AK09911_DEVICE_ID
 390          * AK8975   |  DEVICE_ID |  NA
 391          * AK8963   |  DEVICE_ID |  NA
 392          */
 393         ret = i2c_smbus_read_i2c_block_data(client, AK09912_REG_WIA1,
 394                                             2, wia_val);
 395         if (ret < 0) {
 396                 dev_err(&client->dev, "Error reading WIA\n");
 397                 return ret;
 398         }
 399
 400         if (wia_val[0] != AK8975_DEVICE_ID)
 401                 return -ENODEV;
 402
 403         switch (type) {
 404         case AK8975:
 405         case AK8963:
 406                 return 0;
 407         case AK09911:
 408                 if (wia_val[1] == AK09911_DEVICE_ID)
 409                         return 0;
 410                 break;
 411         case AK09912:
 412                 if (wia_val[1] == AK09912_DEVICE_ID)
 413                         return 0;
 414                 break;
 415         default:
 416                 dev_err(&client->dev, "Type %d unknown\n", type);
 417         }
 418         return -ENODEV;
 419 }
 420
 421 /*
 422  * Helper function to write to CNTL register.
 423  */
 424 static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode)
 425 {
 426         u8 regval;
 427         int ret;
 428
 429         regval = (data->cntl_cache & ~data->def->ctrl_masks[CNTL_MODE]) |
 430                  data->def->ctrl_modes[mode];
 431         ret = i2c_smbus_write_byte_data(data->client,
 432                                         data->def->ctrl_regs[CNTL], regval);
 433         if (ret < 0) {
 434                 return ret;
 435         }
 436         data->cntl_cache = regval;
 437         /* After mode change wait atleast 100us */
 438         usleep_range(100, 500);
 439
 440         return 0;
 441 }
 442
 443 /*
 444  * Handle data ready irq
 445  */
 446 static irqreturn_t ak8975_irq_handler(int irq, void *data)
 447 {
 448         struct ak8975_data *ak8975 = data;
 449
 450         set_bit(0, &ak8975->flags);
 451         wake_up(&ak8975->data_ready_queue);
 452
 453         return IRQ_HANDLED;
 454 }
 455
 456 /*
 457  * Install data ready interrupt handler
 458  */
 459 static int ak8975_setup_irq(struct ak8975_data *data)
 460 {
 461         struct i2c_client *client = data->client;
 462         int rc;
 463         int irq;
 464
 465         if (client->irq)
 466                 irq = client->irq;
 467         else
 468                 irq = gpio_to_irq(data->eoc_gpio);
 469
 470         rc = devm_request_irq(&client->dev, irq, ak8975_irq_handler,
 471                               IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 472                               dev_name(&client->dev), data);
 473         if (rc < 0) {
 474                 dev_err(&client->dev,
 475                         "irq %d request failed, (gpio %d): %d\n",
 476                         irq, data->eoc_gpio, rc);
 477                 return rc;
 478         }
 479
 480         init_waitqueue_head(&data->data_ready_queue);
 481         clear_bit(0, &data->flags);
 482         data->eoc_irq = irq;
 483
 484         return rc;
 485 }
 486
 487
 488 /*
 489  * Perform some start-of-day setup, including reading the asa calibration
 490  * values and caching them.
 491  */
 492 static int ak8975_setup(struct i2c_client *client)
 493 {
 494         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 495         struct ak8975_data *data = iio_priv(indio_dev);
 496         int ret;
 497
 498         /* Write the fused rom access mode. */
 499         ret = ak8975_set_mode(data, FUSE_ROM);
 500         if (ret < 0) {
 501                 dev_err(&client->dev, "Error in setting fuse access mode\n");
 502                 return ret;
 503         }
 504
 505         /* Get asa data and store in the device data. */
 506         ret = i2c_smbus_read_i2c_block_data(client,
 507                                             data->def->ctrl_regs[ASA_BASE],
 508                                             3, data->asa);
 509         if (ret < 0) {
 510                 dev_err(&client->dev, "Not able to read asa data\n");
 511                 return ret;
 512         }
 513
 514         /* After reading fuse ROM data set power-down mode */
 515         ret = ak8975_set_mode(data, POWER_DOWN);
 516         if (ret < 0) {
 517                 dev_err(&client->dev, "Error in setting power-down mode\n");
 518                 return ret;
 519         }
 520
 521         if (data->eoc_gpio > 0 || client->irq > 0) {
 522                 ret = ak8975_setup_irq(data);
 523                 if (ret < 0) {
 524                         dev_err(&client->dev,
 525                                 "Error setting data ready interrupt\n");
 526                         return ret;
 527                 }
 528         }
 529
 530         data->raw_to_gauss[0] = data->def->raw_to_gauss(data->asa[0]);
 531         data->raw_to_gauss[1] = data->def->raw_to_gauss(data->asa[1]);
 532         data->raw_to_gauss[2] = data->def->raw_to_gauss(data->asa[2]);
 533
 534         return 0;
 535 }
 536
 537 static int wait_conversion_complete_gpio(struct ak8975_data *data)
 538 {
 539         struct i2c_client *client = data->client;
 540         u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
 541         int ret;
 542
 543         /* Wait for the conversion to complete. */
 544         while (timeout_ms) {
 545                 msleep(AK8975_CONVERSION_DONE_POLL_TIME);
 546                 if (gpio_get_value(data->eoc_gpio))
 547                         break;
 548                 timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
 549         }
 550         if (!timeout_ms) {
 551                 dev_err(&client->dev, "Conversion timeout happened\n");
 552                 return -EINVAL;
 553         }
 554
 555         ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]);
 556         if (ret < 0)
 557                 dev_err(&client->dev, "Error in reading ST1\n");
 558
 559         return ret;
 560 }
 561
 562 static int wait_conversion_complete_polled(struct ak8975_data *data)
 563 {
 564         struct i2c_client *client = data->client;
 565         u8 read_status;
 566         u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
 567         int ret;
 568
 569         /* Wait for the conversion to complete. */
 570         while (timeout_ms) {
 571                 msleep(AK8975_CONVERSION_DONE_POLL_TIME);
 572                 ret = i2c_smbus_read_byte_data(client,
 573                                                data->def->ctrl_regs[ST1]);
 574                 if (ret < 0) {
 575                         dev_err(&client->dev, "Error in reading ST1\n");
 576                         return ret;
 577                 }
 578                 read_status = ret;
 579                 if (read_status)
 580                         break;
 581                 timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
 582         }
 583         if (!timeout_ms) {
 584                 dev_err(&client->dev, "Conversion timeout happened\n");
 585                 return -EINVAL;
 586         }
 587
 588         return read_status;
 589 }
 590
 591 /* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
 592 static int wait_conversion_complete_interrupt(struct ak8975_data *data)
 593 {
 594         int ret;
 595
 596         ret = wait_event_timeout(data->data_ready_queue,
 597                                  test_bit(0, &data->flags),
 598                                  AK8975_DATA_READY_TIMEOUT);
 599         clear_bit(0, &data->flags);
 600
 601         return ret > 0 ? 0 : -ETIME;
 602 }
 603
 604 /*
 605  * Emits the raw flux value for the x, y, or z axis.
 606  */
 607 static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
 608 {
 609         struct ak8975_data *data = iio_priv(indio_dev);
 610         struct i2c_client *client = data->client;
 611         int ret;
 612
 613         mutex_lock(&data->lock);
 614
 615         /* Set up the device for taking a sample. */
 616         ret = ak8975_set_mode(data, MODE_ONCE);
 617         if (ret < 0) {
 618                 dev_err(&client->dev, "Error in setting operating mode\n");
 619                 goto exit;
 620         }
 621
 622         /* Wait for the conversion to complete. */
 623         if (data->eoc_irq)
 624                 ret = wait_conversion_complete_interrupt(data);
 625         else if (gpio_is_valid(data->eoc_gpio))
 626                 ret = wait_conversion_complete_gpio(data);
 627         else
 628                 ret = wait_conversion_complete_polled(data);
 629         if (ret < 0)
 630                 goto exit;
 631
 632         /* This will be executed only for non-interrupt based waiting case */
 633         if (ret & data->def->ctrl_masks[ST1_DRDY]) {
 634                 ret = i2c_smbus_read_byte_data(client,
 635                                                data->def->ctrl_regs[ST2]);
 636                 if (ret < 0) {
 637                         dev_err(&client->dev, "Error in reading ST2\n");
 638                         goto exit;
 639                 }
 640                 if (ret & (data->def->ctrl_masks[ST2_DERR] |
 641                            data->def->ctrl_masks[ST2_HOFL])) {
 642                         dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
 643                         ret = -EINVAL;
 644                         goto exit;
 645                 }
 646         }
 647
 648         /* Read the flux value from the appropriate register
 649            (the register is specified in the iio device attributes). */
 650         ret = i2c_smbus_read_word_data(client, data->def->data_regs[index]);
 651         if (ret < 0) {
 652                 dev_err(&client->dev, "Read axis data fails\n");
 653                 goto exit;
 654         }
 655
 656         mutex_unlock(&data->lock);
 657
 658         /* Clamp to valid range. */
 659         *val = clamp_t(s16, ret, -data->def->range, data->def->range);
 660         return IIO_VAL_INT;
 661
 662 exit:
 663         mutex_unlock(&data->lock);
 664         return ret;
 665 }
 666
 667 static int ak8975_read_raw(struct iio_dev *indio_dev,
 668                            struct iio_chan_spec const *chan,
 669                            int *val, int *val2,
 670                            long mask)
 671 {
 672         struct ak8975_data *data = iio_priv(indio_dev);
 673
 674         switch (mask) {
 675         case IIO_CHAN_INFO_RAW:
 676                 return ak8975_read_axis(indio_dev, chan->address, val);
 677         case IIO_CHAN_INFO_SCALE:
 678                 *val = 0;
 679                 *val2 = data->raw_to_gauss[chan->address];
 680                 return IIO_VAL_INT_PLUS_MICRO;
 681         }
 682         return -EINVAL;
 683 }
 684
 685 #define AK8975_CHANNEL(axis, index)                                     \
 686         {                                                               \
 687                 .type = IIO_MAGN,                                       \
 688                 .modified = 1,                                          \
 689                 .channel2 = IIO_MOD_##axis,                             \
 690                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
 691                              BIT(IIO_CHAN_INFO_SCALE),                  \
 692                 .address = index,                                       \
 693         }
 694
 695 static const struct iio_chan_spec ak8975_channels[] = {
 696         AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
 697 };
 698
 699 static const struct iio_info ak8975_info = {
 700         .read_raw = &ak8975_read_raw,
 701         .driver_module = THIS_MODULE,
 702 };
 703
 704 static const struct acpi_device_id ak_acpi_match[] = {
 705         {"AK8975", AK8975},
 706         {"AK8963", AK8963},
 707         {"INVN6500", AK8963},
 708         {"AK09911", AK09911},
 709         {"AK09912", AK09912},
 710         { },
 711 };
 712 MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
 713
 714 static const char *ak8975_match_acpi_device(struct device *dev,
 715                                             enum asahi_compass_chipset *chipset)
 716 {
 717         const struct acpi_device_id *id;
 718
 719         id = acpi_match_device(dev->driver->acpi_match_table, dev);
 720         if (!id)
 721                 return NULL;
 722         *chipset = (int)id->driver_data;
 723
 724         return dev_name(dev);
 725 }
 726
 727 static int ak8975_probe(struct i2c_client *client,
 728                         const struct i2c_device_id *id)
 729 {
 730         struct ak8975_data *data;
 731         struct iio_dev *indio_dev;
 732         int eoc_gpio;
 733         int err;
 734         const char *name = NULL;
 735         enum asahi_compass_chipset chipset;
 736
 737         /* Grab and set up the supplied GPIO. */
 738         if (client->dev.platform_data)
 739                 eoc_gpio = *(int *)(client->dev.platform_data);
 740         else if (client->dev.of_node)
 741                 eoc_gpio = of_get_gpio(client->dev.of_node, 0);
 742         else
 743                 eoc_gpio = -1;
 744
 745         if (eoc_gpio == -EPROBE_DEFER)
 746                 return -EPROBE_DEFER;
 747
 748         /* We may not have a GPIO based IRQ to scan, that is fine, we will
 749            poll if so */
 750         if (gpio_is_valid(eoc_gpio)) {
 751                 err = devm_gpio_request_one(&client->dev, eoc_gpio,
 752                                                         GPIOF_IN, "ak_8975");
 753                 if (err < 0) {
 754                         dev_err(&client->dev,
 755                                 "failed to request GPIO %d, error %d\n",
 756                                                         eoc_gpio, err);
 757                         return err;
 758                 }
 759         }
 760
 761         /* Register with IIO */
 762         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 763         if (indio_dev == NULL)
 764                 return -ENOMEM;
 765
 766         data = iio_priv(indio_dev);
 767         i2c_set_clientdata(client, indio_dev);
 768
 769         data->client = client;
 770         data->eoc_gpio = eoc_gpio;
 771         data->eoc_irq = 0;
 772
 773         /* id will be NULL when enumerated via ACPI */
 774         if (id) {
 775                 chipset = (enum asahi_compass_chipset)(id->driver_data);
 776                 name = id->name;
 777         } else if (ACPI_HANDLE(&client->dev))
 778                 name = ak8975_match_acpi_device(&client->dev, &chipset);
 779         else
 780                 return -ENOSYS;
 781
 782         if (chipset >= AK_MAX_TYPE) {
 783                 dev_err(&client->dev, "AKM device type unsupported: %d\n",
 784                         chipset);
 785                 return -ENODEV;
 786         }
 787
 788         data->def = &ak_def_array[chipset];
 789         err = ak8975_who_i_am(client, data->def->type);
 790         if (err < 0) {
 791                 dev_err(&client->dev, "Unexpected device\n");
 792                 return err;
 793         }
 794         dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
 795
 796         /* Perform some basic start-of-day setup of the device. */
 797         err = ak8975_setup(client);
 798         if (err < 0) {
 799                 dev_err(&client->dev, "%s initialization fails\n", name);
 800                 return err;
 801         }
 802
 803         mutex_init(&data->lock);
 804         indio_dev->dev.parent = &client->dev;
 805         indio_dev->channels = ak8975_channels;
 806         indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
 807         indio_dev->info = &ak8975_info;
 808         indio_dev->modes = INDIO_DIRECT_MODE;
 809         indio_dev->name = name;
 810         return devm_iio_device_register(&client->dev, indio_dev);
 811 }
 812
 813 static const struct i2c_device_id ak8975_id[] = {
 814         {"ak8975", AK8975},
 815         {"ak8963", AK8963},
 816         {"AK8963", AK8963},
 817         {"ak09911", AK09911},
 818         {"ak09912", AK09912},
 819         {}
 820 };
 821
 822 MODULE_DEVICE_TABLE(i2c, ak8975_id);
 823
 824 static const struct of_device_id ak8975_of_match[] = {
 825         { .compatible = "asahi-kasei,ak8975", },
 826         { .compatible = "ak8975", },
 827         { .compatible = "asahi-kasei,ak8963", },
 828         { .compatible = "ak8963", },
 829         { .compatible = "asahi-kasei,ak09911", },
 830         { .compatible = "ak09911", },
 831         { .compatible = "asahi-kasei,ak09912", },
 832         { .compatible = "ak09912", },
 833         {}
 834 };
 835 MODULE_DEVICE_TABLE(of, ak8975_of_match);
 836
 837 static struct i2c_driver ak8975_driver = {
 838         .driver = {
 839                 .name   = "ak8975",
 840                 .of_match_table = of_match_ptr(ak8975_of_match),
 841                 .acpi_match_table = ACPI_PTR(ak_acpi_match),
 842         },
 843         .probe          = ak8975_probe,
 844         .id_table       = ak8975_id,
 845 };
 846 module_i2c_driver(ak8975_driver);
 847
 848 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 849 MODULE_DESCRIPTION("AK8975 magnetometer driver");
 850 MODULE_LICENSE("GPL");