drivers/iio/magnetometer/ak8974.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for the Asahi Kasei EMD Corporation AK8974
   4  * and Aichi Steel AMI305 magnetometer chips.
   5  * Based on a patch from Samu Onkalo and the AK8975 IIO driver.
   6  *
   7  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
   8  * Copyright (c) 2010 NVIDIA Corporation.
   9  * Copyright (C) 2016 Linaro Ltd.
  10  *
  11  * Author: Samu Onkalo <samu.p.onkalo@nokia.com>
  12  * Author: Linus Walleij <linus.walleij@linaro.org>
  13  */
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/i2c.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/irq.h> /* For irq_get_irq_data() */
  19 #include <linux/completion.h>
  20 #include <linux/err.h>
  21 #include <linux/mutex.h>
  22 #include <linux/delay.h>
  23 #include <linux/bitops.h>
  24 #include <linux/random.h>
  25 #include <linux/regmap.h>
  26 #include <linux/regulator/consumer.h>
  27 #include <linux/pm_runtime.h>
  28
  29 #include <linux/iio/iio.h>
  30 #include <linux/iio/sysfs.h>
  31 #include <linux/iio/buffer.h>
  32 #include <linux/iio/trigger.h>
  33 #include <linux/iio/trigger_consumer.h>
  34 #include <linux/iio/triggered_buffer.h>
  35
  36 /*
  37  * 16-bit registers are little-endian. LSB is at the address defined below
  38  * and MSB is at the next higher address.
  39  */
  40
  41 /* These registers are common for AK8974 and AMI30x */
  42 #define AK8974_SELFTEST         0x0C
  43 #define AK8974_SELFTEST_IDLE    0x55
  44 #define AK8974_SELFTEST_OK      0xAA
  45
  46 #define AK8974_INFO             0x0D
  47
  48 #define AK8974_WHOAMI           0x0F
  49 #define AK8974_WHOAMI_VALUE_AMI306 0x46
  50 #define AK8974_WHOAMI_VALUE_AMI305 0x47
  51 #define AK8974_WHOAMI_VALUE_AK8974 0x48
  52 #define AK8974_WHOAMI_VALUE_HSCDTD008A 0x49
  53
  54 #define AK8974_DATA_X           0x10
  55 #define AK8974_DATA_Y           0x12
  56 #define AK8974_DATA_Z           0x14
  57 #define AK8974_INT_SRC          0x16
  58 #define AK8974_STATUS           0x18
  59 #define AK8974_INT_CLEAR        0x1A
  60 #define AK8974_CTRL1            0x1B
  61 #define AK8974_CTRL2            0x1C
  62 #define AK8974_CTRL3            0x1D
  63 #define AK8974_INT_CTRL         0x1E
  64 #define AK8974_INT_THRES        0x26  /* Absolute any axis value threshold */
  65 #define AK8974_PRESET           0x30
  66
  67 /* AK8974-specific offsets */
  68 #define AK8974_OFFSET_X         0x20
  69 #define AK8974_OFFSET_Y         0x22
  70 #define AK8974_OFFSET_Z         0x24
  71 /* AMI305-specific offsets */
  72 #define AMI305_OFFSET_X         0x6C
  73 #define AMI305_OFFSET_Y         0x72
  74 #define AMI305_OFFSET_Z         0x78
  75
  76 /* Different temperature registers */
  77 #define AK8974_TEMP             0x31
  78 #define AMI305_TEMP             0x60
  79
  80 /* AMI306-specific control register */
  81 #define AMI306_CTRL4            0x5C
  82
  83 /* AMI306 factory calibration data */
  84
  85 /* fine axis sensitivity */
  86 #define AMI306_FINEOUTPUT_X     0x90
  87 #define AMI306_FINEOUTPUT_Y     0x92
  88 #define AMI306_FINEOUTPUT_Z     0x94
  89
  90 /* axis sensitivity */
  91 #define AMI306_SENS_X           0x96
  92 #define AMI306_SENS_Y           0x98
  93 #define AMI306_SENS_Z           0x9A
  94
  95 /* axis cross-interference */
  96 #define AMI306_GAIN_PARA_XZ     0x9C
  97 #define AMI306_GAIN_PARA_XY     0x9D
  98 #define AMI306_GAIN_PARA_YZ     0x9E
  99 #define AMI306_GAIN_PARA_YX     0x9F
 100 #define AMI306_GAIN_PARA_ZY     0xA0
 101 #define AMI306_GAIN_PARA_ZX     0xA1
 102
 103 /* offset at ZERO magnetic field */
 104 #define AMI306_OFFZERO_X        0xF8
 105 #define AMI306_OFFZERO_Y        0xFA
 106 #define AMI306_OFFZERO_Z        0xFC
 107
 108
 109 #define AK8974_INT_X_HIGH       BIT(7) /* Axis over +threshold  */
 110 #define AK8974_INT_Y_HIGH       BIT(6)
 111 #define AK8974_INT_Z_HIGH       BIT(5)
 112 #define AK8974_INT_X_LOW        BIT(4) /* Axis below -threshold */
 113 #define AK8974_INT_Y_LOW        BIT(3)
 114 #define AK8974_INT_Z_LOW        BIT(2)
 115 #define AK8974_INT_RANGE        BIT(1) /* Range overflow (any axis) */
 116
 117 #define AK8974_STATUS_DRDY      BIT(6) /* Data ready */
 118 #define AK8974_STATUS_OVERRUN   BIT(5) /* Data overrun */
 119 #define AK8974_STATUS_INT       BIT(4) /* Interrupt occurred */
 120
 121 #define AK8974_CTRL1_POWER      BIT(7) /* 0 = standby; 1 = active */
 122 #define AK8974_CTRL1_RATE       BIT(4) /* 0 = 10 Hz; 1 = 20 Hz   */
 123 #define AK8974_CTRL1_FORCE_EN   BIT(1) /* 0 = normal; 1 = force  */
 124 #define AK8974_CTRL1_MODE2      BIT(0) /* 0 */
 125
 126 #define AK8974_CTRL2_INT_EN     BIT(4)  /* 1 = enable interrupts              */
 127 #define AK8974_CTRL2_DRDY_EN    BIT(3)  /* 1 = enable data ready signal */
 128 #define AK8974_CTRL2_DRDY_POL   BIT(2)  /* 1 = data ready active high   */
 129 #define AK8974_CTRL2_RESDEF     (AK8974_CTRL2_DRDY_POL)
 130
 131 #define AK8974_CTRL3_RESET      BIT(7) /* Software reset                  */
 132 #define AK8974_CTRL3_FORCE      BIT(6) /* Start forced measurement */
 133 #define AK8974_CTRL3_SELFTEST   BIT(4) /* Set selftest register   */
 134 #define AK8974_CTRL3_RESDEF     0x00
 135
 136 #define AK8974_INT_CTRL_XEN     BIT(7) /* Enable interrupt for this axis */
 137 #define AK8974_INT_CTRL_YEN     BIT(6)
 138 #define AK8974_INT_CTRL_ZEN     BIT(5)
 139 #define AK8974_INT_CTRL_XYZEN   (BIT(7)|BIT(6)|BIT(5))
 140 #define AK8974_INT_CTRL_POL     BIT(3) /* 0 = active low; 1 = active high */
 141 #define AK8974_INT_CTRL_PULSE   BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
 142 #define AK8974_INT_CTRL_RESDEF  (AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
 143
 144 /* HSCDTD008A-specific control register */
 145 #define HSCDTD008A_CTRL4        0x1E
 146 #define HSCDTD008A_CTRL4_MMD    BIT(7)  /* must be set to 1 */
 147 #define HSCDTD008A_CTRL4_RANGE  BIT(4)  /* 0 = 14-bit output; 1 = 15-bit output */
 148 #define HSCDTD008A_CTRL4_RESDEF (HSCDTD008A_CTRL4_MMD | HSCDTD008A_CTRL4_RANGE)
 149
 150 /* The AMI305 has elaborate FW version and serial number registers */
 151 #define AMI305_VER              0xE8
 152 #define AMI305_SN               0xEA
 153
 154 #define AK8974_MAX_RANGE        2048
 155
 156 #define AK8974_POWERON_DELAY    50
 157 #define AK8974_ACTIVATE_DELAY   1
 158 #define AK8974_SELFTEST_DELAY   1
 159 /*
 160  * Set the autosuspend to two orders of magnitude larger than the poweron
 161  * delay to make sane reasonable power tradeoff savings (5 seconds in
 162  * this case).
 163  */
 164 #define AK8974_AUTOSUSPEND_DELAY 5000
 165
 166 #define AK8974_MEASTIME         3
 167
 168 #define AK8974_PWR_ON           1
 169 #define AK8974_PWR_OFF          0
 170
 171 /**
 172  * struct ak8974 - state container for the AK8974 driver
 173  * @i2c: parent I2C client
 174  * @orientation: mounting matrix, flipped axis etc
 175  * @map: regmap to access the AK8974 registers over I2C
 176  * @regs: the avdd and dvdd power regulators
 177  * @name: the name of the part
 178  * @variant: the whoami ID value (for selecting code paths)
 179  * @lock: locks the magnetometer for exclusive use during a measurement
 180  * @drdy_irq: uses the DRDY IRQ line
 181  * @drdy_complete: completion for DRDY
 182  * @drdy_active_low: the DRDY IRQ is active low
 183  * @scan: timestamps
 184  */
 185 struct ak8974 {
 186         struct i2c_client *i2c;
 187         struct iio_mount_matrix orientation;
 188         struct regmap *map;
 189         struct regulator_bulk_data regs[2];
 190         const char *name;
 191         u8 variant;
 192         struct mutex lock;
 193         bool drdy_irq;
 194         struct completion drdy_complete;
 195         bool drdy_active_low;
 196         /* Ensure timestamp is naturally aligned */
 197         struct {
 198                 __le16 channels[3];
 199                 s64 ts __aligned(8);
 200         } scan;
 201 };
 202
 203 static const char ak8974_reg_avdd[] = "avdd";
 204 static const char ak8974_reg_dvdd[] = "dvdd";
 205
 206 static int ak8974_get_u16_val(struct ak8974 *ak8974, u8 reg, u16 *val)
 207 {
 208         int ret;
 209         __le16 bulk;
 210
 211         ret = regmap_bulk_read(ak8974->map, reg, &bulk, 2);
 212         if (ret)
 213                 return ret;
 214         *val = le16_to_cpu(bulk);
 215
 216         return 0;
 217 }
 218
 219 static int ak8974_set_u16_val(struct ak8974 *ak8974, u8 reg, u16 val)
 220 {
 221         __le16 bulk = cpu_to_le16(val);
 222
 223         return regmap_bulk_write(ak8974->map, reg, &bulk, 2);
 224 }
 225
 226 static int ak8974_set_power(struct ak8974 *ak8974, bool mode)
 227 {
 228         int ret;
 229         u8 val;
 230
 231         val = mode ? AK8974_CTRL1_POWER : 0;
 232         val |= AK8974_CTRL1_FORCE_EN;
 233         ret = regmap_write(ak8974->map, AK8974_CTRL1, val);
 234         if (ret < 0)
 235                 return ret;
 236
 237         if (mode)
 238                 msleep(AK8974_ACTIVATE_DELAY);
 239
 240         return 0;
 241 }
 242
 243 static int ak8974_reset(struct ak8974 *ak8974)
 244 {
 245         int ret;
 246
 247         /* Power on to get register access. Sets CTRL1 reg to reset state */
 248         ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
 249         if (ret)
 250                 return ret;
 251         ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_RESDEF);
 252         if (ret)
 253                 return ret;
 254         ret = regmap_write(ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
 255         if (ret)
 256                 return ret;
 257         if (ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A) {
 258                 ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
 259                                    AK8974_INT_CTRL_RESDEF);
 260                 if (ret)
 261                         return ret;
 262         } else {
 263                 ret = regmap_write(ak8974->map, HSCDTD008A_CTRL4,
 264                                    HSCDTD008A_CTRL4_RESDEF);
 265                 if (ret)
 266                         return ret;
 267         }
 268
 269         /* After reset, power off is default state */
 270         return ak8974_set_power(ak8974, AK8974_PWR_OFF);
 271 }
 272
 273 static int ak8974_configure(struct ak8974 *ak8974)
 274 {
 275         int ret;
 276
 277         ret = regmap_write(ak8974->map, AK8974_CTRL2, AK8974_CTRL2_DRDY_EN |
 278                            AK8974_CTRL2_INT_EN);
 279         if (ret)
 280                 return ret;
 281         ret = regmap_write(ak8974->map, AK8974_CTRL3, 0);
 282         if (ret)
 283                 return ret;
 284         if (ak8974->variant == AK8974_WHOAMI_VALUE_AMI306) {
 285                 /* magic from datasheet: set high-speed measurement mode */
 286                 ret = ak8974_set_u16_val(ak8974, AMI306_CTRL4, 0xA07E);
 287                 if (ret)
 288                         return ret;
 289         }
 290         if (ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A)
 291                 return 0;
 292         ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
 293         if (ret)
 294                 return ret;
 295
 296         return regmap_write(ak8974->map, AK8974_PRESET, 0);
 297 }
 298
 299 static int ak8974_trigmeas(struct ak8974 *ak8974)
 300 {
 301         unsigned int clear;
 302         u8 mask;
 303         u8 val;
 304         int ret;
 305
 306         /* Clear any previous measurement overflow status */
 307         ret = regmap_read(ak8974->map, AK8974_INT_CLEAR, &clear);
 308         if (ret)
 309                 return ret;
 310
 311         /* If we have a DRDY IRQ line, use it */
 312         if (ak8974->drdy_irq) {
 313                 mask = AK8974_CTRL2_INT_EN |
 314                         AK8974_CTRL2_DRDY_EN |
 315                         AK8974_CTRL2_DRDY_POL;
 316                 val = AK8974_CTRL2_DRDY_EN;
 317
 318                 if (!ak8974->drdy_active_low)
 319                         val |= AK8974_CTRL2_DRDY_POL;
 320
 321                 init_completion(&ak8974->drdy_complete);
 322                 ret = regmap_update_bits(ak8974->map, AK8974_CTRL2,
 323                                          mask, val);
 324                 if (ret)
 325                         return ret;
 326         }
 327
 328         /* Force a measurement */
 329         return regmap_update_bits(ak8974->map,
 330                                   AK8974_CTRL3,
 331                                   AK8974_CTRL3_FORCE,
 332                                   AK8974_CTRL3_FORCE);
 333 }
 334
 335 static int ak8974_await_drdy(struct ak8974 *ak8974)
 336 {
 337         int timeout = 2;
 338         unsigned int val;
 339         int ret;
 340
 341         if (ak8974->drdy_irq) {
 342                 ret = wait_for_completion_timeout(&ak8974->drdy_complete,
 343                                         1 + msecs_to_jiffies(1000));
 344                 if (!ret) {
 345                         dev_err(&ak8974->i2c->dev,
 346                                 "timeout waiting for DRDY IRQ\n");
 347                         return -ETIMEDOUT;
 348                 }
 349                 return 0;
 350         }
 351
 352         /* Default delay-based poll loop */
 353         do {
 354                 msleep(AK8974_MEASTIME);
 355                 ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
 356                 if (ret < 0)
 357                         return ret;
 358                 if (val & AK8974_STATUS_DRDY)
 359                         return 0;
 360         } while (--timeout);
 361
 362         dev_err(&ak8974->i2c->dev, "timeout waiting for DRDY\n");
 363         return -ETIMEDOUT;
 364 }
 365
 366 static int ak8974_getresult(struct ak8974 *ak8974, __le16 *result)
 367 {
 368         unsigned int src;
 369         int ret;
 370
 371         ret = ak8974_await_drdy(ak8974);
 372         if (ret)
 373                 return ret;
 374         ret = regmap_read(ak8974->map, AK8974_INT_SRC, &src);
 375         if (ret < 0)
 376                 return ret;
 377
 378         /* Out of range overflow! Strong magnet close? */
 379         if (src & AK8974_INT_RANGE) {
 380                 dev_err(&ak8974->i2c->dev,
 381                         "range overflow in sensor\n");
 382                 return -ERANGE;
 383         }
 384
 385         ret = regmap_bulk_read(ak8974->map, AK8974_DATA_X, result, 6);
 386         if (ret)
 387                 return ret;
 388
 389         return ret;
 390 }
 391
 392 static irqreturn_t ak8974_drdy_irq(int irq, void *d)
 393 {
 394         struct ak8974 *ak8974 = d;
 395
 396         if (!ak8974->drdy_irq)
 397                 return IRQ_NONE;
 398
 399         /* TODO: timestamp here to get good measurement stamps */
 400         return IRQ_WAKE_THREAD;
 401 }
 402
 403 static irqreturn_t ak8974_drdy_irq_thread(int irq, void *d)
 404 {
 405         struct ak8974 *ak8974 = d;
 406         unsigned int val;
 407         int ret;
 408
 409         /* Check if this was a DRDY from us */
 410         ret = regmap_read(ak8974->map, AK8974_STATUS, &val);
 411         if (ret < 0) {
 412                 dev_err(&ak8974->i2c->dev, "error reading DRDY status\n");
 413                 return IRQ_HANDLED;
 414         }
 415         if (val & AK8974_STATUS_DRDY) {
 416                 /* Yes this was our IRQ */
 417                 complete(&ak8974->drdy_complete);
 418                 return IRQ_HANDLED;
 419         }
 420
 421         /* We may be on a shared IRQ, let the next client check */
 422         return IRQ_NONE;
 423 }
 424
 425 static int ak8974_selftest(struct ak8974 *ak8974)
 426 {
 427         struct device *dev = &ak8974->i2c->dev;
 428         unsigned int val;
 429         int ret;
 430
 431         ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
 432         if (ret)
 433                 return ret;
 434         if (val != AK8974_SELFTEST_IDLE) {
 435                 dev_err(dev, "selftest not idle before test\n");
 436                 return -EIO;
 437         }
 438
 439         /* Trigger self-test */
 440         ret = regmap_update_bits(ak8974->map,
 441                         AK8974_CTRL3,
 442                         AK8974_CTRL3_SELFTEST,
 443                         AK8974_CTRL3_SELFTEST);
 444         if (ret) {
 445                 dev_err(dev, "could not write CTRL3\n");
 446                 return ret;
 447         }
 448
 449         msleep(AK8974_SELFTEST_DELAY);
 450
 451         ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
 452         if (ret)
 453                 return ret;
 454         if (val != AK8974_SELFTEST_OK) {
 455                 dev_err(dev, "selftest result NOT OK (%02x)\n", val);
 456                 return -EIO;
 457         }
 458
 459         ret = regmap_read(ak8974->map, AK8974_SELFTEST, &val);
 460         if (ret)
 461                 return ret;
 462         if (val != AK8974_SELFTEST_IDLE) {
 463                 dev_err(dev, "selftest not idle after test (%02x)\n", val);
 464                 return -EIO;
 465         }
 466         dev_dbg(dev, "passed self-test\n");
 467
 468         return 0;
 469 }
 470
 471 static void ak8974_read_calib_data(struct ak8974 *ak8974, unsigned int reg,
 472                                    __le16 *tab, size_t tab_size)
 473 {
 474         int ret = regmap_bulk_read(ak8974->map, reg, tab, tab_size);
 475         if (ret) {
 476                 memset(tab, 0xFF, tab_size);
 477                 dev_warn(&ak8974->i2c->dev,
 478                          "can't read calibration data (regs %u..%zu): %d\n",
 479                          reg, reg + tab_size - 1, ret);
 480         } else {
 481                 add_device_randomness(tab, tab_size);
 482         }
 483 }
 484
 485 static int ak8974_detect(struct ak8974 *ak8974)
 486 {
 487         unsigned int whoami;
 488         const char *name;
 489         int ret;
 490         unsigned int fw;
 491         u16 sn;
 492
 493         ret = regmap_read(ak8974->map, AK8974_WHOAMI, &whoami);
 494         if (ret)
 495                 return ret;
 496
 497         name = "ami305";
 498
 499         switch (whoami) {
 500         case AK8974_WHOAMI_VALUE_AMI306:
 501                 name = "ami306";
 502                 /* fall-through */
 503         case AK8974_WHOAMI_VALUE_AMI305:
 504                 ret = regmap_read(ak8974->map, AMI305_VER, &fw);
 505                 if (ret)
 506                         return ret;
 507                 fw &= 0x7f; /* only bits 0 thru 6 valid */
 508                 ret = ak8974_get_u16_val(ak8974, AMI305_SN, &sn);
 509                 if (ret)
 510                         return ret;
 511                 add_device_randomness(&sn, sizeof(sn));
 512                 dev_info(&ak8974->i2c->dev,
 513                          "detected %s, FW ver %02x, S/N: %04x\n",
 514                          name, fw, sn);
 515                 break;
 516         case AK8974_WHOAMI_VALUE_AK8974:
 517                 name = "ak8974";
 518                 dev_info(&ak8974->i2c->dev, "detected AK8974\n");
 519                 break;
 520         case AK8974_WHOAMI_VALUE_HSCDTD008A:
 521                 name = "hscdtd008a";
 522                 dev_info(&ak8974->i2c->dev, "detected hscdtd008a\n");
 523                 break;
 524         default:
 525                 dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
 526                         whoami);
 527                 return -ENODEV;
 528         }
 529
 530         ak8974->name = name;
 531         ak8974->variant = whoami;
 532
 533         if (whoami == AK8974_WHOAMI_VALUE_AMI306) {
 534                 __le16 fab_data1[9], fab_data2[3];
 535                 int i;
 536
 537                 ak8974_read_calib_data(ak8974, AMI306_FINEOUTPUT_X,
 538                                        fab_data1, sizeof(fab_data1));
 539                 ak8974_read_calib_data(ak8974, AMI306_OFFZERO_X,
 540                                        fab_data2, sizeof(fab_data2));
 541
 542                 for (i = 0; i < 3; ++i) {
 543                         static const char axis[3] = "XYZ";
 544                         static const char pgaxis[6] = "ZYZXYX";
 545                         unsigned offz = le16_to_cpu(fab_data2[i]) & 0x7F;
 546                         unsigned fine = le16_to_cpu(fab_data1[i]);
 547                         unsigned sens = le16_to_cpu(fab_data1[i + 3]);
 548                         unsigned pgain1 = le16_to_cpu(fab_data1[i + 6]);
 549                         unsigned pgain2 = pgain1 >> 8;
 550
 551                         pgain1 &= 0xFF;
 552
 553                         dev_info(&ak8974->i2c->dev,
 554                                  "factory calibration for axis %c: offz=%u sens=%u fine=%u pga%c=%u pga%c=%u\n",
 555                                  axis[i], offz, sens, fine, pgaxis[i * 2],
 556                                  pgain1, pgaxis[i * 2 + 1], pgain2);
 557                 }
 558         }
 559
 560         return 0;
 561 }
 562
 563 static int ak8974_measure_channel(struct ak8974 *ak8974, unsigned long address,
 564                                   int *val)
 565 {
 566         __le16 hw_values[3];
 567         int ret;
 568
 569         pm_runtime_get_sync(&ak8974->i2c->dev);
 570         mutex_lock(&ak8974->lock);
 571
 572         /*
 573          * We read all axes and discard all but one, for optimized
 574          * reading, use the triggered buffer.
 575          */
 576         ret = ak8974_trigmeas(ak8974);
 577         if (ret)
 578                 goto out_unlock;
 579         ret = ak8974_getresult(ak8974, hw_values);
 580         if (ret)
 581                 goto out_unlock;
 582         /*
 583          * This explicit cast to (s16) is necessary as the measurement
 584          * is done in 2's complement with positive and negative values.
 585          * The follwing assignment to *val will then convert the signed
 586          * s16 value to a signed int value.
 587          */
 588         *val = (s16)le16_to_cpu(hw_values[address]);
 589 out_unlock:
 590         mutex_unlock(&ak8974->lock);
 591         pm_runtime_mark_last_busy(&ak8974->i2c->dev);
 592         pm_runtime_put_autosuspend(&ak8974->i2c->dev);
 593
 594         return ret;
 595 }
 596
 597 static int ak8974_read_raw(struct iio_dev *indio_dev,
 598                            struct iio_chan_spec const *chan,
 599                            int *val, int *val2,
 600                            long mask)
 601 {
 602         struct ak8974 *ak8974 = iio_priv(indio_dev);
 603         int ret;
 604
 605         switch (mask) {
 606         case IIO_CHAN_INFO_RAW:
 607                 if (chan->address > 2) {
 608                         dev_err(&ak8974->i2c->dev, "faulty channel address\n");
 609                         return -EIO;
 610                 }
 611                 ret = ak8974_measure_channel(ak8974, chan->address, val);
 612                 if (ret)
 613                         return ret;
 614                 return IIO_VAL_INT;
 615         case IIO_CHAN_INFO_SCALE:
 616                 switch (ak8974->variant) {
 617                 case AK8974_WHOAMI_VALUE_AMI306:
 618                 case AK8974_WHOAMI_VALUE_AMI305:
 619                         /*
 620                          * The datasheet for AMI305 and AMI306, page 6
 621                          * specifies the range of the sensor to be
 622                          * +/- 12 Gauss.
 623                          */
 624                         *val = 12;
 625                         /*
 626                          * 12 bits are used, +/- 2^11
 627                          * [ -2048 .. 2047 ] (manual page 20)
 628                          * [ 0xf800 .. 0x07ff ]
 629                          */
 630                         *val2 = 11;
 631                         return IIO_VAL_FRACTIONAL_LOG2;
 632                 case AK8974_WHOAMI_VALUE_HSCDTD008A:
 633                         /*
 634                          * The datasheet for HSCDTF008A, page 3 specifies the
 635                          * range of the sensor as +/- 2.4 mT per axis, which
 636                          * corresponds to +/- 2400 uT = +/- 24 Gauss.
 637                          */
 638                         *val = 24;
 639                         /*
 640                          * 15 bits are used (set up in CTRL4), +/- 2^14
 641                          * [ -16384 .. 16383 ] (manual page 24)
 642                          * [ 0xc000 .. 0x3fff ]
 643                          */
 644                         *val2 = 14;
 645                         return IIO_VAL_FRACTIONAL_LOG2;
 646                 default:
 647                         /* GUESSING +/- 12 Gauss */
 648                         *val = 12;
 649                         /* GUESSING 12 bits ADC +/- 2^11 */
 650                         *val2 = 11;
 651                         return IIO_VAL_FRACTIONAL_LOG2;
 652                 }
 653                 break;
 654         default:
 655                 /* Unknown request */
 656                 break;
 657         }
 658
 659         return -EINVAL;
 660 }
 661
 662 static void ak8974_fill_buffer(struct iio_dev *indio_dev)
 663 {
 664         struct ak8974 *ak8974 = iio_priv(indio_dev);
 665         int ret;
 666
 667         pm_runtime_get_sync(&ak8974->i2c->dev);
 668         mutex_lock(&ak8974->lock);
 669
 670         ret = ak8974_trigmeas(ak8974);
 671         if (ret) {
 672                 dev_err(&ak8974->i2c->dev, "error triggering measure\n");
 673                 goto out_unlock;
 674         }
 675         ret = ak8974_getresult(ak8974, ak8974->scan.channels);
 676         if (ret) {
 677                 dev_err(&ak8974->i2c->dev, "error getting measures\n");
 678                 goto out_unlock;
 679         }
 680
 681         iio_push_to_buffers_with_timestamp(indio_dev, &ak8974->scan,
 682                                            iio_get_time_ns(indio_dev));
 683
 684  out_unlock:
 685         mutex_unlock(&ak8974->lock);
 686         pm_runtime_mark_last_busy(&ak8974->i2c->dev);
 687         pm_runtime_put_autosuspend(&ak8974->i2c->dev);
 688 }
 689
 690 static irqreturn_t ak8974_handle_trigger(int irq, void *p)
 691 {
 692         const struct iio_poll_func *pf = p;
 693         struct iio_dev *indio_dev = pf->indio_dev;
 694
 695         ak8974_fill_buffer(indio_dev);
 696         iio_trigger_notify_done(indio_dev->trig);
 697
 698         return IRQ_HANDLED;
 699 }
 700
 701 static const struct iio_mount_matrix *
 702 ak8974_get_mount_matrix(const struct iio_dev *indio_dev,
 703                         const struct iio_chan_spec *chan)
 704 {
 705         struct ak8974 *ak8974 = iio_priv(indio_dev);
 706
 707         return &ak8974->orientation;
 708 }
 709
 710 static const struct iio_chan_spec_ext_info ak8974_ext_info[] = {
 711         IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8974_get_mount_matrix),
 712         { },
 713 };
 714
 715 #define AK8974_AXIS_CHANNEL(axis, index, bits)                          \
 716         {                                                               \
 717                 .type = IIO_MAGN,                                       \
 718                 .modified = 1,                                          \
 719                 .channel2 = IIO_MOD_##axis,                             \
 720                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
 721                         BIT(IIO_CHAN_INFO_SCALE),                       \
 722                 .ext_info = ak8974_ext_info,                            \
 723                 .address = index,                                       \
 724                 .scan_index = index,                                    \
 725                 .scan_type = {                                          \
 726                         .sign = 's',                                    \
 727                         .realbits = bits,                               \
 728                         .storagebits = 16,                              \
 729                         .endianness = IIO_LE                            \
 730                 },                                                      \
 731         }
 732
 733 /*
 734  * We have no datasheet for the AK8974 but we guess that its
 735  * ADC is 12 bits. The AMI305 and AMI306 certainly has 12bit
 736  * ADC.
 737  */
 738 static const struct iio_chan_spec ak8974_12_bits_channels[] = {
 739         AK8974_AXIS_CHANNEL(X, 0, 12),
 740         AK8974_AXIS_CHANNEL(Y, 1, 12),
 741         AK8974_AXIS_CHANNEL(Z, 2, 12),
 742         IIO_CHAN_SOFT_TIMESTAMP(3),
 743 };
 744
 745 /*
 746  * The HSCDTD008A has 15 bits resolution the way we set it up
 747  * in CTRL4.
 748  */
 749 static const struct iio_chan_spec ak8974_15_bits_channels[] = {
 750         AK8974_AXIS_CHANNEL(X, 0, 15),
 751         AK8974_AXIS_CHANNEL(Y, 1, 15),
 752         AK8974_AXIS_CHANNEL(Z, 2, 15),
 753         IIO_CHAN_SOFT_TIMESTAMP(3),
 754 };
 755
 756 static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
 757
 758 static const struct iio_info ak8974_info = {
 759         .read_raw = &ak8974_read_raw,
 760 };
 761
 762 static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
 763 {
 764         struct i2c_client *i2c = to_i2c_client(dev);
 765         struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
 766         struct ak8974 *ak8974 = iio_priv(indio_dev);
 767
 768         switch (reg) {
 769         case AK8974_CTRL1:
 770         case AK8974_CTRL2:
 771         case AK8974_CTRL3:
 772         case AK8974_INT_CTRL:
 773         case AK8974_INT_THRES:
 774         case AK8974_INT_THRES + 1:
 775                 return true;
 776         case AK8974_PRESET:
 777         case AK8974_PRESET + 1:
 778                 return ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A;
 779         case AK8974_OFFSET_X:
 780         case AK8974_OFFSET_X + 1:
 781         case AK8974_OFFSET_Y:
 782         case AK8974_OFFSET_Y + 1:
 783         case AK8974_OFFSET_Z:
 784         case AK8974_OFFSET_Z + 1:
 785                 return ak8974->variant == AK8974_WHOAMI_VALUE_AK8974 ||
 786                        ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A;
 787         case AMI305_OFFSET_X:
 788         case AMI305_OFFSET_X + 1:
 789         case AMI305_OFFSET_Y:
 790         case AMI305_OFFSET_Y + 1:
 791         case AMI305_OFFSET_Z:
 792         case AMI305_OFFSET_Z + 1:
 793                 return ak8974->variant == AK8974_WHOAMI_VALUE_AMI305 ||
 794                        ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
 795         case AMI306_CTRL4:
 796         case AMI306_CTRL4 + 1:
 797                 return ak8974->variant == AK8974_WHOAMI_VALUE_AMI306;
 798         default:
 799                 return false;
 800         }
 801 }
 802
 803 static bool ak8974_precious_reg(struct device *dev, unsigned int reg)
 804 {
 805         return reg == AK8974_INT_CLEAR;
 806 }
 807
 808 static const struct regmap_config ak8974_regmap_config = {
 809         .reg_bits = 8,
 810         .val_bits = 8,
 811         .max_register = 0xff,
 812         .writeable_reg = ak8974_writeable_reg,
 813         .precious_reg = ak8974_precious_reg,
 814 };
 815
 816 static int ak8974_probe(struct i2c_client *i2c,
 817                         const struct i2c_device_id *id)
 818 {
 819         struct iio_dev *indio_dev;
 820         struct ak8974 *ak8974;
 821         unsigned long irq_trig;
 822         int irq = i2c->irq;
 823         int ret;
 824
 825         /* Register with IIO */
 826         indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*ak8974));
 827         if (indio_dev == NULL)
 828                 return -ENOMEM;
 829
 830         ak8974 = iio_priv(indio_dev);
 831         i2c_set_clientdata(i2c, indio_dev);
 832         ak8974->i2c = i2c;
 833         mutex_init(&ak8974->lock);
 834
 835         ret = iio_read_mount_matrix(&i2c->dev, "mount-matrix",
 836                                     &ak8974->orientation);
 837         if (ret)
 838                 return ret;
 839
 840         ak8974->regs[0].supply = ak8974_reg_avdd;
 841         ak8974->regs[1].supply = ak8974_reg_dvdd;
 842
 843         ret = devm_regulator_bulk_get(&i2c->dev,
 844                                       ARRAY_SIZE(ak8974->regs),
 845                                       ak8974->regs);
 846         if (ret < 0) {
 847                 if (ret != -EPROBE_DEFER)
 848                         dev_err(&i2c->dev, "cannot get regulators: %d\n", ret);
 849                 else
 850                         dev_dbg(&i2c->dev,
 851                                 "regulators unavailable, deferring probe\n");
 852
 853                 return ret;
 854         }
 855
 856         ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
 857         if (ret < 0) {
 858                 dev_err(&i2c->dev, "cannot enable regulators\n");
 859                 return ret;
 860         }
 861
 862         /* Take runtime PM online */
 863         pm_runtime_get_noresume(&i2c->dev);
 864         pm_runtime_set_active(&i2c->dev);
 865         pm_runtime_enable(&i2c->dev);
 866
 867         ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config);
 868         if (IS_ERR(ak8974->map)) {
 869                 dev_err(&i2c->dev, "failed to allocate register map\n");
 870                 pm_runtime_put_noidle(&i2c->dev);
 871                 pm_runtime_disable(&i2c->dev);
 872                 return PTR_ERR(ak8974->map);
 873         }
 874
 875         ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
 876         if (ret) {
 877                 dev_err(&i2c->dev, "could not power on\n");
 878                 goto disable_pm;
 879         }
 880
 881         ret = ak8974_detect(ak8974);
 882         if (ret) {
 883                 dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n");
 884                 goto disable_pm;
 885         }
 886
 887         ret = ak8974_selftest(ak8974);
 888         if (ret)
 889                 dev_err(&i2c->dev, "selftest failed (continuing anyway)\n");
 890
 891         ret = ak8974_reset(ak8974);
 892         if (ret) {
 893                 dev_err(&i2c->dev, "AK8974 reset failed\n");
 894                 goto disable_pm;
 895         }
 896
 897         switch (ak8974->variant) {
 898         case AK8974_WHOAMI_VALUE_AMI306:
 899         case AK8974_WHOAMI_VALUE_AMI305:
 900                 indio_dev->channels = ak8974_12_bits_channels;
 901                 indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
 902                 break;
 903         case AK8974_WHOAMI_VALUE_HSCDTD008A:
 904                 indio_dev->channels = ak8974_15_bits_channels;
 905                 indio_dev->num_channels = ARRAY_SIZE(ak8974_15_bits_channels);
 906                 break;
 907         default:
 908                 indio_dev->channels = ak8974_12_bits_channels;
 909                 indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
 910                 break;
 911         }
 912         indio_dev->info = &ak8974_info;
 913         indio_dev->available_scan_masks = ak8974_scan_masks;
 914         indio_dev->modes = INDIO_DIRECT_MODE;
 915         indio_dev->name = ak8974->name;
 916
 917         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 918                                          ak8974_handle_trigger,
 919                                          NULL);
 920         if (ret) {
 921                 dev_err(&i2c->dev, "triggered buffer setup failed\n");
 922                 goto disable_pm;
 923         }
 924
 925         /* If we have a valid DRDY IRQ, make use of it */
 926         if (irq > 0) {
 927                 irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
 928                 if (irq_trig == IRQF_TRIGGER_RISING) {
 929                         dev_info(&i2c->dev, "enable rising edge DRDY IRQ\n");
 930                 } else if (irq_trig == IRQF_TRIGGER_FALLING) {
 931                         ak8974->drdy_active_low = true;
 932                         dev_info(&i2c->dev, "enable falling edge DRDY IRQ\n");
 933                 } else {
 934                         irq_trig = IRQF_TRIGGER_RISING;
 935                 }
 936                 irq_trig |= IRQF_ONESHOT;
 937                 irq_trig |= IRQF_SHARED;
 938
 939                 ret = devm_request_threaded_irq(&i2c->dev,
 940                                                 irq,
 941                                                 ak8974_drdy_irq,
 942                                                 ak8974_drdy_irq_thread,
 943                                                 irq_trig,
 944                                                 ak8974->name,
 945                                                 ak8974);
 946                 if (ret) {
 947                         dev_err(&i2c->dev, "unable to request DRDY IRQ "
 948                                 "- proceeding without IRQ\n");
 949                         goto no_irq;
 950                 }
 951                 ak8974->drdy_irq = true;
 952         }
 953
 954 no_irq:
 955         ret = iio_device_register(indio_dev);
 956         if (ret) {
 957                 dev_err(&i2c->dev, "device register failed\n");
 958                 goto cleanup_buffer;
 959         }
 960
 961         pm_runtime_set_autosuspend_delay(&i2c->dev,
 962                                          AK8974_AUTOSUSPEND_DELAY);
 963         pm_runtime_use_autosuspend(&i2c->dev);
 964         pm_runtime_put(&i2c->dev);
 965
 966         return 0;
 967
 968 cleanup_buffer:
 969         iio_triggered_buffer_cleanup(indio_dev);
 970 disable_pm:
 971         pm_runtime_put_noidle(&i2c->dev);
 972         pm_runtime_disable(&i2c->dev);
 973         ak8974_set_power(ak8974, AK8974_PWR_OFF);
 974         regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
 975
 976         return ret;
 977 }
 978
 979 static int ak8974_remove(struct i2c_client *i2c)
 980 {
 981         struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
 982         struct ak8974 *ak8974 = iio_priv(indio_dev);
 983
 984         iio_device_unregister(indio_dev);
 985         iio_triggered_buffer_cleanup(indio_dev);
 986         pm_runtime_get_sync(&i2c->dev);
 987         pm_runtime_put_noidle(&i2c->dev);
 988         pm_runtime_disable(&i2c->dev);
 989         ak8974_set_power(ak8974, AK8974_PWR_OFF);
 990         regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
 991
 992         return 0;
 993 }
 994
 995 static int __maybe_unused ak8974_runtime_suspend(struct device *dev)
 996 {
 997         struct ak8974 *ak8974 =
 998                 iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 999
1000         ak8974_set_power(ak8974, AK8974_PWR_OFF);
1001         regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
1002
1003         return 0;
1004 }
1005
1006 static int __maybe_unused ak8974_runtime_resume(struct device *dev)
1007 {
1008         struct ak8974 *ak8974 =
1009                 iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
1010         int ret;
1011
1012         ret = regulator_bulk_enable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
1013         if (ret)
1014                 return ret;
1015         msleep(AK8974_POWERON_DELAY);
1016         ret = ak8974_set_power(ak8974, AK8974_PWR_ON);
1017         if (ret)
1018                 goto out_regulator_disable;
1019
1020         ret = ak8974_configure(ak8974);
1021         if (ret)
1022                 goto out_disable_power;
1023
1024         return 0;
1025
1026 out_disable_power:
1027         ak8974_set_power(ak8974, AK8974_PWR_OFF);
1028 out_regulator_disable:
1029         regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
1030
1031         return ret;
1032 }
1033
1034 static const struct dev_pm_ops ak8974_dev_pm_ops = {
1035         SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
1036                                 pm_runtime_force_resume)
1037         SET_RUNTIME_PM_OPS(ak8974_runtime_suspend,
1038                            ak8974_runtime_resume, NULL)
1039 };
1040
1041 static const struct i2c_device_id ak8974_id[] = {
1042         {"ami305", 0 },
1043         {"ami306", 0 },
1044         {"ak8974", 0 },
1045         {"hscdtd008a", 0 },
1046         {}
1047 };
1048 MODULE_DEVICE_TABLE(i2c, ak8974_id);
1049
1050 static const struct of_device_id ak8974_of_match[] = {
1051         { .compatible = "asahi-kasei,ak8974", },
1052         { .compatible = "alps,hscdtd008a", },
1053         {}
1054 };
1055 MODULE_DEVICE_TABLE(of, ak8974_of_match);
1056
1057 static struct i2c_driver ak8974_driver = {
1058         .driver  = {
1059                 .name   = "ak8974",
1060                 .pm = &ak8974_dev_pm_ops,
1061                 .of_match_table = of_match_ptr(ak8974_of_match),
1062         },
1063         .probe    = ak8974_probe,
1064         .remove   = ak8974_remove,
1065         .id_table = ak8974_id,
1066 };
1067 module_i2c_driver(ak8974_driver);
1068
1069 MODULE_DESCRIPTION("AK8974 and AMI30x 3-axis magnetometer driver");
1070 MODULE_AUTHOR("Samu Onkalo");
1071 MODULE_AUTHOR("Linus Walleij");
1072 MODULE_LICENSE("GPL v2");