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