linux/drivers/iio/magnetometer/ak8974.c
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   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 */
 186struct 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
 204static const char ak8974_reg_avdd[] = "avdd";
 205static const char ak8974_reg_dvdd[] = "dvdd";
 206
 207static 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
 220static 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
 227static 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
 244static 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
 274static 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
 300static 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
 336static 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
 367static 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
 393static 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
 404static 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
 426static 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
 472static 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
 486static 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
 564static 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]);
 590out_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
 598static 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
 663static 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
 691static 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
 702static const struct iio_mount_matrix *
 703ak8974_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
 711static 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 */
 739static 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 */
 750static 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
 757static const unsigned long ak8974_scan_masks[] = { 0x7, 0 };
 758
 759static const struct iio_info ak8974_info = {
 760        .read_raw = &ak8974_read_raw,
 761};
 762
 763static 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
 804static bool ak8974_precious_reg(struct device *dev, unsigned int reg)
 805{
 806        return reg == AK8974_INT_CLEAR;
 807}
 808
 809static 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
 817static 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
 947no_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
 961cleanup_buffer:
 962        iio_triggered_buffer_cleanup(indio_dev);
 963disable_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
 972static 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
 988static 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
 999static 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
1019out_disable_power:
1020        ak8974_set_power(ak8974, AK8974_PWR_OFF);
1021out_regulator_disable:
1022        regulator_bulk_disable(ARRAY_SIZE(ak8974->regs), ak8974->regs);
1023
1024        return ret;
1025}
1026
1027static 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
1034static const struct i2c_device_id ak8974_id[] = {
1035        {"ami305", 0 },
1036        {"ami306", 0 },
1037        {"ak8974", 0 },
1038        {"hscdtd008a", 0 },
1039        {}
1040};
1041MODULE_DEVICE_TABLE(i2c, ak8974_id);
1042
1043static const struct of_device_id ak8974_of_match[] = {
1044        { .compatible = "asahi-kasei,ak8974", },
1045        { .compatible = "alps,hscdtd008a", },
1046        {}
1047};
1048MODULE_DEVICE_TABLE(of, ak8974_of_match);
1049
1050static 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};
1060module_i2c_driver(ak8974_driver);
1061
1062MODULE_DESCRIPTION("AK8974 and AMI30x 3-axis magnetometer driver");
1063MODULE_AUTHOR("Samu Onkalo");
1064MODULE_AUTHOR("Linus Walleij");
1065MODULE_LICENSE("GPL v2");
1066