linux/drivers/gpio/gpio-max732x.c
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   1/*
   2 *  MAX732x I2C Port Expander with 8/16 I/O
   3 *
   4 *  Copyright (C) 2007 Marvell International Ltd.
   5 *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
   6 *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
   7 *
   8 *  Derived from drivers/gpio/pca953x.c
   9 *
  10 *  This program is free software; you can redistribute it and/or modify
  11 *  it under the terms of the GNU General Public License as published by
  12 *  the Free Software Foundation; version 2 of the License.
  13 */
  14
  15#include <linux/module.h>
  16#include <linux/init.h>
  17#include <linux/slab.h>
  18#include <linux/string.h>
  19#include <linux/gpio.h>
  20#include <linux/interrupt.h>
  21#include <linux/irq.h>
  22#include <linux/i2c.h>
  23#include <linux/i2c/max732x.h>
  24
  25
  26/*
  27 * Each port of MAX732x (including MAX7319) falls into one of the
  28 * following three types:
  29 *
  30 *   - Push Pull Output
  31 *   - Input
  32 *   - Open Drain I/O
  33 *
  34 * designated by 'O', 'I' and 'P' individually according to MAXIM's
  35 * datasheets. 'I' and 'P' ports are interrupt capables, some with
  36 * a dedicated interrupt mask.
  37 *
  38 * There are two groups of I/O ports, each group usually includes
  39 * up to 8 I/O ports, and is accessed by a specific I2C address:
  40 *
  41 *   - Group A : by I2C address 0b'110xxxx
  42 *   - Group B : by I2C address 0b'101xxxx
  43 *
  44 * where 'xxxx' is decided by the connections of pin AD2/AD0.  The
  45 * address used also affects the initial state of output signals.
  46 *
  47 * Within each group of ports, there are five known combinations of
  48 * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
  49 * the detailed organization of these ports. Only Goup A is interrupt
  50 * capable.
  51 *
  52 * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
  53 * and GPIOs from GROUP_A are numbered before those from GROUP_B
  54 * (if there are two groups).
  55 *
  56 * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
  57 * they are not supported by this driver.
  58 */
  59
  60#define PORT_NONE       0x0     /* '/' No Port */
  61#define PORT_OUTPUT     0x1     /* 'O' Push-Pull, Output Only */
  62#define PORT_INPUT      0x2     /* 'I' Input Only */
  63#define PORT_OPENDRAIN  0x3     /* 'P' Open-Drain, I/O */
  64
  65#define IO_4I4O         0x5AA5  /* O7 O6 I5 I4 I3 I2 O1 O0 */
  66#define IO_4P4O         0x5FF5  /* O7 O6 P5 P4 P3 P2 O1 O0 */
  67#define IO_8I           0xAAAA  /* I7 I6 I5 I4 I3 I2 I1 I0 */
  68#define IO_8P           0xFFFF  /* P7 P6 P5 P4 P3 P2 P1 P0 */
  69#define IO_8O           0x5555  /* O7 O6 O5 O4 O3 O2 O1 O0 */
  70
  71#define GROUP_A(x)      ((x) & 0xffff)  /* I2C Addr: 0b'110xxxx */
  72#define GROUP_B(x)      ((x) << 16)     /* I2C Addr: 0b'101xxxx */
  73
  74#define INT_NONE        0x0     /* No interrupt capability */
  75#define INT_NO_MASK     0x1     /* Has interrupts, no mask */
  76#define INT_INDEP_MASK  0x2     /* Has interrupts, independent mask */
  77#define INT_MERGED_MASK 0x3     /* Has interrupts, merged mask */
  78
  79#define INT_CAPS(x)     (((uint64_t)(x)) << 32)
  80
  81enum {
  82        MAX7319,
  83        MAX7320,
  84        MAX7321,
  85        MAX7322,
  86        MAX7323,
  87        MAX7324,
  88        MAX7325,
  89        MAX7326,
  90        MAX7327,
  91};
  92
  93static uint64_t max732x_features[] = {
  94        [MAX7319] = GROUP_A(IO_8I) | INT_CAPS(INT_MERGED_MASK),
  95        [MAX7320] = GROUP_B(IO_8O),
  96        [MAX7321] = GROUP_A(IO_8P) | INT_CAPS(INT_NO_MASK),
  97        [MAX7322] = GROUP_A(IO_4I4O) | INT_CAPS(INT_MERGED_MASK),
  98        [MAX7323] = GROUP_A(IO_4P4O) | INT_CAPS(INT_INDEP_MASK),
  99        [MAX7324] = GROUP_A(IO_8I) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
 100        [MAX7325] = GROUP_A(IO_8P) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
 101        [MAX7326] = GROUP_A(IO_4I4O) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
 102        [MAX7327] = GROUP_A(IO_4P4O) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
 103};
 104
 105static const struct i2c_device_id max732x_id[] = {
 106        { "max7319", MAX7319 },
 107        { "max7320", MAX7320 },
 108        { "max7321", MAX7321 },
 109        { "max7322", MAX7322 },
 110        { "max7323", MAX7323 },
 111        { "max7324", MAX7324 },
 112        { "max7325", MAX7325 },
 113        { "max7326", MAX7326 },
 114        { "max7327", MAX7327 },
 115        { },
 116};
 117MODULE_DEVICE_TABLE(i2c, max732x_id);
 118
 119struct max732x_chip {
 120        struct gpio_chip gpio_chip;
 121
 122        struct i2c_client *client;      /* "main" client */
 123        struct i2c_client *client_dummy;
 124        struct i2c_client *client_group_a;
 125        struct i2c_client *client_group_b;
 126
 127        unsigned int    mask_group_a;
 128        unsigned int    dir_input;
 129        unsigned int    dir_output;
 130
 131        struct mutex    lock;
 132        uint8_t         reg_out[2];
 133
 134#ifdef CONFIG_GPIO_MAX732X_IRQ
 135        struct mutex    irq_lock;
 136        int             irq_base;
 137        uint8_t         irq_mask;
 138        uint8_t         irq_mask_cur;
 139        uint8_t         irq_trig_raise;
 140        uint8_t         irq_trig_fall;
 141        uint8_t         irq_features;
 142#endif
 143};
 144
 145static int max732x_writeb(struct max732x_chip *chip, int group_a, uint8_t val)
 146{
 147        struct i2c_client *client;
 148        int ret;
 149
 150        client = group_a ? chip->client_group_a : chip->client_group_b;
 151        ret = i2c_smbus_write_byte(client, val);
 152        if (ret < 0) {
 153                dev_err(&client->dev, "failed writing\n");
 154                return ret;
 155        }
 156
 157        return 0;
 158}
 159
 160static int max732x_readb(struct max732x_chip *chip, int group_a, uint8_t *val)
 161{
 162        struct i2c_client *client;
 163        int ret;
 164
 165        client = group_a ? chip->client_group_a : chip->client_group_b;
 166        ret = i2c_smbus_read_byte(client);
 167        if (ret < 0) {
 168                dev_err(&client->dev, "failed reading\n");
 169                return ret;
 170        }
 171
 172        *val = (uint8_t)ret;
 173        return 0;
 174}
 175
 176static inline int is_group_a(struct max732x_chip *chip, unsigned off)
 177{
 178        return (1u << off) & chip->mask_group_a;
 179}
 180
 181static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
 182{
 183        struct max732x_chip *chip;
 184        uint8_t reg_val;
 185        int ret;
 186
 187        chip = container_of(gc, struct max732x_chip, gpio_chip);
 188
 189        ret = max732x_readb(chip, is_group_a(chip, off), &reg_val);
 190        if (ret < 0)
 191                return 0;
 192
 193        return reg_val & (1u << (off & 0x7));
 194}
 195
 196static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
 197{
 198        struct max732x_chip *chip;
 199        uint8_t reg_out, mask = 1u << (off & 0x7);
 200        int ret;
 201
 202        chip = container_of(gc, struct max732x_chip, gpio_chip);
 203
 204        mutex_lock(&chip->lock);
 205
 206        reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
 207        reg_out = (val) ? reg_out | mask : reg_out & ~mask;
 208
 209        ret = max732x_writeb(chip, is_group_a(chip, off), reg_out);
 210        if (ret < 0)
 211                goto out;
 212
 213        /* update the shadow register then */
 214        if (off > 7)
 215                chip->reg_out[1] = reg_out;
 216        else
 217                chip->reg_out[0] = reg_out;
 218out:
 219        mutex_unlock(&chip->lock);
 220}
 221
 222static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
 223{
 224        struct max732x_chip *chip;
 225        unsigned int mask = 1u << off;
 226
 227        chip = container_of(gc, struct max732x_chip, gpio_chip);
 228
 229        if ((mask & chip->dir_input) == 0) {
 230                dev_dbg(&chip->client->dev, "%s port %d is output only\n",
 231                        chip->client->name, off);
 232                return -EACCES;
 233        }
 234
 235        /*
 236         * Open-drain pins must be set to high impedance (which is
 237         * equivalent to output-high) to be turned into an input.
 238         */
 239        if ((mask & chip->dir_output))
 240                max732x_gpio_set_value(gc, off, 1);
 241
 242        return 0;
 243}
 244
 245static int max732x_gpio_direction_output(struct gpio_chip *gc,
 246                unsigned off, int val)
 247{
 248        struct max732x_chip *chip;
 249        unsigned int mask = 1u << off;
 250
 251        chip = container_of(gc, struct max732x_chip, gpio_chip);
 252
 253        if ((mask & chip->dir_output) == 0) {
 254                dev_dbg(&chip->client->dev, "%s port %d is input only\n",
 255                        chip->client->name, off);
 256                return -EACCES;
 257        }
 258
 259        max732x_gpio_set_value(gc, off, val);
 260        return 0;
 261}
 262
 263#ifdef CONFIG_GPIO_MAX732X_IRQ
 264static int max732x_writew(struct max732x_chip *chip, uint16_t val)
 265{
 266        int ret;
 267
 268        val = cpu_to_le16(val);
 269
 270        ret = i2c_master_send(chip->client_group_a, (char *)&val, 2);
 271        if (ret < 0) {
 272                dev_err(&chip->client_group_a->dev, "failed writing\n");
 273                return ret;
 274        }
 275
 276        return 0;
 277}
 278
 279static int max732x_readw(struct max732x_chip *chip, uint16_t *val)
 280{
 281        int ret;
 282
 283        ret = i2c_master_recv(chip->client_group_a, (char *)val, 2);
 284        if (ret < 0) {
 285                dev_err(&chip->client_group_a->dev, "failed reading\n");
 286                return ret;
 287        }
 288
 289        *val = le16_to_cpu(*val);
 290        return 0;
 291}
 292
 293static void max732x_irq_update_mask(struct max732x_chip *chip)
 294{
 295        uint16_t msg;
 296
 297        if (chip->irq_mask == chip->irq_mask_cur)
 298                return;
 299
 300        chip->irq_mask = chip->irq_mask_cur;
 301
 302        if (chip->irq_features == INT_NO_MASK)
 303                return;
 304
 305        mutex_lock(&chip->lock);
 306
 307        switch (chip->irq_features) {
 308        case INT_INDEP_MASK:
 309                msg = (chip->irq_mask << 8) | chip->reg_out[0];
 310                max732x_writew(chip, msg);
 311                break;
 312
 313        case INT_MERGED_MASK:
 314                msg = chip->irq_mask | chip->reg_out[0];
 315                max732x_writeb(chip, 1, (uint8_t)msg);
 316                break;
 317        }
 318
 319        mutex_unlock(&chip->lock);
 320}
 321
 322static int max732x_gpio_to_irq(struct gpio_chip *gc, unsigned off)
 323{
 324        struct max732x_chip *chip;
 325
 326        chip = container_of(gc, struct max732x_chip, gpio_chip);
 327        return chip->irq_base + off;
 328}
 329
 330static void max732x_irq_mask(struct irq_data *d)
 331{
 332        struct max732x_chip *chip = irq_data_get_irq_chip_data(d);
 333
 334        chip->irq_mask_cur &= ~(1 << (d->irq - chip->irq_base));
 335}
 336
 337static void max732x_irq_unmask(struct irq_data *d)
 338{
 339        struct max732x_chip *chip = irq_data_get_irq_chip_data(d);
 340
 341        chip->irq_mask_cur |= 1 << (d->irq - chip->irq_base);
 342}
 343
 344static void max732x_irq_bus_lock(struct irq_data *d)
 345{
 346        struct max732x_chip *chip = irq_data_get_irq_chip_data(d);
 347
 348        mutex_lock(&chip->irq_lock);
 349        chip->irq_mask_cur = chip->irq_mask;
 350}
 351
 352static void max732x_irq_bus_sync_unlock(struct irq_data *d)
 353{
 354        struct max732x_chip *chip = irq_data_get_irq_chip_data(d);
 355
 356        max732x_irq_update_mask(chip);
 357        mutex_unlock(&chip->irq_lock);
 358}
 359
 360static int max732x_irq_set_type(struct irq_data *d, unsigned int type)
 361{
 362        struct max732x_chip *chip = irq_data_get_irq_chip_data(d);
 363        uint16_t off = d->irq - chip->irq_base;
 364        uint16_t mask = 1 << off;
 365
 366        if (!(mask & chip->dir_input)) {
 367                dev_dbg(&chip->client->dev, "%s port %d is output only\n",
 368                        chip->client->name, off);
 369                return -EACCES;
 370        }
 371
 372        if (!(type & IRQ_TYPE_EDGE_BOTH)) {
 373                dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
 374                        d->irq, type);
 375                return -EINVAL;
 376        }
 377
 378        if (type & IRQ_TYPE_EDGE_FALLING)
 379                chip->irq_trig_fall |= mask;
 380        else
 381                chip->irq_trig_fall &= ~mask;
 382
 383        if (type & IRQ_TYPE_EDGE_RISING)
 384                chip->irq_trig_raise |= mask;
 385        else
 386                chip->irq_trig_raise &= ~mask;
 387
 388        return max732x_gpio_direction_input(&chip->gpio_chip, off);
 389}
 390
 391static struct irq_chip max732x_irq_chip = {
 392        .name                   = "max732x",
 393        .irq_mask               = max732x_irq_mask,
 394        .irq_unmask             = max732x_irq_unmask,
 395        .irq_bus_lock           = max732x_irq_bus_lock,
 396        .irq_bus_sync_unlock    = max732x_irq_bus_sync_unlock,
 397        .irq_set_type           = max732x_irq_set_type,
 398};
 399
 400static uint8_t max732x_irq_pending(struct max732x_chip *chip)
 401{
 402        uint8_t cur_stat;
 403        uint8_t old_stat;
 404        uint8_t trigger;
 405        uint8_t pending;
 406        uint16_t status;
 407        int ret;
 408
 409        ret = max732x_readw(chip, &status);
 410        if (ret)
 411                return 0;
 412
 413        trigger = status >> 8;
 414        trigger &= chip->irq_mask;
 415
 416        if (!trigger)
 417                return 0;
 418
 419        cur_stat = status & 0xFF;
 420        cur_stat &= chip->irq_mask;
 421
 422        old_stat = cur_stat ^ trigger;
 423
 424        pending = (old_stat & chip->irq_trig_fall) |
 425                  (cur_stat & chip->irq_trig_raise);
 426        pending &= trigger;
 427
 428        return pending;
 429}
 430
 431static irqreturn_t max732x_irq_handler(int irq, void *devid)
 432{
 433        struct max732x_chip *chip = devid;
 434        uint8_t pending;
 435        uint8_t level;
 436
 437        pending = max732x_irq_pending(chip);
 438
 439        if (!pending)
 440                return IRQ_HANDLED;
 441
 442        do {
 443                level = __ffs(pending);
 444                handle_nested_irq(level + chip->irq_base);
 445
 446                pending &= ~(1 << level);
 447        } while (pending);
 448
 449        return IRQ_HANDLED;
 450}
 451
 452static int max732x_irq_setup(struct max732x_chip *chip,
 453                             const struct i2c_device_id *id)
 454{
 455        struct i2c_client *client = chip->client;
 456        struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
 457        int has_irq = max732x_features[id->driver_data] >> 32;
 458        int ret;
 459
 460        if (pdata->irq_base && has_irq != INT_NONE) {
 461                int lvl;
 462
 463                chip->irq_base = pdata->irq_base;
 464                chip->irq_features = has_irq;
 465                mutex_init(&chip->irq_lock);
 466
 467                for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) {
 468                        int irq = lvl + chip->irq_base;
 469
 470                        if (!(chip->dir_input & (1 << lvl)))
 471                                continue;
 472
 473                        irq_set_chip_data(irq, chip);
 474                        irq_set_chip_and_handler(irq, &max732x_irq_chip,
 475                                                 handle_edge_irq);
 476                        irq_set_nested_thread(irq, 1);
 477#ifdef CONFIG_ARM
 478                        set_irq_flags(irq, IRQF_VALID);
 479#else
 480                        irq_set_noprobe(irq);
 481#endif
 482                }
 483
 484                ret = request_threaded_irq(client->irq,
 485                                           NULL,
 486                                           max732x_irq_handler,
 487                                           IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 488                                           dev_name(&client->dev), chip);
 489                if (ret) {
 490                        dev_err(&client->dev, "failed to request irq %d\n",
 491                                client->irq);
 492                        goto out_failed;
 493                }
 494
 495                chip->gpio_chip.to_irq = max732x_gpio_to_irq;
 496        }
 497
 498        return 0;
 499
 500out_failed:
 501        chip->irq_base = 0;
 502        return ret;
 503}
 504
 505static void max732x_irq_teardown(struct max732x_chip *chip)
 506{
 507        if (chip->irq_base)
 508                free_irq(chip->client->irq, chip);
 509}
 510#else /* CONFIG_GPIO_MAX732X_IRQ */
 511static int max732x_irq_setup(struct max732x_chip *chip,
 512                             const struct i2c_device_id *id)
 513{
 514        struct i2c_client *client = chip->client;
 515        struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
 516        int has_irq = max732x_features[id->driver_data] >> 32;
 517
 518        if (pdata->irq_base && has_irq != INT_NONE)
 519                dev_warn(&client->dev, "interrupt support not compiled in\n");
 520
 521        return 0;
 522}
 523
 524static void max732x_irq_teardown(struct max732x_chip *chip)
 525{
 526}
 527#endif
 528
 529static int max732x_setup_gpio(struct max732x_chip *chip,
 530                                        const struct i2c_device_id *id,
 531                                        unsigned gpio_start)
 532{
 533        struct gpio_chip *gc = &chip->gpio_chip;
 534        uint32_t id_data = (uint32_t)max732x_features[id->driver_data];
 535        int i, port = 0;
 536
 537        for (i = 0; i < 16; i++, id_data >>= 2) {
 538                unsigned int mask = 1 << port;
 539
 540                switch (id_data & 0x3) {
 541                case PORT_OUTPUT:
 542                        chip->dir_output |= mask;
 543                        break;
 544                case PORT_INPUT:
 545                        chip->dir_input |= mask;
 546                        break;
 547                case PORT_OPENDRAIN:
 548                        chip->dir_output |= mask;
 549                        chip->dir_input |= mask;
 550                        break;
 551                default:
 552                        continue;
 553                }
 554
 555                if (i < 8)
 556                        chip->mask_group_a |= mask;
 557                port++;
 558        }
 559
 560        if (chip->dir_input)
 561                gc->direction_input = max732x_gpio_direction_input;
 562        if (chip->dir_output) {
 563                gc->direction_output = max732x_gpio_direction_output;
 564                gc->set = max732x_gpio_set_value;
 565        }
 566        gc->get = max732x_gpio_get_value;
 567        gc->can_sleep = 1;
 568
 569        gc->base = gpio_start;
 570        gc->ngpio = port;
 571        gc->label = chip->client->name;
 572        gc->owner = THIS_MODULE;
 573
 574        return port;
 575}
 576
 577static int max732x_probe(struct i2c_client *client,
 578                                   const struct i2c_device_id *id)
 579{
 580        struct max732x_platform_data *pdata;
 581        struct max732x_chip *chip;
 582        struct i2c_client *c;
 583        uint16_t addr_a, addr_b;
 584        int ret, nr_port;
 585
 586        pdata = dev_get_platdata(&client->dev);
 587        if (pdata == NULL) {
 588                dev_dbg(&client->dev, "no platform data\n");
 589                return -EINVAL;
 590        }
 591
 592        chip = devm_kzalloc(&client->dev, sizeof(struct max732x_chip),
 593                        GFP_KERNEL);
 594        if (chip == NULL)
 595                return -ENOMEM;
 596        chip->client = client;
 597
 598        nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
 599
 600        addr_a = (client->addr & 0x0f) | 0x60;
 601        addr_b = (client->addr & 0x0f) | 0x50;
 602
 603        switch (client->addr & 0x70) {
 604        case 0x60:
 605                chip->client_group_a = client;
 606                if (nr_port > 8) {
 607                        c = i2c_new_dummy(client->adapter, addr_b);
 608                        chip->client_group_b = chip->client_dummy = c;
 609                }
 610                break;
 611        case 0x50:
 612                chip->client_group_b = client;
 613                if (nr_port > 8) {
 614                        c = i2c_new_dummy(client->adapter, addr_a);
 615                        chip->client_group_a = chip->client_dummy = c;
 616                }
 617                break;
 618        default:
 619                dev_err(&client->dev, "invalid I2C address specified %02x\n",
 620                                client->addr);
 621                ret = -EINVAL;
 622                goto out_failed;
 623        }
 624
 625        mutex_init(&chip->lock);
 626
 627        max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
 628        if (nr_port > 8)
 629                max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
 630
 631        ret = max732x_irq_setup(chip, id);
 632        if (ret)
 633                goto out_failed;
 634
 635        ret = gpiochip_add(&chip->gpio_chip);
 636        if (ret)
 637                goto out_failed;
 638
 639        if (pdata->setup) {
 640                ret = pdata->setup(client, chip->gpio_chip.base,
 641                                chip->gpio_chip.ngpio, pdata->context);
 642                if (ret < 0)
 643                        dev_warn(&client->dev, "setup failed, %d\n", ret);
 644        }
 645
 646        i2c_set_clientdata(client, chip);
 647        return 0;
 648
 649out_failed:
 650        max732x_irq_teardown(chip);
 651        return ret;
 652}
 653
 654static int max732x_remove(struct i2c_client *client)
 655{
 656        struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
 657        struct max732x_chip *chip = i2c_get_clientdata(client);
 658        int ret;
 659
 660        if (pdata->teardown) {
 661                ret = pdata->teardown(client, chip->gpio_chip.base,
 662                                chip->gpio_chip.ngpio, pdata->context);
 663                if (ret < 0) {
 664                        dev_err(&client->dev, "%s failed, %d\n",
 665                                        "teardown", ret);
 666                        return ret;
 667                }
 668        }
 669
 670        ret = gpiochip_remove(&chip->gpio_chip);
 671        if (ret) {
 672                dev_err(&client->dev, "%s failed, %d\n",
 673                                "gpiochip_remove()", ret);
 674                return ret;
 675        }
 676
 677        max732x_irq_teardown(chip);
 678
 679        /* unregister any dummy i2c_client */
 680        if (chip->client_dummy)
 681                i2c_unregister_device(chip->client_dummy);
 682
 683        return 0;
 684}
 685
 686static struct i2c_driver max732x_driver = {
 687        .driver = {
 688                .name   = "max732x",
 689                .owner  = THIS_MODULE,
 690        },
 691        .probe          = max732x_probe,
 692        .remove         = max732x_remove,
 693        .id_table       = max732x_id,
 694};
 695
 696static int __init max732x_init(void)
 697{
 698        return i2c_add_driver(&max732x_driver);
 699}
 700/* register after i2c postcore initcall and before
 701 * subsys initcalls that may rely on these GPIOs
 702 */
 703subsys_initcall(max732x_init);
 704
 705static void __exit max732x_exit(void)
 706{
 707        i2c_del_driver(&max732x_driver);
 708}
 709module_exit(max732x_exit);
 710
 711MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
 712MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
 713MODULE_LICENSE("GPL");
 714
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