drivers/gpio/max732x.c

   1 /*
   2  *  max732x.c - 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
  81 enum {
  82         MAX7319,
  83         MAX7320,
  84         MAX7321,
  85         MAX7322,
  86         MAX7323,
  87         MAX7324,
  88         MAX7325,
  89         MAX7326,
  90         MAX7327,
  91 };
  92
  93 static 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
 105 static 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 };
 117 MODULE_DEVICE_TABLE(i2c, max732x_id);
 118
 119 struct 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
 145 static 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
 160 static 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
 176 static inline int is_group_a(struct max732x_chip *chip, unsigned off)
 177 {
 178         return (1u << off) & chip->mask_group_a;
 179 }
 180
 181 static 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
 196 static 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;
 218 out:
 219         mutex_unlock(&chip->lock);
 220 }
 221
 222 static 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
 245 static 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
 264 static 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
 279 static 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
 293 static 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
 322 static 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
 330 static 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
 337 static 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
 344 static 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
 352 static 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
 360 static 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
 391 static 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
 400 static 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
 431 static 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
 452 static 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 = client->dev.platform_data;
 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
 500 out_failed:
 501         chip->irq_base = 0;
 502         return ret;
 503 }
 504
 505 static 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 */
 511 static 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 = client->dev.platform_data;
 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
 524 static void max732x_irq_teardown(struct max732x_chip *chip)
 525 {
 526 }
 527 #endif
 528
 529 static int __devinit 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
 577 static int __devinit 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 = client->dev.platform_data;
 587         if (pdata == NULL) {
 588                 dev_dbg(&client->dev, "no platform data\n");
 589                 return -EINVAL;
 590         }
 591
 592         chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
 593         if (chip == NULL)
 594                 return -ENOMEM;
 595         chip->client = client;
 596
 597         nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
 598
 599         addr_a = (client->addr & 0x0f) | 0x60;
 600         addr_b = (client->addr & 0x0f) | 0x50;
 601
 602         switch (client->addr & 0x70) {
 603         case 0x60:
 604                 chip->client_group_a = client;
 605                 if (nr_port > 8) {
 606                         c = i2c_new_dummy(client->adapter, addr_b);
 607                         chip->client_group_b = chip->client_dummy = c;
 608                 }
 609                 break;
 610         case 0x50:
 611                 chip->client_group_b = client;
 612                 if (nr_port > 8) {
 613                         c = i2c_new_dummy(client->adapter, addr_a);
 614                         chip->client_group_a = chip->client_dummy = c;
 615                 }
 616                 break;
 617         default:
 618                 dev_err(&client->dev, "invalid I2C address specified %02x\n",
 619                                 client->addr);
 620                 ret = -EINVAL;
 621                 goto out_failed;
 622         }
 623
 624         mutex_init(&chip->lock);
 625
 626         max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
 627         if (nr_port > 8)
 628                 max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
 629
 630         ret = max732x_irq_setup(chip, id);
 631         if (ret)
 632                 goto out_failed;
 633
 634         ret = gpiochip_add(&chip->gpio_chip);
 635         if (ret)
 636                 goto out_failed;
 637
 638         if (pdata->setup) {
 639                 ret = pdata->setup(client, chip->gpio_chip.base,
 640                                 chip->gpio_chip.ngpio, pdata->context);
 641                 if (ret < 0)
 642                         dev_warn(&client->dev, "setup failed, %d\n", ret);
 643         }
 644
 645         i2c_set_clientdata(client, chip);
 646         return 0;
 647
 648 out_failed:
 649         max732x_irq_teardown(chip);
 650         kfree(chip);
 651         return ret;
 652 }
 653
 654 static int __devexit max732x_remove(struct i2c_client *client)
 655 {
 656         struct max732x_platform_data *pdata = client->dev.platform_data;
 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         kfree(chip);
 684         return 0;
 685 }
 686
 687 static struct i2c_driver max732x_driver = {
 688         .driver = {
 689                 .name   = "max732x",
 690                 .owner  = THIS_MODULE,
 691         },
 692         .probe          = max732x_probe,
 693         .remove         = __devexit_p(max732x_remove),
 694         .id_table       = max732x_id,
 695 };
 696
 697 static int __init max732x_init(void)
 698 {
 699         return i2c_add_driver(&max732x_driver);
 700 }
 701 /* register after i2c postcore initcall and before
 702  * subsys initcalls that may rely on these GPIOs
 703  */
 704 subsys_initcall(max732x_init);
 705
 706 static void __exit max732x_exit(void)
 707 {
 708         i2c_del_driver(&max732x_driver);
 709 }
 710 module_exit(max732x_exit);
 711
 712 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
 713 MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
 714 MODULE_LICENSE("GPL");