1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * MAX732x I2C Port Expander with 8/16 I/O 4 * 5 * Copyright (C) 2007 Marvell International Ltd. 6 * Copyright (C) 2008 Jack Ren <jack.ren@marvell.com> 7 * Copyright (C) 2008 Eric Miao <eric.miao@marvell.com> 8 * Copyright (C) 2015 Linus Walleij <linus.walleij@linaro.org> 9 * 10 * Derived from drivers/gpio/pca953x.c 11 */ 12 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/slab.h> 16 #include <linux/string.h> 17 #include <linux/gpio/driver.h> 18 #include <linux/interrupt.h> 19 #include <linux/i2c.h> 20 #include <linux/platform_data/max732x.h> 21 #include <linux/of.h> 22 23 24 /* 25 * Each port of MAX732x (including MAX7319) falls into one of the 26 * following three types: 27 * 28 * - Push Pull Output 29 * - Input 30 * - Open Drain I/O 31 * 32 * designated by 'O', 'I' and 'P' individually according to MAXIM's 33 * datasheets. 'I' and 'P' ports are interrupt capables, some with 34 * a dedicated interrupt mask. 35 * 36 * There are two groups of I/O ports, each group usually includes 37 * up to 8 I/O ports, and is accessed by a specific I2C address: 38 * 39 * - Group A : by I2C address 0b'110xxxx 40 * - Group B : by I2C address 0b'101xxxx 41 * 42 * where 'xxxx' is decided by the connections of pin AD2/AD0. The 43 * address used also affects the initial state of output signals. 44 * 45 * Within each group of ports, there are five known combinations of 46 * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for 47 * the detailed organization of these ports. Only Goup A is interrupt 48 * capable. 49 * 50 * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16', 51 * and GPIOs from GROUP_A are numbered before those from GROUP_B 52 * (if there are two groups). 53 * 54 * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so 55 * they are not supported by this driver. 56 */ 57 58 #define PORT_NONE 0x0 /* '/' No Port */ 59 #define PORT_OUTPUT 0x1 /* 'O' Push-Pull, Output Only */ 60 #define PORT_INPUT 0x2 /* 'I' Input Only */ 61 #define PORT_OPENDRAIN 0x3 /* 'P' Open-Drain, I/O */ 62 63 #define IO_4I4O 0x5AA5 /* O7 O6 I5 I4 I3 I2 O1 O0 */ 64 #define IO_4P4O 0x5FF5 /* O7 O6 P5 P4 P3 P2 O1 O0 */ 65 #define IO_8I 0xAAAA /* I7 I6 I5 I4 I3 I2 I1 I0 */ 66 #define IO_8P 0xFFFF /* P7 P6 P5 P4 P3 P2 P1 P0 */ 67 #define IO_8O 0x5555 /* O7 O6 O5 O4 O3 O2 O1 O0 */ 68 69 #define GROUP_A(x) ((x) & 0xffff) /* I2C Addr: 0b'110xxxx */ 70 #define GROUP_B(x) ((x) << 16) /* I2C Addr: 0b'101xxxx */ 71 72 #define INT_NONE 0x0 /* No interrupt capability */ 73 #define INT_NO_MASK 0x1 /* Has interrupts, no mask */ 74 #define INT_INDEP_MASK 0x2 /* Has interrupts, independent mask */ 75 #define INT_MERGED_MASK 0x3 /* Has interrupts, merged mask */ 76 77 #define INT_CAPS(x) (((uint64_t)(x)) << 32) 78 79 enum { 80 MAX7319, 81 MAX7320, 82 MAX7321, 83 MAX7322, 84 MAX7323, 85 MAX7324, 86 MAX7325, 87 MAX7326, 88 MAX7327, 89 }; 90 91 static uint64_t max732x_features[] = { 92 [MAX7319] = GROUP_A(IO_8I) | INT_CAPS(INT_MERGED_MASK), 93 [MAX7320] = GROUP_B(IO_8O), 94 [MAX7321] = GROUP_A(IO_8P) | INT_CAPS(INT_NO_MASK), 95 [MAX7322] = GROUP_A(IO_4I4O) | INT_CAPS(INT_MERGED_MASK), 96 [MAX7323] = GROUP_A(IO_4P4O) | INT_CAPS(INT_INDEP_MASK), 97 [MAX7324] = GROUP_A(IO_8I) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK), 98 [MAX7325] = GROUP_A(IO_8P) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK), 99 [MAX7326] = GROUP_A(IO_4I4O) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK), 100 [MAX7327] = GROUP_A(IO_4P4O) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK), 101 }; 102 103 static const struct i2c_device_id max732x_id[] = { 104 { "max7319", MAX7319 }, 105 { "max7320", MAX7320 }, 106 { "max7321", MAX7321 }, 107 { "max7322", MAX7322 }, 108 { "max7323", MAX7323 }, 109 { "max7324", MAX7324 }, 110 { "max7325", MAX7325 }, 111 { "max7326", MAX7326 }, 112 { "max7327", MAX7327 }, 113 { }, 114 }; 115 MODULE_DEVICE_TABLE(i2c, max732x_id); 116 117 #ifdef CONFIG_OF 118 static const struct of_device_id max732x_of_table[] = { 119 { .compatible = "maxim,max7319" }, 120 { .compatible = "maxim,max7320" }, 121 { .compatible = "maxim,max7321" }, 122 { .compatible = "maxim,max7322" }, 123 { .compatible = "maxim,max7323" }, 124 { .compatible = "maxim,max7324" }, 125 { .compatible = "maxim,max7325" }, 126 { .compatible = "maxim,max7326" }, 127 { .compatible = "maxim,max7327" }, 128 { } 129 }; 130 MODULE_DEVICE_TABLE(of, max732x_of_table); 131 #endif 132 133 struct max732x_chip { 134 struct gpio_chip gpio_chip; 135 136 struct i2c_client *client; /* "main" client */ 137 struct i2c_client *client_dummy; 138 struct i2c_client *client_group_a; 139 struct i2c_client *client_group_b; 140 141 unsigned int mask_group_a; 142 unsigned int dir_input; 143 unsigned int dir_output; 144 145 struct mutex lock; 146 uint8_t reg_out[2]; 147 148 #ifdef CONFIG_GPIO_MAX732X_IRQ 149 struct mutex irq_lock; 150 uint8_t irq_mask; 151 uint8_t irq_mask_cur; 152 uint8_t irq_trig_raise; 153 uint8_t irq_trig_fall; 154 uint8_t irq_features; 155 #endif 156 }; 157 158 static int max732x_writeb(struct max732x_chip *chip, int group_a, uint8_t val) 159 { 160 struct i2c_client *client; 161 int ret; 162 163 client = group_a ? chip->client_group_a : chip->client_group_b; 164 ret = i2c_smbus_write_byte(client, val); 165 if (ret < 0) { 166 dev_err(&client->dev, "failed writing\n"); 167 return ret; 168 } 169 170 return 0; 171 } 172 173 static int max732x_readb(struct max732x_chip *chip, int group_a, uint8_t *val) 174 { 175 struct i2c_client *client; 176 int ret; 177 178 client = group_a ? chip->client_group_a : chip->client_group_b; 179 ret = i2c_smbus_read_byte(client); 180 if (ret < 0) { 181 dev_err(&client->dev, "failed reading\n"); 182 return ret; 183 } 184 185 *val = (uint8_t)ret; 186 return 0; 187 } 188 189 static inline int is_group_a(struct max732x_chip *chip, unsigned off) 190 { 191 return (1u << off) & chip->mask_group_a; 192 } 193 194 static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off) 195 { 196 struct max732x_chip *chip = gpiochip_get_data(gc); 197 uint8_t reg_val; 198 int ret; 199 200 ret = max732x_readb(chip, is_group_a(chip, off), ®_val); 201 if (ret < 0) 202 return ret; 203 204 return !!(reg_val & (1u << (off & 0x7))); 205 } 206 207 static void max732x_gpio_set_mask(struct gpio_chip *gc, unsigned off, int mask, 208 int val) 209 { 210 struct max732x_chip *chip = gpiochip_get_data(gc); 211 uint8_t reg_out; 212 int ret; 213 214 mutex_lock(&chip->lock); 215 216 reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0]; 217 reg_out = (reg_out & ~mask) | (val & mask); 218 219 ret = max732x_writeb(chip, is_group_a(chip, off), reg_out); 220 if (ret < 0) 221 goto out; 222 223 /* update the shadow register then */ 224 if (off > 7) 225 chip->reg_out[1] = reg_out; 226 else 227 chip->reg_out[0] = reg_out; 228 out: 229 mutex_unlock(&chip->lock); 230 } 231 232 static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) 233 { 234 unsigned base = off & ~0x7; 235 uint8_t mask = 1u << (off & 0x7); 236 237 max732x_gpio_set_mask(gc, base, mask, val << (off & 0x7)); 238 } 239 240 static void max732x_gpio_set_multiple(struct gpio_chip *gc, 241 unsigned long *mask, unsigned long *bits) 242 { 243 unsigned mask_lo = mask[0] & 0xff; 244 unsigned mask_hi = (mask[0] >> 8) & 0xff; 245 246 if (mask_lo) 247 max732x_gpio_set_mask(gc, 0, mask_lo, bits[0] & 0xff); 248 if (mask_hi) 249 max732x_gpio_set_mask(gc, 8, mask_hi, (bits[0] >> 8) & 0xff); 250 } 251 252 static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off) 253 { 254 struct max732x_chip *chip = gpiochip_get_data(gc); 255 unsigned int mask = 1u << off; 256 257 if ((mask & chip->dir_input) == 0) { 258 dev_dbg(&chip->client->dev, "%s port %d is output only\n", 259 chip->client->name, off); 260 return -EACCES; 261 } 262 263 /* 264 * Open-drain pins must be set to high impedance (which is 265 * equivalent to output-high) to be turned into an input. 266 */ 267 if ((mask & chip->dir_output)) 268 max732x_gpio_set_value(gc, off, 1); 269 270 return 0; 271 } 272 273 static int max732x_gpio_direction_output(struct gpio_chip *gc, 274 unsigned off, int val) 275 { 276 struct max732x_chip *chip = gpiochip_get_data(gc); 277 unsigned int mask = 1u << off; 278 279 if ((mask & chip->dir_output) == 0) { 280 dev_dbg(&chip->client->dev, "%s port %d is input only\n", 281 chip->client->name, off); 282 return -EACCES; 283 } 284 285 max732x_gpio_set_value(gc, off, val); 286 return 0; 287 } 288 289 #ifdef CONFIG_GPIO_MAX732X_IRQ 290 static int max732x_writew(struct max732x_chip *chip, uint16_t val) 291 { 292 int ret; 293 294 val = cpu_to_le16(val); 295 296 ret = i2c_master_send(chip->client_group_a, (char *)&val, 2); 297 if (ret < 0) { 298 dev_err(&chip->client_group_a->dev, "failed writing\n"); 299 return ret; 300 } 301 302 return 0; 303 } 304 305 static int max732x_readw(struct max732x_chip *chip, uint16_t *val) 306 { 307 int ret; 308 309 ret = i2c_master_recv(chip->client_group_a, (char *)val, 2); 310 if (ret < 0) { 311 dev_err(&chip->client_group_a->dev, "failed reading\n"); 312 return ret; 313 } 314 315 *val = le16_to_cpu(*val); 316 return 0; 317 } 318 319 static void max732x_irq_update_mask(struct max732x_chip *chip) 320 { 321 uint16_t msg; 322 323 if (chip->irq_mask == chip->irq_mask_cur) 324 return; 325 326 chip->irq_mask = chip->irq_mask_cur; 327 328 if (chip->irq_features == INT_NO_MASK) 329 return; 330 331 mutex_lock(&chip->lock); 332 333 switch (chip->irq_features) { 334 case INT_INDEP_MASK: 335 msg = (chip->irq_mask << 8) | chip->reg_out[0]; 336 max732x_writew(chip, msg); 337 break; 338 339 case INT_MERGED_MASK: 340 msg = chip->irq_mask | chip->reg_out[0]; 341 max732x_writeb(chip, 1, (uint8_t)msg); 342 break; 343 } 344 345 mutex_unlock(&chip->lock); 346 } 347 348 static void max732x_irq_mask(struct irq_data *d) 349 { 350 struct gpio_chip *gc = irq_data_get_irq_chip_data(d); 351 struct max732x_chip *chip = gpiochip_get_data(gc); 352 353 chip->irq_mask_cur &= ~(1 << d->hwirq); 354 } 355 356 static void max732x_irq_unmask(struct irq_data *d) 357 { 358 struct gpio_chip *gc = irq_data_get_irq_chip_data(d); 359 struct max732x_chip *chip = gpiochip_get_data(gc); 360 361 chip->irq_mask_cur |= 1 << d->hwirq; 362 } 363 364 static void max732x_irq_bus_lock(struct irq_data *d) 365 { 366 struct gpio_chip *gc = irq_data_get_irq_chip_data(d); 367 struct max732x_chip *chip = gpiochip_get_data(gc); 368 369 mutex_lock(&chip->irq_lock); 370 chip->irq_mask_cur = chip->irq_mask; 371 } 372 373 static void max732x_irq_bus_sync_unlock(struct irq_data *d) 374 { 375 struct gpio_chip *gc = irq_data_get_irq_chip_data(d); 376 struct max732x_chip *chip = gpiochip_get_data(gc); 377 uint16_t new_irqs; 378 uint16_t level; 379 380 max732x_irq_update_mask(chip); 381 382 new_irqs = chip->irq_trig_fall | chip->irq_trig_raise; 383 while (new_irqs) { 384 level = __ffs(new_irqs); 385 max732x_gpio_direction_input(&chip->gpio_chip, level); 386 new_irqs &= ~(1 << level); 387 } 388 389 mutex_unlock(&chip->irq_lock); 390 } 391 392 static int max732x_irq_set_type(struct irq_data *d, unsigned int type) 393 { 394 struct gpio_chip *gc = irq_data_get_irq_chip_data(d); 395 struct max732x_chip *chip = gpiochip_get_data(gc); 396 uint16_t off = d->hwirq; 397 uint16_t mask = 1 << off; 398 399 if (!(mask & chip->dir_input)) { 400 dev_dbg(&chip->client->dev, "%s port %d is output only\n", 401 chip->client->name, off); 402 return -EACCES; 403 } 404 405 if (!(type & IRQ_TYPE_EDGE_BOTH)) { 406 dev_err(&chip->client->dev, "irq %d: unsupported type %d\n", 407 d->irq, type); 408 return -EINVAL; 409 } 410 411 if (type & IRQ_TYPE_EDGE_FALLING) 412 chip->irq_trig_fall |= mask; 413 else 414 chip->irq_trig_fall &= ~mask; 415 416 if (type & IRQ_TYPE_EDGE_RISING) 417 chip->irq_trig_raise |= mask; 418 else 419 chip->irq_trig_raise &= ~mask; 420 421 return 0; 422 } 423 424 static int max732x_irq_set_wake(struct irq_data *data, unsigned int on) 425 { 426 struct max732x_chip *chip = irq_data_get_irq_chip_data(data); 427 428 irq_set_irq_wake(chip->client->irq, on); 429 return 0; 430 } 431 432 static struct irq_chip max732x_irq_chip = { 433 .name = "max732x", 434 .irq_mask = max732x_irq_mask, 435 .irq_unmask = max732x_irq_unmask, 436 .irq_bus_lock = max732x_irq_bus_lock, 437 .irq_bus_sync_unlock = max732x_irq_bus_sync_unlock, 438 .irq_set_type = max732x_irq_set_type, 439 .irq_set_wake = max732x_irq_set_wake, 440 }; 441 442 static uint8_t max732x_irq_pending(struct max732x_chip *chip) 443 { 444 uint8_t cur_stat; 445 uint8_t old_stat; 446 uint8_t trigger; 447 uint8_t pending; 448 uint16_t status; 449 int ret; 450 451 ret = max732x_readw(chip, &status); 452 if (ret) 453 return 0; 454 455 trigger = status >> 8; 456 trigger &= chip->irq_mask; 457 458 if (!trigger) 459 return 0; 460 461 cur_stat = status & 0xFF; 462 cur_stat &= chip->irq_mask; 463 464 old_stat = cur_stat ^ trigger; 465 466 pending = (old_stat & chip->irq_trig_fall) | 467 (cur_stat & chip->irq_trig_raise); 468 pending &= trigger; 469 470 return pending; 471 } 472 473 static irqreturn_t max732x_irq_handler(int irq, void *devid) 474 { 475 struct max732x_chip *chip = devid; 476 uint8_t pending; 477 uint8_t level; 478 479 pending = max732x_irq_pending(chip); 480 481 if (!pending) 482 return IRQ_HANDLED; 483 484 do { 485 level = __ffs(pending); 486 handle_nested_irq(irq_find_mapping(chip->gpio_chip.irq.domain, 487 level)); 488 489 pending &= ~(1 << level); 490 } while (pending); 491 492 return IRQ_HANDLED; 493 } 494 495 static int max732x_irq_setup(struct max732x_chip *chip, 496 const struct i2c_device_id *id) 497 { 498 struct i2c_client *client = chip->client; 499 int has_irq = max732x_features[id->driver_data] >> 32; 500 int irq_base = 0; 501 int ret; 502 503 if (client->irq && has_irq != INT_NONE) { 504 struct gpio_irq_chip *girq; 505 506 chip->irq_features = has_irq; 507 mutex_init(&chip->irq_lock); 508 509 ret = devm_request_threaded_irq(&client->dev, client->irq, 510 NULL, max732x_irq_handler, IRQF_ONESHOT | 511 IRQF_TRIGGER_FALLING | IRQF_SHARED, 512 dev_name(&client->dev), chip); 513 if (ret) { 514 dev_err(&client->dev, "failed to request irq %d\n", 515 client->irq); 516 return ret; 517 } 518 519 girq = &chip->gpio_chip.irq; 520 girq->chip = &max732x_irq_chip; 521 /* This will let us handle the parent IRQ in the driver */ 522 girq->parent_handler = NULL; 523 girq->num_parents = 0; 524 girq->parents = NULL; 525 girq->default_type = IRQ_TYPE_NONE; 526 girq->handler = handle_simple_irq; 527 girq->threaded = true; 528 girq->first = irq_base; /* FIXME: get rid of this */ 529 } 530 531 return 0; 532 } 533 534 #else /* CONFIG_GPIO_MAX732X_IRQ */ 535 static int max732x_irq_setup(struct max732x_chip *chip, 536 const struct i2c_device_id *id) 537 { 538 struct i2c_client *client = chip->client; 539 int has_irq = max732x_features[id->driver_data] >> 32; 540 541 if (client->irq && has_irq != INT_NONE) 542 dev_warn(&client->dev, "interrupt support not compiled in\n"); 543 544 return 0; 545 } 546 #endif 547 548 static int max732x_setup_gpio(struct max732x_chip *chip, 549 const struct i2c_device_id *id, 550 unsigned gpio_start) 551 { 552 struct gpio_chip *gc = &chip->gpio_chip; 553 uint32_t id_data = (uint32_t)max732x_features[id->driver_data]; 554 int i, port = 0; 555 556 for (i = 0; i < 16; i++, id_data >>= 2) { 557 unsigned int mask = 1 << port; 558 559 switch (id_data & 0x3) { 560 case PORT_OUTPUT: 561 chip->dir_output |= mask; 562 break; 563 case PORT_INPUT: 564 chip->dir_input |= mask; 565 break; 566 case PORT_OPENDRAIN: 567 chip->dir_output |= mask; 568 chip->dir_input |= mask; 569 break; 570 default: 571 continue; 572 } 573 574 if (i < 8) 575 chip->mask_group_a |= mask; 576 port++; 577 } 578 579 if (chip->dir_input) 580 gc->direction_input = max732x_gpio_direction_input; 581 if (chip->dir_output) { 582 gc->direction_output = max732x_gpio_direction_output; 583 gc->set = max732x_gpio_set_value; 584 gc->set_multiple = max732x_gpio_set_multiple; 585 } 586 gc->get = max732x_gpio_get_value; 587 gc->can_sleep = true; 588 589 gc->base = gpio_start; 590 gc->ngpio = port; 591 gc->label = chip->client->name; 592 gc->parent = &chip->client->dev; 593 gc->owner = THIS_MODULE; 594 595 return port; 596 } 597 598 static struct max732x_platform_data *of_gpio_max732x(struct device *dev) 599 { 600 struct max732x_platform_data *pdata; 601 602 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 603 if (!pdata) 604 return NULL; 605 606 pdata->gpio_base = -1; 607 608 return pdata; 609 } 610 611 static int max732x_probe(struct i2c_client *client, 612 const struct i2c_device_id *id) 613 { 614 struct max732x_platform_data *pdata; 615 struct device_node *node; 616 struct max732x_chip *chip; 617 struct i2c_client *c; 618 uint16_t addr_a, addr_b; 619 int ret, nr_port; 620 621 pdata = dev_get_platdata(&client->dev); 622 node = client->dev.of_node; 623 624 if (!pdata && node) 625 pdata = of_gpio_max732x(&client->dev); 626 627 if (!pdata) { 628 dev_dbg(&client->dev, "no platform data\n"); 629 return -EINVAL; 630 } 631 632 chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL); 633 if (chip == NULL) 634 return -ENOMEM; 635 chip->client = client; 636 637 nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base); 638 chip->gpio_chip.parent = &client->dev; 639 640 addr_a = (client->addr & 0x0f) | 0x60; 641 addr_b = (client->addr & 0x0f) | 0x50; 642 643 switch (client->addr & 0x70) { 644 case 0x60: 645 chip->client_group_a = client; 646 if (nr_port > 8) { 647 c = devm_i2c_new_dummy_device(&client->dev, 648 client->adapter, addr_b); 649 if (IS_ERR(c)) { 650 dev_err(&client->dev, 651 "Failed to allocate I2C device\n"); 652 return PTR_ERR(c); 653 } 654 chip->client_group_b = chip->client_dummy = c; 655 } 656 break; 657 case 0x50: 658 chip->client_group_b = client; 659 if (nr_port > 8) { 660 c = devm_i2c_new_dummy_device(&client->dev, 661 client->adapter, addr_a); 662 if (IS_ERR(c)) { 663 dev_err(&client->dev, 664 "Failed to allocate I2C device\n"); 665 return PTR_ERR(c); 666 } 667 chip->client_group_a = chip->client_dummy = c; 668 } 669 break; 670 default: 671 dev_err(&client->dev, "invalid I2C address specified %02x\n", 672 client->addr); 673 return -EINVAL; 674 } 675 676 if (nr_port > 8 && !chip->client_dummy) { 677 dev_err(&client->dev, 678 "Failed to allocate second group I2C device\n"); 679 return -ENODEV; 680 } 681 682 mutex_init(&chip->lock); 683 684 ret = max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]); 685 if (ret) 686 return ret; 687 if (nr_port > 8) { 688 ret = max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]); 689 if (ret) 690 return ret; 691 } 692 693 ret = max732x_irq_setup(chip, id); 694 if (ret) 695 return ret; 696 697 ret = devm_gpiochip_add_data(&client->dev, &chip->gpio_chip, chip); 698 if (ret) 699 return ret; 700 701 i2c_set_clientdata(client, chip); 702 return 0; 703 } 704 705 static struct i2c_driver max732x_driver = { 706 .driver = { 707 .name = "max732x", 708 .of_match_table = of_match_ptr(max732x_of_table), 709 }, 710 .probe = max732x_probe, 711 .id_table = max732x_id, 712 }; 713 714 static int __init max732x_init(void) 715 { 716 return i2c_add_driver(&max732x_driver); 717 } 718 /* register after i2c postcore initcall and before 719 * subsys initcalls that may rely on these GPIOs 720 */ 721 subsys_initcall(max732x_init); 722 723 static void __exit max732x_exit(void) 724 { 725 i2c_del_driver(&max732x_driver); 726 } 727 module_exit(max732x_exit); 728 729 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); 730 MODULE_DESCRIPTION("GPIO expander driver for MAX732X"); 731 MODULE_LICENSE("GPL"); 732