1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * GPIO testing driver based on configfs. 4 * 5 * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl> 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/array_size.h> 11 #include <linux/bitmap.h> 12 #include <linux/cleanup.h> 13 #include <linux/completion.h> 14 #include <linux/configfs.h> 15 #include <linux/device.h> 16 #include <linux/err.h> 17 #include <linux/gpio/consumer.h> 18 #include <linux/gpio/driver.h> 19 #include <linux/gpio/machine.h> 20 #include <linux/idr.h> 21 #include <linux/interrupt.h> 22 #include <linux/irq.h> 23 #include <linux/irq_sim.h> 24 #include <linux/list.h> 25 #include <linux/lockdep.h> 26 #include <linux/minmax.h> 27 #include <linux/mod_devicetable.h> 28 #include <linux/module.h> 29 #include <linux/mutex.h> 30 #include <linux/notifier.h> 31 #include <linux/platform_device.h> 32 #include <linux/property.h> 33 #include <linux/seq_file.h> 34 #include <linux/slab.h> 35 #include <linux/string.h> 36 #include <linux/string_helpers.h> 37 #include <linux/sysfs.h> 38 #include <linux/types.h> 39 40 #define GPIO_SIM_NGPIO_MAX 1024 41 #define GPIO_SIM_PROP_MAX 4 /* Max 3 properties + sentinel. */ 42 #define GPIO_SIM_NUM_ATTRS 3 /* value, pull and sentinel */ 43 44 static DEFINE_IDA(gpio_sim_ida); 45 46 struct gpio_sim_chip { 47 struct gpio_chip gc; 48 struct device *dev; 49 unsigned long *request_map; 50 unsigned long *direction_map; 51 unsigned long *value_map; 52 unsigned long *pull_map; 53 struct irq_domain *irq_sim; 54 struct mutex lock; 55 const struct attribute_group **attr_groups; 56 }; 57 58 struct gpio_sim_attribute { 59 struct device_attribute dev_attr; 60 unsigned int offset; 61 }; 62 63 static struct gpio_sim_attribute * 64 to_gpio_sim_attr(struct device_attribute *dev_attr) 65 { 66 return container_of(dev_attr, struct gpio_sim_attribute, dev_attr); 67 } 68 69 static int gpio_sim_apply_pull(struct gpio_sim_chip *chip, 70 unsigned int offset, int value) 71 { 72 int irq, irq_type, ret; 73 74 guard(mutex)(&chip->lock); 75 76 if (test_bit(offset, chip->request_map) && 77 test_bit(offset, chip->direction_map)) { 78 if (value == !!test_bit(offset, chip->value_map)) 79 goto set_pull; 80 81 /* 82 * This is fine - it just means, nobody is listening 83 * for interrupts on this line, otherwise 84 * irq_create_mapping() would have been called from 85 * the to_irq() callback. 86 */ 87 irq = irq_find_mapping(chip->irq_sim, offset); 88 if (!irq) 89 goto set_value; 90 91 irq_type = irq_get_trigger_type(irq); 92 93 if ((value && (irq_type & IRQ_TYPE_EDGE_RISING)) || 94 (!value && (irq_type & IRQ_TYPE_EDGE_FALLING))) { 95 ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, 96 true); 97 if (ret) 98 goto set_pull; 99 } 100 } 101 102 set_value: 103 /* Change the value unless we're actively driving the line. */ 104 if (!test_bit(offset, chip->request_map) || 105 test_bit(offset, chip->direction_map)) 106 __assign_bit(offset, chip->value_map, value); 107 108 set_pull: 109 __assign_bit(offset, chip->pull_map, value); 110 return 0; 111 } 112 113 static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset) 114 { 115 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 116 117 guard(mutex)(&chip->lock); 118 119 return !!test_bit(offset, chip->value_map); 120 } 121 122 static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value) 123 { 124 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 125 126 scoped_guard(mutex, &chip->lock) 127 __assign_bit(offset, chip->value_map, value); 128 } 129 130 static int gpio_sim_get_multiple(struct gpio_chip *gc, 131 unsigned long *mask, unsigned long *bits) 132 { 133 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 134 135 scoped_guard(mutex, &chip->lock) 136 bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio); 137 138 return 0; 139 } 140 141 static void gpio_sim_set_multiple(struct gpio_chip *gc, 142 unsigned long *mask, unsigned long *bits) 143 { 144 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 145 146 scoped_guard(mutex, &chip->lock) 147 bitmap_replace(chip->value_map, chip->value_map, bits, mask, 148 gc->ngpio); 149 } 150 151 static int gpio_sim_direction_output(struct gpio_chip *gc, 152 unsigned int offset, int value) 153 { 154 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 155 156 scoped_guard(mutex, &chip->lock) { 157 __clear_bit(offset, chip->direction_map); 158 __assign_bit(offset, chip->value_map, value); 159 } 160 161 return 0; 162 } 163 164 static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset) 165 { 166 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 167 168 scoped_guard(mutex, &chip->lock) 169 __set_bit(offset, chip->direction_map); 170 171 return 0; 172 } 173 174 static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset) 175 { 176 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 177 int direction; 178 179 scoped_guard(mutex, &chip->lock) 180 direction = !!test_bit(offset, chip->direction_map); 181 182 return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT; 183 } 184 185 static int gpio_sim_set_config(struct gpio_chip *gc, unsigned int offset, 186 unsigned long config) 187 { 188 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 189 190 switch (pinconf_to_config_param(config)) { 191 case PIN_CONFIG_BIAS_PULL_UP: 192 return gpio_sim_apply_pull(chip, offset, 1); 193 case PIN_CONFIG_BIAS_PULL_DOWN: 194 return gpio_sim_apply_pull(chip, offset, 0); 195 default: 196 break; 197 } 198 199 return -ENOTSUPP; 200 } 201 202 static int gpio_sim_to_irq(struct gpio_chip *gc, unsigned int offset) 203 { 204 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 205 206 return irq_create_mapping(chip->irq_sim, offset); 207 } 208 209 static int gpio_sim_request(struct gpio_chip *gc, unsigned int offset) 210 { 211 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 212 213 scoped_guard(mutex, &chip->lock) 214 __set_bit(offset, chip->request_map); 215 216 return 0; 217 } 218 219 static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset) 220 { 221 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 222 223 scoped_guard(mutex, &chip->lock) { 224 __assign_bit(offset, chip->value_map, 225 !!test_bit(offset, chip->pull_map)); 226 __clear_bit(offset, chip->request_map); 227 } 228 } 229 230 static int gpio_sim_irq_requested(struct irq_domain *domain, 231 irq_hw_number_t hwirq, void *data) 232 { 233 struct gpio_sim_chip *chip = data; 234 235 return gpiochip_lock_as_irq(&chip->gc, hwirq); 236 } 237 238 static void gpio_sim_irq_released(struct irq_domain *domain, 239 irq_hw_number_t hwirq, void *data) 240 { 241 struct gpio_sim_chip *chip = data; 242 243 gpiochip_unlock_as_irq(&chip->gc, hwirq); 244 } 245 246 static const struct irq_sim_ops gpio_sim_irq_sim_ops = { 247 .irq_sim_irq_requested = gpio_sim_irq_requested, 248 .irq_sim_irq_released = gpio_sim_irq_released, 249 }; 250 251 static void gpio_sim_dbg_show(struct seq_file *seq, struct gpio_chip *gc) 252 { 253 struct gpio_sim_chip *chip = gpiochip_get_data(gc); 254 const char *label; 255 int i; 256 257 guard(mutex)(&chip->lock); 258 259 for_each_hwgpio(gc, i, label) 260 seq_printf(seq, " gpio-%-3d (%s) %s,%s\n", 261 gc->base + i, 262 label ?: "<unused>", 263 test_bit(i, chip->direction_map) ? "input" : 264 test_bit(i, chip->value_map) ? "output-high" : 265 "output-low", 266 test_bit(i, chip->pull_map) ? "pull-up" : 267 "pull-down"); 268 } 269 270 static ssize_t gpio_sim_sysfs_val_show(struct device *dev, 271 struct device_attribute *attr, char *buf) 272 { 273 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); 274 struct gpio_sim_chip *chip = dev_get_drvdata(dev); 275 int val; 276 277 scoped_guard(mutex, &chip->lock) 278 val = !!test_bit(line_attr->offset, chip->value_map); 279 280 return sysfs_emit(buf, "%d\n", val); 281 } 282 283 static ssize_t gpio_sim_sysfs_val_store(struct device *dev, 284 struct device_attribute *attr, 285 const char *buf, size_t count) 286 { 287 /* 288 * Not assigning this function will result in write() returning -EIO 289 * which is confusing. Return -EPERM explicitly. 290 */ 291 return -EPERM; 292 } 293 294 static const char *const gpio_sim_sysfs_pull_strings[] = { 295 [0] = "pull-down", 296 [1] = "pull-up", 297 }; 298 299 static ssize_t gpio_sim_sysfs_pull_show(struct device *dev, 300 struct device_attribute *attr, 301 char *buf) 302 { 303 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); 304 struct gpio_sim_chip *chip = dev_get_drvdata(dev); 305 int pull; 306 307 scoped_guard(mutex, &chip->lock) 308 pull = !!test_bit(line_attr->offset, chip->pull_map); 309 310 return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]); 311 } 312 313 static ssize_t gpio_sim_sysfs_pull_store(struct device *dev, 314 struct device_attribute *attr, 315 const char *buf, size_t len) 316 { 317 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); 318 struct gpio_sim_chip *chip = dev_get_drvdata(dev); 319 int ret, pull; 320 321 pull = sysfs_match_string(gpio_sim_sysfs_pull_strings, buf); 322 if (pull < 0) 323 return pull; 324 325 ret = gpio_sim_apply_pull(chip, line_attr->offset, pull); 326 if (ret) 327 return ret; 328 329 return len; 330 } 331 332 static void gpio_sim_put_device(void *data) 333 { 334 struct device *dev = data; 335 336 put_device(dev); 337 } 338 339 static void gpio_sim_dispose_mappings(void *data) 340 { 341 struct gpio_sim_chip *chip = data; 342 unsigned int i; 343 344 for (i = 0; i < chip->gc.ngpio; i++) 345 irq_dispose_mapping(irq_find_mapping(chip->irq_sim, i)); 346 } 347 348 static void gpio_sim_sysfs_remove(void *data) 349 { 350 struct gpio_sim_chip *chip = data; 351 352 sysfs_remove_groups(&chip->dev->kobj, chip->attr_groups); 353 } 354 355 static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip) 356 { 357 struct device_attribute *val_dev_attr, *pull_dev_attr; 358 struct gpio_sim_attribute *val_attr, *pull_attr; 359 unsigned int num_lines = chip->gc.ngpio; 360 struct device *dev = chip->gc.parent; 361 struct attribute_group *attr_group; 362 struct attribute **attrs; 363 int i, ret; 364 365 chip->attr_groups = devm_kcalloc(dev, sizeof(*chip->attr_groups), 366 num_lines + 1, GFP_KERNEL); 367 if (!chip->attr_groups) 368 return -ENOMEM; 369 370 for (i = 0; i < num_lines; i++) { 371 attr_group = devm_kzalloc(dev, sizeof(*attr_group), GFP_KERNEL); 372 attrs = devm_kcalloc(dev, GPIO_SIM_NUM_ATTRS, sizeof(*attrs), 373 GFP_KERNEL); 374 val_attr = devm_kzalloc(dev, sizeof(*val_attr), GFP_KERNEL); 375 pull_attr = devm_kzalloc(dev, sizeof(*pull_attr), GFP_KERNEL); 376 if (!attr_group || !attrs || !val_attr || !pull_attr) 377 return -ENOMEM; 378 379 attr_group->name = devm_kasprintf(dev, GFP_KERNEL, 380 "sim_gpio%u", i); 381 if (!attr_group->name) 382 return -ENOMEM; 383 384 val_attr->offset = pull_attr->offset = i; 385 386 val_dev_attr = &val_attr->dev_attr; 387 pull_dev_attr = &pull_attr->dev_attr; 388 389 sysfs_attr_init(&val_dev_attr->attr); 390 sysfs_attr_init(&pull_dev_attr->attr); 391 392 val_dev_attr->attr.name = "value"; 393 pull_dev_attr->attr.name = "pull"; 394 395 val_dev_attr->attr.mode = pull_dev_attr->attr.mode = 0644; 396 397 val_dev_attr->show = gpio_sim_sysfs_val_show; 398 val_dev_attr->store = gpio_sim_sysfs_val_store; 399 pull_dev_attr->show = gpio_sim_sysfs_pull_show; 400 pull_dev_attr->store = gpio_sim_sysfs_pull_store; 401 402 attrs[0] = &val_dev_attr->attr; 403 attrs[1] = &pull_dev_attr->attr; 404 405 attr_group->attrs = attrs; 406 chip->attr_groups[i] = attr_group; 407 } 408 409 ret = sysfs_create_groups(&chip->dev->kobj, chip->attr_groups); 410 if (ret) 411 return ret; 412 413 return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip); 414 } 415 416 static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev) 417 { 418 struct gpio_sim_chip *chip; 419 struct gpio_chip *gc; 420 const char *label; 421 u32 num_lines; 422 int ret; 423 424 ret = fwnode_property_read_u32(swnode, "ngpios", &num_lines); 425 if (ret) 426 return ret; 427 428 if (num_lines > GPIO_SIM_NGPIO_MAX) 429 return -ERANGE; 430 431 ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label); 432 if (ret) { 433 label = devm_kasprintf(dev, GFP_KERNEL, "%s:%pfwP", 434 dev_name(dev), swnode); 435 if (!label) 436 return -ENOMEM; 437 } 438 439 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); 440 if (!chip) 441 return -ENOMEM; 442 443 chip->request_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL); 444 if (!chip->request_map) 445 return -ENOMEM; 446 447 chip->direction_map = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL); 448 if (!chip->direction_map) 449 return -ENOMEM; 450 451 /* Default to input mode. */ 452 bitmap_fill(chip->direction_map, num_lines); 453 454 chip->value_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL); 455 if (!chip->value_map) 456 return -ENOMEM; 457 458 chip->pull_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL); 459 if (!chip->pull_map) 460 return -ENOMEM; 461 462 chip->irq_sim = devm_irq_domain_create_sim_full(dev, swnode, num_lines, 463 &gpio_sim_irq_sim_ops, 464 chip); 465 if (IS_ERR(chip->irq_sim)) 466 return PTR_ERR(chip->irq_sim); 467 468 ret = devm_add_action_or_reset(dev, gpio_sim_dispose_mappings, chip); 469 if (ret) 470 return ret; 471 472 ret = devm_mutex_init(dev, &chip->lock); 473 if (ret) 474 return ret; 475 476 gc = &chip->gc; 477 gc->base = -1; 478 gc->ngpio = num_lines; 479 gc->label = label; 480 gc->owner = THIS_MODULE; 481 gc->parent = dev; 482 gc->fwnode = swnode; 483 gc->get = gpio_sim_get; 484 gc->set = gpio_sim_set; 485 gc->get_multiple = gpio_sim_get_multiple; 486 gc->set_multiple = gpio_sim_set_multiple; 487 gc->direction_output = gpio_sim_direction_output; 488 gc->direction_input = gpio_sim_direction_input; 489 gc->get_direction = gpio_sim_get_direction; 490 gc->set_config = gpio_sim_set_config; 491 gc->to_irq = gpio_sim_to_irq; 492 gc->request = gpio_sim_request; 493 gc->free = gpio_sim_free; 494 gc->dbg_show = PTR_IF(IS_ENABLED(CONFIG_DEBUG_FS), gpio_sim_dbg_show); 495 gc->can_sleep = true; 496 497 ret = devm_gpiochip_add_data(dev, gc, chip); 498 if (ret) 499 return ret; 500 501 chip->dev = device_find_child(dev, swnode, device_match_fwnode); 502 if (!chip->dev) 503 return -ENODEV; 504 505 ret = devm_add_action_or_reset(dev, gpio_sim_put_device, chip->dev); 506 if (ret) 507 return ret; 508 509 /* Used by sysfs callbacks. */ 510 dev_set_drvdata(chip->dev, chip); 511 512 return gpio_sim_setup_sysfs(chip); 513 } 514 515 static int gpio_sim_probe(struct platform_device *pdev) 516 { 517 struct device *dev = &pdev->dev; 518 int ret; 519 520 device_for_each_child_node_scoped(dev, swnode) { 521 ret = gpio_sim_add_bank(swnode, dev); 522 if (ret) 523 return ret; 524 } 525 526 return 0; 527 } 528 529 static const struct of_device_id gpio_sim_of_match[] = { 530 { .compatible = "gpio-simulator" }, 531 { } 532 }; 533 MODULE_DEVICE_TABLE(of, gpio_sim_of_match); 534 535 static struct platform_driver gpio_sim_driver = { 536 .driver = { 537 .name = "gpio-sim", 538 .of_match_table = gpio_sim_of_match, 539 }, 540 .probe = gpio_sim_probe, 541 }; 542 543 struct gpio_sim_device { 544 struct config_group group; 545 546 /* 547 * If pdev is NULL, the device is 'pending' (waiting for configuration). 548 * Once the pointer is assigned, the device has been created and the 549 * item is 'live'. 550 */ 551 struct platform_device *pdev; 552 int id; 553 554 /* 555 * Each configfs filesystem operation is protected with the subsystem 556 * mutex. Each separate attribute is protected with the buffer mutex. 557 * This structure however can be modified by callbacks of different 558 * attributes so we need another lock. 559 * 560 * We use this lock for protecting all data structures owned by this 561 * object too. 562 */ 563 struct mutex lock; 564 565 /* 566 * This is used to synchronously wait for the driver's probe to complete 567 * and notify the user-space about any errors. 568 */ 569 struct notifier_block bus_notifier; 570 struct completion probe_completion; 571 bool driver_bound; 572 573 struct gpiod_hog *hogs; 574 575 struct list_head bank_list; 576 }; 577 578 /* This is called with dev->lock already taken. */ 579 static int gpio_sim_bus_notifier_call(struct notifier_block *nb, 580 unsigned long action, void *data) 581 { 582 struct gpio_sim_device *simdev = container_of(nb, 583 struct gpio_sim_device, 584 bus_notifier); 585 struct device *dev = data; 586 char devname[32]; 587 588 snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id); 589 590 if (!device_match_name(dev, devname)) 591 return NOTIFY_DONE; 592 593 if (action == BUS_NOTIFY_BOUND_DRIVER) 594 simdev->driver_bound = true; 595 else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND) 596 simdev->driver_bound = false; 597 else 598 return NOTIFY_DONE; 599 600 complete(&simdev->probe_completion); 601 602 return NOTIFY_OK; 603 } 604 605 static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item) 606 { 607 struct config_group *group = to_config_group(item); 608 609 return container_of(group, struct gpio_sim_device, group); 610 } 611 612 struct gpio_sim_bank { 613 struct config_group group; 614 615 /* 616 * We could have used the ci_parent field of the config_item but 617 * configfs is stupid and calls the item's release callback after 618 * already having cleared the parent pointer even though the parent 619 * is guaranteed to survive the child... 620 * 621 * So we need to store the pointer to the parent struct here. We can 622 * dereference it anywhere we need with no checks and no locking as 623 * it's guaranteed to survive the children and protected by configfs 624 * locks. 625 * 626 * Same for other structures. 627 */ 628 struct gpio_sim_device *parent; 629 struct list_head siblings; 630 631 char *label; 632 unsigned int num_lines; 633 634 struct list_head line_list; 635 636 struct fwnode_handle *swnode; 637 }; 638 639 static struct gpio_sim_bank *to_gpio_sim_bank(struct config_item *item) 640 { 641 struct config_group *group = to_config_group(item); 642 643 return container_of(group, struct gpio_sim_bank, group); 644 } 645 646 static bool gpio_sim_bank_has_label(struct gpio_sim_bank *bank) 647 { 648 return bank->label && *bank->label; 649 } 650 651 static struct gpio_sim_device * 652 gpio_sim_bank_get_device(struct gpio_sim_bank *bank) 653 { 654 return bank->parent; 655 } 656 657 struct gpio_sim_hog; 658 659 struct gpio_sim_line { 660 struct config_group group; 661 662 struct gpio_sim_bank *parent; 663 struct list_head siblings; 664 665 unsigned int offset; 666 char *name; 667 668 /* There can only be one hog per line. */ 669 struct gpio_sim_hog *hog; 670 }; 671 672 static struct gpio_sim_line *to_gpio_sim_line(struct config_item *item) 673 { 674 struct config_group *group = to_config_group(item); 675 676 return container_of(group, struct gpio_sim_line, group); 677 } 678 679 static struct gpio_sim_device * 680 gpio_sim_line_get_device(struct gpio_sim_line *line) 681 { 682 struct gpio_sim_bank *bank = line->parent; 683 684 return gpio_sim_bank_get_device(bank); 685 } 686 687 struct gpio_sim_hog { 688 struct config_item item; 689 struct gpio_sim_line *parent; 690 691 char *name; 692 int dir; 693 }; 694 695 static struct gpio_sim_hog *to_gpio_sim_hog(struct config_item *item) 696 { 697 return container_of(item, struct gpio_sim_hog, item); 698 } 699 700 static struct gpio_sim_device *gpio_sim_hog_get_device(struct gpio_sim_hog *hog) 701 { 702 struct gpio_sim_line *line = hog->parent; 703 704 return gpio_sim_line_get_device(line); 705 } 706 707 static bool gpio_sim_device_is_live(struct gpio_sim_device *dev) 708 { 709 lockdep_assert_held(&dev->lock); 710 711 return !!dev->pdev; 712 } 713 714 static char *gpio_sim_strdup_trimmed(const char *str, size_t count) 715 { 716 char *trimmed; 717 718 trimmed = kstrndup(skip_spaces(str), count, GFP_KERNEL); 719 if (!trimmed) 720 return NULL; 721 722 return strim(trimmed); 723 } 724 725 static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item, 726 char *page) 727 { 728 struct gpio_sim_device *dev = to_gpio_sim_device(item); 729 struct platform_device *pdev; 730 731 guard(mutex)(&dev->lock); 732 733 pdev = dev->pdev; 734 if (pdev) 735 return sprintf(page, "%s\n", dev_name(&pdev->dev)); 736 737 return sprintf(page, "gpio-sim.%d\n", dev->id); 738 } 739 740 CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name); 741 742 static ssize_t 743 gpio_sim_device_config_live_show(struct config_item *item, char *page) 744 { 745 struct gpio_sim_device *dev = to_gpio_sim_device(item); 746 bool live; 747 748 scoped_guard(mutex, &dev->lock) 749 live = gpio_sim_device_is_live(dev); 750 751 return sprintf(page, "%c\n", live ? '1' : '0'); 752 } 753 754 static unsigned int gpio_sim_get_line_names_size(struct gpio_sim_bank *bank) 755 { 756 struct gpio_sim_line *line; 757 unsigned int size = 0; 758 759 list_for_each_entry(line, &bank->line_list, siblings) { 760 if (!line->name || (line->offset >= bank->num_lines)) 761 continue; 762 763 size = max(size, line->offset + 1); 764 } 765 766 return size; 767 } 768 769 static void 770 gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names) 771 { 772 struct gpio_sim_line *line; 773 774 list_for_each_entry(line, &bank->line_list, siblings) { 775 if (!line->name || (line->offset >= bank->num_lines)) 776 continue; 777 778 line_names[line->offset] = line->name; 779 } 780 } 781 782 static void gpio_sim_remove_hogs(struct gpio_sim_device *dev) 783 { 784 struct gpiod_hog *hog; 785 786 if (!dev->hogs) 787 return; 788 789 gpiod_remove_hogs(dev->hogs); 790 791 for (hog = dev->hogs; hog->chip_label; hog++) { 792 kfree(hog->chip_label); 793 kfree(hog->line_name); 794 } 795 796 kfree(dev->hogs); 797 dev->hogs = NULL; 798 } 799 800 static int gpio_sim_add_hogs(struct gpio_sim_device *dev) 801 { 802 unsigned int num_hogs = 0, idx = 0; 803 struct gpio_sim_bank *bank; 804 struct gpio_sim_line *line; 805 struct gpiod_hog *hog; 806 807 list_for_each_entry(bank, &dev->bank_list, siblings) { 808 list_for_each_entry(line, &bank->line_list, siblings) { 809 if (line->offset >= bank->num_lines) 810 continue; 811 812 if (line->hog) 813 num_hogs++; 814 } 815 } 816 817 if (!num_hogs) 818 return 0; 819 820 /* Allocate one more for the sentinel. */ 821 dev->hogs = kcalloc(num_hogs + 1, sizeof(*dev->hogs), GFP_KERNEL); 822 if (!dev->hogs) 823 return -ENOMEM; 824 825 list_for_each_entry(bank, &dev->bank_list, siblings) { 826 list_for_each_entry(line, &bank->line_list, siblings) { 827 if (line->offset >= bank->num_lines) 828 continue; 829 830 if (!line->hog) 831 continue; 832 833 hog = &dev->hogs[idx++]; 834 835 /* 836 * We need to make this string manually because at this 837 * point the device doesn't exist yet and so dev_name() 838 * is not available. 839 */ 840 if (gpio_sim_bank_has_label(bank)) 841 hog->chip_label = kstrdup(bank->label, 842 GFP_KERNEL); 843 else 844 hog->chip_label = kasprintf(GFP_KERNEL, 845 "gpio-sim.%u:%pfwP", 846 dev->id, 847 bank->swnode); 848 if (!hog->chip_label) { 849 gpio_sim_remove_hogs(dev); 850 return -ENOMEM; 851 } 852 853 /* 854 * We need to duplicate this because the hog config 855 * item can be removed at any time (and we can't block 856 * it) and gpiolib doesn't make a deep copy of the hog 857 * data. 858 */ 859 if (line->hog->name) { 860 hog->line_name = kstrdup(line->hog->name, 861 GFP_KERNEL); 862 if (!hog->line_name) { 863 gpio_sim_remove_hogs(dev); 864 return -ENOMEM; 865 } 866 } 867 868 hog->chip_hwnum = line->offset; 869 hog->dflags = line->hog->dir; 870 } 871 } 872 873 gpiod_add_hogs(dev->hogs); 874 875 return 0; 876 } 877 878 static struct fwnode_handle * 879 gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank, 880 struct fwnode_handle *parent) 881 { 882 struct property_entry properties[GPIO_SIM_PROP_MAX]; 883 unsigned int prop_idx = 0, line_names_size; 884 char **line_names __free(kfree) = NULL; 885 886 memset(properties, 0, sizeof(properties)); 887 888 properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines); 889 890 if (gpio_sim_bank_has_label(bank)) 891 properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label", 892 bank->label); 893 894 line_names_size = gpio_sim_get_line_names_size(bank); 895 if (line_names_size) { 896 line_names = kcalloc(line_names_size, sizeof(*line_names), 897 GFP_KERNEL); 898 if (!line_names) 899 return ERR_PTR(-ENOMEM); 900 901 gpio_sim_set_line_names(bank, line_names); 902 903 properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN( 904 "gpio-line-names", 905 line_names, line_names_size); 906 } 907 908 return fwnode_create_software_node(properties, parent); 909 } 910 911 static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode) 912 { 913 struct fwnode_handle *child; 914 915 fwnode_for_each_child_node(swnode, child) 916 fwnode_remove_software_node(child); 917 918 fwnode_remove_software_node(swnode); 919 } 920 921 static bool gpio_sim_bank_labels_non_unique(struct gpio_sim_device *dev) 922 { 923 struct gpio_sim_bank *this, *pos; 924 925 list_for_each_entry(this, &dev->bank_list, siblings) { 926 list_for_each_entry(pos, &dev->bank_list, siblings) { 927 if (this == pos || (!this->label || !pos->label)) 928 continue; 929 930 if (strcmp(this->label, pos->label) == 0) 931 return true; 932 } 933 } 934 935 return false; 936 } 937 938 static int gpio_sim_device_activate(struct gpio_sim_device *dev) 939 { 940 struct platform_device_info pdevinfo; 941 struct fwnode_handle *swnode; 942 struct platform_device *pdev; 943 struct gpio_sim_bank *bank; 944 int ret; 945 946 lockdep_assert_held(&dev->lock); 947 948 if (list_empty(&dev->bank_list)) 949 return -ENODATA; 950 951 /* 952 * Non-unique GPIO device labels are a corner-case we don't support 953 * as it would interfere with machine hogging mechanism and has little 954 * use in real life. 955 */ 956 if (gpio_sim_bank_labels_non_unique(dev)) 957 return -EINVAL; 958 959 memset(&pdevinfo, 0, sizeof(pdevinfo)); 960 961 swnode = fwnode_create_software_node(NULL, NULL); 962 if (IS_ERR(swnode)) 963 return PTR_ERR(swnode); 964 965 list_for_each_entry(bank, &dev->bank_list, siblings) { 966 bank->swnode = gpio_sim_make_bank_swnode(bank, swnode); 967 if (IS_ERR(bank->swnode)) { 968 ret = PTR_ERR(bank->swnode); 969 gpio_sim_remove_swnode_recursive(swnode); 970 return ret; 971 } 972 } 973 974 ret = gpio_sim_add_hogs(dev); 975 if (ret) { 976 gpio_sim_remove_swnode_recursive(swnode); 977 return ret; 978 } 979 980 pdevinfo.name = "gpio-sim"; 981 pdevinfo.fwnode = swnode; 982 pdevinfo.id = dev->id; 983 984 reinit_completion(&dev->probe_completion); 985 dev->driver_bound = false; 986 bus_register_notifier(&platform_bus_type, &dev->bus_notifier); 987 988 pdev = platform_device_register_full(&pdevinfo); 989 if (IS_ERR(pdev)) { 990 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier); 991 gpio_sim_remove_hogs(dev); 992 gpio_sim_remove_swnode_recursive(swnode); 993 return PTR_ERR(pdev); 994 } 995 996 wait_for_completion(&dev->probe_completion); 997 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier); 998 999 if (!dev->driver_bound) { 1000 /* Probe failed, check kernel log. */ 1001 platform_device_unregister(pdev); 1002 gpio_sim_remove_hogs(dev); 1003 gpio_sim_remove_swnode_recursive(swnode); 1004 return -ENXIO; 1005 } 1006 1007 dev->pdev = pdev; 1008 1009 return 0; 1010 } 1011 1012 static void gpio_sim_device_deactivate(struct gpio_sim_device *dev) 1013 { 1014 struct fwnode_handle *swnode; 1015 1016 lockdep_assert_held(&dev->lock); 1017 1018 swnode = dev_fwnode(&dev->pdev->dev); 1019 platform_device_unregister(dev->pdev); 1020 gpio_sim_remove_hogs(dev); 1021 gpio_sim_remove_swnode_recursive(swnode); 1022 dev->pdev = NULL; 1023 } 1024 1025 static void 1026 gpio_sim_device_lockup_configfs(struct gpio_sim_device *dev, bool lock) 1027 { 1028 struct configfs_subsystem *subsys = dev->group.cg_subsys; 1029 struct gpio_sim_bank *bank; 1030 struct gpio_sim_line *line; 1031 struct config_item *item; 1032 1033 /* 1034 * The device only needs to depend on leaf entries. This is 1035 * sufficient to lock up all the configfs entries that the 1036 * instantiated, alive device depends on. 1037 */ 1038 list_for_each_entry(bank, &dev->bank_list, siblings) { 1039 list_for_each_entry(line, &bank->line_list, siblings) { 1040 item = line->hog ? &line->hog->item 1041 : &line->group.cg_item; 1042 1043 if (lock) 1044 WARN_ON(configfs_depend_item_unlocked(subsys, 1045 item)); 1046 else 1047 configfs_undepend_item_unlocked(item); 1048 } 1049 } 1050 } 1051 1052 static ssize_t 1053 gpio_sim_device_config_live_store(struct config_item *item, 1054 const char *page, size_t count) 1055 { 1056 struct gpio_sim_device *dev = to_gpio_sim_device(item); 1057 bool live; 1058 int ret; 1059 1060 ret = kstrtobool(page, &live); 1061 if (ret) 1062 return ret; 1063 1064 if (live) 1065 gpio_sim_device_lockup_configfs(dev, true); 1066 1067 scoped_guard(mutex, &dev->lock) { 1068 if (live == gpio_sim_device_is_live(dev)) 1069 ret = -EPERM; 1070 else if (live) 1071 ret = gpio_sim_device_activate(dev); 1072 else 1073 gpio_sim_device_deactivate(dev); 1074 } 1075 1076 /* 1077 * Undepend is required only if device disablement (live == 0) 1078 * succeeds or if device enablement (live == 1) fails. 1079 */ 1080 if (live == !!ret) 1081 gpio_sim_device_lockup_configfs(dev, false); 1082 1083 return ret ?: count; 1084 } 1085 1086 CONFIGFS_ATTR(gpio_sim_device_config_, live); 1087 1088 static struct configfs_attribute *gpio_sim_device_config_attrs[] = { 1089 &gpio_sim_device_config_attr_dev_name, 1090 &gpio_sim_device_config_attr_live, 1091 NULL 1092 }; 1093 1094 struct gpio_sim_chip_name_ctx { 1095 struct fwnode_handle *swnode; 1096 char *page; 1097 }; 1098 1099 static int gpio_sim_emit_chip_name(struct device *dev, void *data) 1100 { 1101 struct gpio_sim_chip_name_ctx *ctx = data; 1102 1103 /* This would be the sysfs device exported in /sys/class/gpio. */ 1104 if (dev->class) 1105 return 0; 1106 1107 if (device_match_fwnode(dev, ctx->swnode)) 1108 return sprintf(ctx->page, "%s\n", dev_name(dev)); 1109 1110 return 0; 1111 } 1112 1113 static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item, 1114 char *page) 1115 { 1116 struct gpio_sim_bank *bank = to_gpio_sim_bank(item); 1117 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); 1118 struct gpio_sim_chip_name_ctx ctx = { bank->swnode, page }; 1119 1120 guard(mutex)(&dev->lock); 1121 1122 if (gpio_sim_device_is_live(dev)) 1123 return device_for_each_child(&dev->pdev->dev, &ctx, 1124 gpio_sim_emit_chip_name); 1125 1126 return sprintf(page, "none\n"); 1127 } 1128 1129 CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name); 1130 1131 static ssize_t 1132 gpio_sim_bank_config_label_show(struct config_item *item, char *page) 1133 { 1134 struct gpio_sim_bank *bank = to_gpio_sim_bank(item); 1135 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); 1136 1137 guard(mutex)(&dev->lock); 1138 1139 return sprintf(page, "%s\n", bank->label ?: ""); 1140 } 1141 1142 static ssize_t gpio_sim_bank_config_label_store(struct config_item *item, 1143 const char *page, size_t count) 1144 { 1145 struct gpio_sim_bank *bank = to_gpio_sim_bank(item); 1146 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); 1147 char *trimmed; 1148 1149 guard(mutex)(&dev->lock); 1150 1151 if (gpio_sim_device_is_live(dev)) 1152 return -EBUSY; 1153 1154 trimmed = gpio_sim_strdup_trimmed(page, count); 1155 if (!trimmed) 1156 return -ENOMEM; 1157 1158 kfree(bank->label); 1159 bank->label = trimmed; 1160 1161 return count; 1162 } 1163 1164 CONFIGFS_ATTR(gpio_sim_bank_config_, label); 1165 1166 static ssize_t 1167 gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page) 1168 { 1169 struct gpio_sim_bank *bank = to_gpio_sim_bank(item); 1170 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); 1171 1172 guard(mutex)(&dev->lock); 1173 1174 return sprintf(page, "%u\n", bank->num_lines); 1175 } 1176 1177 static ssize_t 1178 gpio_sim_bank_config_num_lines_store(struct config_item *item, 1179 const char *page, size_t count) 1180 { 1181 struct gpio_sim_bank *bank = to_gpio_sim_bank(item); 1182 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); 1183 unsigned int num_lines; 1184 int ret; 1185 1186 ret = kstrtouint(page, 0, &num_lines); 1187 if (ret) 1188 return ret; 1189 1190 if (num_lines == 0) 1191 return -EINVAL; 1192 1193 guard(mutex)(&dev->lock); 1194 1195 if (gpio_sim_device_is_live(dev)) 1196 return -EBUSY; 1197 1198 bank->num_lines = num_lines; 1199 1200 return count; 1201 } 1202 1203 CONFIGFS_ATTR(gpio_sim_bank_config_, num_lines); 1204 1205 static struct configfs_attribute *gpio_sim_bank_config_attrs[] = { 1206 &gpio_sim_bank_config_attr_chip_name, 1207 &gpio_sim_bank_config_attr_label, 1208 &gpio_sim_bank_config_attr_num_lines, 1209 NULL 1210 }; 1211 1212 static ssize_t 1213 gpio_sim_line_config_name_show(struct config_item *item, char *page) 1214 { 1215 struct gpio_sim_line *line = to_gpio_sim_line(item); 1216 struct gpio_sim_device *dev = gpio_sim_line_get_device(line); 1217 1218 guard(mutex)(&dev->lock); 1219 1220 return sprintf(page, "%s\n", line->name ?: ""); 1221 } 1222 1223 static ssize_t gpio_sim_line_config_name_store(struct config_item *item, 1224 const char *page, size_t count) 1225 { 1226 struct gpio_sim_line *line = to_gpio_sim_line(item); 1227 struct gpio_sim_device *dev = gpio_sim_line_get_device(line); 1228 char *trimmed; 1229 1230 guard(mutex)(&dev->lock); 1231 1232 if (gpio_sim_device_is_live(dev)) 1233 return -EBUSY; 1234 1235 trimmed = gpio_sim_strdup_trimmed(page, count); 1236 if (!trimmed) 1237 return -ENOMEM; 1238 1239 kfree(line->name); 1240 line->name = trimmed; 1241 1242 return count; 1243 } 1244 1245 CONFIGFS_ATTR(gpio_sim_line_config_, name); 1246 1247 static struct configfs_attribute *gpio_sim_line_config_attrs[] = { 1248 &gpio_sim_line_config_attr_name, 1249 NULL 1250 }; 1251 1252 static ssize_t gpio_sim_hog_config_name_show(struct config_item *item, 1253 char *page) 1254 { 1255 struct gpio_sim_hog *hog = to_gpio_sim_hog(item); 1256 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); 1257 1258 guard(mutex)(&dev->lock); 1259 1260 return sprintf(page, "%s\n", hog->name ?: ""); 1261 } 1262 1263 static ssize_t gpio_sim_hog_config_name_store(struct config_item *item, 1264 const char *page, size_t count) 1265 { 1266 struct gpio_sim_hog *hog = to_gpio_sim_hog(item); 1267 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); 1268 char *trimmed; 1269 1270 guard(mutex)(&dev->lock); 1271 1272 if (gpio_sim_device_is_live(dev)) 1273 return -EBUSY; 1274 1275 trimmed = gpio_sim_strdup_trimmed(page, count); 1276 if (!trimmed) 1277 return -ENOMEM; 1278 1279 kfree(hog->name); 1280 hog->name = trimmed; 1281 1282 return count; 1283 } 1284 1285 CONFIGFS_ATTR(gpio_sim_hog_config_, name); 1286 1287 static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item, 1288 char *page) 1289 { 1290 struct gpio_sim_hog *hog = to_gpio_sim_hog(item); 1291 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); 1292 char *repr; 1293 int dir; 1294 1295 scoped_guard(mutex, &dev->lock) 1296 dir = hog->dir; 1297 1298 switch (dir) { 1299 case GPIOD_IN: 1300 repr = "input"; 1301 break; 1302 case GPIOD_OUT_HIGH: 1303 repr = "output-high"; 1304 break; 1305 case GPIOD_OUT_LOW: 1306 repr = "output-low"; 1307 break; 1308 default: 1309 /* This would be a programmer bug. */ 1310 WARN(1, "Unexpected hog direction value: %d", dir); 1311 return -EINVAL; 1312 } 1313 1314 return sprintf(page, "%s\n", repr); 1315 } 1316 1317 static ssize_t 1318 gpio_sim_hog_config_direction_store(struct config_item *item, 1319 const char *page, size_t count) 1320 { 1321 struct gpio_sim_hog *hog = to_gpio_sim_hog(item); 1322 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); 1323 int dir; 1324 1325 guard(mutex)(&dev->lock); 1326 1327 if (gpio_sim_device_is_live(dev)) 1328 return -EBUSY; 1329 1330 if (sysfs_streq(page, "input")) 1331 dir = GPIOD_IN; 1332 else if (sysfs_streq(page, "output-high")) 1333 dir = GPIOD_OUT_HIGH; 1334 else if (sysfs_streq(page, "output-low")) 1335 dir = GPIOD_OUT_LOW; 1336 else 1337 return -EINVAL; 1338 1339 hog->dir = dir; 1340 1341 return count; 1342 } 1343 1344 CONFIGFS_ATTR(gpio_sim_hog_config_, direction); 1345 1346 static struct configfs_attribute *gpio_sim_hog_config_attrs[] = { 1347 &gpio_sim_hog_config_attr_name, 1348 &gpio_sim_hog_config_attr_direction, 1349 NULL 1350 }; 1351 1352 static void gpio_sim_hog_config_item_release(struct config_item *item) 1353 { 1354 struct gpio_sim_hog *hog = to_gpio_sim_hog(item); 1355 struct gpio_sim_line *line = hog->parent; 1356 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); 1357 1358 scoped_guard(mutex, &dev->lock) 1359 line->hog = NULL; 1360 1361 kfree(hog->name); 1362 kfree(hog); 1363 } 1364 1365 static struct configfs_item_operations gpio_sim_hog_config_item_ops = { 1366 .release = gpio_sim_hog_config_item_release, 1367 }; 1368 1369 static const struct config_item_type gpio_sim_hog_config_type = { 1370 .ct_item_ops = &gpio_sim_hog_config_item_ops, 1371 .ct_attrs = gpio_sim_hog_config_attrs, 1372 .ct_owner = THIS_MODULE, 1373 }; 1374 1375 static struct config_item * 1376 gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name) 1377 { 1378 struct gpio_sim_line *line = to_gpio_sim_line(&group->cg_item); 1379 struct gpio_sim_device *dev = gpio_sim_line_get_device(line); 1380 struct gpio_sim_hog *hog; 1381 1382 if (strcmp(name, "hog") != 0) 1383 return ERR_PTR(-EINVAL); 1384 1385 guard(mutex)(&dev->lock); 1386 1387 hog = kzalloc(sizeof(*hog), GFP_KERNEL); 1388 if (!hog) 1389 return ERR_PTR(-ENOMEM); 1390 1391 config_item_init_type_name(&hog->item, name, 1392 &gpio_sim_hog_config_type); 1393 1394 hog->dir = GPIOD_IN; 1395 hog->name = NULL; 1396 hog->parent = line; 1397 line->hog = hog; 1398 1399 return &hog->item; 1400 } 1401 1402 static void gpio_sim_line_config_group_release(struct config_item *item) 1403 { 1404 struct gpio_sim_line *line = to_gpio_sim_line(item); 1405 struct gpio_sim_device *dev = gpio_sim_line_get_device(line); 1406 1407 scoped_guard(mutex, &dev->lock) 1408 list_del(&line->siblings); 1409 1410 kfree(line->name); 1411 kfree(line); 1412 } 1413 1414 static struct configfs_item_operations gpio_sim_line_config_item_ops = { 1415 .release = gpio_sim_line_config_group_release, 1416 }; 1417 1418 static struct configfs_group_operations gpio_sim_line_config_group_ops = { 1419 .make_item = gpio_sim_line_config_make_hog_item, 1420 }; 1421 1422 static const struct config_item_type gpio_sim_line_config_type = { 1423 .ct_item_ops = &gpio_sim_line_config_item_ops, 1424 .ct_group_ops = &gpio_sim_line_config_group_ops, 1425 .ct_attrs = gpio_sim_line_config_attrs, 1426 .ct_owner = THIS_MODULE, 1427 }; 1428 1429 static struct config_group * 1430 gpio_sim_bank_config_make_line_group(struct config_group *group, 1431 const char *name) 1432 { 1433 struct gpio_sim_bank *bank = to_gpio_sim_bank(&group->cg_item); 1434 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); 1435 struct gpio_sim_line *line; 1436 unsigned int offset; 1437 int ret, nchar; 1438 1439 ret = sscanf(name, "line%u%n", &offset, &nchar); 1440 if (ret != 1 || nchar != strlen(name)) 1441 return ERR_PTR(-EINVAL); 1442 1443 guard(mutex)(&dev->lock); 1444 1445 if (gpio_sim_device_is_live(dev)) 1446 return ERR_PTR(-EBUSY); 1447 1448 line = kzalloc(sizeof(*line), GFP_KERNEL); 1449 if (!line) 1450 return ERR_PTR(-ENOMEM); 1451 1452 config_group_init_type_name(&line->group, name, 1453 &gpio_sim_line_config_type); 1454 1455 line->parent = bank; 1456 line->offset = offset; 1457 list_add_tail(&line->siblings, &bank->line_list); 1458 1459 return &line->group; 1460 } 1461 1462 static void gpio_sim_bank_config_group_release(struct config_item *item) 1463 { 1464 struct gpio_sim_bank *bank = to_gpio_sim_bank(item); 1465 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); 1466 1467 scoped_guard(mutex, &dev->lock) 1468 list_del(&bank->siblings); 1469 1470 kfree(bank->label); 1471 kfree(bank); 1472 } 1473 1474 static struct configfs_item_operations gpio_sim_bank_config_item_ops = { 1475 .release = gpio_sim_bank_config_group_release, 1476 }; 1477 1478 static struct configfs_group_operations gpio_sim_bank_config_group_ops = { 1479 .make_group = gpio_sim_bank_config_make_line_group, 1480 }; 1481 1482 static const struct config_item_type gpio_sim_bank_config_group_type = { 1483 .ct_item_ops = &gpio_sim_bank_config_item_ops, 1484 .ct_group_ops = &gpio_sim_bank_config_group_ops, 1485 .ct_attrs = gpio_sim_bank_config_attrs, 1486 .ct_owner = THIS_MODULE, 1487 }; 1488 1489 static struct config_group * 1490 gpio_sim_device_config_make_bank_group(struct config_group *group, 1491 const char *name) 1492 { 1493 struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item); 1494 struct gpio_sim_bank *bank; 1495 1496 guard(mutex)(&dev->lock); 1497 1498 if (gpio_sim_device_is_live(dev)) 1499 return ERR_PTR(-EBUSY); 1500 1501 bank = kzalloc(sizeof(*bank), GFP_KERNEL); 1502 if (!bank) 1503 return ERR_PTR(-ENOMEM); 1504 1505 config_group_init_type_name(&bank->group, name, 1506 &gpio_sim_bank_config_group_type); 1507 bank->num_lines = 1; 1508 bank->parent = dev; 1509 INIT_LIST_HEAD(&bank->line_list); 1510 list_add_tail(&bank->siblings, &dev->bank_list); 1511 1512 return &bank->group; 1513 } 1514 1515 static void gpio_sim_device_config_group_release(struct config_item *item) 1516 { 1517 struct gpio_sim_device *dev = to_gpio_sim_device(item); 1518 1519 scoped_guard(mutex, &dev->lock) { 1520 if (gpio_sim_device_is_live(dev)) 1521 gpio_sim_device_deactivate(dev); 1522 } 1523 1524 mutex_destroy(&dev->lock); 1525 ida_free(&gpio_sim_ida, dev->id); 1526 kfree(dev); 1527 } 1528 1529 static struct configfs_item_operations gpio_sim_device_config_item_ops = { 1530 .release = gpio_sim_device_config_group_release, 1531 }; 1532 1533 static struct configfs_group_operations gpio_sim_device_config_group_ops = { 1534 .make_group = gpio_sim_device_config_make_bank_group, 1535 }; 1536 1537 static const struct config_item_type gpio_sim_device_config_group_type = { 1538 .ct_item_ops = &gpio_sim_device_config_item_ops, 1539 .ct_group_ops = &gpio_sim_device_config_group_ops, 1540 .ct_attrs = gpio_sim_device_config_attrs, 1541 .ct_owner = THIS_MODULE, 1542 }; 1543 1544 static struct config_group * 1545 gpio_sim_config_make_device_group(struct config_group *group, const char *name) 1546 { 1547 int id; 1548 1549 struct gpio_sim_device *dev __free(kfree) = kzalloc(sizeof(*dev), 1550 GFP_KERNEL); 1551 if (!dev) 1552 return ERR_PTR(-ENOMEM); 1553 1554 id = ida_alloc(&gpio_sim_ida, GFP_KERNEL); 1555 if (id < 0) 1556 return ERR_PTR(id); 1557 1558 config_group_init_type_name(&dev->group, name, 1559 &gpio_sim_device_config_group_type); 1560 dev->id = id; 1561 mutex_init(&dev->lock); 1562 INIT_LIST_HEAD(&dev->bank_list); 1563 1564 dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call; 1565 init_completion(&dev->probe_completion); 1566 1567 return &no_free_ptr(dev)->group; 1568 } 1569 1570 static struct configfs_group_operations gpio_sim_config_group_ops = { 1571 .make_group = gpio_sim_config_make_device_group, 1572 }; 1573 1574 static const struct config_item_type gpio_sim_config_type = { 1575 .ct_group_ops = &gpio_sim_config_group_ops, 1576 .ct_owner = THIS_MODULE, 1577 }; 1578 1579 static struct configfs_subsystem gpio_sim_config_subsys = { 1580 .su_group = { 1581 .cg_item = { 1582 .ci_namebuf = "gpio-sim", 1583 .ci_type = &gpio_sim_config_type, 1584 }, 1585 }, 1586 }; 1587 1588 static int __init gpio_sim_init(void) 1589 { 1590 int ret; 1591 1592 ret = platform_driver_register(&gpio_sim_driver); 1593 if (ret) { 1594 pr_err("Error %d while registering the platform driver\n", ret); 1595 return ret; 1596 } 1597 1598 config_group_init(&gpio_sim_config_subsys.su_group); 1599 mutex_init(&gpio_sim_config_subsys.su_mutex); 1600 ret = configfs_register_subsystem(&gpio_sim_config_subsys); 1601 if (ret) { 1602 pr_err("Error %d while registering the configfs subsystem %s\n", 1603 ret, gpio_sim_config_subsys.su_group.cg_item.ci_namebuf); 1604 mutex_destroy(&gpio_sim_config_subsys.su_mutex); 1605 platform_driver_unregister(&gpio_sim_driver); 1606 return ret; 1607 } 1608 1609 return 0; 1610 } 1611 module_init(gpio_sim_init); 1612 1613 static void __exit gpio_sim_exit(void) 1614 { 1615 configfs_unregister_subsystem(&gpio_sim_config_subsys); 1616 mutex_destroy(&gpio_sim_config_subsys.su_mutex); 1617 platform_driver_unregister(&gpio_sim_driver); 1618 } 1619 module_exit(gpio_sim_exit); 1620 1621 MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>"); 1622 MODULE_DESCRIPTION("GPIO Simulator Module"); 1623 MODULE_LICENSE("GPL"); 1624