drivers/gpio/gpio-sim.c

   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_dev_match_fwnode(struct device *dev, void *data)
 417 {
 418         return device_match_fwnode(dev, data);
 419 }
 420
 421 static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
 422 {
 423         struct gpio_sim_chip *chip;
 424         struct gpio_chip *gc;
 425         const char *label;
 426         u32 num_lines;
 427         int ret;
 428
 429         ret = fwnode_property_read_u32(swnode, "ngpios", &num_lines);
 430         if (ret)
 431                 return ret;
 432
 433         if (num_lines > GPIO_SIM_NGPIO_MAX)
 434                 return -ERANGE;
 435
 436         ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label);
 437         if (ret) {
 438                 label = devm_kasprintf(dev, GFP_KERNEL, "%s:%pfwP",
 439                                        dev_name(dev), swnode);
 440                 if (!label)
 441                         return -ENOMEM;
 442         }
 443
 444         chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
 445         if (!chip)
 446                 return -ENOMEM;
 447
 448         chip->request_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
 449         if (!chip->request_map)
 450                 return -ENOMEM;
 451
 452         chip->direction_map = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL);
 453         if (!chip->direction_map)
 454                 return -ENOMEM;
 455
 456         /* Default to input mode. */
 457         bitmap_fill(chip->direction_map, num_lines);
 458
 459         chip->value_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
 460         if (!chip->value_map)
 461                 return -ENOMEM;
 462
 463         chip->pull_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
 464         if (!chip->pull_map)
 465                 return -ENOMEM;
 466
 467         chip->irq_sim = devm_irq_domain_create_sim_full(dev, swnode, num_lines,
 468                                                         &gpio_sim_irq_sim_ops,
 469                                                         chip);
 470         if (IS_ERR(chip->irq_sim))
 471                 return PTR_ERR(chip->irq_sim);
 472
 473         ret = devm_add_action_or_reset(dev, gpio_sim_dispose_mappings, chip);
 474         if (ret)
 475                 return ret;
 476
 477         ret = devm_mutex_init(dev, &chip->lock);
 478         if (ret)
 479                 return ret;
 480
 481         gc = &chip->gc;
 482         gc->base = -1;
 483         gc->ngpio = num_lines;
 484         gc->label = label;
 485         gc->owner = THIS_MODULE;
 486         gc->parent = dev;
 487         gc->fwnode = swnode;
 488         gc->get = gpio_sim_get;
 489         gc->set = gpio_sim_set;
 490         gc->get_multiple = gpio_sim_get_multiple;
 491         gc->set_multiple = gpio_sim_set_multiple;
 492         gc->direction_output = gpio_sim_direction_output;
 493         gc->direction_input = gpio_sim_direction_input;
 494         gc->get_direction = gpio_sim_get_direction;
 495         gc->set_config = gpio_sim_set_config;
 496         gc->to_irq = gpio_sim_to_irq;
 497         gc->request = gpio_sim_request;
 498         gc->free = gpio_sim_free;
 499         gc->dbg_show = PTR_IF(IS_ENABLED(CONFIG_DEBUG_FS), gpio_sim_dbg_show);
 500         gc->can_sleep = true;
 501
 502         ret = devm_gpiochip_add_data(dev, gc, chip);
 503         if (ret)
 504                 return ret;
 505
 506         chip->dev = device_find_child(dev, swnode, gpio_sim_dev_match_fwnode);
 507         if (!chip->dev)
 508                 return -ENODEV;
 509
 510         ret = devm_add_action_or_reset(dev, gpio_sim_put_device, chip->dev);
 511         if (ret)
 512                 return ret;
 513
 514         /* Used by sysfs callbacks. */
 515         dev_set_drvdata(chip->dev, chip);
 516
 517         return gpio_sim_setup_sysfs(chip);
 518 }
 519
 520 static int gpio_sim_probe(struct platform_device *pdev)
 521 {
 522         struct device *dev = &pdev->dev;
 523         int ret;
 524
 525         device_for_each_child_node_scoped(dev, swnode) {
 526                 ret = gpio_sim_add_bank(swnode, dev);
 527                 if (ret)
 528                         return ret;
 529         }
 530
 531         return 0;
 532 }
 533
 534 static const struct of_device_id gpio_sim_of_match[] = {
 535         { .compatible = "gpio-simulator" },
 536         { }
 537 };
 538 MODULE_DEVICE_TABLE(of, gpio_sim_of_match);
 539
 540 static struct platform_driver gpio_sim_driver = {
 541         .driver = {
 542                 .name = "gpio-sim",
 543                 .of_match_table = gpio_sim_of_match,
 544         },
 545         .probe = gpio_sim_probe,
 546 };
 547
 548 struct gpio_sim_device {
 549         struct config_group group;
 550
 551         /*
 552          * If pdev is NULL, the device is 'pending' (waiting for configuration).
 553          * Once the pointer is assigned, the device has been created and the
 554          * item is 'live'.
 555          */
 556         struct platform_device *pdev;
 557         int id;
 558
 559         /*
 560          * Each configfs filesystem operation is protected with the subsystem
 561          * mutex. Each separate attribute is protected with the buffer mutex.
 562          * This structure however can be modified by callbacks of different
 563          * attributes so we need another lock.
 564          *
 565          * We use this lock for protecting all data structures owned by this
 566          * object too.
 567          */
 568         struct mutex lock;
 569
 570         /*
 571          * This is used to synchronously wait for the driver's probe to complete
 572          * and notify the user-space about any errors.
 573          */
 574         struct notifier_block bus_notifier;
 575         struct completion probe_completion;
 576         bool driver_bound;
 577
 578         struct gpiod_hog *hogs;
 579
 580         struct list_head bank_list;
 581 };
 582
 583 /* This is called with dev->lock already taken. */
 584 static int gpio_sim_bus_notifier_call(struct notifier_block *nb,
 585                                       unsigned long action, void *data)
 586 {
 587         struct gpio_sim_device *simdev = container_of(nb,
 588                                                       struct gpio_sim_device,
 589                                                       bus_notifier);
 590         struct device *dev = data;
 591         char devname[32];
 592
 593         snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id);
 594
 595         if (!device_match_name(dev, devname))
 596                 return NOTIFY_DONE;
 597
 598         if (action == BUS_NOTIFY_BOUND_DRIVER)
 599                 simdev->driver_bound = true;
 600         else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND)
 601                 simdev->driver_bound = false;
 602         else
 603                 return NOTIFY_DONE;
 604
 605         complete(&simdev->probe_completion);
 606
 607         return NOTIFY_OK;
 608 }
 609
 610 static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item)
 611 {
 612         struct config_group *group = to_config_group(item);
 613
 614         return container_of(group, struct gpio_sim_device, group);
 615 }
 616
 617 struct gpio_sim_bank {
 618         struct config_group group;
 619
 620         /*
 621          * We could have used the ci_parent field of the config_item but
 622          * configfs is stupid and calls the item's release callback after
 623          * already having cleared the parent pointer even though the parent
 624          * is guaranteed to survive the child...
 625          *
 626          * So we need to store the pointer to the parent struct here. We can
 627          * dereference it anywhere we need with no checks and no locking as
 628          * it's guaranteed to survive the children and protected by configfs
 629          * locks.
 630          *
 631          * Same for other structures.
 632          */
 633         struct gpio_sim_device *parent;
 634         struct list_head siblings;
 635
 636         char *label;
 637         unsigned int num_lines;
 638
 639         struct list_head line_list;
 640
 641         struct fwnode_handle *swnode;
 642 };
 643
 644 static struct gpio_sim_bank *to_gpio_sim_bank(struct config_item *item)
 645 {
 646         struct config_group *group = to_config_group(item);
 647
 648         return container_of(group, struct gpio_sim_bank, group);
 649 }
 650
 651 static bool gpio_sim_bank_has_label(struct gpio_sim_bank *bank)
 652 {
 653         return bank->label && *bank->label;
 654 }
 655
 656 static struct gpio_sim_device *
 657 gpio_sim_bank_get_device(struct gpio_sim_bank *bank)
 658 {
 659         return bank->parent;
 660 }
 661
 662 struct gpio_sim_hog;
 663
 664 struct gpio_sim_line {
 665         struct config_group group;
 666
 667         struct gpio_sim_bank *parent;
 668         struct list_head siblings;
 669
 670         unsigned int offset;
 671         char *name;
 672
 673         /* There can only be one hog per line. */
 674         struct gpio_sim_hog *hog;
 675 };
 676
 677 static struct gpio_sim_line *to_gpio_sim_line(struct config_item *item)
 678 {
 679         struct config_group *group = to_config_group(item);
 680
 681         return container_of(group, struct gpio_sim_line, group);
 682 }
 683
 684 static struct gpio_sim_device *
 685 gpio_sim_line_get_device(struct gpio_sim_line *line)
 686 {
 687         struct gpio_sim_bank *bank = line->parent;
 688
 689         return gpio_sim_bank_get_device(bank);
 690 }
 691
 692 struct gpio_sim_hog {
 693         struct config_item item;
 694         struct gpio_sim_line *parent;
 695
 696         char *name;
 697         int dir;
 698 };
 699
 700 static struct gpio_sim_hog *to_gpio_sim_hog(struct config_item *item)
 701 {
 702         return container_of(item, struct gpio_sim_hog, item);
 703 }
 704
 705 static struct gpio_sim_device *gpio_sim_hog_get_device(struct gpio_sim_hog *hog)
 706 {
 707         struct gpio_sim_line *line = hog->parent;
 708
 709         return gpio_sim_line_get_device(line);
 710 }
 711
 712 static bool gpio_sim_device_is_live(struct gpio_sim_device *dev)
 713 {
 714         lockdep_assert_held(&dev->lock);
 715
 716         return !!dev->pdev;
 717 }
 718
 719 static char *gpio_sim_strdup_trimmed(const char *str, size_t count)
 720 {
 721         char *trimmed;
 722
 723         trimmed = kstrndup(skip_spaces(str), count, GFP_KERNEL);
 724         if (!trimmed)
 725                 return NULL;
 726
 727         return strim(trimmed);
 728 }
 729
 730 static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
 731                                                     char *page)
 732 {
 733         struct gpio_sim_device *dev = to_gpio_sim_device(item);
 734         struct platform_device *pdev;
 735
 736         guard(mutex)(&dev->lock);
 737
 738         pdev = dev->pdev;
 739         if (pdev)
 740                 return sprintf(page, "%s\n", dev_name(&pdev->dev));
 741
 742         return sprintf(page, "gpio-sim.%d\n", dev->id);
 743 }
 744
 745 CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name);
 746
 747 static ssize_t
 748 gpio_sim_device_config_live_show(struct config_item *item, char *page)
 749 {
 750         struct gpio_sim_device *dev = to_gpio_sim_device(item);
 751         bool live;
 752
 753         scoped_guard(mutex, &dev->lock)
 754                 live = gpio_sim_device_is_live(dev);
 755
 756         return sprintf(page, "%c\n", live ? '1' : '0');
 757 }
 758
 759 static unsigned int gpio_sim_get_line_names_size(struct gpio_sim_bank *bank)
 760 {
 761         struct gpio_sim_line *line;
 762         unsigned int size = 0;
 763
 764         list_for_each_entry(line, &bank->line_list, siblings) {
 765                 if (!line->name || (line->offset >= bank->num_lines))
 766                         continue;
 767
 768                 size = max(size, line->offset + 1);
 769         }
 770
 771         return size;
 772 }
 773
 774 static void
 775 gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names)
 776 {
 777         struct gpio_sim_line *line;
 778
 779         list_for_each_entry(line, &bank->line_list, siblings) {
 780                 if (!line->name || (line->offset >= bank->num_lines))
 781                         continue;
 782
 783                 line_names[line->offset] = line->name;
 784         }
 785 }
 786
 787 static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
 788 {
 789         struct gpiod_hog *hog;
 790
 791         if (!dev->hogs)
 792                 return;
 793
 794         gpiod_remove_hogs(dev->hogs);
 795
 796         for (hog = dev->hogs; hog->chip_label; hog++) {
 797                 kfree(hog->chip_label);
 798                 kfree(hog->line_name);
 799         }
 800
 801         kfree(dev->hogs);
 802         dev->hogs = NULL;
 803 }
 804
 805 static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
 806 {
 807         unsigned int num_hogs = 0, idx = 0;
 808         struct gpio_sim_bank *bank;
 809         struct gpio_sim_line *line;
 810         struct gpiod_hog *hog;
 811
 812         list_for_each_entry(bank, &dev->bank_list, siblings) {
 813                 list_for_each_entry(line, &bank->line_list, siblings) {
 814                         if (line->offset >= bank->num_lines)
 815                                 continue;
 816
 817                         if (line->hog)
 818                                 num_hogs++;
 819                 }
 820         }
 821
 822         if (!num_hogs)
 823                 return 0;
 824
 825         /* Allocate one more for the sentinel. */
 826         dev->hogs = kcalloc(num_hogs + 1, sizeof(*dev->hogs), GFP_KERNEL);
 827         if (!dev->hogs)
 828                 return -ENOMEM;
 829
 830         list_for_each_entry(bank, &dev->bank_list, siblings) {
 831                 list_for_each_entry(line, &bank->line_list, siblings) {
 832                         if (line->offset >= bank->num_lines)
 833                                 continue;
 834
 835                         if (!line->hog)
 836                                 continue;
 837
 838                         hog = &dev->hogs[idx++];
 839
 840                         /*
 841                          * We need to make this string manually because at this
 842                          * point the device doesn't exist yet and so dev_name()
 843                          * is not available.
 844                          */
 845                         if (gpio_sim_bank_has_label(bank))
 846                                 hog->chip_label = kstrdup(bank->label,
 847                                                           GFP_KERNEL);
 848                         else
 849                                 hog->chip_label = kasprintf(GFP_KERNEL,
 850                                                         "gpio-sim.%u:%pfwP",
 851                                                         dev->id,
 852                                                         bank->swnode);
 853                         if (!hog->chip_label) {
 854                                 gpio_sim_remove_hogs(dev);
 855                                 return -ENOMEM;
 856                         }
 857
 858                         /*
 859                          * We need to duplicate this because the hog config
 860                          * item can be removed at any time (and we can't block
 861                          * it) and gpiolib doesn't make a deep copy of the hog
 862                          * data.
 863                          */
 864                         if (line->hog->name) {
 865                                 hog->line_name = kstrdup(line->hog->name,
 866                                                          GFP_KERNEL);
 867                                 if (!hog->line_name) {
 868                                         gpio_sim_remove_hogs(dev);
 869                                         return -ENOMEM;
 870                                 }
 871                         }
 872
 873                         hog->chip_hwnum = line->offset;
 874                         hog->dflags = line->hog->dir;
 875                 }
 876         }
 877
 878         gpiod_add_hogs(dev->hogs);
 879
 880         return 0;
 881 }
 882
 883 static struct fwnode_handle *
 884 gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
 885                           struct fwnode_handle *parent)
 886 {
 887         struct property_entry properties[GPIO_SIM_PROP_MAX];
 888         unsigned int prop_idx = 0, line_names_size;
 889         char **line_names __free(kfree) = NULL;
 890
 891         memset(properties, 0, sizeof(properties));
 892
 893         properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines);
 894
 895         if (gpio_sim_bank_has_label(bank))
 896                 properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label",
 897                                                                bank->label);
 898
 899         line_names_size = gpio_sim_get_line_names_size(bank);
 900         if (line_names_size) {
 901                 line_names = kcalloc(line_names_size, sizeof(*line_names),
 902                                      GFP_KERNEL);
 903                 if (!line_names)
 904                         return ERR_PTR(-ENOMEM);
 905
 906                 gpio_sim_set_line_names(bank, line_names);
 907
 908                 properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
 909                                                 "gpio-line-names",
 910                                                 line_names, line_names_size);
 911         }
 912
 913         return fwnode_create_software_node(properties, parent);
 914 }
 915
 916 static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
 917 {
 918         struct fwnode_handle *child;
 919
 920         fwnode_for_each_child_node(swnode, child)
 921                 fwnode_remove_software_node(child);
 922
 923         fwnode_remove_software_node(swnode);
 924 }
 925
 926 static bool gpio_sim_bank_labels_non_unique(struct gpio_sim_device *dev)
 927 {
 928         struct gpio_sim_bank *this, *pos;
 929
 930         list_for_each_entry(this, &dev->bank_list, siblings) {
 931                 list_for_each_entry(pos, &dev->bank_list, siblings) {
 932                         if (this == pos || (!this->label || !pos->label))
 933                                 continue;
 934
 935                         if (strcmp(this->label, pos->label) == 0)
 936                                 return true;
 937                 }
 938         }
 939
 940         return false;
 941 }
 942
 943 static int gpio_sim_device_activate(struct gpio_sim_device *dev)
 944 {
 945         struct platform_device_info pdevinfo;
 946         struct fwnode_handle *swnode;
 947         struct platform_device *pdev;
 948         struct gpio_sim_bank *bank;
 949         int ret;
 950
 951         lockdep_assert_held(&dev->lock);
 952
 953         if (list_empty(&dev->bank_list))
 954                 return -ENODATA;
 955
 956         /*
 957          * Non-unique GPIO device labels are a corner-case we don't support
 958          * as it would interfere with machine hogging mechanism and has little
 959          * use in real life.
 960          */
 961         if (gpio_sim_bank_labels_non_unique(dev))
 962                 return -EINVAL;
 963
 964         memset(&pdevinfo, 0, sizeof(pdevinfo));
 965
 966         swnode = fwnode_create_software_node(NULL, NULL);
 967         if (IS_ERR(swnode))
 968                 return PTR_ERR(swnode);
 969
 970         list_for_each_entry(bank, &dev->bank_list, siblings) {
 971                 bank->swnode = gpio_sim_make_bank_swnode(bank, swnode);
 972                 if (IS_ERR(bank->swnode)) {
 973                         ret = PTR_ERR(bank->swnode);
 974                         gpio_sim_remove_swnode_recursive(swnode);
 975                         return ret;
 976                 }
 977         }
 978
 979         ret = gpio_sim_add_hogs(dev);
 980         if (ret) {
 981                 gpio_sim_remove_swnode_recursive(swnode);
 982                 return ret;
 983         }
 984
 985         pdevinfo.name = "gpio-sim";
 986         pdevinfo.fwnode = swnode;
 987         pdevinfo.id = dev->id;
 988
 989         reinit_completion(&dev->probe_completion);
 990         dev->driver_bound = false;
 991         bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
 992
 993         pdev = platform_device_register_full(&pdevinfo);
 994         if (IS_ERR(pdev)) {
 995                 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
 996                 gpio_sim_remove_hogs(dev);
 997                 gpio_sim_remove_swnode_recursive(swnode);
 998                 return PTR_ERR(pdev);
 999         }
1000
1001         wait_for_completion(&dev->probe_completion);
1002         bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
1003
1004         if (!dev->driver_bound) {
1005                 /* Probe failed, check kernel log. */
1006                 platform_device_unregister(pdev);
1007                 gpio_sim_remove_hogs(dev);
1008                 gpio_sim_remove_swnode_recursive(swnode);
1009                 return -ENXIO;
1010         }
1011
1012         dev->pdev = pdev;
1013
1014         return 0;
1015 }
1016
1017 static void gpio_sim_device_deactivate(struct gpio_sim_device *dev)
1018 {
1019         struct fwnode_handle *swnode;
1020
1021         lockdep_assert_held(&dev->lock);
1022
1023         swnode = dev_fwnode(&dev->pdev->dev);
1024         platform_device_unregister(dev->pdev);
1025         gpio_sim_remove_hogs(dev);
1026         gpio_sim_remove_swnode_recursive(swnode);
1027         dev->pdev = NULL;
1028 }
1029
1030 static ssize_t
1031 gpio_sim_device_config_live_store(struct config_item *item,
1032                                   const char *page, size_t count)
1033 {
1034         struct gpio_sim_device *dev = to_gpio_sim_device(item);
1035         bool live;
1036         int ret;
1037
1038         ret = kstrtobool(page, &live);
1039         if (ret)
1040                 return ret;
1041
1042         guard(mutex)(&dev->lock);
1043
1044         if (live == gpio_sim_device_is_live(dev))
1045                 ret = -EPERM;
1046         else if (live)
1047                 ret = gpio_sim_device_activate(dev);
1048         else
1049                 gpio_sim_device_deactivate(dev);
1050
1051         return ret ?: count;
1052 }
1053
1054 CONFIGFS_ATTR(gpio_sim_device_config_, live);
1055
1056 static struct configfs_attribute *gpio_sim_device_config_attrs[] = {
1057         &gpio_sim_device_config_attr_dev_name,
1058         &gpio_sim_device_config_attr_live,
1059         NULL
1060 };
1061
1062 struct gpio_sim_chip_name_ctx {
1063         struct fwnode_handle *swnode;
1064         char *page;
1065 };
1066
1067 static int gpio_sim_emit_chip_name(struct device *dev, void *data)
1068 {
1069         struct gpio_sim_chip_name_ctx *ctx = data;
1070
1071         /* This would be the sysfs device exported in /sys/class/gpio. */
1072         if (dev->class)
1073                 return 0;
1074
1075         if (device_match_fwnode(dev, ctx->swnode))
1076                 return sprintf(ctx->page, "%s\n", dev_name(dev));
1077
1078         return 0;
1079 }
1080
1081 static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
1082                                                    char *page)
1083 {
1084         struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1085         struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1086         struct gpio_sim_chip_name_ctx ctx = { bank->swnode, page };
1087
1088         guard(mutex)(&dev->lock);
1089
1090         if (gpio_sim_device_is_live(dev))
1091                 return device_for_each_child(&dev->pdev->dev, &ctx,
1092                                              gpio_sim_emit_chip_name);
1093
1094         return sprintf(page, "none\n");
1095 }
1096
1097 CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name);
1098
1099 static ssize_t
1100 gpio_sim_bank_config_label_show(struct config_item *item, char *page)
1101 {
1102         struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1103         struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1104
1105         guard(mutex)(&dev->lock);
1106
1107         return sprintf(page, "%s\n", bank->label ?: "");
1108 }
1109
1110 static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
1111                                                 const char *page, size_t count)
1112 {
1113         struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1114         struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1115         char *trimmed;
1116
1117         guard(mutex)(&dev->lock);
1118
1119         if (gpio_sim_device_is_live(dev))
1120                 return -EBUSY;
1121
1122         trimmed = gpio_sim_strdup_trimmed(page, count);
1123         if (!trimmed)
1124                 return -ENOMEM;
1125
1126         kfree(bank->label);
1127         bank->label = trimmed;
1128
1129         return count;
1130 }
1131
1132 CONFIGFS_ATTR(gpio_sim_bank_config_, label);
1133
1134 static ssize_t
1135 gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page)
1136 {
1137         struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1138         struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1139
1140         guard(mutex)(&dev->lock);
1141
1142         return sprintf(page, "%u\n", bank->num_lines);
1143 }
1144
1145 static ssize_t
1146 gpio_sim_bank_config_num_lines_store(struct config_item *item,
1147                                      const char *page, size_t count)
1148 {
1149         struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1150         struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1151         unsigned int num_lines;
1152         int ret;
1153
1154         ret = kstrtouint(page, 0, &num_lines);
1155         if (ret)
1156                 return ret;
1157
1158         if (num_lines == 0)
1159                 return -EINVAL;
1160
1161         guard(mutex)(&dev->lock);
1162
1163         if (gpio_sim_device_is_live(dev))
1164                 return -EBUSY;
1165
1166         bank->num_lines = num_lines;
1167
1168         return count;
1169 }
1170
1171 CONFIGFS_ATTR(gpio_sim_bank_config_, num_lines);
1172
1173 static struct configfs_attribute *gpio_sim_bank_config_attrs[] = {
1174         &gpio_sim_bank_config_attr_chip_name,
1175         &gpio_sim_bank_config_attr_label,
1176         &gpio_sim_bank_config_attr_num_lines,
1177         NULL
1178 };
1179
1180 static ssize_t
1181 gpio_sim_line_config_name_show(struct config_item *item, char *page)
1182 {
1183         struct gpio_sim_line *line = to_gpio_sim_line(item);
1184         struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1185
1186         guard(mutex)(&dev->lock);
1187
1188         return sprintf(page, "%s\n", line->name ?: "");
1189 }
1190
1191 static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
1192                                                const char *page, size_t count)
1193 {
1194         struct gpio_sim_line *line = to_gpio_sim_line(item);
1195         struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1196         char *trimmed;
1197
1198         guard(mutex)(&dev->lock);
1199
1200         if (gpio_sim_device_is_live(dev))
1201                 return -EBUSY;
1202
1203         trimmed = gpio_sim_strdup_trimmed(page, count);
1204         if (!trimmed)
1205                 return -ENOMEM;
1206
1207         kfree(line->name);
1208         line->name = trimmed;
1209
1210         return count;
1211 }
1212
1213 CONFIGFS_ATTR(gpio_sim_line_config_, name);
1214
1215 static struct configfs_attribute *gpio_sim_line_config_attrs[] = {
1216         &gpio_sim_line_config_attr_name,
1217         NULL
1218 };
1219
1220 static ssize_t gpio_sim_hog_config_name_show(struct config_item *item,
1221                                              char *page)
1222 {
1223         struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1224         struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1225
1226         guard(mutex)(&dev->lock);
1227
1228         return sprintf(page, "%s\n", hog->name ?: "");
1229 }
1230
1231 static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
1232                                               const char *page, size_t count)
1233 {
1234         struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1235         struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1236         char *trimmed;
1237
1238         guard(mutex)(&dev->lock);
1239
1240         if (gpio_sim_device_is_live(dev))
1241                 return -EBUSY;
1242
1243         trimmed = gpio_sim_strdup_trimmed(page, count);
1244         if (!trimmed)
1245                 return -ENOMEM;
1246
1247         kfree(hog->name);
1248         hog->name = trimmed;
1249
1250         return count;
1251 }
1252
1253 CONFIGFS_ATTR(gpio_sim_hog_config_, name);
1254
1255 static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item,
1256                                                   char *page)
1257 {
1258         struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1259         struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1260         char *repr;
1261         int dir;
1262
1263         scoped_guard(mutex, &dev->lock)
1264                 dir = hog->dir;
1265
1266         switch (dir) {
1267         case GPIOD_IN:
1268                 repr = "input";
1269                 break;
1270         case GPIOD_OUT_HIGH:
1271                 repr = "output-high";
1272                 break;
1273         case GPIOD_OUT_LOW:
1274                 repr = "output-low";
1275                 break;
1276         default:
1277                 /* This would be a programmer bug. */
1278                 WARN(1, "Unexpected hog direction value: %d", dir);
1279                 return -EINVAL;
1280         }
1281
1282         return sprintf(page, "%s\n", repr);
1283 }
1284
1285 static ssize_t
1286 gpio_sim_hog_config_direction_store(struct config_item *item,
1287                                     const char *page, size_t count)
1288 {
1289         struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1290         struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1291         int dir;
1292
1293         guard(mutex)(&dev->lock);
1294
1295         if (gpio_sim_device_is_live(dev))
1296                 return -EBUSY;
1297
1298         if (sysfs_streq(page, "input"))
1299                 dir = GPIOD_IN;
1300         else if (sysfs_streq(page, "output-high"))
1301                 dir = GPIOD_OUT_HIGH;
1302         else if (sysfs_streq(page, "output-low"))
1303                 dir = GPIOD_OUT_LOW;
1304         else
1305                 return -EINVAL;
1306
1307         hog->dir = dir;
1308
1309         return count;
1310 }
1311
1312 CONFIGFS_ATTR(gpio_sim_hog_config_, direction);
1313
1314 static struct configfs_attribute *gpio_sim_hog_config_attrs[] = {
1315         &gpio_sim_hog_config_attr_name,
1316         &gpio_sim_hog_config_attr_direction,
1317         NULL
1318 };
1319
1320 static void gpio_sim_hog_config_item_release(struct config_item *item)
1321 {
1322         struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1323         struct gpio_sim_line *line = hog->parent;
1324         struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1325
1326         scoped_guard(mutex, &dev->lock)
1327                 line->hog = NULL;
1328
1329         kfree(hog->name);
1330         kfree(hog);
1331 }
1332
1333 static struct configfs_item_operations gpio_sim_hog_config_item_ops = {
1334         .release        = gpio_sim_hog_config_item_release,
1335 };
1336
1337 static const struct config_item_type gpio_sim_hog_config_type = {
1338         .ct_item_ops    = &gpio_sim_hog_config_item_ops,
1339         .ct_attrs       = gpio_sim_hog_config_attrs,
1340         .ct_owner       = THIS_MODULE,
1341 };
1342
1343 static struct config_item *
1344 gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
1345 {
1346         struct gpio_sim_line *line = to_gpio_sim_line(&group->cg_item);
1347         struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1348         struct gpio_sim_hog *hog;
1349
1350         if (strcmp(name, "hog") != 0)
1351                 return ERR_PTR(-EINVAL);
1352
1353         guard(mutex)(&dev->lock);
1354
1355         hog = kzalloc(sizeof(*hog), GFP_KERNEL);
1356         if (!hog)
1357                 return ERR_PTR(-ENOMEM);
1358
1359         config_item_init_type_name(&hog->item, name,
1360                                    &gpio_sim_hog_config_type);
1361
1362         hog->dir = GPIOD_IN;
1363         hog->name = NULL;
1364         hog->parent = line;
1365         line->hog = hog;
1366
1367         return &hog->item;
1368 }
1369
1370 static void gpio_sim_line_config_group_release(struct config_item *item)
1371 {
1372         struct gpio_sim_line *line = to_gpio_sim_line(item);
1373         struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1374
1375         scoped_guard(mutex, &dev->lock)
1376                 list_del(&line->siblings);
1377
1378         kfree(line->name);
1379         kfree(line);
1380 }
1381
1382 static struct configfs_item_operations gpio_sim_line_config_item_ops = {
1383         .release        = gpio_sim_line_config_group_release,
1384 };
1385
1386 static struct configfs_group_operations gpio_sim_line_config_group_ops = {
1387         .make_item      = gpio_sim_line_config_make_hog_item,
1388 };
1389
1390 static const struct config_item_type gpio_sim_line_config_type = {
1391         .ct_item_ops    = &gpio_sim_line_config_item_ops,
1392         .ct_group_ops   = &gpio_sim_line_config_group_ops,
1393         .ct_attrs       = gpio_sim_line_config_attrs,
1394         .ct_owner       = THIS_MODULE,
1395 };
1396
1397 static struct config_group *
1398 gpio_sim_bank_config_make_line_group(struct config_group *group,
1399                                      const char *name)
1400 {
1401         struct gpio_sim_bank *bank = to_gpio_sim_bank(&group->cg_item);
1402         struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1403         struct gpio_sim_line *line;
1404         unsigned int offset;
1405         int ret, nchar;
1406
1407         ret = sscanf(name, "line%u%n", &offset, &nchar);
1408         if (ret != 1 || nchar != strlen(name))
1409                 return ERR_PTR(-EINVAL);
1410
1411         guard(mutex)(&dev->lock);
1412
1413         if (gpio_sim_device_is_live(dev))
1414                 return ERR_PTR(-EBUSY);
1415
1416         line = kzalloc(sizeof(*line), GFP_KERNEL);
1417         if (!line)
1418                 return ERR_PTR(-ENOMEM);
1419
1420         config_group_init_type_name(&line->group, name,
1421                                     &gpio_sim_line_config_type);
1422
1423         line->parent = bank;
1424         line->offset = offset;
1425         list_add_tail(&line->siblings, &bank->line_list);
1426
1427         return &line->group;
1428 }
1429
1430 static void gpio_sim_bank_config_group_release(struct config_item *item)
1431 {
1432         struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1433         struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1434
1435         scoped_guard(mutex, &dev->lock)
1436                 list_del(&bank->siblings);
1437
1438         kfree(bank->label);
1439         kfree(bank);
1440 }
1441
1442 static struct configfs_item_operations gpio_sim_bank_config_item_ops = {
1443         .release        = gpio_sim_bank_config_group_release,
1444 };
1445
1446 static struct configfs_group_operations gpio_sim_bank_config_group_ops = {
1447         .make_group     = gpio_sim_bank_config_make_line_group,
1448 };
1449
1450 static const struct config_item_type gpio_sim_bank_config_group_type = {
1451         .ct_item_ops    = &gpio_sim_bank_config_item_ops,
1452         .ct_group_ops   = &gpio_sim_bank_config_group_ops,
1453         .ct_attrs       = gpio_sim_bank_config_attrs,
1454         .ct_owner       = THIS_MODULE,
1455 };
1456
1457 static struct config_group *
1458 gpio_sim_device_config_make_bank_group(struct config_group *group,
1459                                        const char *name)
1460 {
1461         struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item);
1462         struct gpio_sim_bank *bank;
1463
1464         guard(mutex)(&dev->lock);
1465
1466         if (gpio_sim_device_is_live(dev))
1467                 return ERR_PTR(-EBUSY);
1468
1469         bank = kzalloc(sizeof(*bank), GFP_KERNEL);
1470         if (!bank)
1471                 return ERR_PTR(-ENOMEM);
1472
1473         config_group_init_type_name(&bank->group, name,
1474                                     &gpio_sim_bank_config_group_type);
1475         bank->num_lines = 1;
1476         bank->parent = dev;
1477         INIT_LIST_HEAD(&bank->line_list);
1478         list_add_tail(&bank->siblings, &dev->bank_list);
1479
1480         return &bank->group;
1481 }
1482
1483 static void gpio_sim_device_config_group_release(struct config_item *item)
1484 {
1485         struct gpio_sim_device *dev = to_gpio_sim_device(item);
1486
1487         scoped_guard(mutex, &dev->lock) {
1488                 if (gpio_sim_device_is_live(dev))
1489                         gpio_sim_device_deactivate(dev);
1490         }
1491
1492         mutex_destroy(&dev->lock);
1493         ida_free(&gpio_sim_ida, dev->id);
1494         kfree(dev);
1495 }
1496
1497 static struct configfs_item_operations gpio_sim_device_config_item_ops = {
1498         .release        = gpio_sim_device_config_group_release,
1499 };
1500
1501 static struct configfs_group_operations gpio_sim_device_config_group_ops = {
1502         .make_group     = gpio_sim_device_config_make_bank_group,
1503 };
1504
1505 static const struct config_item_type gpio_sim_device_config_group_type = {
1506         .ct_item_ops    = &gpio_sim_device_config_item_ops,
1507         .ct_group_ops   = &gpio_sim_device_config_group_ops,
1508         .ct_attrs       = gpio_sim_device_config_attrs,
1509         .ct_owner       = THIS_MODULE,
1510 };
1511
1512 static struct config_group *
1513 gpio_sim_config_make_device_group(struct config_group *group, const char *name)
1514 {
1515         int id;
1516
1517         struct gpio_sim_device *dev __free(kfree) = kzalloc(sizeof(*dev),
1518                                                             GFP_KERNEL);
1519         if (!dev)
1520                 return ERR_PTR(-ENOMEM);
1521
1522         id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
1523         if (id < 0)
1524                 return ERR_PTR(id);
1525
1526         config_group_init_type_name(&dev->group, name,
1527                                     &gpio_sim_device_config_group_type);
1528         dev->id = id;
1529         mutex_init(&dev->lock);
1530         INIT_LIST_HEAD(&dev->bank_list);
1531
1532         dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
1533         init_completion(&dev->probe_completion);
1534
1535         return &no_free_ptr(dev)->group;
1536 }
1537
1538 static struct configfs_group_operations gpio_sim_config_group_ops = {
1539         .make_group     = gpio_sim_config_make_device_group,
1540 };
1541
1542 static const struct config_item_type gpio_sim_config_type = {
1543         .ct_group_ops   = &gpio_sim_config_group_ops,
1544         .ct_owner       = THIS_MODULE,
1545 };
1546
1547 static struct configfs_subsystem gpio_sim_config_subsys = {
1548         .su_group = {
1549                 .cg_item = {
1550                         .ci_namebuf     = "gpio-sim",
1551                         .ci_type        = &gpio_sim_config_type,
1552                 },
1553         },
1554 };
1555
1556 static int __init gpio_sim_init(void)
1557 {
1558         int ret;
1559
1560         ret = platform_driver_register(&gpio_sim_driver);
1561         if (ret) {
1562                 pr_err("Error %d while registering the platform driver\n", ret);
1563                 return ret;
1564         }
1565
1566         config_group_init(&gpio_sim_config_subsys.su_group);
1567         mutex_init(&gpio_sim_config_subsys.su_mutex);
1568         ret = configfs_register_subsystem(&gpio_sim_config_subsys);
1569         if (ret) {
1570                 pr_err("Error %d while registering the configfs subsystem %s\n",
1571                        ret, gpio_sim_config_subsys.su_group.cg_item.ci_namebuf);
1572                 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1573                 platform_driver_unregister(&gpio_sim_driver);
1574                 return ret;
1575         }
1576
1577         return 0;
1578 }
1579 module_init(gpio_sim_init);
1580
1581 static void __exit gpio_sim_exit(void)
1582 {
1583         configfs_unregister_subsystem(&gpio_sim_config_subsys);
1584         mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1585         platform_driver_unregister(&gpio_sim_driver);
1586 }
1587 module_exit(gpio_sim_exit);
1588
1589 MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
1590 MODULE_DESCRIPTION("GPIO Simulator Module");
1591 MODULE_LICENSE("GPL");