drivers/gpio/gpio-virtuser.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Configurable virtual GPIO consumer module.
   4  *
   5  * Copyright (C) 2023-2024 Bartosz Golaszewski <[email protected]>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/array_size.h>
  11 #include <linux/atomic.h>
  12 #include <linux/bitmap.h>
  13 #include <linux/cleanup.h>
  14 #include <linux/completion.h>
  15 #include <linux/configfs.h>
  16 #include <linux/debugfs.h>
  17 #include <linux/device.h>
  18 #include <linux/err.h>
  19 #include <linux/gpio/consumer.h>
  20 #include <linux/gpio/machine.h>
  21 #include <linux/idr.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/irq_work.h>
  24 #include <linux/limits.h>
  25 #include <linux/list.h>
  26 #include <linux/lockdep.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/of.h>
  32 #include <linux/overflow.h>
  33 #include <linux/platform_device.h>
  34 #include <linux/printk.h>
  35 #include <linux/property.h>
  36 #include <linux/slab.h>
  37 #include <linux/string_helpers.h>
  38 #include <linux/types.h>
  39
  40 #define GPIO_VIRTUSER_NAME_BUF_LEN 32
  41
  42 static DEFINE_IDA(gpio_virtuser_ida);
  43 static struct dentry *gpio_virtuser_dbg_root;
  44
  45 struct gpio_virtuser_attr_data {
  46         union {
  47                 struct gpio_desc *desc;
  48                 struct gpio_descs *descs;
  49         };
  50         struct dentry *dbgfs_dir;
  51 };
  52
  53 struct gpio_virtuser_line_array_data {
  54         struct gpio_virtuser_attr_data ad;
  55 };
  56
  57 struct gpio_virtuser_line_data {
  58         struct gpio_virtuser_attr_data ad;
  59         char consumer[GPIO_VIRTUSER_NAME_BUF_LEN];
  60         struct mutex consumer_lock;
  61         unsigned int debounce;
  62         atomic_t irq;
  63         atomic_t irq_count;
  64 };
  65
  66 struct gpio_virtuser_dbgfs_attr_descr {
  67         const char *name;
  68         const struct file_operations *fops;
  69 };
  70
  71 struct gpio_virtuser_irq_work_context {
  72         struct irq_work work;
  73         struct completion work_completion;
  74         union {
  75                 struct {
  76                         struct gpio_desc *desc;
  77                         int dir;
  78                         int val;
  79                         int ret;
  80                 };
  81                 struct {
  82                         struct gpio_descs *descs;
  83                         unsigned long *values;
  84                 };
  85         };
  86 };
  87
  88 static struct gpio_virtuser_irq_work_context *
  89 to_gpio_virtuser_irq_work_context(struct irq_work *work)
  90 {
  91         return container_of(work, struct gpio_virtuser_irq_work_context, work);
  92 }
  93
  94 static void
  95 gpio_virtuser_init_irq_work_context(struct gpio_virtuser_irq_work_context *ctx)
  96 {
  97         memset(ctx, 0, sizeof(*ctx));
  98         init_completion(&ctx->work_completion);
  99 }
 100
 101 static void
 102 gpio_virtuser_irq_work_queue_sync(struct gpio_virtuser_irq_work_context *ctx)
 103 {
 104         irq_work_queue(&ctx->work);
 105         wait_for_completion(&ctx->work_completion);
 106 }
 107
 108 static void gpio_virtuser_dbgfs_emit_value_array(char *buf,
 109                                                  unsigned long *values,
 110                                                  size_t num_values)
 111 {
 112         size_t i;
 113
 114         for (i = 0; i < num_values; i++)
 115                 buf[i] = test_bit(i, values) ? '1' : '0';
 116
 117         buf[i++] = '\n';
 118 }
 119
 120 static void gpio_virtuser_get_value_array_atomic(struct irq_work *work)
 121 {
 122         struct gpio_virtuser_irq_work_context *ctx =
 123                                 to_gpio_virtuser_irq_work_context(work);
 124         struct gpio_descs *descs = ctx->descs;
 125
 126         ctx->ret = gpiod_get_array_value(descs->ndescs, descs->desc,
 127                                          descs->info, ctx->values);
 128         complete(&ctx->work_completion);
 129 }
 130
 131 static int gpio_virtuser_get_array_value(struct gpio_descs *descs,
 132                                          unsigned long *values, bool atomic)
 133 {
 134         struct gpio_virtuser_irq_work_context ctx;
 135
 136         if (!atomic)
 137                 return gpiod_get_array_value_cansleep(descs->ndescs,
 138                                                       descs->desc,
 139                                                       descs->info, values);
 140
 141         gpio_virtuser_init_irq_work_context(&ctx);
 142         ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_get_value_array_atomic);
 143         ctx.descs = descs;
 144         ctx.values = values;
 145
 146         gpio_virtuser_irq_work_queue_sync(&ctx);
 147
 148         return ctx.ret;
 149 }
 150
 151 static ssize_t gpio_virtuser_value_array_do_read(struct file *file,
 152                                                  char __user *user_buf,
 153                                                  size_t size, loff_t *ppos,
 154                                                  bool atomic)
 155 {
 156         struct gpio_virtuser_line_data *data = file->private_data;
 157         struct gpio_descs *descs = data->ad.descs;
 158         size_t bufsize;
 159         int ret;
 160
 161         unsigned long *values __free(bitmap) = bitmap_zalloc(descs->ndescs,
 162                                                              GFP_KERNEL);
 163         if (!values)
 164                 return -ENOMEM;
 165
 166         ret = gpio_virtuser_get_array_value(descs, values, atomic);
 167         if (ret)
 168                 return ret;
 169
 170         bufsize = descs->ndescs + 2;
 171
 172         char *buf __free(kfree) = kzalloc(bufsize, GFP_KERNEL);
 173         if (!buf)
 174                 return -ENOMEM;
 175
 176         gpio_virtuser_dbgfs_emit_value_array(buf, values, descs->ndescs);
 177
 178         return simple_read_from_buffer(user_buf, size, ppos, buf,
 179                                        descs->ndescs + 1);
 180 }
 181
 182 static int gpio_virtuser_dbgfs_parse_value_array(const char *buf,
 183                                                  size_t len,
 184                                                  unsigned long *values)
 185 {
 186         size_t i;
 187
 188         for (i = 0; i < len; i++) {
 189                 if (buf[i] == '0')
 190                         clear_bit(i, values);
 191                 else if (buf[i] == '1')
 192                         set_bit(i, values);
 193                 else
 194                         return -EINVAL;
 195         }
 196
 197         return 0;
 198 }
 199
 200 static void gpio_virtuser_set_value_array_atomic(struct irq_work *work)
 201 {
 202         struct gpio_virtuser_irq_work_context *ctx =
 203                                 to_gpio_virtuser_irq_work_context(work);
 204         struct gpio_descs *descs = ctx->descs;
 205
 206         ctx->ret = gpiod_set_array_value(descs->ndescs, descs->desc,
 207                                          descs->info, ctx->values);
 208         complete(&ctx->work_completion);
 209 }
 210
 211 static int gpio_virtuser_set_array_value(struct gpio_descs *descs,
 212                                          unsigned long *values, bool atomic)
 213 {
 214         struct gpio_virtuser_irq_work_context ctx;
 215
 216         if (!atomic)
 217                 return gpiod_set_array_value_cansleep(descs->ndescs,
 218                                                       descs->desc,
 219                                                       descs->info, values);
 220
 221         gpio_virtuser_init_irq_work_context(&ctx);
 222         ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_set_value_array_atomic);
 223         ctx.descs = descs;
 224         ctx.values = values;
 225
 226         gpio_virtuser_irq_work_queue_sync(&ctx);
 227
 228         return ctx.ret;
 229 }
 230
 231 static ssize_t gpio_virtuser_value_array_do_write(struct file *file,
 232                                                   const char __user *user_buf,
 233                                                   size_t count, loff_t *ppos,
 234                                                   bool atomic)
 235 {
 236         struct gpio_virtuser_line_data *data = file->private_data;
 237         struct gpio_descs *descs = data->ad.descs;
 238         int ret;
 239
 240         if (count - 1 != descs->ndescs)
 241                 return -EINVAL;
 242
 243         char *buf __free(kfree) = kzalloc(count, GFP_KERNEL);
 244         if (!buf)
 245                 return -ENOMEM;
 246
 247         ret = simple_write_to_buffer(buf, count, ppos, user_buf, count);
 248         if (ret < 0)
 249                 return ret;
 250
 251         unsigned long *values __free(bitmap) = bitmap_zalloc(descs->ndescs,
 252                                                              GFP_KERNEL);
 253         if (!values)
 254                 return -ENOMEM;
 255
 256         ret = gpio_virtuser_dbgfs_parse_value_array(buf, count - 1, values);
 257         if (ret)
 258                 return ret;
 259
 260         ret = gpio_virtuser_set_array_value(descs, values, atomic);
 261         if (ret)
 262                 return ret;
 263
 264         return count;
 265 }
 266
 267 static ssize_t gpio_virtuser_value_array_read(struct file *file,
 268                                               char __user *user_buf,
 269                                               size_t count, loff_t *ppos)
 270 {
 271         return gpio_virtuser_value_array_do_read(file, user_buf, count, ppos,
 272                                                  false);
 273 }
 274
 275 static ssize_t gpio_virtuser_value_array_write(struct file *file,
 276                                                const char __user *user_buf,
 277                                                size_t count, loff_t *ppos)
 278 {
 279         return gpio_virtuser_value_array_do_write(file, user_buf, count, ppos,
 280                                                   false);
 281 }
 282
 283 static const struct file_operations gpio_virtuser_value_array_fops = {
 284         .read = gpio_virtuser_value_array_read,
 285         .write = gpio_virtuser_value_array_write,
 286         .open = simple_open,
 287         .owner = THIS_MODULE,
 288         .llseek = default_llseek,
 289 };
 290
 291 static ssize_t
 292 gpio_virtuser_value_array_atomic_read(struct file *file, char __user *user_buf,
 293                                       size_t count, loff_t *ppos)
 294 {
 295         return gpio_virtuser_value_array_do_read(file, user_buf, count, ppos,
 296                                                  true);
 297 }
 298
 299 static ssize_t
 300 gpio_virtuser_value_array_atomic_write(struct file *file,
 301                                        const char __user *user_buf,
 302                                        size_t count, loff_t *ppos)
 303 {
 304         return gpio_virtuser_value_array_do_write(file, user_buf, count, ppos,
 305                                                   true);
 306 }
 307
 308 static const struct file_operations gpio_virtuser_value_array_atomic_fops = {
 309         .read = gpio_virtuser_value_array_atomic_read,
 310         .write = gpio_virtuser_value_array_atomic_write,
 311         .open = simple_open,
 312         .owner = THIS_MODULE,
 313         .llseek = default_llseek,
 314 };
 315
 316 static void gpio_virtuser_do_get_direction_atomic(struct irq_work *work)
 317 {
 318         struct gpio_virtuser_irq_work_context *ctx =
 319                                 to_gpio_virtuser_irq_work_context(work);
 320
 321         ctx->ret = gpiod_get_direction(ctx->desc);
 322         complete(&ctx->work_completion);
 323 }
 324
 325 static int gpio_virtuser_get_direction_atomic(struct gpio_desc *desc)
 326 {
 327         struct gpio_virtuser_irq_work_context ctx;
 328
 329         gpio_virtuser_init_irq_work_context(&ctx);
 330         ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_do_get_direction_atomic);
 331         ctx.desc = desc;
 332
 333         gpio_virtuser_irq_work_queue_sync(&ctx);
 334
 335         return ctx.ret;
 336 }
 337
 338 static ssize_t gpio_virtuser_direction_do_read(struct file *file,
 339                                                char __user *user_buf,
 340                                                size_t size, loff_t *ppos,
 341                                                bool atomic)
 342 {
 343         struct gpio_virtuser_line_data *data = file->private_data;
 344         struct gpio_desc *desc = data->ad.desc;
 345         char buf[32];
 346         int dir;
 347
 348         if (!atomic)
 349                 dir = gpiod_get_direction(desc);
 350         else
 351                 dir = gpio_virtuser_get_direction_atomic(desc);
 352         if (dir < 0)
 353                 return dir;
 354
 355         snprintf(buf, sizeof(buf), "%s\n", dir ? "input" : "output");
 356
 357         return simple_read_from_buffer(user_buf, size, ppos, buf, strlen(buf));
 358 }
 359
 360 static int gpio_virtuser_set_direction(struct gpio_desc *desc, int dir, int val)
 361 {
 362         if (dir)
 363                 return gpiod_direction_input(desc);
 364
 365         return gpiod_direction_output(desc, val);
 366 }
 367
 368 static void gpio_virtuser_do_set_direction_atomic(struct irq_work *work)
 369 {
 370         struct gpio_virtuser_irq_work_context *ctx =
 371                                 to_gpio_virtuser_irq_work_context(work);
 372
 373         ctx->ret = gpio_virtuser_set_direction(ctx->desc, ctx->dir, ctx->val);
 374         complete(&ctx->work_completion);
 375 }
 376
 377 static int gpio_virtuser_set_direction_atomic(struct gpio_desc *desc,
 378                                               int dir, int val)
 379 {
 380         struct gpio_virtuser_irq_work_context ctx;
 381
 382         gpio_virtuser_init_irq_work_context(&ctx);
 383         ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_do_set_direction_atomic);
 384         ctx.desc = desc;
 385         ctx.dir = dir;
 386         ctx.val = val;
 387
 388         gpio_virtuser_irq_work_queue_sync(&ctx);
 389
 390         return ctx.ret;
 391 }
 392
 393 static ssize_t gpio_virtuser_direction_do_write(struct file *file,
 394                                                 const char __user *user_buf,
 395                                                 size_t count, loff_t *ppos,
 396                                                 bool atomic)
 397 {
 398         struct gpio_virtuser_line_data *data = file->private_data;
 399         struct gpio_desc *desc = data->ad.desc;
 400         char buf[32], *trimmed;
 401         int ret, dir, val = 0;
 402
 403         ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count);
 404         if (ret < 0)
 405                 return ret;
 406
 407         trimmed = strim(buf);
 408
 409         if (strcmp(trimmed, "input") == 0) {
 410                 dir = 1;
 411         } else if (strcmp(trimmed, "output-high") == 0) {
 412                 dir = 0;
 413                 val = 1;
 414         } else if (strcmp(trimmed, "output-low") == 0) {
 415                 dir = val = 0;
 416         } else {
 417                 return -EINVAL;
 418         }
 419
 420         if (!atomic)
 421                 ret = gpio_virtuser_set_direction(desc, dir, val);
 422         else
 423                 ret = gpio_virtuser_set_direction_atomic(desc, dir, val);
 424         if (ret)
 425                 return ret;
 426
 427         return count;
 428 }
 429
 430 static ssize_t gpio_virtuser_direction_read(struct file *file,
 431                                             char __user *user_buf,
 432                                             size_t size, loff_t *ppos)
 433 {
 434         return gpio_virtuser_direction_do_read(file, user_buf, size, ppos,
 435                                                false);
 436 }
 437
 438 static ssize_t gpio_virtuser_direction_write(struct file *file,
 439                                              const char __user *user_buf,
 440                                              size_t count, loff_t *ppos)
 441 {
 442         return gpio_virtuser_direction_do_write(file, user_buf, count, ppos,
 443                                                 false);
 444 }
 445
 446 static const struct file_operations gpio_virtuser_direction_fops = {
 447         .read = gpio_virtuser_direction_read,
 448         .write = gpio_virtuser_direction_write,
 449         .open = simple_open,
 450         .owner = THIS_MODULE,
 451         .llseek = default_llseek,
 452 };
 453
 454 static ssize_t gpio_virtuser_direction_atomic_read(struct file *file,
 455                                                    char __user *user_buf,
 456                                                    size_t size, loff_t *ppos)
 457 {
 458         return gpio_virtuser_direction_do_read(file, user_buf, size, ppos,
 459                                                true);
 460 }
 461
 462 static ssize_t gpio_virtuser_direction_atomic_write(struct file *file,
 463                                                     const char __user *user_buf,
 464                                                     size_t count, loff_t *ppos)
 465 {
 466         return gpio_virtuser_direction_do_write(file, user_buf, count, ppos,
 467                                                 true);
 468 }
 469
 470 static const struct file_operations gpio_virtuser_direction_atomic_fops = {
 471         .read = gpio_virtuser_direction_atomic_read,
 472         .write = gpio_virtuser_direction_atomic_write,
 473         .open = simple_open,
 474         .owner = THIS_MODULE,
 475         .llseek = default_llseek,
 476 };
 477
 478 static int gpio_virtuser_value_get(void *data, u64 *val)
 479 {
 480         struct gpio_virtuser_line_data *ld = data;
 481         int ret;
 482
 483         ret = gpiod_get_value_cansleep(ld->ad.desc);
 484         if (ret < 0)
 485                 return ret;
 486
 487         *val = ret;
 488
 489         return 0;
 490 }
 491
 492 static int gpio_virtuser_value_set(void *data, u64 val)
 493 {
 494         struct gpio_virtuser_line_data *ld = data;
 495
 496         if (val > 1)
 497                 return -EINVAL;
 498
 499         gpiod_set_value_cansleep(ld->ad.desc, (int)val);
 500
 501         return 0;
 502 }
 503
 504 DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_value_fops,
 505                          gpio_virtuser_value_get,
 506                          gpio_virtuser_value_set,
 507                          "%llu\n");
 508
 509 static void gpio_virtuser_get_value_atomic(struct irq_work *work)
 510 {
 511         struct gpio_virtuser_irq_work_context *ctx =
 512                                 to_gpio_virtuser_irq_work_context(work);
 513
 514         ctx->val = gpiod_get_value(ctx->desc);
 515         complete(&ctx->work_completion);
 516 }
 517
 518 static int gpio_virtuser_value_atomic_get(void *data, u64 *val)
 519 {
 520         struct gpio_virtuser_line_data *ld = data;
 521         struct gpio_virtuser_irq_work_context ctx;
 522
 523         gpio_virtuser_init_irq_work_context(&ctx);
 524         ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_get_value_atomic);
 525         ctx.desc = ld->ad.desc;
 526
 527         gpio_virtuser_irq_work_queue_sync(&ctx);
 528
 529         if (ctx.val < 0)
 530                 return ctx.val;
 531
 532         *val = ctx.val;
 533
 534         return 0;
 535 }
 536
 537 static void gpio_virtuser_set_value_atomic(struct irq_work *work)
 538 {
 539         struct gpio_virtuser_irq_work_context *ctx =
 540                         to_gpio_virtuser_irq_work_context(work);
 541
 542         gpiod_set_value(ctx->desc, ctx->val);
 543         complete(&ctx->work_completion);
 544 }
 545
 546 static int gpio_virtuser_value_atomic_set(void *data, u64 val)
 547 {
 548         struct gpio_virtuser_line_data *ld = data;
 549         struct gpio_virtuser_irq_work_context ctx;
 550
 551         if (val > 1)
 552                 return -EINVAL;
 553
 554         gpio_virtuser_init_irq_work_context(&ctx);
 555         ctx.work = IRQ_WORK_INIT_HARD(gpio_virtuser_set_value_atomic);
 556         ctx.desc = ld->ad.desc;
 557         ctx.val = (int)val;
 558
 559         gpio_virtuser_irq_work_queue_sync(&ctx);
 560
 561         return 0;
 562 }
 563
 564 DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_value_atomic_fops,
 565                          gpio_virtuser_value_atomic_get,
 566                          gpio_virtuser_value_atomic_set,
 567                          "%llu\n");
 568
 569 static int gpio_virtuser_debounce_get(void *data, u64 *val)
 570 {
 571         struct gpio_virtuser_line_data *ld = data;
 572
 573         *val = READ_ONCE(ld->debounce);
 574
 575         return 0;
 576 }
 577
 578 static int gpio_virtuser_debounce_set(void *data, u64 val)
 579 {
 580         struct gpio_virtuser_line_data *ld = data;
 581         int ret;
 582
 583         if (val > UINT_MAX)
 584                 return -E2BIG;
 585
 586         ret = gpiod_set_debounce(ld->ad.desc, (unsigned int)val);
 587         if (ret)
 588                 /* Don't propagate errno unknown to user-space. */
 589                 return ret == -ENOTSUPP ? -EOPNOTSUPP : ret;
 590
 591         WRITE_ONCE(ld->debounce, (unsigned int)val);
 592
 593         return 0;
 594 }
 595
 596 DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_debounce_fops,
 597                          gpio_virtuser_debounce_get,
 598                          gpio_virtuser_debounce_set,
 599                          "%llu\n");
 600
 601 static ssize_t gpio_virtuser_consumer_read(struct file *file,
 602                                            char __user *user_buf,
 603                                            size_t size, loff_t *ppos)
 604 {
 605         struct gpio_virtuser_line_data *data = file->private_data;
 606         char buf[GPIO_VIRTUSER_NAME_BUF_LEN + 1];
 607         ssize_t ret;
 608
 609         memset(buf, 0x0, sizeof(buf));
 610
 611         scoped_guard(mutex, &data->consumer_lock)
 612                 ret = snprintf(buf, sizeof(buf), "%s\n", data->consumer);
 613
 614         return simple_read_from_buffer(user_buf, size, ppos, buf, ret);
 615 }
 616
 617 static ssize_t gpio_virtuser_consumer_write(struct file *file,
 618                                             const char __user *user_buf,
 619                                             size_t count, loff_t *ppos)
 620 {
 621         struct gpio_virtuser_line_data *data = file->private_data;
 622         char buf[GPIO_VIRTUSER_NAME_BUF_LEN + 2];
 623         int ret;
 624
 625         ret = simple_write_to_buffer(buf, GPIO_VIRTUSER_NAME_BUF_LEN, ppos,
 626                                      user_buf, count);
 627         if (ret < 0)
 628                 return ret;
 629
 630         buf[strlen(buf) - 1] = '\0';
 631
 632         ret = gpiod_set_consumer_name(data->ad.desc, buf);
 633         if (ret)
 634                 return ret;
 635
 636         scoped_guard(mutex, &data->consumer_lock)
 637                 strscpy(data->consumer, buf, sizeof(data->consumer));
 638
 639         return count;
 640 }
 641
 642 static const struct file_operations gpio_virtuser_consumer_fops = {
 643         .read = gpio_virtuser_consumer_read,
 644         .write = gpio_virtuser_consumer_write,
 645         .open = simple_open,
 646         .owner = THIS_MODULE,
 647         .llseek = default_llseek,
 648 };
 649
 650 static int gpio_virtuser_interrupts_get(void *data, u64 *val)
 651 {
 652         struct gpio_virtuser_line_data *ld = data;
 653
 654         *val = atomic_read(&ld->irq_count);
 655
 656         return 0;
 657 }
 658
 659 static irqreturn_t gpio_virtuser_irq_handler(int irq, void *data)
 660 {
 661         struct gpio_virtuser_line_data *ld = data;
 662
 663         atomic_inc(&ld->irq_count);
 664
 665         return IRQ_HANDLED;
 666 }
 667
 668 static int gpio_virtuser_interrupts_set(void *data, u64 val)
 669 {
 670         struct gpio_virtuser_line_data *ld = data;
 671         int irq, ret;
 672
 673         if (val > 1)
 674                 return -EINVAL;
 675
 676         if (val) {
 677                 irq = gpiod_to_irq(ld->ad.desc);
 678                 if (irq < 0)
 679                         return irq;
 680
 681                 ret = request_threaded_irq(irq, NULL,
 682                                            gpio_virtuser_irq_handler,
 683                                            IRQF_TRIGGER_RISING |
 684                                            IRQF_TRIGGER_FALLING |
 685                                            IRQF_ONESHOT,
 686                                            ld->consumer, data);
 687                 if (ret)
 688                         return ret;
 689
 690                 atomic_set(&ld->irq, irq);
 691         } else {
 692                 irq = atomic_xchg(&ld->irq, 0);
 693                 free_irq(irq, ld);
 694         }
 695
 696         return 0;
 697 }
 698
 699 DEFINE_DEBUGFS_ATTRIBUTE(gpio_virtuser_interrupts_fops,
 700                          gpio_virtuser_interrupts_get,
 701                          gpio_virtuser_interrupts_set,
 702                          "%llu\n");
 703
 704 static const struct gpio_virtuser_dbgfs_attr_descr
 705 gpio_virtuser_line_array_dbgfs_attrs[] = {
 706         {
 707                 .name = "values",
 708                 .fops = &gpio_virtuser_value_array_fops,
 709         },
 710         {
 711                 .name = "values_atomic",
 712                 .fops = &gpio_virtuser_value_array_atomic_fops,
 713         },
 714 };
 715
 716 static const struct gpio_virtuser_dbgfs_attr_descr
 717 gpio_virtuser_line_dbgfs_attrs[] = {
 718         {
 719                 .name = "direction",
 720                 .fops = &gpio_virtuser_direction_fops,
 721         },
 722         {
 723                 .name = "direction_atomic",
 724                 .fops = &gpio_virtuser_direction_atomic_fops,
 725         },
 726         {
 727                 .name = "value",
 728                 .fops = &gpio_virtuser_value_fops,
 729         },
 730         {
 731                 .name = "value_atomic",
 732                 .fops = &gpio_virtuser_value_atomic_fops,
 733         },
 734         {
 735                 .name = "debounce",
 736                 .fops = &gpio_virtuser_debounce_fops,
 737         },
 738         {
 739                 .name = "consumer",
 740                 .fops = &gpio_virtuser_consumer_fops,
 741         },
 742         {
 743                 .name = "interrupts",
 744                 .fops = &gpio_virtuser_interrupts_fops,
 745         },
 746 };
 747
 748 static int gpio_virtuser_create_debugfs_attrs(
 749                         const struct gpio_virtuser_dbgfs_attr_descr *attr,
 750                         size_t num_attrs, struct dentry *parent, void *data)
 751 {
 752         struct dentry *ret;
 753         size_t i;
 754
 755         for (i = 0; i < num_attrs; i++, attr++) {
 756                 ret = debugfs_create_file(attr->name, 0644, parent, data,
 757                                           attr->fops);
 758                 if (IS_ERR(ret))
 759                         return PTR_ERR(ret);
 760         }
 761
 762         return 0;
 763 }
 764
 765 static int gpio_virtuser_dbgfs_init_line_array_attrs(struct device *dev,
 766                                                      struct gpio_descs *descs,
 767                                                      const char *id,
 768                                                      struct dentry *dbgfs_entry)
 769 {
 770         struct gpio_virtuser_line_array_data *data;
 771         char *name;
 772
 773         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 774         if (!data)
 775                 return -ENOMEM;
 776
 777         data->ad.descs = descs;
 778
 779         name = devm_kasprintf(dev, GFP_KERNEL, "gpiod:%s", id);
 780         if (!name)
 781                 return -ENOMEM;
 782
 783         data->ad.dbgfs_dir = debugfs_create_dir(name, dbgfs_entry);
 784         if (IS_ERR(data->ad.dbgfs_dir))
 785                 return PTR_ERR(data->ad.dbgfs_dir);
 786
 787         return gpio_virtuser_create_debugfs_attrs(
 788                         gpio_virtuser_line_array_dbgfs_attrs,
 789                         ARRAY_SIZE(gpio_virtuser_line_array_dbgfs_attrs),
 790                         data->ad.dbgfs_dir, data);
 791 }
 792
 793 static int gpio_virtuser_dbgfs_init_line_attrs(struct device *dev,
 794                                                struct gpio_desc *desc,
 795                                                const char *id,
 796                                                unsigned int index,
 797                                                struct dentry *dbgfs_entry)
 798 {
 799         struct gpio_virtuser_line_data *data;
 800         char *name;
 801         int ret;
 802
 803         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 804         if (!data)
 805                 return -ENOMEM;
 806
 807         data->ad.desc = desc;
 808         strscpy(data->consumer, id);
 809         atomic_set(&data->irq, 0);
 810         atomic_set(&data->irq_count, 0);
 811
 812         name = devm_kasprintf(dev, GFP_KERNEL, "gpiod:%s:%u", id, index);
 813         if (!name)
 814                 return -ENOMEM;
 815
 816         ret = devm_mutex_init(dev, &data->consumer_lock);
 817         if (ret)
 818                 return ret;
 819
 820         data->ad.dbgfs_dir = debugfs_create_dir(name, dbgfs_entry);
 821         if (IS_ERR(data->ad.dbgfs_dir))
 822                 return PTR_ERR(data->ad.dbgfs_dir);
 823
 824         return gpio_virtuser_create_debugfs_attrs(
 825                                 gpio_virtuser_line_dbgfs_attrs,
 826                                 ARRAY_SIZE(gpio_virtuser_line_dbgfs_attrs),
 827                                 data->ad.dbgfs_dir, data);
 828 }
 829
 830 static void gpio_virtuser_debugfs_remove(void *data)
 831 {
 832         struct dentry *dbgfs_entry = data;
 833
 834         debugfs_remove_recursive(dbgfs_entry);
 835 }
 836
 837 static int gpio_virtuser_prop_is_gpio(struct property *prop)
 838 {
 839         char *dash = strrchr(prop->name, '-');
 840
 841         return dash && strcmp(dash, "-gpios") == 0;
 842 }
 843
 844 /*
 845  * If this is an OF-based system, then we iterate over properties and consider
 846  * all whose names end in "-gpios". For configfs we expect an additional string
 847  * array property - "gpio-virtuser,ids" - containing the list of all GPIO IDs
 848  * to request.
 849  */
 850 static int gpio_virtuser_count_ids(struct device *dev)
 851 {
 852         struct device_node *of_node = dev_of_node(dev);
 853         struct property *prop;
 854         int ret = 0;
 855
 856         if (!of_node)
 857                 return device_property_string_array_count(dev,
 858                                                           "gpio-virtuser,ids");
 859
 860         for_each_property_of_node(of_node, prop) {
 861                 if (gpio_virtuser_prop_is_gpio(prop))
 862                         ++ret;
 863         }
 864
 865         return ret;
 866 }
 867
 868 static int gpio_virtuser_get_ids(struct device *dev, const char **ids,
 869                                  int num_ids)
 870 {
 871         struct device_node *of_node = dev_of_node(dev);
 872         struct property *prop;
 873         size_t pos = 0, diff;
 874         char *dash, *tmp;
 875
 876         if (!of_node)
 877                 return device_property_read_string_array(dev,
 878                                                          "gpio-virtuser,ids",
 879                                                          ids, num_ids);
 880
 881         for_each_property_of_node(of_node, prop) {
 882                 if (!gpio_virtuser_prop_is_gpio(prop))
 883                         continue;
 884
 885                 dash = strrchr(prop->name, '-');
 886                 diff = dash - prop->name;
 887
 888                 tmp = devm_kmemdup(dev, prop->name, diff + 1,
 889                                    GFP_KERNEL);
 890                 if (!tmp)
 891                         return -ENOMEM;
 892
 893                 tmp[diff] = '\0';
 894                 ids[pos++] = tmp;
 895         }
 896
 897         return 0;
 898 }
 899
 900 static int gpio_virtuser_probe(struct platform_device *pdev)
 901 {
 902         struct device *dev = &pdev->dev;
 903         struct dentry *dbgfs_entry;
 904         struct gpio_descs *descs;
 905         int ret, num_ids = 0, i;
 906         const char **ids;
 907         unsigned int j;
 908
 909         num_ids = gpio_virtuser_count_ids(dev);
 910         if (num_ids < 0)
 911                 return dev_err_probe(dev, num_ids,
 912                                      "Failed to get the number of GPIOs to request\n");
 913
 914         if (num_ids == 0)
 915                 return dev_err_probe(dev, -EINVAL, "No GPIO IDs specified\n");
 916
 917         ids = devm_kcalloc(dev, num_ids, sizeof(*ids), GFP_KERNEL);
 918         if (!ids)
 919                 return -ENOMEM;
 920
 921         ret = gpio_virtuser_get_ids(dev, ids, num_ids);
 922         if (ret < 0)
 923                 return dev_err_probe(dev, ret,
 924                                      "Failed to get the IDs of GPIOs to request\n");
 925
 926         dbgfs_entry = debugfs_create_dir(dev_name(dev), gpio_virtuser_dbg_root);
 927         ret = devm_add_action_or_reset(dev, gpio_virtuser_debugfs_remove,
 928                                        dbgfs_entry);
 929         if (ret)
 930                 return ret;
 931
 932         for (i = 0; i < num_ids; i++) {
 933                 descs = devm_gpiod_get_array(dev, ids[i], GPIOD_ASIS);
 934                 if (IS_ERR(descs))
 935                         return dev_err_probe(dev, PTR_ERR(descs),
 936                                              "Failed to request the '%s' GPIOs\n",
 937                                              ids[i]);
 938
 939                 ret = gpio_virtuser_dbgfs_init_line_array_attrs(dev, descs,
 940                                                                 ids[i],
 941                                                                 dbgfs_entry);
 942                 if (ret)
 943                         return dev_err_probe(dev, ret,
 944                                              "Failed to setup the debugfs array interface for the '%s' GPIOs\n",
 945                                              ids[i]);
 946
 947                 for (j = 0; j < descs->ndescs; j++) {
 948                         ret = gpio_virtuser_dbgfs_init_line_attrs(dev,
 949                                                         descs->desc[j], ids[i],
 950                                                         j, dbgfs_entry);
 951                         if (ret)
 952                                 return dev_err_probe(dev, ret,
 953                                                      "Failed to setup the debugfs line interface for the '%s' GPIOs\n",
 954                                                      ids[i]);
 955                 }
 956         }
 957
 958         return 0;
 959 }
 960
 961 static const struct of_device_id gpio_virtuser_of_match[] = {
 962         { .compatible = "gpio-virtuser" },
 963         { }
 964 };
 965 MODULE_DEVICE_TABLE(of, gpio_virtuser_of_match);
 966
 967 static struct platform_driver gpio_virtuser_driver = {
 968         .driver = {
 969                 .name = "gpio-virtuser",
 970                 .of_match_table = gpio_virtuser_of_match,
 971         },
 972         .probe = gpio_virtuser_probe,
 973 };
 974
 975 struct gpio_virtuser_device {
 976         struct config_group group;
 977
 978         struct platform_device *pdev;
 979         int id;
 980         struct mutex lock;
 981
 982         struct notifier_block bus_notifier;
 983         struct completion probe_completion;
 984         bool driver_bound;
 985
 986         struct gpiod_lookup_table *lookup_table;
 987
 988         struct list_head lookup_list;
 989 };
 990
 991 static int gpio_virtuser_bus_notifier_call(struct notifier_block *nb,
 992                                            unsigned long action, void *data)
 993 {
 994         struct gpio_virtuser_device *vdev;
 995         struct device *dev = data;
 996         char devname[32];
 997
 998         vdev = container_of(nb, struct gpio_virtuser_device, bus_notifier);
 999         snprintf(devname, sizeof(devname), "gpio-virtuser.%d", vdev->id);
1000
1001         if (!device_match_name(dev, devname))
1002                 return NOTIFY_DONE;
1003
1004         switch (action) {
1005         case BUS_NOTIFY_BOUND_DRIVER:
1006                 vdev->driver_bound = true;
1007                 break;
1008         case BUS_NOTIFY_DRIVER_NOT_BOUND:
1009                 vdev->driver_bound = false;
1010                 break;
1011         default:
1012                 return NOTIFY_DONE;
1013         }
1014
1015         complete(&vdev->probe_completion);
1016         return NOTIFY_OK;
1017 }
1018
1019 static struct gpio_virtuser_device *
1020 to_gpio_virtuser_device(struct config_item *item)
1021 {
1022         struct config_group *group = to_config_group(item);
1023
1024         return container_of(group, struct gpio_virtuser_device, group);
1025 }
1026
1027 static bool
1028 gpio_virtuser_device_is_live(struct gpio_virtuser_device *dev)
1029 {
1030         lockdep_assert_held(&dev->lock);
1031
1032         return !!dev->pdev;
1033 }
1034
1035 struct gpio_virtuser_lookup {
1036         struct config_group group;
1037
1038         struct gpio_virtuser_device *parent;
1039         struct list_head siblings;
1040
1041         char *con_id;
1042
1043         struct list_head entry_list;
1044 };
1045
1046 static struct gpio_virtuser_lookup *
1047 to_gpio_virtuser_lookup(struct config_item *item)
1048 {
1049         struct config_group *group = to_config_group(item);
1050
1051         return container_of(group, struct gpio_virtuser_lookup, group);
1052 }
1053
1054 struct gpio_virtuser_lookup_entry {
1055         struct config_group group;
1056
1057         struct gpio_virtuser_lookup *parent;
1058         struct list_head siblings;
1059
1060         char *key;
1061         /* Can be negative to indicate lookup by name. */
1062         int offset;
1063         enum gpio_lookup_flags flags;
1064 };
1065
1066 static struct gpio_virtuser_lookup_entry *
1067 to_gpio_virtuser_lookup_entry(struct config_item *item)
1068 {
1069         struct config_group *group = to_config_group(item);
1070
1071         return container_of(group, struct gpio_virtuser_lookup_entry, group);
1072 }
1073
1074 static ssize_t
1075 gpio_virtuser_lookup_entry_config_key_show(struct config_item *item, char *page)
1076 {
1077         struct gpio_virtuser_lookup_entry *entry =
1078                                         to_gpio_virtuser_lookup_entry(item);
1079         struct gpio_virtuser_device *dev = entry->parent->parent;
1080
1081         guard(mutex)(&dev->lock);
1082
1083         return sprintf(page, "%s\n", entry->key ?: "");
1084 }
1085
1086 static ssize_t
1087 gpio_virtuser_lookup_entry_config_key_store(struct config_item *item,
1088                                             const char *page, size_t count)
1089 {
1090         struct gpio_virtuser_lookup_entry *entry =
1091                                         to_gpio_virtuser_lookup_entry(item);
1092         struct gpio_virtuser_device *dev = entry->parent->parent;
1093
1094         char *key __free(kfree) = kstrndup(skip_spaces(page), count,
1095                                            GFP_KERNEL);
1096         if (!key)
1097                 return -ENOMEM;
1098
1099         strim(key);
1100
1101         guard(mutex)(&dev->lock);
1102
1103         if (gpio_virtuser_device_is_live(dev))
1104                 return -EBUSY;
1105
1106         kfree(entry->key);
1107         entry->key = no_free_ptr(key);
1108
1109         return count;
1110 }
1111
1112 CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, key);
1113
1114 static ssize_t
1115 gpio_virtuser_lookup_entry_config_offset_show(struct config_item *item,
1116                                               char *page)
1117 {
1118         struct gpio_virtuser_lookup_entry *entry =
1119                                         to_gpio_virtuser_lookup_entry(item);
1120         struct gpio_virtuser_device *dev = entry->parent->parent;
1121         unsigned int offset;
1122
1123         scoped_guard(mutex, &dev->lock)
1124                 offset = entry->offset;
1125
1126         return sprintf(page, "%d\n", offset);
1127 }
1128
1129 static ssize_t
1130 gpio_virtuser_lookup_entry_config_offset_store(struct config_item *item,
1131                                                const char *page, size_t count)
1132 {
1133         struct gpio_virtuser_lookup_entry *entry =
1134                                         to_gpio_virtuser_lookup_entry(item);
1135         struct gpio_virtuser_device *dev = entry->parent->parent;
1136         int offset, ret;
1137
1138         ret = kstrtoint(page, 0, &offset);
1139         if (ret)
1140                 return ret;
1141
1142         /*
1143          * Negative number here means: 'key' represents a line name to lookup.
1144          * Non-negative means: 'key' represents the label of the chip with
1145          * the 'offset' value representing the line within that chip.
1146          *
1147          * GPIOLIB uses the U16_MAX value to indicate lookup by line name so
1148          * the greatest offset we can accept is (U16_MAX - 1).
1149          */
1150         if (offset > (U16_MAX - 1))
1151                 return -EINVAL;
1152
1153         guard(mutex)(&dev->lock);
1154
1155         if (gpio_virtuser_device_is_live(dev))
1156                 return -EBUSY;
1157
1158         entry->offset = offset;
1159
1160         return count;
1161 }
1162
1163 CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, offset);
1164
1165 static enum gpio_lookup_flags
1166 gpio_virtuser_lookup_get_flags(struct config_item *item)
1167 {
1168         struct gpio_virtuser_lookup_entry *entry =
1169                                         to_gpio_virtuser_lookup_entry(item);
1170         struct gpio_virtuser_device *dev = entry->parent->parent;
1171
1172         guard(mutex)(&dev->lock);
1173
1174         return entry->flags;
1175 }
1176
1177 static ssize_t
1178 gpio_virtuser_lookup_entry_config_drive_show(struct config_item *item, char *page)
1179 {
1180         enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item);
1181         const char *repr;
1182
1183         if (flags & GPIO_OPEN_DRAIN)
1184                 repr = "open-drain";
1185         else if (flags & GPIO_OPEN_SOURCE)
1186                 repr = "open-source";
1187         else
1188                 repr = "push-pull";
1189
1190         return sprintf(page, "%s\n", repr);
1191 }
1192
1193 static ssize_t
1194 gpio_virtuser_lookup_entry_config_drive_store(struct config_item *item,
1195                                               const char *page, size_t count)
1196 {
1197         struct gpio_virtuser_lookup_entry *entry =
1198                                         to_gpio_virtuser_lookup_entry(item);
1199         struct gpio_virtuser_device *dev = entry->parent->parent;
1200
1201         guard(mutex)(&dev->lock);
1202
1203         if (gpio_virtuser_device_is_live(dev))
1204                 return -EBUSY;
1205
1206         if (sysfs_streq(page, "push-pull")) {
1207                 entry->flags &= ~(GPIO_OPEN_DRAIN | GPIO_OPEN_SOURCE);
1208         } else if (sysfs_streq(page, "open-drain")) {
1209                 entry->flags &= ~GPIO_OPEN_SOURCE;
1210                 entry->flags |= GPIO_OPEN_DRAIN;
1211         } else if (sysfs_streq(page, "open-source")) {
1212                 entry->flags &= ~GPIO_OPEN_DRAIN;
1213                 entry->flags |= GPIO_OPEN_SOURCE;
1214         } else {
1215                 count = -EINVAL;
1216         }
1217
1218         return count;
1219 }
1220
1221 CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, drive);
1222
1223 static ssize_t
1224 gpio_virtuser_lookup_entry_config_pull_show(struct config_item *item, char *page)
1225 {
1226         enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item);
1227         const char *repr;
1228
1229         if (flags & GPIO_PULL_UP)
1230                 repr = "pull-up";
1231         else if (flags & GPIO_PULL_DOWN)
1232                 repr = "pull-down";
1233         else if (flags & GPIO_PULL_DISABLE)
1234                 repr = "pull-disabled";
1235         else
1236                 repr = "as-is";
1237
1238         return sprintf(page, "%s\n", repr);
1239 }
1240
1241 static ssize_t
1242 gpio_virtuser_lookup_entry_config_pull_store(struct config_item *item,
1243                                              const char *page, size_t count)
1244 {
1245         struct gpio_virtuser_lookup_entry *entry =
1246                                         to_gpio_virtuser_lookup_entry(item);
1247         struct gpio_virtuser_device *dev = entry->parent->parent;
1248
1249         guard(mutex)(&dev->lock);
1250
1251         if (gpio_virtuser_device_is_live(dev))
1252                 return -EBUSY;
1253
1254         if (sysfs_streq(page, "pull-up")) {
1255                 entry->flags &= ~(GPIO_PULL_DOWN | GPIO_PULL_DISABLE);
1256                 entry->flags |= GPIO_PULL_UP;
1257         } else if (sysfs_streq(page, "pull-down")) {
1258                 entry->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DISABLE);
1259                 entry->flags |= GPIO_PULL_DOWN;
1260         } else if (sysfs_streq(page, "pull-disabled")) {
1261                 entry->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DOWN);
1262                 entry->flags |= GPIO_PULL_DISABLE;
1263         } else if (sysfs_streq(page, "as-is")) {
1264                 entry->flags &= ~(GPIO_PULL_UP | GPIO_PULL_DOWN |
1265                                   GPIO_PULL_DISABLE);
1266         } else {
1267                 count = -EINVAL;
1268         }
1269
1270         return count;
1271 }
1272
1273 CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, pull);
1274
1275 static ssize_t
1276 gpio_virtuser_lookup_entry_config_active_low_show(struct config_item *item,
1277                                                   char *page)
1278 {
1279         enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item);
1280
1281         return sprintf(page, "%c\n", flags & GPIO_ACTIVE_LOW ? '1' : '0');
1282 }
1283
1284 static ssize_t
1285 gpio_virtuser_lookup_entry_config_active_low_store(struct config_item *item,
1286                                                    const char *page,
1287                                                    size_t count)
1288 {
1289         struct gpio_virtuser_lookup_entry *entry =
1290                                         to_gpio_virtuser_lookup_entry(item);
1291         struct gpio_virtuser_device *dev = entry->parent->parent;
1292         bool active_low;
1293         int ret;
1294
1295         ret = kstrtobool(page, &active_low);
1296         if (ret)
1297                 return ret;
1298
1299         guard(mutex)(&dev->lock);
1300
1301         if (gpio_virtuser_device_is_live(dev))
1302                 return -EBUSY;
1303
1304         if (active_low)
1305                 entry->flags |= GPIO_ACTIVE_LOW;
1306         else
1307                 entry->flags &= ~GPIO_ACTIVE_LOW;
1308
1309         return count;
1310 }
1311
1312 CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, active_low);
1313
1314 static ssize_t
1315 gpio_virtuser_lookup_entry_config_transitory_show(struct config_item *item,
1316                                                   char *page)
1317 {
1318         enum gpio_lookup_flags flags = gpio_virtuser_lookup_get_flags(item);
1319
1320         return sprintf(page, "%c\n", flags & GPIO_TRANSITORY ? '1' : '0');
1321 }
1322
1323 static ssize_t
1324 gpio_virtuser_lookup_entry_config_transitory_store(struct config_item *item,
1325                                                    const char *page,
1326                                                    size_t count)
1327 {
1328         struct gpio_virtuser_lookup_entry *entry =
1329                                         to_gpio_virtuser_lookup_entry(item);
1330         struct gpio_virtuser_device *dev = entry->parent->parent;
1331         bool transitory;
1332         int ret;
1333
1334         ret = kstrtobool(page, &transitory);
1335         if (ret)
1336                 return ret;
1337
1338         guard(mutex)(&dev->lock);
1339
1340         if (gpio_virtuser_device_is_live(dev))
1341                 return -EBUSY;
1342
1343         if (transitory)
1344                 entry->flags |= GPIO_TRANSITORY;
1345         else
1346                 entry->flags &= ~GPIO_TRANSITORY;
1347
1348         return count;
1349 }
1350
1351 CONFIGFS_ATTR(gpio_virtuser_lookup_entry_config_, transitory);
1352
1353 static struct configfs_attribute *gpio_virtuser_lookup_entry_config_attrs[] = {
1354         &gpio_virtuser_lookup_entry_config_attr_key,
1355         &gpio_virtuser_lookup_entry_config_attr_offset,
1356         &gpio_virtuser_lookup_entry_config_attr_drive,
1357         &gpio_virtuser_lookup_entry_config_attr_pull,
1358         &gpio_virtuser_lookup_entry_config_attr_active_low,
1359         &gpio_virtuser_lookup_entry_config_attr_transitory,
1360         NULL
1361 };
1362
1363 static ssize_t
1364 gpio_virtuser_device_config_dev_name_show(struct config_item *item,
1365                                           char *page)
1366 {
1367         struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
1368         struct platform_device *pdev;
1369
1370         guard(mutex)(&dev->lock);
1371
1372         pdev = dev->pdev;
1373         if (pdev)
1374                 return sprintf(page, "%s\n", dev_name(&pdev->dev));
1375
1376         return sprintf(page, "gpio-sim.%d\n", dev->id);
1377 }
1378
1379 CONFIGFS_ATTR_RO(gpio_virtuser_device_config_, dev_name);
1380
1381 static ssize_t gpio_virtuser_device_config_live_show(struct config_item *item,
1382                                                      char *page)
1383 {
1384         struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
1385         bool live;
1386
1387         scoped_guard(mutex, &dev->lock)
1388                 live = gpio_virtuser_device_is_live(dev);
1389
1390         return sprintf(page, "%c\n", live ? '1' : '0');
1391 }
1392
1393 static size_t
1394 gpio_virtuser_get_lookup_count(struct gpio_virtuser_device *dev)
1395 {
1396         struct gpio_virtuser_lookup *lookup;
1397         size_t count = 0;
1398
1399         lockdep_assert_held(&dev->lock);
1400
1401         list_for_each_entry(lookup, &dev->lookup_list, siblings)
1402                 count += list_count_nodes(&lookup->entry_list);
1403
1404         return count;
1405 }
1406
1407 static int
1408 gpio_virtuser_make_lookup_table(struct gpio_virtuser_device *dev)
1409 {
1410         size_t num_entries = gpio_virtuser_get_lookup_count(dev);
1411         struct gpio_virtuser_lookup_entry *entry;
1412         struct gpio_virtuser_lookup *lookup;
1413         unsigned int i = 0;
1414
1415         lockdep_assert_held(&dev->lock);
1416
1417         struct gpiod_lookup_table *table __free(kfree) =
1418                 kzalloc(struct_size(table, table, num_entries + 1), GFP_KERNEL);
1419         if (!table)
1420                 return -ENOMEM;
1421
1422         table->dev_id = kasprintf(GFP_KERNEL, "gpio-virtuser.%d", dev->id);
1423         if (!table->dev_id)
1424                 return -ENOMEM;
1425
1426         list_for_each_entry(lookup, &dev->lookup_list, siblings) {
1427                 list_for_each_entry(entry, &lookup->entry_list, siblings) {
1428                         table->table[i] =
1429                                 GPIO_LOOKUP_IDX(entry->key,
1430                                                 entry->offset < 0 ? U16_MAX : entry->offset,
1431                                                 lookup->con_id, i, entry->flags);
1432                         i++;
1433                 }
1434         }
1435
1436         gpiod_add_lookup_table(table);
1437         dev->lookup_table = no_free_ptr(table);
1438
1439         return 0;
1440 }
1441
1442 static struct fwnode_handle *
1443 gpio_virtuser_make_device_swnode(struct gpio_virtuser_device *dev)
1444 {
1445         struct property_entry properties[2];
1446         struct gpio_virtuser_lookup *lookup;
1447         unsigned int i = 0;
1448         size_t num_ids;
1449
1450         memset(properties, 0, sizeof(properties));
1451
1452         num_ids = list_count_nodes(&dev->lookup_list);
1453         char **ids __free(kfree) = kcalloc(num_ids + 1, sizeof(*ids),
1454                                            GFP_KERNEL);
1455         if (!ids)
1456                 return ERR_PTR(-ENOMEM);
1457
1458         list_for_each_entry(lookup, &dev->lookup_list, siblings)
1459                 ids[i++] = lookup->con_id;
1460
1461         properties[0] = PROPERTY_ENTRY_STRING_ARRAY_LEN("gpio-virtuser,ids",
1462                                                         ids, num_ids);
1463
1464         return fwnode_create_software_node(properties, NULL);
1465 }
1466
1467 static int
1468 gpio_virtuser_device_activate(struct gpio_virtuser_device *dev)
1469 {
1470         struct platform_device_info pdevinfo;
1471         struct fwnode_handle *swnode;
1472         struct platform_device *pdev;
1473         int ret;
1474
1475         lockdep_assert_held(&dev->lock);
1476
1477         if (list_empty(&dev->lookup_list))
1478                 return -ENODATA;
1479
1480         swnode = gpio_virtuser_make_device_swnode(dev);
1481         if (IS_ERR(swnode))
1482                 return PTR_ERR(swnode);
1483
1484         memset(&pdevinfo, 0, sizeof(pdevinfo));
1485         pdevinfo.name = "gpio-virtuser";
1486         pdevinfo.id = dev->id;
1487         pdevinfo.fwnode = swnode;
1488
1489         ret = gpio_virtuser_make_lookup_table(dev);
1490         if (ret) {
1491                 fwnode_remove_software_node(swnode);
1492                 return ret;
1493         }
1494
1495         reinit_completion(&dev->probe_completion);
1496         dev->driver_bound = false;
1497         bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
1498
1499         pdev = platform_device_register_full(&pdevinfo);
1500         if (IS_ERR(pdev)) {
1501                 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
1502                 fwnode_remove_software_node(swnode);
1503                 return PTR_ERR(pdev);
1504         }
1505
1506         wait_for_completion(&dev->probe_completion);
1507         bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
1508
1509         if (!dev->driver_bound) {
1510                 platform_device_unregister(pdev);
1511                 fwnode_remove_software_node(swnode);
1512                 return -ENXIO;
1513         }
1514
1515         dev->pdev = pdev;
1516
1517         return 0;
1518 }
1519
1520 static void
1521 gpio_virtuser_device_deactivate(struct gpio_virtuser_device *dev)
1522 {
1523         struct fwnode_handle *swnode;
1524
1525         lockdep_assert_held(&dev->lock);
1526
1527         swnode = dev_fwnode(&dev->pdev->dev);
1528         platform_device_unregister(dev->pdev);
1529         fwnode_remove_software_node(swnode);
1530         dev->pdev = NULL;
1531         gpiod_remove_lookup_table(dev->lookup_table);
1532         kfree(dev->lookup_table);
1533 }
1534
1535 static ssize_t
1536 gpio_virtuser_device_config_live_store(struct config_item *item,
1537                                        const char *page, size_t count)
1538 {
1539         struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
1540         int ret = 0;
1541         bool live;
1542
1543         ret = kstrtobool(page, &live);
1544         if (ret)
1545                 return ret;
1546
1547         guard(mutex)(&dev->lock);
1548
1549         if (live == gpio_virtuser_device_is_live(dev))
1550                 return -EPERM;
1551
1552         if (live)
1553                 ret = gpio_virtuser_device_activate(dev);
1554         else
1555                 gpio_virtuser_device_deactivate(dev);
1556
1557         return ret ?: count;
1558 }
1559
1560 CONFIGFS_ATTR(gpio_virtuser_device_config_, live);
1561
1562 static struct configfs_attribute *gpio_virtuser_device_config_attrs[] = {
1563         &gpio_virtuser_device_config_attr_dev_name,
1564         &gpio_virtuser_device_config_attr_live,
1565         NULL
1566 };
1567
1568 static void
1569 gpio_virtuser_lookup_entry_config_group_release(struct config_item *item)
1570 {
1571         struct gpio_virtuser_lookup_entry *entry =
1572                                         to_gpio_virtuser_lookup_entry(item);
1573         struct gpio_virtuser_device *dev = entry->parent->parent;
1574
1575         guard(mutex)(&dev->lock);
1576
1577         list_del(&entry->siblings);
1578
1579         kfree(entry->key);
1580         kfree(entry);
1581 }
1582
1583 static struct
1584 configfs_item_operations gpio_virtuser_lookup_entry_config_item_ops = {
1585         .release        = gpio_virtuser_lookup_entry_config_group_release,
1586 };
1587
1588 static const struct
1589 config_item_type gpio_virtuser_lookup_entry_config_group_type = {
1590         .ct_item_ops    = &gpio_virtuser_lookup_entry_config_item_ops,
1591         .ct_attrs       = gpio_virtuser_lookup_entry_config_attrs,
1592         .ct_owner       = THIS_MODULE,
1593 };
1594
1595 static struct config_group *
1596 gpio_virtuser_make_lookup_entry_group(struct config_group *group,
1597                                       const char *name)
1598 {
1599         struct gpio_virtuser_lookup *lookup =
1600                                 to_gpio_virtuser_lookup(&group->cg_item);
1601         struct gpio_virtuser_device *dev = lookup->parent;
1602
1603         guard(mutex)(&dev->lock);
1604
1605         if (gpio_virtuser_device_is_live(dev))
1606                 return ERR_PTR(-EBUSY);
1607
1608         struct gpio_virtuser_lookup_entry *entry __free(kfree) =
1609                                 kzalloc(sizeof(*entry), GFP_KERNEL);
1610         if (!entry)
1611                 return ERR_PTR(-ENOMEM);
1612
1613         config_group_init_type_name(&entry->group, name,
1614                         &gpio_virtuser_lookup_entry_config_group_type);
1615         entry->flags = GPIO_LOOKUP_FLAGS_DEFAULT;
1616         entry->parent = lookup;
1617         list_add_tail(&entry->siblings, &lookup->entry_list);
1618
1619         return &no_free_ptr(entry)->group;
1620 }
1621
1622 static void gpio_virtuser_lookup_config_group_release(struct config_item *item)
1623 {
1624         struct gpio_virtuser_lookup *lookup = to_gpio_virtuser_lookup(item);
1625         struct gpio_virtuser_device *dev = lookup->parent;
1626
1627         guard(mutex)(&dev->lock);
1628
1629         list_del(&lookup->siblings);
1630
1631         kfree(lookup->con_id);
1632         kfree(lookup);
1633 }
1634
1635 static struct configfs_item_operations gpio_virtuser_lookup_config_item_ops = {
1636         .release        = gpio_virtuser_lookup_config_group_release,
1637 };
1638
1639 static struct
1640 configfs_group_operations gpio_virtuser_lookup_config_group_ops = {
1641         .make_group     = gpio_virtuser_make_lookup_entry_group,
1642 };
1643
1644 static const struct config_item_type gpio_virtuser_lookup_config_group_type = {
1645         .ct_group_ops   = &gpio_virtuser_lookup_config_group_ops,
1646         .ct_item_ops    = &gpio_virtuser_lookup_config_item_ops,
1647         .ct_owner       = THIS_MODULE,
1648 };
1649
1650 static struct config_group *
1651 gpio_virtuser_make_lookup_group(struct config_group *group, const char *name)
1652 {
1653         struct gpio_virtuser_device *dev =
1654                                 to_gpio_virtuser_device(&group->cg_item);
1655
1656         if (strlen(name) > (GPIO_VIRTUSER_NAME_BUF_LEN - 1))
1657                 return ERR_PTR(-E2BIG);
1658
1659         guard(mutex)(&dev->lock);
1660
1661         if (gpio_virtuser_device_is_live(dev))
1662                 return ERR_PTR(-EBUSY);
1663
1664         struct gpio_virtuser_lookup *lookup __free(kfree) =
1665                                 kzalloc(sizeof(*lookup), GFP_KERNEL);
1666         if (!lookup)
1667                 return ERR_PTR(-ENOMEM);
1668
1669         lookup->con_id = kstrdup(name, GFP_KERNEL);
1670         if (!lookup->con_id)
1671                 return ERR_PTR(-ENOMEM);
1672
1673         config_group_init_type_name(&lookup->group, name,
1674                                     &gpio_virtuser_lookup_config_group_type);
1675         INIT_LIST_HEAD(&lookup->entry_list);
1676         lookup->parent = dev;
1677         list_add_tail(&lookup->siblings, &dev->lookup_list);
1678
1679         return &no_free_ptr(lookup)->group;
1680 }
1681
1682 static void gpio_virtuser_device_config_group_release(struct config_item *item)
1683 {
1684         struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);
1685
1686         guard(mutex)(&dev->lock);
1687
1688         if (gpio_virtuser_device_is_live(dev))
1689                 gpio_virtuser_device_deactivate(dev);
1690
1691         mutex_destroy(&dev->lock);
1692         ida_free(&gpio_virtuser_ida, dev->id);
1693         kfree(dev);
1694 }
1695
1696 static struct configfs_item_operations gpio_virtuser_device_config_item_ops = {
1697         .release        = gpio_virtuser_device_config_group_release,
1698 };
1699
1700 static struct configfs_group_operations gpio_virtuser_device_config_group_ops = {
1701         .make_group     = gpio_virtuser_make_lookup_group,
1702 };
1703
1704 static const struct config_item_type gpio_virtuser_device_config_group_type = {
1705         .ct_group_ops   = &gpio_virtuser_device_config_group_ops,
1706         .ct_item_ops    = &gpio_virtuser_device_config_item_ops,
1707         .ct_attrs       = gpio_virtuser_device_config_attrs,
1708         .ct_owner       = THIS_MODULE,
1709 };
1710
1711 static struct config_group *
1712 gpio_virtuser_config_make_device_group(struct config_group *group,
1713                                        const char *name)
1714 {
1715         struct gpio_virtuser_device *dev __free(kfree) = kzalloc(sizeof(*dev),
1716                                                                  GFP_KERNEL);
1717         if (!dev)
1718                 return ERR_PTR(-ENOMEM);
1719
1720         dev->id = ida_alloc(&gpio_virtuser_ida, GFP_KERNEL);
1721         if (dev->id < 0)
1722                 return ERR_PTR(dev->id);
1723
1724         config_group_init_type_name(&dev->group, name,
1725                                     &gpio_virtuser_device_config_group_type);
1726         mutex_init(&dev->lock);
1727         INIT_LIST_HEAD(&dev->lookup_list);
1728         dev->bus_notifier.notifier_call = gpio_virtuser_bus_notifier_call;
1729         init_completion(&dev->probe_completion);
1730
1731         return &no_free_ptr(dev)->group;
1732 }
1733
1734 static struct configfs_group_operations gpio_virtuser_config_group_ops = {
1735         .make_group     = gpio_virtuser_config_make_device_group,
1736 };
1737
1738 static const struct config_item_type gpio_virtuser_config_type = {
1739         .ct_group_ops   = &gpio_virtuser_config_group_ops,
1740         .ct_owner       = THIS_MODULE,
1741 };
1742
1743 static struct configfs_subsystem gpio_virtuser_config_subsys = {
1744         .su_group = {
1745                 .cg_item = {
1746                         .ci_namebuf     = "gpio-virtuser",
1747                         .ci_type        = &gpio_virtuser_config_type,
1748                 },
1749         },
1750 };
1751
1752 static int __init gpio_virtuser_init(void)
1753 {
1754         int ret;
1755
1756         ret = platform_driver_register(&gpio_virtuser_driver);
1757         if (ret) {
1758                 pr_err("Failed to register the platform driver: %d\n", ret);
1759                 return ret;
1760         }
1761
1762         config_group_init(&gpio_virtuser_config_subsys.su_group);
1763         mutex_init(&gpio_virtuser_config_subsys.su_mutex);
1764         ret = configfs_register_subsystem(&gpio_virtuser_config_subsys);
1765         if (ret) {
1766                 pr_err("Failed to register the '%s' configfs subsystem: %d\n",
1767                        gpio_virtuser_config_subsys.su_group.cg_item.ci_namebuf,
1768                        ret);
1769                 goto err_plat_drv_unreg;
1770         }
1771
1772         gpio_virtuser_dbg_root = debugfs_create_dir("gpio-virtuser", NULL);
1773         if (IS_ERR(gpio_virtuser_dbg_root)) {
1774                 ret = PTR_ERR(gpio_virtuser_dbg_root);
1775                 pr_err("Failed to create the debugfs tree: %d\n", ret);
1776                 goto err_configfs_unreg;
1777         }
1778
1779         return 0;
1780
1781 err_configfs_unreg:
1782         configfs_unregister_subsystem(&gpio_virtuser_config_subsys);
1783 err_plat_drv_unreg:
1784         mutex_destroy(&gpio_virtuser_config_subsys.su_mutex);
1785         platform_driver_unregister(&gpio_virtuser_driver);
1786
1787         return ret;
1788 }
1789 module_init(gpio_virtuser_init);
1790
1791 static void __exit gpio_virtuser_exit(void)
1792 {
1793         configfs_unregister_subsystem(&gpio_virtuser_config_subsys);
1794         mutex_destroy(&gpio_virtuser_config_subsys.su_mutex);
1795         platform_driver_unregister(&gpio_virtuser_driver);
1796         debugfs_remove_recursive(gpio_virtuser_dbg_root);
1797 }
1798 module_exit(gpio_virtuser_exit);
1799
1800 MODULE_AUTHOR("Bartosz Golaszewski <[email protected]>");
1801 MODULE_DESCRIPTION("Virtual GPIO consumer module");
1802 MODULE_LICENSE("GPL");