target/linux/generic/backport-6.6/819-v6.8-0005-nvmem-core-Rework-layouts-to-become-regular-devices.patch

   1 From fc29fd821d9ac2ae3d32a722fac39ce874efb883 Mon Sep 17 00:00:00 2001
   2 From: Miquel Raynal <miquel.raynal@bootlin.com>
   3 Date: Fri, 15 Dec 2023 11:15:32 +0000
   4 Subject: [PATCH] nvmem: core: Rework layouts to become regular devices
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Current layout support was initially written without modules support in
  10 mind. When the requirement for module support rose, the existing base
  11 was improved to adopt modularization support, but kind of a design flaw
  12 was introduced. With the existing implementation, when a storage device
  13 registers into NVMEM, the core tries to hook a layout (if any) and
  14 populates its cells immediately. This means, if the hardware description
  15 expects a layout to be hooked up, but no driver was provided for that,
  16 the storage medium will fail to probe and try later from
  17 scratch. Even if we consider that the hardware description shall be
  18 correct, we could still probe the storage device (especially if it
  19 contains the rootfs).
  20
  21 One way to overcome this situation is to consider the layouts as
  22 devices, and leverage the native notifier mechanism. When a new NVMEM
  23 device is registered, we can populate its nvmem-layout child, if any,
  24 and wait for the matching to be done in order to get the cells (the
  25 waiting can be easily done with the NVMEM notifiers). If the layout
  26 driver is compiled as a module, it should automatically be loaded. This
  27 way, there is no strong order to enforce, any NVMEM device creation
  28 or NVMEM layout driver insertion will be observed as a new event which
  29 may lead to the creation of additional cells, without disturbing the
  30 probes with costly (and sometimes endless) deferrals.
  31
  32 In order to achieve that goal we create a new bus for the nvmem-layouts
  33 with minimal logic to match nvmem-layout devices with nvmem-layout
  34 drivers. All this infrastructure code is created in the layouts.c file.
  35
  36 Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
  37 Tested-by: Rafał Miłecki <rafal@milecki.pl>
  38 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  39 Link: https://lore.kernel.org/r/20231215111536.316972-7-srinivas.kandagatla@linaro.org
  40 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  41 ---
  42  drivers/nvmem/Kconfig            |   1 +
  43  drivers/nvmem/Makefile           |   2 +
  44  drivers/nvmem/core.c             | 170 ++++++++++----------------
  45  drivers/nvmem/internals.h        |  21 ++++
  46  drivers/nvmem/layouts.c          | 201 +++++++++++++++++++++++++++++++
  47  drivers/nvmem/layouts/Kconfig    |   8 ++
  48  drivers/nvmem/layouts/onie-tlv.c |  24 +++-
  49  drivers/nvmem/layouts/sl28vpd.c  |  24 +++-
  50  include/linux/nvmem-provider.h   |  38 +++---
  51  9 files changed, 354 insertions(+), 135 deletions(-)
  52  create mode 100644 drivers/nvmem/layouts.c
  53
  54 --- a/drivers/nvmem/Kconfig
  55 +++ b/drivers/nvmem/Kconfig
  56 @@ -1,6 +1,7 @@
  57  # SPDX-License-Identifier: GPL-2.0-only
  58  menuconfig NVMEM
  59         bool "NVMEM Support"
  60 +       imply NVMEM_LAYOUTS
  61         help
  62           Support for NVMEM(Non Volatile Memory) devices like EEPROM, EFUSES...
  63
  64 --- a/drivers/nvmem/Makefile
  65 +++ b/drivers/nvmem/Makefile
  66 @@ -5,6 +5,8 @@
  67
  68  obj-$(CONFIG_NVMEM)            += nvmem_core.o
  69  nvmem_core-y                   := core.o
  70 +obj-$(CONFIG_NVMEM_LAYOUTS)    += nvmem_layouts.o
  71 +nvmem_layouts-y                        := layouts.o
  72  obj-y                          += layouts/
  73
  74  # Devices
  75 --- a/drivers/nvmem/core.c
  76 +++ b/drivers/nvmem/core.c
  77 @@ -55,9 +55,6 @@ static LIST_HEAD(nvmem_lookup_list);
  78
  79  static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
  80
  81 -static DEFINE_SPINLOCK(nvmem_layout_lock);
  82 -static LIST_HEAD(nvmem_layouts);
  83 -
  84  static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
  85                             void *val, size_t bytes)
  86  {
  87 @@ -740,97 +737,22 @@ static int nvmem_add_cells_from_fixed_la
  88         return err;
  89  }
  90
  91 -int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner)
  92 +int nvmem_layout_register(struct nvmem_layout *layout)
  93  {
  94 -       layout->owner = owner;
  95 -
  96 -       spin_lock(&nvmem_layout_lock);
  97 -       list_add(&layout->node, &nvmem_layouts);
  98 -       spin_unlock(&nvmem_layout_lock);
  99 -
 100 -       blocking_notifier_call_chain(&nvmem_notifier, NVMEM_LAYOUT_ADD, layout);
 101 +       if (!layout->add_cells)
 102 +               return -EINVAL;
 103
 104 -       return 0;
 105 +       /* Populate the cells */
 106 +       return layout->add_cells(&layout->nvmem->dev, layout->nvmem);
 107  }
 108 -EXPORT_SYMBOL_GPL(__nvmem_layout_register);
 109 +EXPORT_SYMBOL_GPL(nvmem_layout_register);
 110
 111  void nvmem_layout_unregister(struct nvmem_layout *layout)
 112  {
 113 -       blocking_notifier_call_chain(&nvmem_notifier, NVMEM_LAYOUT_REMOVE, layout);
 114 -
 115 -       spin_lock(&nvmem_layout_lock);
 116 -       list_del(&layout->node);
 117 -       spin_unlock(&nvmem_layout_lock);
 118 +       /* Keep the API even with an empty stub in case we need it later */
 119  }
 120  EXPORT_SYMBOL_GPL(nvmem_layout_unregister);
 121
 122 -static struct nvmem_layout *nvmem_layout_get(struct nvmem_device *nvmem)
 123 -{
 124 -       struct device_node *layout_np;
 125 -       struct nvmem_layout *l, *layout = ERR_PTR(-EPROBE_DEFER);
 126 -
 127 -       layout_np = of_nvmem_layout_get_container(nvmem);
 128 -       if (!layout_np)
 129 -               return NULL;
 130 -
 131 -       /* Fixed layouts don't have a matching driver */
 132 -       if (of_device_is_compatible(layout_np, "fixed-layout")) {
 133 -               of_node_put(layout_np);
 134 -               return NULL;
 135 -       }
 136 -
 137 -       /*
 138 -        * In case the nvmem device was built-in while the layout was built as a
 139 -        * module, we shall manually request the layout driver loading otherwise
 140 -        * we'll never have any match.
 141 -        */
 142 -       of_request_module(layout_np);
 143 -
 144 -       spin_lock(&nvmem_layout_lock);
 145 -
 146 -       list_for_each_entry(l, &nvmem_layouts, node) {
 147 -               if (of_match_node(l->of_match_table, layout_np)) {
 148 -                       if (try_module_get(l->owner))
 149 -                               layout = l;
 150 -
 151 -                       break;
 152 -               }
 153 -       }
 154 -
 155 -       spin_unlock(&nvmem_layout_lock);
 156 -       of_node_put(layout_np);
 157 -
 158 -       return layout;
 159 -}
 160 -
 161 -static void nvmem_layout_put(struct nvmem_layout *layout)
 162 -{
 163 -       if (layout)
 164 -               module_put(layout->owner);
 165 -}
 166 -
 167 -static int nvmem_add_cells_from_layout(struct nvmem_device *nvmem)
 168 -{
 169 -       struct nvmem_layout *layout = nvmem->layout;
 170 -       int ret;
 171 -
 172 -       if (layout && layout->add_cells) {
 173 -               ret = layout->add_cells(&nvmem->dev, nvmem);
 174 -               if (ret)
 175 -                       return ret;
 176 -       }
 177 -
 178 -       return 0;
 179 -}
 180 -
 181 -#if IS_ENABLED(CONFIG_OF)
 182 -struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
 183 -{
 184 -       return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout");
 185 -}
 186 -EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container);
 187 -#endif
 188 -
 189  const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem,
 190                                         struct nvmem_layout *layout)
 191  {
 192 @@ -838,7 +760,7 @@ const void *nvmem_layout_get_match_data(
 193         const struct of_device_id *match;
 194
 195         layout_np = of_nvmem_layout_get_container(nvmem);
 196 -       match = of_match_node(layout->of_match_table, layout_np);
 197 +       match = of_match_node(layout->dev.driver->of_match_table, layout_np);
 198
 199         return match ? match->data : NULL;
 200  }
 201 @@ -950,19 +872,6 @@ struct nvmem_device *nvmem_register(cons
 202                         goto err_put_device;
 203         }
 204
 205 -       /*
 206 -        * If the driver supplied a layout by config->layout, the module
 207 -        * pointer will be NULL and nvmem_layout_put() will be a noop.
 208 -        */
 209 -       nvmem->layout = config->layout ?: nvmem_layout_get(nvmem);
 210 -       if (IS_ERR(nvmem->layout)) {
 211 -               rval = PTR_ERR(nvmem->layout);
 212 -               nvmem->layout = NULL;
 213 -
 214 -               if (rval == -EPROBE_DEFER)
 215 -                       goto err_teardown_compat;
 216 -       }
 217 -
 218         if (config->cells) {
 219                 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
 220                 if (rval)
 221 @@ -983,24 +892,24 @@ struct nvmem_device *nvmem_register(cons
 222         if (rval)
 223                 goto err_remove_cells;
 224
 225 -       rval = nvmem_add_cells_from_layout(nvmem);
 226 -       if (rval)
 227 -               goto err_remove_cells;
 228 -
 229         dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
 230
 231         rval = device_add(&nvmem->dev);
 232         if (rval)
 233                 goto err_remove_cells;
 234
 235 +       rval = nvmem_populate_layout(nvmem);
 236 +       if (rval)
 237 +               goto err_remove_dev;
 238 +
 239         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
 240
 241         return nvmem;
 242
 243 +err_remove_dev:
 244 +       device_del(&nvmem->dev);
 245  err_remove_cells:
 246         nvmem_device_remove_all_cells(nvmem);
 247 -       nvmem_layout_put(nvmem->layout);
 248 -err_teardown_compat:
 249         if (config->compat)
 250                 nvmem_sysfs_remove_compat(nvmem, config);
 251  err_put_device:
 252 @@ -1022,7 +931,7 @@ static void nvmem_device_release(struct
 253                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
 254
 255         nvmem_device_remove_all_cells(nvmem);
 256 -       nvmem_layout_put(nvmem->layout);
 257 +       nvmem_destroy_layout(nvmem);
 258         device_unregister(&nvmem->dev);
 259  }
 260
 261 @@ -1324,6 +1233,12 @@ nvmem_cell_get_from_lookup(struct device
 262         return cell;
 263  }
 264
 265 +static void nvmem_layout_module_put(struct nvmem_device *nvmem)
 266 +{
 267 +       if (nvmem->layout && nvmem->layout->dev.driver)
 268 +               module_put(nvmem->layout->dev.driver->owner);
 269 +}
 270 +
 271  #if IS_ENABLED(CONFIG_OF)
 272  static struct nvmem_cell_entry *
 273  nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np)
 274 @@ -1342,6 +1257,18 @@ nvmem_find_cell_entry_by_node(struct nvm
 275         return cell;
 276  }
 277
 278 +static int nvmem_layout_module_get_optional(struct nvmem_device *nvmem)
 279 +{
 280 +       if (!nvmem->layout)
 281 +               return 0;
 282 +
 283 +       if (!nvmem->layout->dev.driver ||
 284 +           !try_module_get(nvmem->layout->dev.driver->owner))
 285 +               return -EPROBE_DEFER;
 286 +
 287 +       return 0;
 288 +}
 289 +
 290  /**
 291   * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
 292   *
 293 @@ -1404,16 +1331,29 @@ struct nvmem_cell *of_nvmem_cell_get(str
 294                 return ERR_CAST(nvmem);
 295         }
 296
 297 +       ret = nvmem_layout_module_get_optional(nvmem);
 298 +       if (ret) {
 299 +               of_node_put(cell_np);
 300 +               __nvmem_device_put(nvmem);
 301 +               return ERR_PTR(ret);
 302 +       }
 303 +
 304         cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
 305         of_node_put(cell_np);
 306         if (!cell_entry) {
 307                 __nvmem_device_put(nvmem);
 308 -               return ERR_PTR(-ENOENT);
 309 +               nvmem_layout_module_put(nvmem);
 310 +               if (nvmem->layout)
 311 +                       return ERR_PTR(-EPROBE_DEFER);
 312 +               else
 313 +                       return ERR_PTR(-ENOENT);
 314         }
 315
 316         cell = nvmem_create_cell(cell_entry, id, cell_index);
 317 -       if (IS_ERR(cell))
 318 +       if (IS_ERR(cell)) {
 319                 __nvmem_device_put(nvmem);
 320 +               nvmem_layout_module_put(nvmem);
 321 +       }
 322
 323         return cell;
 324  }
 325 @@ -1527,6 +1467,7 @@ void nvmem_cell_put(struct nvmem_cell *c
 326
 327         kfree(cell);
 328         __nvmem_device_put(nvmem);
 329 +       nvmem_layout_module_put(nvmem);
 330  }
 331  EXPORT_SYMBOL_GPL(nvmem_cell_put);
 332
 333 @@ -2104,11 +2045,22 @@ EXPORT_SYMBOL_GPL(nvmem_dev_name);
 334
 335  static int __init nvmem_init(void)
 336  {
 337 -       return bus_register(&nvmem_bus_type);
 338 +       int ret;
 339 +
 340 +       ret = bus_register(&nvmem_bus_type);
 341 +       if (ret)
 342 +               return ret;
 343 +
 344 +       ret = nvmem_layout_bus_register();
 345 +       if (ret)
 346 +               bus_unregister(&nvmem_bus_type);
 347 +
 348 +       return ret;
 349  }
 350
 351  static void __exit nvmem_exit(void)
 352  {
 353 +       nvmem_layout_bus_unregister();
 354         bus_unregister(&nvmem_bus_type);
 355  }
 356
 357 --- a/drivers/nvmem/internals.h
 358 +++ b/drivers/nvmem/internals.h
 359 @@ -34,4 +34,25 @@ struct nvmem_device {
 360         void *priv;
 361  };
 362
 363 +#if IS_ENABLED(CONFIG_OF)
 364 +int nvmem_layout_bus_register(void);
 365 +void nvmem_layout_bus_unregister(void);
 366 +int nvmem_populate_layout(struct nvmem_device *nvmem);
 367 +void nvmem_destroy_layout(struct nvmem_device *nvmem);
 368 +#else /* CONFIG_OF */
 369 +static inline int nvmem_layout_bus_register(void)
 370 +{
 371 +       return 0;
 372 +}
 373 +
 374 +static inline void nvmem_layout_bus_unregister(void) {}
 375 +
 376 +static inline int nvmem_populate_layout(struct nvmem_device *nvmem)
 377 +{
 378 +       return 0;
 379 +}
 380 +
 381 +static inline void nvmem_destroy_layout(struct nvmem_device *nvmem) { }
 382 +#endif /* CONFIG_OF */
 383 +
 384  #endif  /* ifndef _LINUX_NVMEM_INTERNALS_H */
 385 --- /dev/null
 386 +++ b/drivers/nvmem/layouts.c
 387 @@ -0,0 +1,201 @@
 388 +// SPDX-License-Identifier: GPL-2.0
 389 +/*
 390 + * NVMEM layout bus handling
 391 + *
 392 + * Copyright (C) 2023 Bootlin
 393 + * Author: Miquel Raynal <miquel.raynal@bootlin.com
 394 + */
 395 +
 396 +#include <linux/device.h>
 397 +#include <linux/dma-mapping.h>
 398 +#include <linux/nvmem-consumer.h>
 399 +#include <linux/nvmem-provider.h>
 400 +#include <linux/of.h>
 401 +#include <linux/of_device.h>
 402 +#include <linux/of_irq.h>
 403 +
 404 +#include "internals.h"
 405 +
 406 +#define to_nvmem_layout_driver(drv) \
 407 +       (container_of((drv), struct nvmem_layout_driver, driver))
 408 +#define to_nvmem_layout_device(_dev) \
 409 +       container_of((_dev), struct nvmem_layout, dev)
 410 +
 411 +static int nvmem_layout_bus_match(struct device *dev, struct device_driver *drv)
 412 +{
 413 +       return of_driver_match_device(dev, drv);
 414 +}
 415 +
 416 +static int nvmem_layout_bus_probe(struct device *dev)
 417 +{
 418 +       struct nvmem_layout_driver *drv = to_nvmem_layout_driver(dev->driver);
 419 +       struct nvmem_layout *layout = to_nvmem_layout_device(dev);
 420 +
 421 +       if (!drv->probe || !drv->remove)
 422 +               return -EINVAL;
 423 +
 424 +       return drv->probe(layout);
 425 +}
 426 +
 427 +static void nvmem_layout_bus_remove(struct device *dev)
 428 +{
 429 +       struct nvmem_layout_driver *drv = to_nvmem_layout_driver(dev->driver);
 430 +       struct nvmem_layout *layout = to_nvmem_layout_device(dev);
 431 +
 432 +       return drv->remove(layout);
 433 +}
 434 +
 435 +static struct bus_type nvmem_layout_bus_type = {
 436 +       .name           = "nvmem-layout",
 437 +       .match          = nvmem_layout_bus_match,
 438 +       .probe          = nvmem_layout_bus_probe,
 439 +       .remove         = nvmem_layout_bus_remove,
 440 +};
 441 +
 442 +int nvmem_layout_driver_register(struct nvmem_layout_driver *drv)
 443 +{
 444 +       drv->driver.bus = &nvmem_layout_bus_type;
 445 +
 446 +       return driver_register(&drv->driver);
 447 +}
 448 +EXPORT_SYMBOL_GPL(nvmem_layout_driver_register);
 449 +
 450 +void nvmem_layout_driver_unregister(struct nvmem_layout_driver *drv)
 451 +{
 452 +       driver_unregister(&drv->driver);
 453 +}
 454 +EXPORT_SYMBOL_GPL(nvmem_layout_driver_unregister);
 455 +
 456 +static void nvmem_layout_release_device(struct device *dev)
 457 +{
 458 +       struct nvmem_layout *layout = to_nvmem_layout_device(dev);
 459 +
 460 +       of_node_put(layout->dev.of_node);
 461 +       kfree(layout);
 462 +}
 463 +
 464 +static int nvmem_layout_create_device(struct nvmem_device *nvmem,
 465 +                                     struct device_node *np)
 466 +{
 467 +       struct nvmem_layout *layout;
 468 +       struct device *dev;
 469 +       int ret;
 470 +
 471 +       layout = kzalloc(sizeof(*layout), GFP_KERNEL);
 472 +       if (!layout)
 473 +               return -ENOMEM;
 474 +
 475 +       /* Create a bidirectional link */
 476 +       layout->nvmem = nvmem;
 477 +       nvmem->layout = layout;
 478 +
 479 +       /* Device model registration */
 480 +       dev = &layout->dev;
 481 +       device_initialize(dev);
 482 +       dev->parent = &nvmem->dev;
 483 +       dev->bus = &nvmem_layout_bus_type;
 484 +       dev->release = nvmem_layout_release_device;
 485 +       dev->coherent_dma_mask = DMA_BIT_MASK(32);
 486 +       dev->dma_mask = &dev->coherent_dma_mask;
 487 +       device_set_node(dev, of_fwnode_handle(of_node_get(np)));
 488 +       of_device_make_bus_id(dev);
 489 +       of_msi_configure(dev, dev->of_node);
 490 +
 491 +       ret = device_add(dev);
 492 +       if (ret) {
 493 +               put_device(dev);
 494 +               return ret;
 495 +       }
 496 +
 497 +       return 0;
 498 +}
 499 +
 500 +static const struct of_device_id of_nvmem_layout_skip_table[] = {
 501 +       { .compatible = "fixed-layout", },
 502 +       {}
 503 +};
 504 +
 505 +static int nvmem_layout_bus_populate(struct nvmem_device *nvmem,
 506 +                                    struct device_node *layout_dn)
 507 +{
 508 +       int ret;
 509 +
 510 +       /* Make sure it has a compatible property */
 511 +       if (!of_get_property(layout_dn, "compatible", NULL)) {
 512 +               pr_debug("%s() - skipping %pOF, no compatible prop\n",
 513 +                        __func__, layout_dn);
 514 +               return 0;
 515 +       }
 516 +
 517 +       /* Fixed layouts are parsed manually somewhere else for now */
 518 +       if (of_match_node(of_nvmem_layout_skip_table, layout_dn)) {
 519 +               pr_debug("%s() - skipping %pOF node\n", __func__, layout_dn);
 520 +               return 0;
 521 +       }
 522 +
 523 +       if (of_node_check_flag(layout_dn, OF_POPULATED_BUS)) {
 524 +               pr_debug("%s() - skipping %pOF, already populated\n",
 525 +                        __func__, layout_dn);
 526 +
 527 +               return 0;
 528 +       }
 529 +
 530 +       /* NVMEM layout buses expect only a single device representing the layout */
 531 +       ret = nvmem_layout_create_device(nvmem, layout_dn);
 532 +       if (ret)
 533 +               return ret;
 534 +
 535 +       of_node_set_flag(layout_dn, OF_POPULATED_BUS);
 536 +
 537 +       return 0;
 538 +}
 539 +
 540 +struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
 541 +{
 542 +       return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout");
 543 +}
 544 +EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container);
 545 +
 546 +/*
 547 + * Returns the number of devices populated, 0 if the operation was not relevant
 548 + * for this nvmem device, an error code otherwise.
 549 + */
 550 +int nvmem_populate_layout(struct nvmem_device *nvmem)
 551 +{
 552 +       struct device_node *layout_dn;
 553 +       int ret;
 554 +
 555 +       layout_dn = of_nvmem_layout_get_container(nvmem);
 556 +       if (!layout_dn)
 557 +               return 0;
 558 +
 559 +       /* Populate the layout device */
 560 +       device_links_supplier_sync_state_pause();
 561 +       ret = nvmem_layout_bus_populate(nvmem, layout_dn);
 562 +       device_links_supplier_sync_state_resume();
 563 +
 564 +       of_node_put(layout_dn);
 565 +       return ret;
 566 +}
 567 +
 568 +void nvmem_destroy_layout(struct nvmem_device *nvmem)
 569 +{
 570 +       struct device *dev;
 571 +
 572 +       if (!nvmem->layout)
 573 +               return;
 574 +
 575 +       dev = &nvmem->layout->dev;
 576 +       of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
 577 +       device_unregister(dev);
 578 +}
 579 +
 580 +int nvmem_layout_bus_register(void)
 581 +{
 582 +       return bus_register(&nvmem_layout_bus_type);
 583 +}
 584 +
 585 +void nvmem_layout_bus_unregister(void)
 586 +{
 587 +       bus_unregister(&nvmem_layout_bus_type);
 588 +}
 589 --- a/drivers/nvmem/layouts/Kconfig
 590 +++ b/drivers/nvmem/layouts/Kconfig
 591 @@ -1,5 +1,11 @@
 592  # SPDX-License-Identifier: GPL-2.0
 593
 594 +config NVMEM_LAYOUTS
 595 +       bool
 596 +       depends on OF
 597 +
 598 +if NVMEM_LAYOUTS
 599 +
 600  menu "Layout Types"
 601
 602  config NVMEM_LAYOUT_SL28_VPD
 603 @@ -21,3 +27,5 @@ config NVMEM_LAYOUT_ONIE_TLV
 604           If unsure, say N.
 605
 606  endmenu
 607 +
 608 +endif
 609 --- a/drivers/nvmem/layouts/onie-tlv.c
 610 +++ b/drivers/nvmem/layouts/onie-tlv.c
 611 @@ -225,16 +225,32 @@ static int onie_tlv_parse_table(struct d
 612         return 0;
 613  }
 614
 615 +static int onie_tlv_probe(struct nvmem_layout *layout)
 616 +{
 617 +       layout->add_cells = onie_tlv_parse_table;
 618 +
 619 +       return nvmem_layout_register(layout);
 620 +}
 621 +
 622 +static void onie_tlv_remove(struct nvmem_layout *layout)
 623 +{
 624 +       nvmem_layout_unregister(layout);
 625 +}
 626 +
 627  static const struct of_device_id onie_tlv_of_match_table[] = {
 628         { .compatible = "onie,tlv-layout", },
 629         {},
 630  };
 631  MODULE_DEVICE_TABLE(of, onie_tlv_of_match_table);
 632
 633 -static struct nvmem_layout onie_tlv_layout = {
 634 -       .name = "ONIE tlv layout",
 635 -       .of_match_table = onie_tlv_of_match_table,
 636 -       .add_cells = onie_tlv_parse_table,
 637 +static struct nvmem_layout_driver onie_tlv_layout = {
 638 +       .driver = {
 639 +               .owner = THIS_MODULE,
 640 +               .name = "onie-tlv-layout",
 641 +               .of_match_table = onie_tlv_of_match_table,
 642 +       },
 643 +       .probe = onie_tlv_probe,
 644 +       .remove = onie_tlv_remove,
 645  };
 646  module_nvmem_layout_driver(onie_tlv_layout);
 647
 648 --- a/drivers/nvmem/layouts/sl28vpd.c
 649 +++ b/drivers/nvmem/layouts/sl28vpd.c
 650 @@ -134,16 +134,32 @@ static int sl28vpd_add_cells(struct devi
 651         return 0;
 652  }
 653
 654 +static int sl28vpd_probe(struct nvmem_layout *layout)
 655 +{
 656 +       layout->add_cells = sl28vpd_add_cells;
 657 +
 658 +       return nvmem_layout_register(layout);
 659 +}
 660 +
 661 +static void sl28vpd_remove(struct nvmem_layout *layout)
 662 +{
 663 +       nvmem_layout_unregister(layout);
 664 +}
 665 +
 666  static const struct of_device_id sl28vpd_of_match_table[] = {
 667         { .compatible = "kontron,sl28-vpd" },
 668         {},
 669  };
 670  MODULE_DEVICE_TABLE(of, sl28vpd_of_match_table);
 671
 672 -static struct nvmem_layout sl28vpd_layout = {
 673 -       .name = "sl28-vpd",
 674 -       .of_match_table = sl28vpd_of_match_table,
 675 -       .add_cells = sl28vpd_add_cells,
 676 +static struct nvmem_layout_driver sl28vpd_layout = {
 677 +       .driver = {
 678 +               .owner = THIS_MODULE,
 679 +               .name = "kontron-sl28vpd-layout",
 680 +               .of_match_table = sl28vpd_of_match_table,
 681 +       },
 682 +       .probe = sl28vpd_probe,
 683 +       .remove = sl28vpd_remove,
 684  };
 685  module_nvmem_layout_driver(sl28vpd_layout);
 686
 687 --- a/include/linux/nvmem-provider.h
 688 +++ b/include/linux/nvmem-provider.h
 689 @@ -9,6 +9,7 @@
 690  #ifndef _LINUX_NVMEM_PROVIDER_H
 691  #define _LINUX_NVMEM_PROVIDER_H
 692
 693 +#include <linux/device.h>
 694  #include <linux/device/driver.h>
 695  #include <linux/err.h>
 696  #include <linux/errno.h>
 697 @@ -158,12 +159,11 @@ struct nvmem_cell_table {
 698  /**
 699   * struct nvmem_layout - NVMEM layout definitions
 700   *
 701 - * @name:              Layout name.
 702 - * @of_match_table:    Open firmware match table.
 703 - * @add_cells:         Called to populate the layout using
 704 - *                     nvmem_add_one_cell().
 705 - * @owner:             Pointer to struct module.
 706 - * @node:              List node.
 707 + * @dev:               Device-model layout device.
 708 + * @nvmem:             The underlying NVMEM device
 709 + * @add_cells:         Will be called if a nvmem device is found which
 710 + *                     has this layout. The function will add layout
 711 + *                     specific cells with nvmem_add_one_cell().
 712   *
 713   * A nvmem device can hold a well defined structure which can just be
 714   * evaluated during runtime. For example a TLV list, or a list of "name=val"
 715 @@ -171,13 +171,15 @@ struct nvmem_cell_table {
 716   * cells.
 717   */
 718  struct nvmem_layout {
 719 -       const char *name;
 720 -       const struct of_device_id *of_match_table;
 721 +       struct device dev;
 722 +       struct nvmem_device *nvmem;
 723         int (*add_cells)(struct device *dev, struct nvmem_device *nvmem);
 724 +};
 725
 726 -       /* private */
 727 -       struct module *owner;
 728 -       struct list_head node;
 729 +struct nvmem_layout_driver {
 730 +       struct device_driver driver;
 731 +       int (*probe)(struct nvmem_layout *layout);
 732 +       void (*remove)(struct nvmem_layout *layout);
 733  };
 734
 735  #if IS_ENABLED(CONFIG_NVMEM)
 736 @@ -194,11 +196,15 @@ void nvmem_del_cell_table(struct nvmem_c
 737  int nvmem_add_one_cell(struct nvmem_device *nvmem,
 738                        const struct nvmem_cell_info *info);
 739
 740 -int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner);
 741 -#define nvmem_layout_register(layout) \
 742 -       __nvmem_layout_register(layout, THIS_MODULE)
 743 +int nvmem_layout_register(struct nvmem_layout *layout);
 744  void nvmem_layout_unregister(struct nvmem_layout *layout);
 745
 746 +int nvmem_layout_driver_register(struct nvmem_layout_driver *drv);
 747 +void nvmem_layout_driver_unregister(struct nvmem_layout_driver *drv);
 748 +#define module_nvmem_layout_driver(__nvmem_layout_driver)              \
 749 +       module_driver(__nvmem_layout_driver, nvmem_layout_driver_register, \
 750 +                     nvmem_layout_driver_unregister)
 751 +
 752  const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem,
 753                                         struct nvmem_layout *layout);
 754
 755 @@ -262,8 +268,4 @@ static inline struct device_node *of_nvm
 756
 757  #endif /* CONFIG_NVMEM && CONFIG_OF */
 758
 759 -#define module_nvmem_layout_driver(__layout_driver)            \
 760 -       module_driver(__layout_driver, nvmem_layout_register,   \
 761 -                     nvmem_layout_unregister)
 762 -
 763  #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */