drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/export.h>
  35 #include <linux/sched/rt.h>
  36 #include <linux/delay.h>
  37 #include <linux/kthread.h>
  38 #include <linux/ioport.h>
  39 #include <linux/acpi.h>
  40
  41 #define CREATE_TRACE_POINTS
  42 #include <trace/events/spi.h>
  43
  44 static void spidev_release(struct device *dev)
  45 {
  46         struct spi_device       *spi = to_spi_device(dev);
  47
  48         /* spi masters may cleanup for released devices */
  49         if (spi->master->cleanup)
  50                 spi->master->cleanup(spi);
  51
  52         spi_master_put(spi->master);
  53         kfree(spi);
  54 }
  55
  56 static ssize_t
  57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  58 {
  59         const struct spi_device *spi = to_spi_device(dev);
  60         int len;
  61
  62         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  63         if (len != -ENODEV)
  64                 return len;
  65
  66         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  67 }
  68 static DEVICE_ATTR_RO(modalias);
  69
  70 #define SPI_STATISTICS_ATTRS(field, file)                               \
  71 static ssize_t spi_master_##field##_show(struct device *dev,            \
  72                                          struct device_attribute *attr, \
  73                                          char *buf)                     \
  74 {                                                                       \
  75         struct spi_master *master = container_of(dev,                   \
  76                                                  struct spi_master, dev); \
  77         return spi_statistics_##field##_show(&master->statistics, buf); \
  78 }                                                                       \
  79 static struct device_attribute dev_attr_spi_master_##field = {          \
  80         .attr = { .name = file, .mode = S_IRUGO },                      \
  81         .show = spi_master_##field##_show,                              \
  82 };                                                                      \
  83 static ssize_t spi_device_##field##_show(struct device *dev,            \
  84                                          struct device_attribute *attr, \
  85                                         char *buf)                      \
  86 {                                                                       \
  87         struct spi_device *spi = container_of(dev,                      \
  88                                               struct spi_device, dev);  \
  89         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  90 }                                                                       \
  91 static struct device_attribute dev_attr_spi_device_##field = {          \
  92         .attr = { .name = file, .mode = S_IRUGO },                      \
  93         .show = spi_device_##field##_show,                              \
  94 }
  95
  96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  98                                             char *buf)                  \
  99 {                                                                       \
 100         unsigned long flags;                                            \
 101         ssize_t len;                                                    \
 102         spin_lock_irqsave(&stat->lock, flags);                          \
 103         len = sprintf(buf, format_string, stat->field);                 \
 104         spin_unlock_irqrestore(&stat->lock, flags);                     \
 105         return len;                                                     \
 106 }                                                                       \
 107 SPI_STATISTICS_ATTRS(name, file)
 108
 109 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 110         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 111                                  field, format_string)
 112
 113 SPI_STATISTICS_SHOW(messages, "%lu");
 114 SPI_STATISTICS_SHOW(transfers, "%lu");
 115 SPI_STATISTICS_SHOW(errors, "%lu");
 116 SPI_STATISTICS_SHOW(timedout, "%lu");
 117
 118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 120 SPI_STATISTICS_SHOW(spi_async, "%lu");
 121
 122 SPI_STATISTICS_SHOW(bytes, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 125
 126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 127         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 128                                  "transfer_bytes_histo_" number,        \
 129                                  transfer_bytes_histo[index],  "%lu")
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 147
 148 static struct attribute *spi_dev_attrs[] = {
 149         &dev_attr_modalias.attr,
 150         NULL,
 151 };
 152
 153 static const struct attribute_group spi_dev_group = {
 154         .attrs  = spi_dev_attrs,
 155 };
 156
 157 static struct attribute *spi_device_statistics_attrs[] = {
 158         &dev_attr_spi_device_messages.attr,
 159         &dev_attr_spi_device_transfers.attr,
 160         &dev_attr_spi_device_errors.attr,
 161         &dev_attr_spi_device_timedout.attr,
 162         &dev_attr_spi_device_spi_sync.attr,
 163         &dev_attr_spi_device_spi_sync_immediate.attr,
 164         &dev_attr_spi_device_spi_async.attr,
 165         &dev_attr_spi_device_bytes.attr,
 166         &dev_attr_spi_device_bytes_rx.attr,
 167         &dev_attr_spi_device_bytes_tx.attr,
 168         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 169         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 185         NULL,
 186 };
 187
 188 static const struct attribute_group spi_device_statistics_group = {
 189         .name  = "statistics",
 190         .attrs  = spi_device_statistics_attrs,
 191 };
 192
 193 static const struct attribute_group *spi_dev_groups[] = {
 194         &spi_dev_group,
 195         &spi_device_statistics_group,
 196         NULL,
 197 };
 198
 199 static struct attribute *spi_master_statistics_attrs[] = {
 200         &dev_attr_spi_master_messages.attr,
 201         &dev_attr_spi_master_transfers.attr,
 202         &dev_attr_spi_master_errors.attr,
 203         &dev_attr_spi_master_timedout.attr,
 204         &dev_attr_spi_master_spi_sync.attr,
 205         &dev_attr_spi_master_spi_sync_immediate.attr,
 206         &dev_attr_spi_master_spi_async.attr,
 207         &dev_attr_spi_master_bytes.attr,
 208         &dev_attr_spi_master_bytes_rx.attr,
 209         &dev_attr_spi_master_bytes_tx.attr,
 210         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 211         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 212         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 226         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 227         NULL,
 228 };
 229
 230 static const struct attribute_group spi_master_statistics_group = {
 231         .name  = "statistics",
 232         .attrs  = spi_master_statistics_attrs,
 233 };
 234
 235 static const struct attribute_group *spi_master_groups[] = {
 236         &spi_master_statistics_group,
 237         NULL,
 238 };
 239
 240 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 241                                        struct spi_transfer *xfer,
 242                                        struct spi_master *master)
 243 {
 244         unsigned long flags;
 245         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 246
 247         if (l2len < 0)
 248                 l2len = 0;
 249
 250         spin_lock_irqsave(&stats->lock, flags);
 251
 252         stats->transfers++;
 253         stats->transfer_bytes_histo[l2len]++;
 254
 255         stats->bytes += xfer->len;
 256         if ((xfer->tx_buf) &&
 257             (xfer->tx_buf != master->dummy_tx))
 258                 stats->bytes_tx += xfer->len;
 259         if ((xfer->rx_buf) &&
 260             (xfer->rx_buf != master->dummy_rx))
 261                 stats->bytes_rx += xfer->len;
 262
 263         spin_unlock_irqrestore(&stats->lock, flags);
 264 }
 265 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 266
 267 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 268  * and the sysfs version makes coldplug work too.
 269  */
 270
 271 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 272                                                 const struct spi_device *sdev)
 273 {
 274         while (id->name[0]) {
 275                 if (!strcmp(sdev->modalias, id->name))
 276                         return id;
 277                 id++;
 278         }
 279         return NULL;
 280 }
 281
 282 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 283 {
 284         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 285
 286         return spi_match_id(sdrv->id_table, sdev);
 287 }
 288 EXPORT_SYMBOL_GPL(spi_get_device_id);
 289
 290 static int spi_match_device(struct device *dev, struct device_driver *drv)
 291 {
 292         const struct spi_device *spi = to_spi_device(dev);
 293         const struct spi_driver *sdrv = to_spi_driver(drv);
 294
 295         /* Attempt an OF style match */
 296         if (of_driver_match_device(dev, drv))
 297                 return 1;
 298
 299         /* Then try ACPI */
 300         if (acpi_driver_match_device(dev, drv))
 301                 return 1;
 302
 303         if (sdrv->id_table)
 304                 return !!spi_match_id(sdrv->id_table, spi);
 305
 306         return strcmp(spi->modalias, drv->name) == 0;
 307 }
 308
 309 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 310 {
 311         const struct spi_device         *spi = to_spi_device(dev);
 312         int rc;
 313
 314         rc = acpi_device_uevent_modalias(dev, env);
 315         if (rc != -ENODEV)
 316                 return rc;
 317
 318         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 319         return 0;
 320 }
 321
 322 struct bus_type spi_bus_type = {
 323         .name           = "spi",
 324         .dev_groups     = spi_dev_groups,
 325         .match          = spi_match_device,
 326         .uevent         = spi_uevent,
 327 };
 328 EXPORT_SYMBOL_GPL(spi_bus_type);
 329
 330
 331 static int spi_drv_probe(struct device *dev)
 332 {
 333         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 334         struct spi_device               *spi = to_spi_device(dev);
 335         int ret;
 336
 337         ret = of_clk_set_defaults(dev->of_node, false);
 338         if (ret)
 339                 return ret;
 340
 341         if (dev->of_node) {
 342                 spi->irq = of_irq_get(dev->of_node, 0);
 343                 if (spi->irq == -EPROBE_DEFER)
 344                         return -EPROBE_DEFER;
 345                 if (spi->irq < 0)
 346                         spi->irq = 0;
 347         }
 348
 349         ret = dev_pm_domain_attach(dev, true);
 350         if (ret != -EPROBE_DEFER) {
 351                 ret = sdrv->probe(spi);
 352                 if (ret)
 353                         dev_pm_domain_detach(dev, true);
 354         }
 355
 356         return ret;
 357 }
 358
 359 static int spi_drv_remove(struct device *dev)
 360 {
 361         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 362         int ret;
 363
 364         ret = sdrv->remove(to_spi_device(dev));
 365         dev_pm_domain_detach(dev, true);
 366
 367         return ret;
 368 }
 369
 370 static void spi_drv_shutdown(struct device *dev)
 371 {
 372         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 373
 374         sdrv->shutdown(to_spi_device(dev));
 375 }
 376
 377 /**
 378  * spi_register_driver - register a SPI driver
 379  * @sdrv: the driver to register
 380  * Context: can sleep
 381  *
 382  * Return: zero on success, else a negative error code.
 383  */
 384 int spi_register_driver(struct spi_driver *sdrv)
 385 {
 386         sdrv->driver.bus = &spi_bus_type;
 387         if (sdrv->probe)
 388                 sdrv->driver.probe = spi_drv_probe;
 389         if (sdrv->remove)
 390                 sdrv->driver.remove = spi_drv_remove;
 391         if (sdrv->shutdown)
 392                 sdrv->driver.shutdown = spi_drv_shutdown;
 393         return driver_register(&sdrv->driver);
 394 }
 395 EXPORT_SYMBOL_GPL(spi_register_driver);
 396
 397 /*-------------------------------------------------------------------------*/
 398
 399 /* SPI devices should normally not be created by SPI device drivers; that
 400  * would make them board-specific.  Similarly with SPI master drivers.
 401  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 402  * with other readonly (flashable) information about mainboard devices.
 403  */
 404
 405 struct boardinfo {
 406         struct list_head        list;
 407         struct spi_board_info   board_info;
 408 };
 409
 410 static LIST_HEAD(board_list);
 411 static LIST_HEAD(spi_master_list);
 412
 413 /*
 414  * Used to protect add/del opertion for board_info list and
 415  * spi_master list, and their matching process
 416  */
 417 static DEFINE_MUTEX(board_lock);
 418
 419 /**
 420  * spi_alloc_device - Allocate a new SPI device
 421  * @master: Controller to which device is connected
 422  * Context: can sleep
 423  *
 424  * Allows a driver to allocate and initialize a spi_device without
 425  * registering it immediately.  This allows a driver to directly
 426  * fill the spi_device with device parameters before calling
 427  * spi_add_device() on it.
 428  *
 429  * Caller is responsible to call spi_add_device() on the returned
 430  * spi_device structure to add it to the SPI master.  If the caller
 431  * needs to discard the spi_device without adding it, then it should
 432  * call spi_dev_put() on it.
 433  *
 434  * Return: a pointer to the new device, or NULL.
 435  */
 436 struct spi_device *spi_alloc_device(struct spi_master *master)
 437 {
 438         struct spi_device       *spi;
 439
 440         if (!spi_master_get(master))
 441                 return NULL;
 442
 443         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 444         if (!spi) {
 445                 spi_master_put(master);
 446                 return NULL;
 447         }
 448
 449         spi->master = master;
 450         spi->dev.parent = &master->dev;
 451         spi->dev.bus = &spi_bus_type;
 452         spi->dev.release = spidev_release;
 453         spi->cs_gpio = -ENOENT;
 454
 455         spin_lock_init(&spi->statistics.lock);
 456
 457         device_initialize(&spi->dev);
 458         return spi;
 459 }
 460 EXPORT_SYMBOL_GPL(spi_alloc_device);
 461
 462 static void spi_dev_set_name(struct spi_device *spi)
 463 {
 464         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 465
 466         if (adev) {
 467                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 468                 return;
 469         }
 470
 471         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 472                      spi->chip_select);
 473 }
 474
 475 static int spi_dev_check(struct device *dev, void *data)
 476 {
 477         struct spi_device *spi = to_spi_device(dev);
 478         struct spi_device *new_spi = data;
 479
 480         if (spi->master == new_spi->master &&
 481             spi->chip_select == new_spi->chip_select)
 482                 return -EBUSY;
 483         return 0;
 484 }
 485
 486 /**
 487  * spi_add_device - Add spi_device allocated with spi_alloc_device
 488  * @spi: spi_device to register
 489  *
 490  * Companion function to spi_alloc_device.  Devices allocated with
 491  * spi_alloc_device can be added onto the spi bus with this function.
 492  *
 493  * Return: 0 on success; negative errno on failure
 494  */
 495 int spi_add_device(struct spi_device *spi)
 496 {
 497         static DEFINE_MUTEX(spi_add_lock);
 498         struct spi_master *master = spi->master;
 499         struct device *dev = master->dev.parent;
 500         int status;
 501
 502         /* Chipselects are numbered 0..max; validate. */
 503         if (spi->chip_select >= master->num_chipselect) {
 504                 dev_err(dev, "cs%d >= max %d\n",
 505                         spi->chip_select,
 506                         master->num_chipselect);
 507                 return -EINVAL;
 508         }
 509
 510         /* Set the bus ID string */
 511         spi_dev_set_name(spi);
 512
 513         /* We need to make sure there's no other device with this
 514          * chipselect **BEFORE** we call setup(), else we'll trash
 515          * its configuration.  Lock against concurrent add() calls.
 516          */
 517         mutex_lock(&spi_add_lock);
 518
 519         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 520         if (status) {
 521                 dev_err(dev, "chipselect %d already in use\n",
 522                                 spi->chip_select);
 523                 goto done;
 524         }
 525
 526         if (master->cs_gpios)
 527                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 528
 529         /* Drivers may modify this initial i/o setup, but will
 530          * normally rely on the device being setup.  Devices
 531          * using SPI_CS_HIGH can't coexist well otherwise...
 532          */
 533         status = spi_setup(spi);
 534         if (status < 0) {
 535                 dev_err(dev, "can't setup %s, status %d\n",
 536                                 dev_name(&spi->dev), status);
 537                 goto done;
 538         }
 539
 540         /* Device may be bound to an active driver when this returns */
 541         status = device_add(&spi->dev);
 542         if (status < 0)
 543                 dev_err(dev, "can't add %s, status %d\n",
 544                                 dev_name(&spi->dev), status);
 545         else
 546                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 547
 548 done:
 549         mutex_unlock(&spi_add_lock);
 550         return status;
 551 }
 552 EXPORT_SYMBOL_GPL(spi_add_device);
 553
 554 /**
 555  * spi_new_device - instantiate one new SPI device
 556  * @master: Controller to which device is connected
 557  * @chip: Describes the SPI device
 558  * Context: can sleep
 559  *
 560  * On typical mainboards, this is purely internal; and it's not needed
 561  * after board init creates the hard-wired devices.  Some development
 562  * platforms may not be able to use spi_register_board_info though, and
 563  * this is exported so that for example a USB or parport based adapter
 564  * driver could add devices (which it would learn about out-of-band).
 565  *
 566  * Return: the new device, or NULL.
 567  */
 568 struct spi_device *spi_new_device(struct spi_master *master,
 569                                   struct spi_board_info *chip)
 570 {
 571         struct spi_device       *proxy;
 572         int                     status;
 573
 574         /* NOTE:  caller did any chip->bus_num checks necessary.
 575          *
 576          * Also, unless we change the return value convention to use
 577          * error-or-pointer (not NULL-or-pointer), troubleshootability
 578          * suggests syslogged diagnostics are best here (ugh).
 579          */
 580
 581         proxy = spi_alloc_device(master);
 582         if (!proxy)
 583                 return NULL;
 584
 585         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 586
 587         proxy->chip_select = chip->chip_select;
 588         proxy->max_speed_hz = chip->max_speed_hz;
 589         proxy->mode = chip->mode;
 590         proxy->irq = chip->irq;
 591         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 592         proxy->dev.platform_data = (void *) chip->platform_data;
 593         proxy->controller_data = chip->controller_data;
 594         proxy->controller_state = NULL;
 595
 596         status = spi_add_device(proxy);
 597         if (status < 0) {
 598                 spi_dev_put(proxy);
 599                 return NULL;
 600         }
 601
 602         return proxy;
 603 }
 604 EXPORT_SYMBOL_GPL(spi_new_device);
 605
 606 static void spi_match_master_to_boardinfo(struct spi_master *master,
 607                                 struct spi_board_info *bi)
 608 {
 609         struct spi_device *dev;
 610
 611         if (master->bus_num != bi->bus_num)
 612                 return;
 613
 614         dev = spi_new_device(master, bi);
 615         if (!dev)
 616                 dev_err(master->dev.parent, "can't create new device for %s\n",
 617                         bi->modalias);
 618 }
 619
 620 /**
 621  * spi_register_board_info - register SPI devices for a given board
 622  * @info: array of chip descriptors
 623  * @n: how many descriptors are provided
 624  * Context: can sleep
 625  *
 626  * Board-specific early init code calls this (probably during arch_initcall)
 627  * with segments of the SPI device table.  Any device nodes are created later,
 628  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 629  * this table of devices forever, so that reloading a controller driver will
 630  * not make Linux forget about these hard-wired devices.
 631  *
 632  * Other code can also call this, e.g. a particular add-on board might provide
 633  * SPI devices through its expansion connector, so code initializing that board
 634  * would naturally declare its SPI devices.
 635  *
 636  * The board info passed can safely be __initdata ... but be careful of
 637  * any embedded pointers (platform_data, etc), they're copied as-is.
 638  *
 639  * Return: zero on success, else a negative error code.
 640  */
 641 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 642 {
 643         struct boardinfo *bi;
 644         int i;
 645
 646         if (!n)
 647                 return -EINVAL;
 648
 649         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 650         if (!bi)
 651                 return -ENOMEM;
 652
 653         for (i = 0; i < n; i++, bi++, info++) {
 654                 struct spi_master *master;
 655
 656                 memcpy(&bi->board_info, info, sizeof(*info));
 657                 mutex_lock(&board_lock);
 658                 list_add_tail(&bi->list, &board_list);
 659                 list_for_each_entry(master, &spi_master_list, list)
 660                         spi_match_master_to_boardinfo(master, &bi->board_info);
 661                 mutex_unlock(&board_lock);
 662         }
 663
 664         return 0;
 665 }
 666
 667 /*-------------------------------------------------------------------------*/
 668
 669 static void spi_set_cs(struct spi_device *spi, bool enable)
 670 {
 671         if (spi->mode & SPI_CS_HIGH)
 672                 enable = !enable;
 673
 674         if (gpio_is_valid(spi->cs_gpio))
 675                 gpio_set_value(spi->cs_gpio, !enable);
 676         else if (spi->master->set_cs)
 677                 spi->master->set_cs(spi, !enable);
 678 }
 679
 680 #ifdef CONFIG_HAS_DMA
 681 static int spi_map_buf(struct spi_master *master, struct device *dev,
 682                        struct sg_table *sgt, void *buf, size_t len,
 683                        enum dma_data_direction dir)
 684 {
 685         const bool vmalloced_buf = is_vmalloc_addr(buf);
 686         int desc_len;
 687         int sgs;
 688         struct page *vm_page;
 689         void *sg_buf;
 690         size_t min;
 691         int i, ret;
 692
 693         if (vmalloced_buf) {
 694                 desc_len = PAGE_SIZE;
 695                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 696         } else {
 697                 desc_len = master->max_dma_len;
 698                 sgs = DIV_ROUND_UP(len, desc_len);
 699         }
 700
 701         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 702         if (ret != 0)
 703                 return ret;
 704
 705         for (i = 0; i < sgs; i++) {
 706
 707                 if (vmalloced_buf) {
 708                         min = min_t(size_t,
 709                                     len, desc_len - offset_in_page(buf));
 710                         vm_page = vmalloc_to_page(buf);
 711                         if (!vm_page) {
 712                                 sg_free_table(sgt);
 713                                 return -ENOMEM;
 714                         }
 715                         sg_set_page(&sgt->sgl[i], vm_page,
 716                                     min, offset_in_page(buf));
 717                 } else {
 718                         min = min_t(size_t, len, desc_len);
 719                         sg_buf = buf;
 720                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
 721                 }
 722
 723
 724                 buf += min;
 725                 len -= min;
 726         }
 727
 728         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 729         if (!ret)
 730                 ret = -ENOMEM;
 731         if (ret < 0) {
 732                 sg_free_table(sgt);
 733                 return ret;
 734         }
 735
 736         sgt->nents = ret;
 737
 738         return 0;
 739 }
 740
 741 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 742                           struct sg_table *sgt, enum dma_data_direction dir)
 743 {
 744         if (sgt->orig_nents) {
 745                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 746                 sg_free_table(sgt);
 747         }
 748 }
 749
 750 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 751 {
 752         struct device *tx_dev, *rx_dev;
 753         struct spi_transfer *xfer;
 754         int ret;
 755
 756         if (!master->can_dma)
 757                 return 0;
 758
 759         if (master->dma_tx)
 760                 tx_dev = master->dma_tx->device->dev;
 761         else
 762                 tx_dev = &master->dev;
 763
 764         if (master->dma_rx)
 765                 rx_dev = master->dma_rx->device->dev;
 766         else
 767                 rx_dev = &master->dev;
 768
 769         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 770                 if (!master->can_dma(master, msg->spi, xfer))
 771                         continue;
 772
 773                 if (xfer->tx_buf != NULL) {
 774                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 775                                           (void *)xfer->tx_buf, xfer->len,
 776                                           DMA_TO_DEVICE);
 777                         if (ret != 0)
 778                                 return ret;
 779                 }
 780
 781                 if (xfer->rx_buf != NULL) {
 782                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 783                                           xfer->rx_buf, xfer->len,
 784                                           DMA_FROM_DEVICE);
 785                         if (ret != 0) {
 786                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 787                                               DMA_TO_DEVICE);
 788                                 return ret;
 789                         }
 790                 }
 791         }
 792
 793         master->cur_msg_mapped = true;
 794
 795         return 0;
 796 }
 797
 798 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 799 {
 800         struct spi_transfer *xfer;
 801         struct device *tx_dev, *rx_dev;
 802
 803         if (!master->cur_msg_mapped || !master->can_dma)
 804                 return 0;
 805
 806         if (master->dma_tx)
 807                 tx_dev = master->dma_tx->device->dev;
 808         else
 809                 tx_dev = &master->dev;
 810
 811         if (master->dma_rx)
 812                 rx_dev = master->dma_rx->device->dev;
 813         else
 814                 rx_dev = &master->dev;
 815
 816         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 817                 if (!master->can_dma(master, msg->spi, xfer))
 818                         continue;
 819
 820                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 821                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 822         }
 823
 824         return 0;
 825 }
 826 #else /* !CONFIG_HAS_DMA */
 827 static inline int __spi_map_msg(struct spi_master *master,
 828                                 struct spi_message *msg)
 829 {
 830         return 0;
 831 }
 832
 833 static inline int __spi_unmap_msg(struct spi_master *master,
 834                                   struct spi_message *msg)
 835 {
 836         return 0;
 837 }
 838 #endif /* !CONFIG_HAS_DMA */
 839
 840 static inline int spi_unmap_msg(struct spi_master *master,
 841                                 struct spi_message *msg)
 842 {
 843         struct spi_transfer *xfer;
 844
 845         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 846                 /*
 847                  * Restore the original value of tx_buf or rx_buf if they are
 848                  * NULL.
 849                  */
 850                 if (xfer->tx_buf == master->dummy_tx)
 851                         xfer->tx_buf = NULL;
 852                 if (xfer->rx_buf == master->dummy_rx)
 853                         xfer->rx_buf = NULL;
 854         }
 855
 856         return __spi_unmap_msg(master, msg);
 857 }
 858
 859 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 860 {
 861         struct spi_transfer *xfer;
 862         void *tmp;
 863         unsigned int max_tx, max_rx;
 864
 865         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 866                 max_tx = 0;
 867                 max_rx = 0;
 868
 869                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 870                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 871                             !xfer->tx_buf)
 872                                 max_tx = max(xfer->len, max_tx);
 873                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 874                             !xfer->rx_buf)
 875                                 max_rx = max(xfer->len, max_rx);
 876                 }
 877
 878                 if (max_tx) {
 879                         tmp = krealloc(master->dummy_tx, max_tx,
 880                                        GFP_KERNEL | GFP_DMA);
 881                         if (!tmp)
 882                                 return -ENOMEM;
 883                         master->dummy_tx = tmp;
 884                         memset(tmp, 0, max_tx);
 885                 }
 886
 887                 if (max_rx) {
 888                         tmp = krealloc(master->dummy_rx, max_rx,
 889                                        GFP_KERNEL | GFP_DMA);
 890                         if (!tmp)
 891                                 return -ENOMEM;
 892                         master->dummy_rx = tmp;
 893                 }
 894
 895                 if (max_tx || max_rx) {
 896                         list_for_each_entry(xfer, &msg->transfers,
 897                                             transfer_list) {
 898                                 if (!xfer->tx_buf)
 899                                         xfer->tx_buf = master->dummy_tx;
 900                                 if (!xfer->rx_buf)
 901                                         xfer->rx_buf = master->dummy_rx;
 902                         }
 903                 }
 904         }
 905
 906         return __spi_map_msg(master, msg);
 907 }
 908
 909 /*
 910  * spi_transfer_one_message - Default implementation of transfer_one_message()
 911  *
 912  * This is a standard implementation of transfer_one_message() for
 913  * drivers which impelment a transfer_one() operation.  It provides
 914  * standard handling of delays and chip select management.
 915  */
 916 static int spi_transfer_one_message(struct spi_master *master,
 917                                     struct spi_message *msg)
 918 {
 919         struct spi_transfer *xfer;
 920         bool keep_cs = false;
 921         int ret = 0;
 922         unsigned long ms = 1;
 923         struct spi_statistics *statm = &master->statistics;
 924         struct spi_statistics *stats = &msg->spi->statistics;
 925
 926         spi_set_cs(msg->spi, true);
 927
 928         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 929         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 930
 931         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 932                 trace_spi_transfer_start(msg, xfer);
 933
 934                 spi_statistics_add_transfer_stats(statm, xfer, master);
 935                 spi_statistics_add_transfer_stats(stats, xfer, master);
 936
 937                 if (xfer->tx_buf || xfer->rx_buf) {
 938                         reinit_completion(&master->xfer_completion);
 939
 940                         ret = master->transfer_one(master, msg->spi, xfer);
 941                         if (ret < 0) {
 942                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 943                                                                errors);
 944                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 945                                                                errors);
 946                                 dev_err(&msg->spi->dev,
 947                                         "SPI transfer failed: %d\n", ret);
 948                                 goto out;
 949                         }
 950
 951                         if (ret > 0) {
 952                                 ret = 0;
 953                                 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
 954                                 ms += ms + 100; /* some tolerance */
 955
 956                                 ms = wait_for_completion_timeout(&master->xfer_completion,
 957                                                                  msecs_to_jiffies(ms));
 958                         }
 959
 960                         if (ms == 0) {
 961                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 962                                                                timedout);
 963                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 964                                                                timedout);
 965                                 dev_err(&msg->spi->dev,
 966                                         "SPI transfer timed out\n");
 967                                 msg->status = -ETIMEDOUT;
 968                         }
 969                 } else {
 970                         if (xfer->len)
 971                                 dev_err(&msg->spi->dev,
 972                                         "Bufferless transfer has length %u\n",
 973                                         xfer->len);
 974                 }
 975
 976                 trace_spi_transfer_stop(msg, xfer);
 977
 978                 if (msg->status != -EINPROGRESS)
 979                         goto out;
 980
 981                 if (xfer->delay_usecs)
 982                         udelay(xfer->delay_usecs);
 983
 984                 if (xfer->cs_change) {
 985                         if (list_is_last(&xfer->transfer_list,
 986                                          &msg->transfers)) {
 987                                 keep_cs = true;
 988                         } else {
 989                                 spi_set_cs(msg->spi, false);
 990                                 udelay(10);
 991                                 spi_set_cs(msg->spi, true);
 992                         }
 993                 }
 994
 995                 msg->actual_length += xfer->len;
 996         }
 997
 998 out:
 999         if (ret != 0 || !keep_cs)
1000                 spi_set_cs(msg->spi, false);
1001
1002         if (msg->status == -EINPROGRESS)
1003                 msg->status = ret;
1004
1005         if (msg->status && master->handle_err)
1006                 master->handle_err(master, msg);
1007
1008         spi_finalize_current_message(master);
1009
1010         return ret;
1011 }
1012
1013 /**
1014  * spi_finalize_current_transfer - report completion of a transfer
1015  * @master: the master reporting completion
1016  *
1017  * Called by SPI drivers using the core transfer_one_message()
1018  * implementation to notify it that the current interrupt driven
1019  * transfer has finished and the next one may be scheduled.
1020  */
1021 void spi_finalize_current_transfer(struct spi_master *master)
1022 {
1023         complete(&master->xfer_completion);
1024 }
1025 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1026
1027 /**
1028  * __spi_pump_messages - function which processes spi message queue
1029  * @master: master to process queue for
1030  * @in_kthread: true if we are in the context of the message pump thread
1031  *
1032  * This function checks if there is any spi message in the queue that
1033  * needs processing and if so call out to the driver to initialize hardware
1034  * and transfer each message.
1035  *
1036  * Note that it is called both from the kthread itself and also from
1037  * inside spi_sync(); the queue extraction handling at the top of the
1038  * function should deal with this safely.
1039  */
1040 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1041 {
1042         unsigned long flags;
1043         bool was_busy = false;
1044         int ret;
1045
1046         /* Lock queue */
1047         spin_lock_irqsave(&master->queue_lock, flags);
1048
1049         /* Make sure we are not already running a message */
1050         if (master->cur_msg) {
1051                 spin_unlock_irqrestore(&master->queue_lock, flags);
1052                 return;
1053         }
1054
1055         /* If another context is idling the device then defer */
1056         if (master->idling) {
1057                 queue_kthread_work(&master->kworker, &master->pump_messages);
1058                 spin_unlock_irqrestore(&master->queue_lock, flags);
1059                 return;
1060         }
1061
1062         /* Check if the queue is idle */
1063         if (list_empty(&master->queue) || !master->running) {
1064                 if (!master->busy) {
1065                         spin_unlock_irqrestore(&master->queue_lock, flags);
1066                         return;
1067                 }
1068
1069                 /* Only do teardown in the thread */
1070                 if (!in_kthread) {
1071                         queue_kthread_work(&master->kworker,
1072                                            &master->pump_messages);
1073                         spin_unlock_irqrestore(&master->queue_lock, flags);
1074                         return;
1075                 }
1076
1077                 master->busy = false;
1078                 master->idling = true;
1079                 spin_unlock_irqrestore(&master->queue_lock, flags);
1080
1081                 kfree(master->dummy_rx);
1082                 master->dummy_rx = NULL;
1083                 kfree(master->dummy_tx);
1084                 master->dummy_tx = NULL;
1085                 if (master->unprepare_transfer_hardware &&
1086                     master->unprepare_transfer_hardware(master))
1087                         dev_err(&master->dev,
1088                                 "failed to unprepare transfer hardware\n");
1089                 if (master->auto_runtime_pm) {
1090                         pm_runtime_mark_last_busy(master->dev.parent);
1091                         pm_runtime_put_autosuspend(master->dev.parent);
1092                 }
1093                 trace_spi_master_idle(master);
1094
1095                 spin_lock_irqsave(&master->queue_lock, flags);
1096                 master->idling = false;
1097                 spin_unlock_irqrestore(&master->queue_lock, flags);
1098                 return;
1099         }
1100
1101         /* Extract head of queue */
1102         master->cur_msg =
1103                 list_first_entry(&master->queue, struct spi_message, queue);
1104
1105         list_del_init(&master->cur_msg->queue);
1106         if (master->busy)
1107                 was_busy = true;
1108         else
1109                 master->busy = true;
1110         spin_unlock_irqrestore(&master->queue_lock, flags);
1111
1112         if (!was_busy && master->auto_runtime_pm) {
1113                 ret = pm_runtime_get_sync(master->dev.parent);
1114                 if (ret < 0) {
1115                         dev_err(&master->dev, "Failed to power device: %d\n",
1116                                 ret);
1117                         return;
1118                 }
1119         }
1120
1121         if (!was_busy)
1122                 trace_spi_master_busy(master);
1123
1124         if (!was_busy && master->prepare_transfer_hardware) {
1125                 ret = master->prepare_transfer_hardware(master);
1126                 if (ret) {
1127                         dev_err(&master->dev,
1128                                 "failed to prepare transfer hardware\n");
1129
1130                         if (master->auto_runtime_pm)
1131                                 pm_runtime_put(master->dev.parent);
1132                         return;
1133                 }
1134         }
1135
1136         trace_spi_message_start(master->cur_msg);
1137
1138         if (master->prepare_message) {
1139                 ret = master->prepare_message(master, master->cur_msg);
1140                 if (ret) {
1141                         dev_err(&master->dev,
1142                                 "failed to prepare message: %d\n", ret);
1143                         master->cur_msg->status = ret;
1144                         spi_finalize_current_message(master);
1145                         return;
1146                 }
1147                 master->cur_msg_prepared = true;
1148         }
1149
1150         ret = spi_map_msg(master, master->cur_msg);
1151         if (ret) {
1152                 master->cur_msg->status = ret;
1153                 spi_finalize_current_message(master);
1154                 return;
1155         }
1156
1157         ret = master->transfer_one_message(master, master->cur_msg);
1158         if (ret) {
1159                 dev_err(&master->dev,
1160                         "failed to transfer one message from queue\n");
1161                 return;
1162         }
1163 }
1164
1165 /**
1166  * spi_pump_messages - kthread work function which processes spi message queue
1167  * @work: pointer to kthread work struct contained in the master struct
1168  */
1169 static void spi_pump_messages(struct kthread_work *work)
1170 {
1171         struct spi_master *master =
1172                 container_of(work, struct spi_master, pump_messages);
1173
1174         __spi_pump_messages(master, true);
1175 }
1176
1177 static int spi_init_queue(struct spi_master *master)
1178 {
1179         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1180
1181         master->running = false;
1182         master->busy = false;
1183
1184         init_kthread_worker(&master->kworker);
1185         master->kworker_task = kthread_run(kthread_worker_fn,
1186                                            &master->kworker, "%s",
1187                                            dev_name(&master->dev));
1188         if (IS_ERR(master->kworker_task)) {
1189                 dev_err(&master->dev, "failed to create message pump task\n");
1190                 return PTR_ERR(master->kworker_task);
1191         }
1192         init_kthread_work(&master->pump_messages, spi_pump_messages);
1193
1194         /*
1195          * Master config will indicate if this controller should run the
1196          * message pump with high (realtime) priority to reduce the transfer
1197          * latency on the bus by minimising the delay between a transfer
1198          * request and the scheduling of the message pump thread. Without this
1199          * setting the message pump thread will remain at default priority.
1200          */
1201         if (master->rt) {
1202                 dev_info(&master->dev,
1203                         "will run message pump with realtime priority\n");
1204                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1205         }
1206
1207         return 0;
1208 }
1209
1210 /**
1211  * spi_get_next_queued_message() - called by driver to check for queued
1212  * messages
1213  * @master: the master to check for queued messages
1214  *
1215  * If there are more messages in the queue, the next message is returned from
1216  * this call.
1217  *
1218  * Return: the next message in the queue, else NULL if the queue is empty.
1219  */
1220 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1221 {
1222         struct spi_message *next;
1223         unsigned long flags;
1224
1225         /* get a pointer to the next message, if any */
1226         spin_lock_irqsave(&master->queue_lock, flags);
1227         next = list_first_entry_or_null(&master->queue, struct spi_message,
1228                                         queue);
1229         spin_unlock_irqrestore(&master->queue_lock, flags);
1230
1231         return next;
1232 }
1233 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1234
1235 /**
1236  * spi_finalize_current_message() - the current message is complete
1237  * @master: the master to return the message to
1238  *
1239  * Called by the driver to notify the core that the message in the front of the
1240  * queue is complete and can be removed from the queue.
1241  */
1242 void spi_finalize_current_message(struct spi_master *master)
1243 {
1244         struct spi_message *mesg;
1245         unsigned long flags;
1246         int ret;
1247
1248         spin_lock_irqsave(&master->queue_lock, flags);
1249         mesg = master->cur_msg;
1250         spin_unlock_irqrestore(&master->queue_lock, flags);
1251
1252         spi_unmap_msg(master, mesg);
1253
1254         if (master->cur_msg_prepared && master->unprepare_message) {
1255                 ret = master->unprepare_message(master, mesg);
1256                 if (ret) {
1257                         dev_err(&master->dev,
1258                                 "failed to unprepare message: %d\n", ret);
1259                 }
1260         }
1261
1262         spin_lock_irqsave(&master->queue_lock, flags);
1263         master->cur_msg = NULL;
1264         master->cur_msg_prepared = false;
1265         queue_kthread_work(&master->kworker, &master->pump_messages);
1266         spin_unlock_irqrestore(&master->queue_lock, flags);
1267
1268         trace_spi_message_done(mesg);
1269
1270         mesg->state = NULL;
1271         if (mesg->complete)
1272                 mesg->complete(mesg->context);
1273 }
1274 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1275
1276 static int spi_start_queue(struct spi_master *master)
1277 {
1278         unsigned long flags;
1279
1280         spin_lock_irqsave(&master->queue_lock, flags);
1281
1282         if (master->running || master->busy) {
1283                 spin_unlock_irqrestore(&master->queue_lock, flags);
1284                 return -EBUSY;
1285         }
1286
1287         master->running = true;
1288         master->cur_msg = NULL;
1289         spin_unlock_irqrestore(&master->queue_lock, flags);
1290
1291         queue_kthread_work(&master->kworker, &master->pump_messages);
1292
1293         return 0;
1294 }
1295
1296 static int spi_stop_queue(struct spi_master *master)
1297 {
1298         unsigned long flags;
1299         unsigned limit = 500;
1300         int ret = 0;
1301
1302         spin_lock_irqsave(&master->queue_lock, flags);
1303
1304         /*
1305          * This is a bit lame, but is optimized for the common execution path.
1306          * A wait_queue on the master->busy could be used, but then the common
1307          * execution path (pump_messages) would be required to call wake_up or
1308          * friends on every SPI message. Do this instead.
1309          */
1310         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1311                 spin_unlock_irqrestore(&master->queue_lock, flags);
1312                 usleep_range(10000, 11000);
1313                 spin_lock_irqsave(&master->queue_lock, flags);
1314         }
1315
1316         if (!list_empty(&master->queue) || master->busy)
1317                 ret = -EBUSY;
1318         else
1319                 master->running = false;
1320
1321         spin_unlock_irqrestore(&master->queue_lock, flags);
1322
1323         if (ret) {
1324                 dev_warn(&master->dev,
1325                          "could not stop message queue\n");
1326                 return ret;
1327         }
1328         return ret;
1329 }
1330
1331 static int spi_destroy_queue(struct spi_master *master)
1332 {
1333         int ret;
1334
1335         ret = spi_stop_queue(master);
1336
1337         /*
1338          * flush_kthread_worker will block until all work is done.
1339          * If the reason that stop_queue timed out is that the work will never
1340          * finish, then it does no good to call flush/stop thread, so
1341          * return anyway.
1342          */
1343         if (ret) {
1344                 dev_err(&master->dev, "problem destroying queue\n");
1345                 return ret;
1346         }
1347
1348         flush_kthread_worker(&master->kworker);
1349         kthread_stop(master->kworker_task);
1350
1351         return 0;
1352 }
1353
1354 static int __spi_queued_transfer(struct spi_device *spi,
1355                                  struct spi_message *msg,
1356                                  bool need_pump)
1357 {
1358         struct spi_master *master = spi->master;
1359         unsigned long flags;
1360
1361         spin_lock_irqsave(&master->queue_lock, flags);
1362
1363         if (!master->running) {
1364                 spin_unlock_irqrestore(&master->queue_lock, flags);
1365                 return -ESHUTDOWN;
1366         }
1367         msg->actual_length = 0;
1368         msg->status = -EINPROGRESS;
1369
1370         list_add_tail(&msg->queue, &master->queue);
1371         if (!master->busy && need_pump)
1372                 queue_kthread_work(&master->kworker, &master->pump_messages);
1373
1374         spin_unlock_irqrestore(&master->queue_lock, flags);
1375         return 0;
1376 }
1377
1378 /**
1379  * spi_queued_transfer - transfer function for queued transfers
1380  * @spi: spi device which is requesting transfer
1381  * @msg: spi message which is to handled is queued to driver queue
1382  *
1383  * Return: zero on success, else a negative error code.
1384  */
1385 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1386 {
1387         return __spi_queued_transfer(spi, msg, true);
1388 }
1389
1390 static int spi_master_initialize_queue(struct spi_master *master)
1391 {
1392         int ret;
1393
1394         master->transfer = spi_queued_transfer;
1395         if (!master->transfer_one_message)
1396                 master->transfer_one_message = spi_transfer_one_message;
1397
1398         /* Initialize and start queue */
1399         ret = spi_init_queue(master);
1400         if (ret) {
1401                 dev_err(&master->dev, "problem initializing queue\n");
1402                 goto err_init_queue;
1403         }
1404         master->queued = true;
1405         ret = spi_start_queue(master);
1406         if (ret) {
1407                 dev_err(&master->dev, "problem starting queue\n");
1408                 goto err_start_queue;
1409         }
1410
1411         return 0;
1412
1413 err_start_queue:
1414         spi_destroy_queue(master);
1415 err_init_queue:
1416         return ret;
1417 }
1418
1419 /*-------------------------------------------------------------------------*/
1420
1421 #if defined(CONFIG_OF)
1422 static struct spi_device *
1423 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1424 {
1425         struct spi_device *spi;
1426         int rc;
1427         u32 value;
1428
1429         /* Alloc an spi_device */
1430         spi = spi_alloc_device(master);
1431         if (!spi) {
1432                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1433                         nc->full_name);
1434                 rc = -ENOMEM;
1435                 goto err_out;
1436         }
1437
1438         /* Select device driver */
1439         rc = of_modalias_node(nc, spi->modalias,
1440                                 sizeof(spi->modalias));
1441         if (rc < 0) {
1442                 dev_err(&master->dev, "cannot find modalias for %s\n",
1443                         nc->full_name);
1444                 goto err_out;
1445         }
1446
1447         /* Device address */
1448         rc = of_property_read_u32(nc, "reg", &value);
1449         if (rc) {
1450                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1451                         nc->full_name, rc);
1452                 goto err_out;
1453         }
1454         spi->chip_select = value;
1455
1456         /* Mode (clock phase/polarity/etc.) */
1457         if (of_find_property(nc, "spi-cpha", NULL))
1458                 spi->mode |= SPI_CPHA;
1459         if (of_find_property(nc, "spi-cpol", NULL))
1460                 spi->mode |= SPI_CPOL;
1461         if (of_find_property(nc, "spi-cs-high", NULL))
1462                 spi->mode |= SPI_CS_HIGH;
1463         if (of_find_property(nc, "spi-3wire", NULL))
1464                 spi->mode |= SPI_3WIRE;
1465         if (of_find_property(nc, "spi-lsb-first", NULL))
1466                 spi->mode |= SPI_LSB_FIRST;
1467
1468         /* Device DUAL/QUAD mode */
1469         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1470                 switch (value) {
1471                 case 1:
1472                         break;
1473                 case 2:
1474                         spi->mode |= SPI_TX_DUAL;
1475                         break;
1476                 case 4:
1477                         spi->mode |= SPI_TX_QUAD;
1478                         break;
1479                 default:
1480                         dev_warn(&master->dev,
1481                                 "spi-tx-bus-width %d not supported\n",
1482                                 value);
1483                         break;
1484                 }
1485         }
1486
1487         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1488                 switch (value) {
1489                 case 1:
1490                         break;
1491                 case 2:
1492                         spi->mode |= SPI_RX_DUAL;
1493                         break;
1494                 case 4:
1495                         spi->mode |= SPI_RX_QUAD;
1496                         break;
1497                 default:
1498                         dev_warn(&master->dev,
1499                                 "spi-rx-bus-width %d not supported\n",
1500                                 value);
1501                         break;
1502                 }
1503         }
1504
1505         /* Device speed */
1506         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1507         if (rc) {
1508                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1509                         nc->full_name, rc);
1510                 goto err_out;
1511         }
1512         spi->max_speed_hz = value;
1513
1514         /* Store a pointer to the node in the device structure */
1515         of_node_get(nc);
1516         spi->dev.of_node = nc;
1517
1518         /* Register the new device */
1519         rc = spi_add_device(spi);
1520         if (rc) {
1521                 dev_err(&master->dev, "spi_device register error %s\n",
1522                         nc->full_name);
1523                 goto err_out;
1524         }
1525
1526         return spi;
1527
1528 err_out:
1529         spi_dev_put(spi);
1530         return ERR_PTR(rc);
1531 }
1532
1533 /**
1534  * of_register_spi_devices() - Register child devices onto the SPI bus
1535  * @master:     Pointer to spi_master device
1536  *
1537  * Registers an spi_device for each child node of master node which has a 'reg'
1538  * property.
1539  */
1540 static void of_register_spi_devices(struct spi_master *master)
1541 {
1542         struct spi_device *spi;
1543         struct device_node *nc;
1544
1545         if (!master->dev.of_node)
1546                 return;
1547
1548         for_each_available_child_of_node(master->dev.of_node, nc) {
1549                 spi = of_register_spi_device(master, nc);
1550                 if (IS_ERR(spi))
1551                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1552                                 nc->full_name);
1553         }
1554 }
1555 #else
1556 static void of_register_spi_devices(struct spi_master *master) { }
1557 #endif
1558
1559 #ifdef CONFIG_ACPI
1560 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1561 {
1562         struct spi_device *spi = data;
1563
1564         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1565                 struct acpi_resource_spi_serialbus *sb;
1566
1567                 sb = &ares->data.spi_serial_bus;
1568                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1569                         spi->chip_select = sb->device_selection;
1570                         spi->max_speed_hz = sb->connection_speed;
1571
1572                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1573                                 spi->mode |= SPI_CPHA;
1574                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1575                                 spi->mode |= SPI_CPOL;
1576                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1577                                 spi->mode |= SPI_CS_HIGH;
1578                 }
1579         } else if (spi->irq < 0) {
1580                 struct resource r;
1581
1582                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1583                         spi->irq = r.start;
1584         }
1585
1586         /* Always tell the ACPI core to skip this resource */
1587         return 1;
1588 }
1589
1590 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1591                                        void *data, void **return_value)
1592 {
1593         struct spi_master *master = data;
1594         struct list_head resource_list;
1595         struct acpi_device *adev;
1596         struct spi_device *spi;
1597         int ret;
1598
1599         if (acpi_bus_get_device(handle, &adev))
1600                 return AE_OK;
1601         if (acpi_bus_get_status(adev) || !adev->status.present)
1602                 return AE_OK;
1603
1604         spi = spi_alloc_device(master);
1605         if (!spi) {
1606                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1607                         dev_name(&adev->dev));
1608                 return AE_NO_MEMORY;
1609         }
1610
1611         ACPI_COMPANION_SET(&spi->dev, adev);
1612         spi->irq = -1;
1613
1614         INIT_LIST_HEAD(&resource_list);
1615         ret = acpi_dev_get_resources(adev, &resource_list,
1616                                      acpi_spi_add_resource, spi);
1617         acpi_dev_free_resource_list(&resource_list);
1618
1619         if (ret < 0 || !spi->max_speed_hz) {
1620                 spi_dev_put(spi);
1621                 return AE_OK;
1622         }
1623
1624         adev->power.flags.ignore_parent = true;
1625         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1626         if (spi_add_device(spi)) {
1627                 adev->power.flags.ignore_parent = false;
1628                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1629                         dev_name(&adev->dev));
1630                 spi_dev_put(spi);
1631         }
1632
1633         return AE_OK;
1634 }
1635
1636 static void acpi_register_spi_devices(struct spi_master *master)
1637 {
1638         acpi_status status;
1639         acpi_handle handle;
1640
1641         handle = ACPI_HANDLE(master->dev.parent);
1642         if (!handle)
1643                 return;
1644
1645         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1646                                      acpi_spi_add_device, NULL,
1647                                      master, NULL);
1648         if (ACPI_FAILURE(status))
1649                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1650 }
1651 #else
1652 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1653 #endif /* CONFIG_ACPI */
1654
1655 static void spi_master_release(struct device *dev)
1656 {
1657         struct spi_master *master;
1658
1659         master = container_of(dev, struct spi_master, dev);
1660         kfree(master);
1661 }
1662
1663 static struct class spi_master_class = {
1664         .name           = "spi_master",
1665         .owner          = THIS_MODULE,
1666         .dev_release    = spi_master_release,
1667         .dev_groups     = spi_master_groups,
1668 };
1669
1670
1671 /**
1672  * spi_alloc_master - allocate SPI master controller
1673  * @dev: the controller, possibly using the platform_bus
1674  * @size: how much zeroed driver-private data to allocate; the pointer to this
1675  *      memory is in the driver_data field of the returned device,
1676  *      accessible with spi_master_get_devdata().
1677  * Context: can sleep
1678  *
1679  * This call is used only by SPI master controller drivers, which are the
1680  * only ones directly touching chip registers.  It's how they allocate
1681  * an spi_master structure, prior to calling spi_register_master().
1682  *
1683  * This must be called from context that can sleep.
1684  *
1685  * The caller is responsible for assigning the bus number and initializing
1686  * the master's methods before calling spi_register_master(); and (after errors
1687  * adding the device) calling spi_master_put() to prevent a memory leak.
1688  *
1689  * Return: the SPI master structure on success, else NULL.
1690  */
1691 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1692 {
1693         struct spi_master       *master;
1694
1695         if (!dev)
1696                 return NULL;
1697
1698         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1699         if (!master)
1700                 return NULL;
1701
1702         device_initialize(&master->dev);
1703         master->bus_num = -1;
1704         master->num_chipselect = 1;
1705         master->dev.class = &spi_master_class;
1706         master->dev.parent = get_device(dev);
1707         spi_master_set_devdata(master, &master[1]);
1708
1709         return master;
1710 }
1711 EXPORT_SYMBOL_GPL(spi_alloc_master);
1712
1713 #ifdef CONFIG_OF
1714 static int of_spi_register_master(struct spi_master *master)
1715 {
1716         int nb, i, *cs;
1717         struct device_node *np = master->dev.of_node;
1718
1719         if (!np)
1720                 return 0;
1721
1722         nb = of_gpio_named_count(np, "cs-gpios");
1723         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1724
1725         /* Return error only for an incorrectly formed cs-gpios property */
1726         if (nb == 0 || nb == -ENOENT)
1727                 return 0;
1728         else if (nb < 0)
1729                 return nb;
1730
1731         cs = devm_kzalloc(&master->dev,
1732                           sizeof(int) * master->num_chipselect,
1733                           GFP_KERNEL);
1734         master->cs_gpios = cs;
1735
1736         if (!master->cs_gpios)
1737                 return -ENOMEM;
1738
1739         for (i = 0; i < master->num_chipselect; i++)
1740                 cs[i] = -ENOENT;
1741
1742         for (i = 0; i < nb; i++)
1743                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1744
1745         return 0;
1746 }
1747 #else
1748 static int of_spi_register_master(struct spi_master *master)
1749 {
1750         return 0;
1751 }
1752 #endif
1753
1754 /**
1755  * spi_register_master - register SPI master controller
1756  * @master: initialized master, originally from spi_alloc_master()
1757  * Context: can sleep
1758  *
1759  * SPI master controllers connect to their drivers using some non-SPI bus,
1760  * such as the platform bus.  The final stage of probe() in that code
1761  * includes calling spi_register_master() to hook up to this SPI bus glue.
1762  *
1763  * SPI controllers use board specific (often SOC specific) bus numbers,
1764  * and board-specific addressing for SPI devices combines those numbers
1765  * with chip select numbers.  Since SPI does not directly support dynamic
1766  * device identification, boards need configuration tables telling which
1767  * chip is at which address.
1768  *
1769  * This must be called from context that can sleep.  It returns zero on
1770  * success, else a negative error code (dropping the master's refcount).
1771  * After a successful return, the caller is responsible for calling
1772  * spi_unregister_master().
1773  *
1774  * Return: zero on success, else a negative error code.
1775  */
1776 int spi_register_master(struct spi_master *master)
1777 {
1778         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1779         struct device           *dev = master->dev.parent;
1780         struct boardinfo        *bi;
1781         int                     status = -ENODEV;
1782         int                     dynamic = 0;
1783
1784         if (!dev)
1785                 return -ENODEV;
1786
1787         status = of_spi_register_master(master);
1788         if (status)
1789                 return status;
1790
1791         /* even if it's just one always-selected device, there must
1792          * be at least one chipselect
1793          */
1794         if (master->num_chipselect == 0)
1795                 return -EINVAL;
1796
1797         if ((master->bus_num < 0) && master->dev.of_node)
1798                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1799
1800         /* convention:  dynamically assigned bus IDs count down from the max */
1801         if (master->bus_num < 0) {
1802                 /* FIXME switch to an IDR based scheme, something like
1803                  * I2C now uses, so we can't run out of "dynamic" IDs
1804                  */
1805                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1806                 dynamic = 1;
1807         }
1808
1809         INIT_LIST_HEAD(&master->queue);
1810         spin_lock_init(&master->queue_lock);
1811         spin_lock_init(&master->bus_lock_spinlock);
1812         mutex_init(&master->bus_lock_mutex);
1813         master->bus_lock_flag = 0;
1814         init_completion(&master->xfer_completion);
1815         if (!master->max_dma_len)
1816                 master->max_dma_len = INT_MAX;
1817
1818         /* register the device, then userspace will see it.
1819          * registration fails if the bus ID is in use.
1820          */
1821         dev_set_name(&master->dev, "spi%u", master->bus_num);
1822         status = device_add(&master->dev);
1823         if (status < 0)
1824                 goto done;
1825         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1826                         dynamic ? " (dynamic)" : "");
1827
1828         /* If we're using a queued driver, start the queue */
1829         if (master->transfer)
1830                 dev_info(dev, "master is unqueued, this is deprecated\n");
1831         else {
1832                 status = spi_master_initialize_queue(master);
1833                 if (status) {
1834                         device_del(&master->dev);
1835                         goto done;
1836                 }
1837         }
1838         /* add statistics */
1839         spin_lock_init(&master->statistics.lock);
1840
1841         mutex_lock(&board_lock);
1842         list_add_tail(&master->list, &spi_master_list);
1843         list_for_each_entry(bi, &board_list, list)
1844                 spi_match_master_to_boardinfo(master, &bi->board_info);
1845         mutex_unlock(&board_lock);
1846
1847         /* Register devices from the device tree and ACPI */
1848         of_register_spi_devices(master);
1849         acpi_register_spi_devices(master);
1850 done:
1851         return status;
1852 }
1853 EXPORT_SYMBOL_GPL(spi_register_master);
1854
1855 static void devm_spi_unregister(struct device *dev, void *res)
1856 {
1857         spi_unregister_master(*(struct spi_master **)res);
1858 }
1859
1860 /**
1861  * dev_spi_register_master - register managed SPI master controller
1862  * @dev:    device managing SPI master
1863  * @master: initialized master, originally from spi_alloc_master()
1864  * Context: can sleep
1865  *
1866  * Register a SPI device as with spi_register_master() which will
1867  * automatically be unregister
1868  *
1869  * Return: zero on success, else a negative error code.
1870  */
1871 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1872 {
1873         struct spi_master **ptr;
1874         int ret;
1875
1876         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1877         if (!ptr)
1878                 return -ENOMEM;
1879
1880         ret = spi_register_master(master);
1881         if (!ret) {
1882                 *ptr = master;
1883                 devres_add(dev, ptr);
1884         } else {
1885                 devres_free(ptr);
1886         }
1887
1888         return ret;
1889 }
1890 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1891
1892 static int __unregister(struct device *dev, void *null)
1893 {
1894         spi_unregister_device(to_spi_device(dev));
1895         return 0;
1896 }
1897
1898 /**
1899  * spi_unregister_master - unregister SPI master controller
1900  * @master: the master being unregistered
1901  * Context: can sleep
1902  *
1903  * This call is used only by SPI master controller drivers, which are the
1904  * only ones directly touching chip registers.
1905  *
1906  * This must be called from context that can sleep.
1907  */
1908 void spi_unregister_master(struct spi_master *master)
1909 {
1910         int dummy;
1911
1912         if (master->queued) {
1913                 if (spi_destroy_queue(master))
1914                         dev_err(&master->dev, "queue remove failed\n");
1915         }
1916
1917         mutex_lock(&board_lock);
1918         list_del(&master->list);
1919         mutex_unlock(&board_lock);
1920
1921         dummy = device_for_each_child(&master->dev, NULL, __unregister);
1922         device_unregister(&master->dev);
1923 }
1924 EXPORT_SYMBOL_GPL(spi_unregister_master);
1925
1926 int spi_master_suspend(struct spi_master *master)
1927 {
1928         int ret;
1929
1930         /* Basically no-ops for non-queued masters */
1931         if (!master->queued)
1932                 return 0;
1933
1934         ret = spi_stop_queue(master);
1935         if (ret)
1936                 dev_err(&master->dev, "queue stop failed\n");
1937
1938         return ret;
1939 }
1940 EXPORT_SYMBOL_GPL(spi_master_suspend);
1941
1942 int spi_master_resume(struct spi_master *master)
1943 {
1944         int ret;
1945
1946         if (!master->queued)
1947                 return 0;
1948
1949         ret = spi_start_queue(master);
1950         if (ret)
1951                 dev_err(&master->dev, "queue restart failed\n");
1952
1953         return ret;
1954 }
1955 EXPORT_SYMBOL_GPL(spi_master_resume);
1956
1957 static int __spi_master_match(struct device *dev, const void *data)
1958 {
1959         struct spi_master *m;
1960         const u16 *bus_num = data;
1961
1962         m = container_of(dev, struct spi_master, dev);
1963         return m->bus_num == *bus_num;
1964 }
1965
1966 /**
1967  * spi_busnum_to_master - look up master associated with bus_num
1968  * @bus_num: the master's bus number
1969  * Context: can sleep
1970  *
1971  * This call may be used with devices that are registered after
1972  * arch init time.  It returns a refcounted pointer to the relevant
1973  * spi_master (which the caller must release), or NULL if there is
1974  * no such master registered.
1975  *
1976  * Return: the SPI master structure on success, else NULL.
1977  */
1978 struct spi_master *spi_busnum_to_master(u16 bus_num)
1979 {
1980         struct device           *dev;
1981         struct spi_master       *master = NULL;
1982
1983         dev = class_find_device(&spi_master_class, NULL, &bus_num,
1984                                 __spi_master_match);
1985         if (dev)
1986                 master = container_of(dev, struct spi_master, dev);
1987         /* reference got in class_find_device */
1988         return master;
1989 }
1990 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1991
1992
1993 /*-------------------------------------------------------------------------*/
1994
1995 /* Core methods for SPI master protocol drivers.  Some of the
1996  * other core methods are currently defined as inline functions.
1997  */
1998
1999 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2000 {
2001         if (master->bits_per_word_mask) {
2002                 /* Only 32 bits fit in the mask */
2003                 if (bits_per_word > 32)
2004                         return -EINVAL;
2005                 if (!(master->bits_per_word_mask &
2006                                 SPI_BPW_MASK(bits_per_word)))
2007                         return -EINVAL;
2008         }
2009
2010         return 0;
2011 }
2012
2013 /**
2014  * spi_setup - setup SPI mode and clock rate
2015  * @spi: the device whose settings are being modified
2016  * Context: can sleep, and no requests are queued to the device
2017  *
2018  * SPI protocol drivers may need to update the transfer mode if the
2019  * device doesn't work with its default.  They may likewise need
2020  * to update clock rates or word sizes from initial values.  This function
2021  * changes those settings, and must be called from a context that can sleep.
2022  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2023  * effect the next time the device is selected and data is transferred to
2024  * or from it.  When this function returns, the spi device is deselected.
2025  *
2026  * Note that this call will fail if the protocol driver specifies an option
2027  * that the underlying controller or its driver does not support.  For
2028  * example, not all hardware supports wire transfers using nine bit words,
2029  * LSB-first wire encoding, or active-high chipselects.
2030  *
2031  * Return: zero on success, else a negative error code.
2032  */
2033 int spi_setup(struct spi_device *spi)
2034 {
2035         unsigned        bad_bits, ugly_bits;
2036         int             status;
2037
2038         /* check mode to prevent that DUAL and QUAD set at the same time
2039          */
2040         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2041                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2042                 dev_err(&spi->dev,
2043                 "setup: can not select dual and quad at the same time\n");
2044                 return -EINVAL;
2045         }
2046         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2047          */
2048         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2049                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2050                 return -EINVAL;
2051         /* help drivers fail *cleanly* when they need options
2052          * that aren't supported with their current master
2053          */
2054         bad_bits = spi->mode & ~spi->master->mode_bits;
2055         ugly_bits = bad_bits &
2056                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2057         if (ugly_bits) {
2058                 dev_warn(&spi->dev,
2059                          "setup: ignoring unsupported mode bits %x\n",
2060                          ugly_bits);
2061                 spi->mode &= ~ugly_bits;
2062                 bad_bits &= ~ugly_bits;
2063         }
2064         if (bad_bits) {
2065                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2066                         bad_bits);
2067                 return -EINVAL;
2068         }
2069
2070         if (!spi->bits_per_word)
2071                 spi->bits_per_word = 8;
2072
2073         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2074         if (status)
2075                 return status;
2076
2077         if (!spi->max_speed_hz)
2078                 spi->max_speed_hz = spi->master->max_speed_hz;
2079
2080         spi_set_cs(spi, false);
2081
2082         if (spi->master->setup)
2083                 status = spi->master->setup(spi);
2084
2085         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2086                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2087                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2088                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2089                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2090                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2091                         spi->bits_per_word, spi->max_speed_hz,
2092                         status);
2093
2094         return status;
2095 }
2096 EXPORT_SYMBOL_GPL(spi_setup);
2097
2098 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2099 {
2100         struct spi_master *master = spi->master;
2101         struct spi_transfer *xfer;
2102         int w_size;
2103
2104         if (list_empty(&message->transfers))
2105                 return -EINVAL;
2106
2107         /* Half-duplex links include original MicroWire, and ones with
2108          * only one data pin like SPI_3WIRE (switches direction) or where
2109          * either MOSI or MISO is missing.  They can also be caused by
2110          * software limitations.
2111          */
2112         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2113                         || (spi->mode & SPI_3WIRE)) {
2114                 unsigned flags = master->flags;
2115
2116                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2117                         if (xfer->rx_buf && xfer->tx_buf)
2118                                 return -EINVAL;
2119                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2120                                 return -EINVAL;
2121                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2122                                 return -EINVAL;
2123                 }
2124         }
2125
2126         /**
2127          * Set transfer bits_per_word and max speed as spi device default if
2128          * it is not set for this transfer.
2129          * Set transfer tx_nbits and rx_nbits as single transfer default
2130          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2131          */
2132         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2133                 message->frame_length += xfer->len;
2134                 if (!xfer->bits_per_word)
2135                         xfer->bits_per_word = spi->bits_per_word;
2136
2137                 if (!xfer->speed_hz)
2138                         xfer->speed_hz = spi->max_speed_hz;
2139                 if (!xfer->speed_hz)
2140                         xfer->speed_hz = master->max_speed_hz;
2141
2142                 if (master->max_speed_hz &&
2143                     xfer->speed_hz > master->max_speed_hz)
2144                         xfer->speed_hz = master->max_speed_hz;
2145
2146                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2147                         return -EINVAL;
2148
2149                 /*
2150                  * SPI transfer length should be multiple of SPI word size
2151                  * where SPI word size should be power-of-two multiple
2152                  */
2153                 if (xfer->bits_per_word <= 8)
2154                         w_size = 1;
2155                 else if (xfer->bits_per_word <= 16)
2156                         w_size = 2;
2157                 else
2158                         w_size = 4;
2159
2160                 /* No partial transfers accepted */
2161                 if (xfer->len % w_size)
2162                         return -EINVAL;
2163
2164                 if (xfer->speed_hz && master->min_speed_hz &&
2165                     xfer->speed_hz < master->min_speed_hz)
2166                         return -EINVAL;
2167
2168                 if (xfer->tx_buf && !xfer->tx_nbits)
2169                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2170                 if (xfer->rx_buf && !xfer->rx_nbits)
2171                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2172                 /* check transfer tx/rx_nbits:
2173                  * 1. check the value matches one of single, dual and quad
2174                  * 2. check tx/rx_nbits match the mode in spi_device
2175                  */
2176                 if (xfer->tx_buf) {
2177                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2178                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2179                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2180                                 return -EINVAL;
2181                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2182                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2183                                 return -EINVAL;
2184                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2185                                 !(spi->mode & SPI_TX_QUAD))
2186                                 return -EINVAL;
2187                 }
2188                 /* check transfer rx_nbits */
2189                 if (xfer->rx_buf) {
2190                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2191                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2192                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2193                                 return -EINVAL;
2194                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2195                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2196                                 return -EINVAL;
2197                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2198                                 !(spi->mode & SPI_RX_QUAD))
2199                                 return -EINVAL;
2200                 }
2201         }
2202
2203         message->status = -EINPROGRESS;
2204
2205         return 0;
2206 }
2207
2208 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2209 {
2210         struct spi_master *master = spi->master;
2211
2212         message->spi = spi;
2213
2214         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2215         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2216
2217         trace_spi_message_submit(message);
2218
2219         return master->transfer(spi, message);
2220 }
2221
2222 /**
2223  * spi_async - asynchronous SPI transfer
2224  * @spi: device with which data will be exchanged
2225  * @message: describes the data transfers, including completion callback
2226  * Context: any (irqs may be blocked, etc)
2227  *
2228  * This call may be used in_irq and other contexts which can't sleep,
2229  * as well as from task contexts which can sleep.
2230  *
2231  * The completion callback is invoked in a context which can't sleep.
2232  * Before that invocation, the value of message->status is undefined.
2233  * When the callback is issued, message->status holds either zero (to
2234  * indicate complete success) or a negative error code.  After that
2235  * callback returns, the driver which issued the transfer request may
2236  * deallocate the associated memory; it's no longer in use by any SPI
2237  * core or controller driver code.
2238  *
2239  * Note that although all messages to a spi_device are handled in
2240  * FIFO order, messages may go to different devices in other orders.
2241  * Some device might be higher priority, or have various "hard" access
2242  * time requirements, for example.
2243  *
2244  * On detection of any fault during the transfer, processing of
2245  * the entire message is aborted, and the device is deselected.
2246  * Until returning from the associated message completion callback,
2247  * no other spi_message queued to that device will be processed.
2248  * (This rule applies equally to all the synchronous transfer calls,
2249  * which are wrappers around this core asynchronous primitive.)
2250  *
2251  * Return: zero on success, else a negative error code.
2252  */
2253 int spi_async(struct spi_device *spi, struct spi_message *message)
2254 {
2255         struct spi_master *master = spi->master;
2256         int ret;
2257         unsigned long flags;
2258
2259         ret = __spi_validate(spi, message);
2260         if (ret != 0)
2261                 return ret;
2262
2263         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2264
2265         if (master->bus_lock_flag)
2266                 ret = -EBUSY;
2267         else
2268                 ret = __spi_async(spi, message);
2269
2270         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2271
2272         return ret;
2273 }
2274 EXPORT_SYMBOL_GPL(spi_async);
2275
2276 /**
2277  * spi_async_locked - version of spi_async with exclusive bus usage
2278  * @spi: device with which data will be exchanged
2279  * @message: describes the data transfers, including completion callback
2280  * Context: any (irqs may be blocked, etc)
2281  *
2282  * This call may be used in_irq and other contexts which can't sleep,
2283  * as well as from task contexts which can sleep.
2284  *
2285  * The completion callback is invoked in a context which can't sleep.
2286  * Before that invocation, the value of message->status is undefined.
2287  * When the callback is issued, message->status holds either zero (to
2288  * indicate complete success) or a negative error code.  After that
2289  * callback returns, the driver which issued the transfer request may
2290  * deallocate the associated memory; it's no longer in use by any SPI
2291  * core or controller driver code.
2292  *
2293  * Note that although all messages to a spi_device are handled in
2294  * FIFO order, messages may go to different devices in other orders.
2295  * Some device might be higher priority, or have various "hard" access
2296  * time requirements, for example.
2297  *
2298  * On detection of any fault during the transfer, processing of
2299  * the entire message is aborted, and the device is deselected.
2300  * Until returning from the associated message completion callback,
2301  * no other spi_message queued to that device will be processed.
2302  * (This rule applies equally to all the synchronous transfer calls,
2303  * which are wrappers around this core asynchronous primitive.)
2304  *
2305  * Return: zero on success, else a negative error code.
2306  */
2307 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2308 {
2309         struct spi_master *master = spi->master;
2310         int ret;
2311         unsigned long flags;
2312
2313         ret = __spi_validate(spi, message);
2314         if (ret != 0)
2315                 return ret;
2316
2317         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2318
2319         ret = __spi_async(spi, message);
2320
2321         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2322
2323         return ret;
2324
2325 }
2326 EXPORT_SYMBOL_GPL(spi_async_locked);
2327
2328
2329 /*-------------------------------------------------------------------------*/
2330
2331 /* Utility methods for SPI master protocol drivers, layered on
2332  * top of the core.  Some other utility methods are defined as
2333  * inline functions.
2334  */
2335
2336 static void spi_complete(void *arg)
2337 {
2338         complete(arg);
2339 }
2340
2341 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2342                       int bus_locked)
2343 {
2344         DECLARE_COMPLETION_ONSTACK(done);
2345         int status;
2346         struct spi_master *master = spi->master;
2347         unsigned long flags;
2348
2349         status = __spi_validate(spi, message);
2350         if (status != 0)
2351                 return status;
2352
2353         message->complete = spi_complete;
2354         message->context = &done;
2355         message->spi = spi;
2356
2357         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2358         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2359
2360         if (!bus_locked)
2361                 mutex_lock(&master->bus_lock_mutex);
2362
2363         /* If we're not using the legacy transfer method then we will
2364          * try to transfer in the calling context so special case.
2365          * This code would be less tricky if we could remove the
2366          * support for driver implemented message queues.
2367          */
2368         if (master->transfer == spi_queued_transfer) {
2369                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2370
2371                 trace_spi_message_submit(message);
2372
2373                 status = __spi_queued_transfer(spi, message, false);
2374
2375                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2376         } else {
2377                 status = spi_async_locked(spi, message);
2378         }
2379
2380         if (!bus_locked)
2381                 mutex_unlock(&master->bus_lock_mutex);
2382
2383         if (status == 0) {
2384                 /* Push out the messages in the calling context if we
2385                  * can.
2386                  */
2387                 if (master->transfer == spi_queued_transfer) {
2388                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2389                                                        spi_sync_immediate);
2390                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2391                                                        spi_sync_immediate);
2392                         __spi_pump_messages(master, false);
2393                 }
2394
2395                 wait_for_completion(&done);
2396                 status = message->status;
2397         }
2398         message->context = NULL;
2399         return status;
2400 }
2401
2402 /**
2403  * spi_sync - blocking/synchronous SPI data transfers
2404  * @spi: device with which data will be exchanged
2405  * @message: describes the data transfers
2406  * Context: can sleep
2407  *
2408  * This call may only be used from a context that may sleep.  The sleep
2409  * is non-interruptible, and has no timeout.  Low-overhead controller
2410  * drivers may DMA directly into and out of the message buffers.
2411  *
2412  * Note that the SPI device's chip select is active during the message,
2413  * and then is normally disabled between messages.  Drivers for some
2414  * frequently-used devices may want to minimize costs of selecting a chip,
2415  * by leaving it selected in anticipation that the next message will go
2416  * to the same chip.  (That may increase power usage.)
2417  *
2418  * Also, the caller is guaranteeing that the memory associated with the
2419  * message will not be freed before this call returns.
2420  *
2421  * Return: zero on success, else a negative error code.
2422  */
2423 int spi_sync(struct spi_device *spi, struct spi_message *message)
2424 {
2425         return __spi_sync(spi, message, 0);
2426 }
2427 EXPORT_SYMBOL_GPL(spi_sync);
2428
2429 /**
2430  * spi_sync_locked - version of spi_sync with exclusive bus usage
2431  * @spi: device with which data will be exchanged
2432  * @message: describes the data transfers
2433  * Context: can sleep
2434  *
2435  * This call may only be used from a context that may sleep.  The sleep
2436  * is non-interruptible, and has no timeout.  Low-overhead controller
2437  * drivers may DMA directly into and out of the message buffers.
2438  *
2439  * This call should be used by drivers that require exclusive access to the
2440  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2441  * be released by a spi_bus_unlock call when the exclusive access is over.
2442  *
2443  * Return: zero on success, else a negative error code.
2444  */
2445 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2446 {
2447         return __spi_sync(spi, message, 1);
2448 }
2449 EXPORT_SYMBOL_GPL(spi_sync_locked);
2450
2451 /**
2452  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2453  * @master: SPI bus master that should be locked for exclusive bus access
2454  * Context: can sleep
2455  *
2456  * This call may only be used from a context that may sleep.  The sleep
2457  * is non-interruptible, and has no timeout.
2458  *
2459  * This call should be used by drivers that require exclusive access to the
2460  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2461  * exclusive access is over. Data transfer must be done by spi_sync_locked
2462  * and spi_async_locked calls when the SPI bus lock is held.
2463  *
2464  * Return: always zero.
2465  */
2466 int spi_bus_lock(struct spi_master *master)
2467 {
2468         unsigned long flags;
2469
2470         mutex_lock(&master->bus_lock_mutex);
2471
2472         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2473         master->bus_lock_flag = 1;
2474         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2475
2476         /* mutex remains locked until spi_bus_unlock is called */
2477
2478         return 0;
2479 }
2480 EXPORT_SYMBOL_GPL(spi_bus_lock);
2481
2482 /**
2483  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2484  * @master: SPI bus master that was locked for exclusive bus access
2485  * Context: can sleep
2486  *
2487  * This call may only be used from a context that may sleep.  The sleep
2488  * is non-interruptible, and has no timeout.
2489  *
2490  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2491  * call.
2492  *
2493  * Return: always zero.
2494  */
2495 int spi_bus_unlock(struct spi_master *master)
2496 {
2497         master->bus_lock_flag = 0;
2498
2499         mutex_unlock(&master->bus_lock_mutex);
2500
2501         return 0;
2502 }
2503 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2504
2505 /* portable code must never pass more than 32 bytes */
2506 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
2507
2508 static u8       *buf;
2509
2510 /**
2511  * spi_write_then_read - SPI synchronous write followed by read
2512  * @spi: device with which data will be exchanged
2513  * @txbuf: data to be written (need not be dma-safe)
2514  * @n_tx: size of txbuf, in bytes
2515  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2516  * @n_rx: size of rxbuf, in bytes
2517  * Context: can sleep
2518  *
2519  * This performs a half duplex MicroWire style transaction with the
2520  * device, sending txbuf and then reading rxbuf.  The return value
2521  * is zero for success, else a negative errno status code.
2522  * This call may only be used from a context that may sleep.
2523  *
2524  * Parameters to this routine are always copied using a small buffer;
2525  * portable code should never use this for more than 32 bytes.
2526  * Performance-sensitive or bulk transfer code should instead use
2527  * spi_{async,sync}() calls with dma-safe buffers.
2528  *
2529  * Return: zero on success, else a negative error code.
2530  */
2531 int spi_write_then_read(struct spi_device *spi,
2532                 const void *txbuf, unsigned n_tx,
2533                 void *rxbuf, unsigned n_rx)
2534 {
2535         static DEFINE_MUTEX(lock);
2536
2537         int                     status;
2538         struct spi_message      message;
2539         struct spi_transfer     x[2];
2540         u8                      *local_buf;
2541
2542         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
2543          * copying here, (as a pure convenience thing), but we can
2544          * keep heap costs out of the hot path unless someone else is
2545          * using the pre-allocated buffer or the transfer is too large.
2546          */
2547         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2548                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2549                                     GFP_KERNEL | GFP_DMA);
2550                 if (!local_buf)
2551                         return -ENOMEM;
2552         } else {
2553                 local_buf = buf;
2554         }
2555
2556         spi_message_init(&message);
2557         memset(x, 0, sizeof(x));
2558         if (n_tx) {
2559                 x[0].len = n_tx;
2560                 spi_message_add_tail(&x[0], &message);
2561         }
2562         if (n_rx) {
2563                 x[1].len = n_rx;
2564                 spi_message_add_tail(&x[1], &message);
2565         }
2566
2567         memcpy(local_buf, txbuf, n_tx);
2568         x[0].tx_buf = local_buf;
2569         x[1].rx_buf = local_buf + n_tx;
2570
2571         /* do the i/o */
2572         status = spi_sync(spi, &message);
2573         if (status == 0)
2574                 memcpy(rxbuf, x[1].rx_buf, n_rx);
2575
2576         if (x[0].tx_buf == buf)
2577                 mutex_unlock(&lock);
2578         else
2579                 kfree(local_buf);
2580
2581         return status;
2582 }
2583 EXPORT_SYMBOL_GPL(spi_write_then_read);
2584
2585 /*-------------------------------------------------------------------------*/
2586
2587 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2588 static int __spi_of_device_match(struct device *dev, void *data)
2589 {
2590         return dev->of_node == data;
2591 }
2592
2593 /* must call put_device() when done with returned spi_device device */
2594 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2595 {
2596         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2597                                                 __spi_of_device_match);
2598         return dev ? to_spi_device(dev) : NULL;
2599 }
2600
2601 static int __spi_of_master_match(struct device *dev, const void *data)
2602 {
2603         return dev->of_node == data;
2604 }
2605
2606 /* the spi masters are not using spi_bus, so we find it with another way */
2607 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2608 {
2609         struct device *dev;
2610
2611         dev = class_find_device(&spi_master_class, NULL, node,
2612                                 __spi_of_master_match);
2613         if (!dev)
2614                 return NULL;
2615
2616         /* reference got in class_find_device */
2617         return container_of(dev, struct spi_master, dev);
2618 }
2619
2620 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2621                          void *arg)
2622 {
2623         struct of_reconfig_data *rd = arg;
2624         struct spi_master *master;
2625         struct spi_device *spi;
2626
2627         switch (of_reconfig_get_state_change(action, arg)) {
2628         case OF_RECONFIG_CHANGE_ADD:
2629                 master = of_find_spi_master_by_node(rd->dn->parent);
2630                 if (master == NULL)
2631                         return NOTIFY_OK;       /* not for us */
2632
2633                 spi = of_register_spi_device(master, rd->dn);
2634                 put_device(&master->dev);
2635
2636                 if (IS_ERR(spi)) {
2637                         pr_err("%s: failed to create for '%s'\n",
2638                                         __func__, rd->dn->full_name);
2639                         return notifier_from_errno(PTR_ERR(spi));
2640                 }
2641                 break;
2642
2643         case OF_RECONFIG_CHANGE_REMOVE:
2644                 /* find our device by node */
2645                 spi = of_find_spi_device_by_node(rd->dn);
2646                 if (spi == NULL)
2647                         return NOTIFY_OK;       /* no? not meant for us */
2648
2649                 /* unregister takes one ref away */
2650                 spi_unregister_device(spi);
2651
2652                 /* and put the reference of the find */
2653                 put_device(&spi->dev);
2654                 break;
2655         }
2656
2657         return NOTIFY_OK;
2658 }
2659
2660 static struct notifier_block spi_of_notifier = {
2661         .notifier_call = of_spi_notify,
2662 };
2663 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2664 extern struct notifier_block spi_of_notifier;
2665 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2666
2667 static int __init spi_init(void)
2668 {
2669         int     status;
2670
2671         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2672         if (!buf) {
2673                 status = -ENOMEM;
2674                 goto err0;
2675         }
2676
2677         status = bus_register(&spi_bus_type);
2678         if (status < 0)
2679                 goto err1;
2680
2681         status = class_register(&spi_master_class);
2682         if (status < 0)
2683                 goto err2;
2684
2685         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2686                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2687
2688         return 0;
2689
2690 err2:
2691         bus_unregister(&spi_bus_type);
2692 err1:
2693         kfree(buf);
2694         buf = NULL;
2695 err0:
2696         return status;
2697 }
2698
2699 /* board_info is normally registered in arch_initcall(),
2700  * but even essential drivers wait till later
2701  *
2702  * REVISIT only boardinfo really needs static linking. the rest (device and
2703  * driver registration) _could_ be dynamically linked (modular) ... costs
2704  * include needing to have boardinfo data structures be much more public.
2705  */
2706 postcore_initcall(spi_init);
2707