linux/include/linux/spi/spi.h
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   1/* SPDX-License-Identifier: GPL-2.0-or-later
   2 *
   3 * Copyright (C) 2005 David Brownell
   4 */
   5
   6#ifndef __LINUX_SPI_H
   7#define __LINUX_SPI_H
   8
   9#include <linux/device.h>
  10#include <linux/mod_devicetable.h>
  11#include <linux/slab.h>
  12#include <linux/kthread.h>
  13#include <linux/completion.h>
  14#include <linux/scatterlist.h>
  15#include <linux/gpio/consumer.h>
  16
  17struct dma_chan;
  18struct property_entry;
  19struct spi_controller;
  20struct spi_transfer;
  21struct spi_controller_mem_ops;
  22
  23/*
  24 * INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
  25 * and SPI infrastructure.
  26 */
  27extern struct bus_type spi_bus_type;
  28
  29/**
  30 * struct spi_statistics - statistics for spi transfers
  31 * @lock:          lock protecting this structure
  32 *
  33 * @messages:      number of spi-messages handled
  34 * @transfers:     number of spi_transfers handled
  35 * @errors:        number of errors during spi_transfer
  36 * @timedout:      number of timeouts during spi_transfer
  37 *
  38 * @spi_sync:      number of times spi_sync is used
  39 * @spi_sync_immediate:
  40 *                 number of times spi_sync is executed immediately
  41 *                 in calling context without queuing and scheduling
  42 * @spi_async:     number of times spi_async is used
  43 *
  44 * @bytes:         number of bytes transferred to/from device
  45 * @bytes_tx:      number of bytes sent to device
  46 * @bytes_rx:      number of bytes received from device
  47 *
  48 * @transfer_bytes_histo:
  49 *                 transfer bytes histogramm
  50 *
  51 * @transfers_split_maxsize:
  52 *                 number of transfers that have been split because of
  53 *                 maxsize limit
  54 */
  55struct spi_statistics {
  56        spinlock_t              lock; /* lock for the whole structure */
  57
  58        unsigned long           messages;
  59        unsigned long           transfers;
  60        unsigned long           errors;
  61        unsigned long           timedout;
  62
  63        unsigned long           spi_sync;
  64        unsigned long           spi_sync_immediate;
  65        unsigned long           spi_async;
  66
  67        unsigned long long      bytes;
  68        unsigned long long      bytes_rx;
  69        unsigned long long      bytes_tx;
  70
  71#define SPI_STATISTICS_HISTO_SIZE 17
  72        unsigned long transfer_bytes_histo[SPI_STATISTICS_HISTO_SIZE];
  73
  74        unsigned long transfers_split_maxsize;
  75};
  76
  77void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
  78                                       struct spi_transfer *xfer,
  79                                       struct spi_controller *ctlr);
  80
  81#define SPI_STATISTICS_ADD_TO_FIELD(stats, field, count)        \
  82        do {                                                    \
  83                unsigned long flags;                            \
  84                spin_lock_irqsave(&(stats)->lock, flags);       \
  85                (stats)->field += count;                        \
  86                spin_unlock_irqrestore(&(stats)->lock, flags);  \
  87        } while (0)
  88
  89#define SPI_STATISTICS_INCREMENT_FIELD(stats, field)    \
  90        SPI_STATISTICS_ADD_TO_FIELD(stats, field, 1)
  91
  92/**
  93 * struct spi_device - Controller side proxy for an SPI slave device
  94 * @dev: Driver model representation of the device.
  95 * @controller: SPI controller used with the device.
  96 * @master: Copy of controller, for backwards compatibility.
  97 * @max_speed_hz: Maximum clock rate to be used with this chip
  98 *      (on this board); may be changed by the device's driver.
  99 *      The spi_transfer.speed_hz can override this for each transfer.
 100 * @chip_select: Chipselect, distinguishing chips handled by @controller.
 101 * @mode: The spi mode defines how data is clocked out and in.
 102 *      This may be changed by the device's driver.
 103 *      The "active low" default for chipselect mode can be overridden
 104 *      (by specifying SPI_CS_HIGH) as can the "MSB first" default for
 105 *      each word in a transfer (by specifying SPI_LSB_FIRST).
 106 * @bits_per_word: Data transfers involve one or more words; word sizes
 107 *      like eight or 12 bits are common.  In-memory wordsizes are
 108 *      powers of two bytes (e.g. 20 bit samples use 32 bits).
 109 *      This may be changed by the device's driver, or left at the
 110 *      default (0) indicating protocol words are eight bit bytes.
 111 *      The spi_transfer.bits_per_word can override this for each transfer.
 112 * @irq: Negative, or the number passed to request_irq() to receive
 113 *      interrupts from this device.
 114 * @controller_state: Controller's runtime state
 115 * @controller_data: Board-specific definitions for controller, such as
 116 *      FIFO initialization parameters; from board_info.controller_data
 117 * @modalias: Name of the driver to use with this device, or an alias
 118 *      for that name.  This appears in the sysfs "modalias" attribute
 119 *      for driver coldplugging, and in uevents used for hotplugging
 120 * @cs_gpio: LEGACY: gpio number of the chipselect line (optional, -ENOENT when
 121 *      not using a GPIO line) use cs_gpiod in new drivers by opting in on
 122 *      the spi_master.
 123 * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when
 124 *      not using a GPIO line)
 125 * @word_delay_usecs: microsecond delay to be inserted between consecutive
 126 *      words of a transfer
 127 *
 128 * @statistics: statistics for the spi_device
 129 *
 130 * A @spi_device is used to interchange data between an SPI slave
 131 * (usually a discrete chip) and CPU memory.
 132 *
 133 * In @dev, the platform_data is used to hold information about this
 134 * device that's meaningful to the device's protocol driver, but not
 135 * to its controller.  One example might be an identifier for a chip
 136 * variant with slightly different functionality; another might be
 137 * information about how this particular board wires the chip's pins.
 138 */
 139struct spi_device {
 140        struct device           dev;
 141        struct spi_controller   *controller;
 142        struct spi_controller   *master;        /* compatibility layer */
 143        u32                     max_speed_hz;
 144        u8                      chip_select;
 145        u8                      bits_per_word;
 146        u16                     mode;
 147#define SPI_CPHA        0x01                    /* clock phase */
 148#define SPI_CPOL        0x02                    /* clock polarity */
 149#define SPI_MODE_0      (0|0)                   /* (original MicroWire) */
 150#define SPI_MODE_1      (0|SPI_CPHA)
 151#define SPI_MODE_2      (SPI_CPOL|0)
 152#define SPI_MODE_3      (SPI_CPOL|SPI_CPHA)
 153#define SPI_CS_HIGH     0x04                    /* chipselect active high? */
 154#define SPI_LSB_FIRST   0x08                    /* per-word bits-on-wire */
 155#define SPI_3WIRE       0x10                    /* SI/SO signals shared */
 156#define SPI_LOOP        0x20                    /* loopback mode */
 157#define SPI_NO_CS       0x40                    /* 1 dev/bus, no chipselect */
 158#define SPI_READY       0x80                    /* slave pulls low to pause */
 159#define SPI_TX_DUAL     0x100                   /* transmit with 2 wires */
 160#define SPI_TX_QUAD     0x200                   /* transmit with 4 wires */
 161#define SPI_RX_DUAL     0x400                   /* receive with 2 wires */
 162#define SPI_RX_QUAD     0x800                   /* receive with 4 wires */
 163#define SPI_CS_WORD     0x1000                  /* toggle cs after each word */
 164#define SPI_TX_OCTAL    0x2000                  /* transmit with 8 wires */
 165#define SPI_RX_OCTAL    0x4000                  /* receive with 8 wires */
 166#define SPI_3WIRE_HIZ   0x8000                  /* high impedance turnaround */
 167        int                     irq;
 168        void                    *controller_state;
 169        void                    *controller_data;
 170        char                    modalias[SPI_NAME_SIZE];
 171        const char              *driver_override;
 172        int                     cs_gpio;        /* LEGACY: chip select gpio */
 173        struct gpio_desc        *cs_gpiod;      /* chip select gpio desc */
 174        uint8_t                 word_delay_usecs; /* inter-word delay */
 175
 176        /* the statistics */
 177        struct spi_statistics   statistics;
 178
 179        /*
 180         * likely need more hooks for more protocol options affecting how
 181         * the controller talks to each chip, like:
 182         *  - memory packing (12 bit samples into low bits, others zeroed)
 183         *  - priority
 184         *  - chipselect delays
 185         *  - ...
 186         */
 187};
 188
 189static inline struct spi_device *to_spi_device(struct device *dev)
 190{
 191        return dev ? container_of(dev, struct spi_device, dev) : NULL;
 192}
 193
 194/* most drivers won't need to care about device refcounting */
 195static inline struct spi_device *spi_dev_get(struct spi_device *spi)
 196{
 197        return (spi && get_device(&spi->dev)) ? spi : NULL;
 198}
 199
 200static inline void spi_dev_put(struct spi_device *spi)
 201{
 202        if (spi)
 203                put_device(&spi->dev);
 204}
 205
 206/* ctldata is for the bus_controller driver's runtime state */
 207static inline void *spi_get_ctldata(struct spi_device *spi)
 208{
 209        return spi->controller_state;
 210}
 211
 212static inline void spi_set_ctldata(struct spi_device *spi, void *state)
 213{
 214        spi->controller_state = state;
 215}
 216
 217/* device driver data */
 218
 219static inline void spi_set_drvdata(struct spi_device *spi, void *data)
 220{
 221        dev_set_drvdata(&spi->dev, data);
 222}
 223
 224static inline void *spi_get_drvdata(struct spi_device *spi)
 225{
 226        return dev_get_drvdata(&spi->dev);
 227}
 228
 229struct spi_message;
 230struct spi_transfer;
 231
 232/**
 233 * struct spi_driver - Host side "protocol" driver
 234 * @id_table: List of SPI devices supported by this driver
 235 * @probe: Binds this driver to the spi device.  Drivers can verify
 236 *      that the device is actually present, and may need to configure
 237 *      characteristics (such as bits_per_word) which weren't needed for
 238 *      the initial configuration done during system setup.
 239 * @remove: Unbinds this driver from the spi device
 240 * @shutdown: Standard shutdown callback used during system state
 241 *      transitions such as powerdown/halt and kexec
 242 * @driver: SPI device drivers should initialize the name and owner
 243 *      field of this structure.
 244 *
 245 * This represents the kind of device driver that uses SPI messages to
 246 * interact with the hardware at the other end of a SPI link.  It's called
 247 * a "protocol" driver because it works through messages rather than talking
 248 * directly to SPI hardware (which is what the underlying SPI controller
 249 * driver does to pass those messages).  These protocols are defined in the
 250 * specification for the device(s) supported by the driver.
 251 *
 252 * As a rule, those device protocols represent the lowest level interface
 253 * supported by a driver, and it will support upper level interfaces too.
 254 * Examples of such upper levels include frameworks like MTD, networking,
 255 * MMC, RTC, filesystem character device nodes, and hardware monitoring.
 256 */
 257struct spi_driver {
 258        const struct spi_device_id *id_table;
 259        int                     (*probe)(struct spi_device *spi);
 260        int                     (*remove)(struct spi_device *spi);
 261        void                    (*shutdown)(struct spi_device *spi);
 262        struct device_driver    driver;
 263};
 264
 265static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
 266{
 267        return drv ? container_of(drv, struct spi_driver, driver) : NULL;
 268}
 269
 270extern int __spi_register_driver(struct module *owner, struct spi_driver *sdrv);
 271
 272/**
 273 * spi_unregister_driver - reverse effect of spi_register_driver
 274 * @sdrv: the driver to unregister
 275 * Context: can sleep
 276 */
 277static inline void spi_unregister_driver(struct spi_driver *sdrv)
 278{
 279        if (sdrv)
 280                driver_unregister(&sdrv->driver);
 281}
 282
 283/* use a define to avoid include chaining to get THIS_MODULE */
 284#define spi_register_driver(driver) \
 285        __spi_register_driver(THIS_MODULE, driver)
 286
 287/**
 288 * module_spi_driver() - Helper macro for registering a SPI driver
 289 * @__spi_driver: spi_driver struct
 290 *
 291 * Helper macro for SPI drivers which do not do anything special in module
 292 * init/exit. This eliminates a lot of boilerplate. Each module may only
 293 * use this macro once, and calling it replaces module_init() and module_exit()
 294 */
 295#define module_spi_driver(__spi_driver) \
 296        module_driver(__spi_driver, spi_register_driver, \
 297                        spi_unregister_driver)
 298
 299/**
 300 * struct spi_controller - interface to SPI master or slave controller
 301 * @dev: device interface to this driver
 302 * @list: link with the global spi_controller list
 303 * @bus_num: board-specific (and often SOC-specific) identifier for a
 304 *      given SPI controller.
 305 * @num_chipselect: chipselects are used to distinguish individual
 306 *      SPI slaves, and are numbered from zero to num_chipselects.
 307 *      each slave has a chipselect signal, but it's common that not
 308 *      every chipselect is connected to a slave.
 309 * @dma_alignment: SPI controller constraint on DMA buffers alignment.
 310 * @mode_bits: flags understood by this controller driver
 311 * @bits_per_word_mask: A mask indicating which values of bits_per_word are
 312 *      supported by the driver. Bit n indicates that a bits_per_word n+1 is
 313 *      supported. If set, the SPI core will reject any transfer with an
 314 *      unsupported bits_per_word. If not set, this value is simply ignored,
 315 *      and it's up to the individual driver to perform any validation.
 316 * @min_speed_hz: Lowest supported transfer speed
 317 * @max_speed_hz: Highest supported transfer speed
 318 * @flags: other constraints relevant to this driver
 319 * @slave: indicates that this is an SPI slave controller
 320 * @max_transfer_size: function that returns the max transfer size for
 321 *      a &spi_device; may be %NULL, so the default %SIZE_MAX will be used.
 322 * @max_message_size: function that returns the max message size for
 323 *      a &spi_device; may be %NULL, so the default %SIZE_MAX will be used.
 324 * @io_mutex: mutex for physical bus access
 325 * @bus_lock_spinlock: spinlock for SPI bus locking
 326 * @bus_lock_mutex: mutex for exclusion of multiple callers
 327 * @bus_lock_flag: indicates that the SPI bus is locked for exclusive use
 328 * @setup: updates the device mode and clocking records used by a
 329 *      device's SPI controller; protocol code may call this.  This
 330 *      must fail if an unrecognized or unsupported mode is requested.
 331 *      It's always safe to call this unless transfers are pending on
 332 *      the device whose settings are being modified.
 333 * @transfer: adds a message to the controller's transfer queue.
 334 * @cleanup: frees controller-specific state
 335 * @can_dma: determine whether this controller supports DMA
 336 * @queued: whether this controller is providing an internal message queue
 337 * @kworker: thread struct for message pump
 338 * @kworker_task: pointer to task for message pump kworker thread
 339 * @pump_messages: work struct for scheduling work to the message pump
 340 * @queue_lock: spinlock to syncronise access to message queue
 341 * @queue: message queue
 342 * @idling: the device is entering idle state
 343 * @cur_msg: the currently in-flight message
 344 * @cur_msg_prepared: spi_prepare_message was called for the currently
 345 *                    in-flight message
 346 * @cur_msg_mapped: message has been mapped for DMA
 347 * @xfer_completion: used by core transfer_one_message()
 348 * @busy: message pump is busy
 349 * @running: message pump is running
 350 * @rt: whether this queue is set to run as a realtime task
 351 * @auto_runtime_pm: the core should ensure a runtime PM reference is held
 352 *                   while the hardware is prepared, using the parent
 353 *                   device for the spidev
 354 * @max_dma_len: Maximum length of a DMA transfer for the device.
 355 * @prepare_transfer_hardware: a message will soon arrive from the queue
 356 *      so the subsystem requests the driver to prepare the transfer hardware
 357 *      by issuing this call
 358 * @transfer_one_message: the subsystem calls the driver to transfer a single
 359 *      message while queuing transfers that arrive in the meantime. When the
 360 *      driver is finished with this message, it must call
 361 *      spi_finalize_current_message() so the subsystem can issue the next
 362 *      message
 363 * @unprepare_transfer_hardware: there are currently no more messages on the
 364 *      queue so the subsystem notifies the driver that it may relax the
 365 *      hardware by issuing this call
 366 * @set_cs: set the logic level of the chip select line.  May be called
 367 *          from interrupt context.
 368 * @prepare_message: set up the controller to transfer a single message,
 369 *                   for example doing DMA mapping.  Called from threaded
 370 *                   context.
 371 * @transfer_one: transfer a single spi_transfer.
 372 *                  - return 0 if the transfer is finished,
 373 *                  - return 1 if the transfer is still in progress. When
 374 *                    the driver is finished with this transfer it must
 375 *                    call spi_finalize_current_transfer() so the subsystem
 376 *                    can issue the next transfer. Note: transfer_one and
 377 *                    transfer_one_message are mutually exclusive; when both
 378 *                    are set, the generic subsystem does not call your
 379 *                    transfer_one callback.
 380 * @handle_err: the subsystem calls the driver to handle an error that occurs
 381 *              in the generic implementation of transfer_one_message().
 382 * @mem_ops: optimized/dedicated operations for interactions with SPI memory.
 383 *           This field is optional and should only be implemented if the
 384 *           controller has native support for memory like operations.
 385 * @unprepare_message: undo any work done by prepare_message().
 386 * @slave_abort: abort the ongoing transfer request on an SPI slave controller
 387 * @cs_gpios: LEGACY: array of GPIO descs to use as chip select lines; one per
 388 *      CS number. Any individual value may be -ENOENT for CS lines that
 389 *      are not GPIOs (driven by the SPI controller itself). Use the cs_gpiods
 390 *      in new drivers.
 391 * @cs_gpiods: Array of GPIO descs to use as chip select lines; one per CS
 392 *      number. Any individual value may be NULL for CS lines that
 393 *      are not GPIOs (driven by the SPI controller itself).
 394 * @use_gpio_descriptors: Turns on the code in the SPI core to parse and grab
 395 *      GPIO descriptors rather than using global GPIO numbers grabbed by the
 396 *      driver. This will fill in @cs_gpiods and @cs_gpios should not be used,
 397 *      and SPI devices will have the cs_gpiod assigned rather than cs_gpio.
 398 * @statistics: statistics for the spi_controller
 399 * @dma_tx: DMA transmit channel
 400 * @dma_rx: DMA receive channel
 401 * @dummy_rx: dummy receive buffer for full-duplex devices
 402 * @dummy_tx: dummy transmit buffer for full-duplex devices
 403 * @fw_translate_cs: If the boot firmware uses different numbering scheme
 404 *      what Linux expects, this optional hook can be used to translate
 405 *      between the two.
 406 *
 407 * Each SPI controller can communicate with one or more @spi_device
 408 * children.  These make a small bus, sharing MOSI, MISO and SCK signals
 409 * but not chip select signals.  Each device may be configured to use a
 410 * different clock rate, since those shared signals are ignored unless
 411 * the chip is selected.
 412 *
 413 * The driver for an SPI controller manages access to those devices through
 414 * a queue of spi_message transactions, copying data between CPU memory and
 415 * an SPI slave device.  For each such message it queues, it calls the
 416 * message's completion function when the transaction completes.
 417 */
 418struct spi_controller {
 419        struct device   dev;
 420
 421        struct list_head list;
 422
 423        /* other than negative (== assign one dynamically), bus_num is fully
 424         * board-specific.  usually that simplifies to being SOC-specific.
 425         * example:  one SOC has three SPI controllers, numbered 0..2,
 426         * and one board's schematics might show it using SPI-2.  software
 427         * would normally use bus_num=2 for that controller.
 428         */
 429        s16                     bus_num;
 430
 431        /* chipselects will be integral to many controllers; some others
 432         * might use board-specific GPIOs.
 433         */
 434        u16                     num_chipselect;
 435
 436        /* some SPI controllers pose alignment requirements on DMAable
 437         * buffers; let protocol drivers know about these requirements.
 438         */
 439        u16                     dma_alignment;
 440
 441        /* spi_device.mode flags understood by this controller driver */
 442        u16                     mode_bits;
 443
 444        /* bitmask of supported bits_per_word for transfers */
 445        u32                     bits_per_word_mask;
 446#define SPI_BPW_MASK(bits) BIT((bits) - 1)
 447#define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0U : (BIT(bits) - 1))
 448#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1))
 449
 450        /* limits on transfer speed */
 451        u32                     min_speed_hz;
 452        u32                     max_speed_hz;
 453
 454        /* other constraints relevant to this driver */
 455        u16                     flags;
 456#define SPI_CONTROLLER_HALF_DUPLEX      BIT(0)  /* can't do full duplex */
 457#define SPI_CONTROLLER_NO_RX            BIT(1)  /* can't do buffer read */
 458#define SPI_CONTROLLER_NO_TX            BIT(2)  /* can't do buffer write */
 459#define SPI_CONTROLLER_MUST_RX          BIT(3)  /* requires rx */
 460#define SPI_CONTROLLER_MUST_TX          BIT(4)  /* requires tx */
 461
 462#define SPI_MASTER_GPIO_SS              BIT(5)  /* GPIO CS must select slave */
 463
 464        /* flag indicating this is an SPI slave controller */
 465        bool                    slave;
 466
 467        /*
 468         * on some hardware transfer / message size may be constrained
 469         * the limit may depend on device transfer settings
 470         */
 471        size_t (*max_transfer_size)(struct spi_device *spi);
 472        size_t (*max_message_size)(struct spi_device *spi);
 473
 474        /* I/O mutex */
 475        struct mutex            io_mutex;
 476
 477        /* lock and mutex for SPI bus locking */
 478        spinlock_t              bus_lock_spinlock;
 479        struct mutex            bus_lock_mutex;
 480
 481        /* flag indicating that the SPI bus is locked for exclusive use */
 482        bool                    bus_lock_flag;
 483
 484        /* Setup mode and clock, etc (spi driver may call many times).
 485         *
 486         * IMPORTANT:  this may be called when transfers to another
 487         * device are active.  DO NOT UPDATE SHARED REGISTERS in ways
 488         * which could break those transfers.
 489         */
 490        int                     (*setup)(struct spi_device *spi);
 491
 492        /* bidirectional bulk transfers
 493         *
 494         * + The transfer() method may not sleep; its main role is
 495         *   just to add the message to the queue.
 496         * + For now there's no remove-from-queue operation, or
 497         *   any other request management
 498         * + To a given spi_device, message queueing is pure fifo
 499         *
 500         * + The controller's main job is to process its message queue,
 501         *   selecting a chip (for masters), then transferring data
 502         * + If there are multiple spi_device children, the i/o queue
 503         *   arbitration algorithm is unspecified (round robin, fifo,
 504         *   priority, reservations, preemption, etc)
 505         *
 506         * + Chipselect stays active during the entire message
 507         *   (unless modified by spi_transfer.cs_change != 0).
 508         * + The message transfers use clock and SPI mode parameters
 509         *   previously established by setup() for this device
 510         */
 511        int                     (*transfer)(struct spi_device *spi,
 512                                                struct spi_message *mesg);
 513
 514        /* called on release() to free memory provided by spi_controller */
 515        void                    (*cleanup)(struct spi_device *spi);
 516
 517        /*
 518         * Used to enable core support for DMA handling, if can_dma()
 519         * exists and returns true then the transfer will be mapped
 520         * prior to transfer_one() being called.  The driver should
 521         * not modify or store xfer and dma_tx and dma_rx must be set
 522         * while the device is prepared.
 523         */
 524        bool                    (*can_dma)(struct spi_controller *ctlr,
 525                                           struct spi_device *spi,
 526                                           struct spi_transfer *xfer);
 527
 528        /*
 529         * These hooks are for drivers that want to use the generic
 530         * controller transfer queueing mechanism. If these are used, the
 531         * transfer() function above must NOT be specified by the driver.
 532         * Over time we expect SPI drivers to be phased over to this API.
 533         */
 534        bool                            queued;
 535        struct kthread_worker           kworker;
 536        struct task_struct              *kworker_task;
 537        struct kthread_work             pump_messages;
 538        spinlock_t                      queue_lock;
 539        struct list_head                queue;
 540        struct spi_message              *cur_msg;
 541        bool                            idling;
 542        bool                            busy;
 543        bool                            running;
 544        bool                            rt;
 545        bool                            auto_runtime_pm;
 546        bool                            cur_msg_prepared;
 547        bool                            cur_msg_mapped;
 548        struct completion               xfer_completion;
 549        size_t                          max_dma_len;
 550
 551        int (*prepare_transfer_hardware)(struct spi_controller *ctlr);
 552        int (*transfer_one_message)(struct spi_controller *ctlr,
 553                                    struct spi_message *mesg);
 554        int (*unprepare_transfer_hardware)(struct spi_controller *ctlr);
 555        int (*prepare_message)(struct spi_controller *ctlr,
 556                               struct spi_message *message);
 557        int (*unprepare_message)(struct spi_controller *ctlr,
 558                                 struct spi_message *message);
 559        int (*slave_abort)(struct spi_controller *ctlr);
 560
 561        /*
 562         * These hooks are for drivers that use a generic implementation
 563         * of transfer_one_message() provied by the core.
 564         */
 565        void (*set_cs)(struct spi_device *spi, bool enable);
 566        int (*transfer_one)(struct spi_controller *ctlr, struct spi_device *spi,
 567                            struct spi_transfer *transfer);
 568        void (*handle_err)(struct spi_controller *ctlr,
 569                           struct spi_message *message);
 570
 571        /* Optimized handlers for SPI memory-like operations. */
 572        const struct spi_controller_mem_ops *mem_ops;
 573
 574        /* gpio chip select */
 575        int                     *cs_gpios;
 576        struct gpio_desc        **cs_gpiods;
 577        bool                    use_gpio_descriptors;
 578
 579        /* statistics */
 580        struct spi_statistics   statistics;
 581
 582        /* DMA channels for use with core dmaengine helpers */
 583        struct dma_chan         *dma_tx;
 584        struct dma_chan         *dma_rx;
 585
 586        /* dummy data for full duplex devices */
 587        void                    *dummy_rx;
 588        void                    *dummy_tx;
 589
 590        int (*fw_translate_cs)(struct spi_controller *ctlr, unsigned cs);
 591};
 592
 593static inline void *spi_controller_get_devdata(struct spi_controller *ctlr)
 594{
 595        return dev_get_drvdata(&ctlr->dev);
 596}
 597
 598static inline void spi_controller_set_devdata(struct spi_controller *ctlr,
 599                                              void *data)
 600{
 601        dev_set_drvdata(&ctlr->dev, data);
 602}
 603
 604static inline struct spi_controller *spi_controller_get(struct spi_controller *ctlr)
 605{
 606        if (!ctlr || !get_device(&ctlr->dev))
 607                return NULL;
 608        return ctlr;
 609}
 610
 611static inline void spi_controller_put(struct spi_controller *ctlr)
 612{
 613        if (ctlr)
 614                put_device(&ctlr->dev);
 615}
 616
 617static inline bool spi_controller_is_slave(struct spi_controller *ctlr)
 618{
 619        return IS_ENABLED(CONFIG_SPI_SLAVE) && ctlr->slave;
 620}
 621
 622/* PM calls that need to be issued by the driver */
 623extern int spi_controller_suspend(struct spi_controller *ctlr);
 624extern int spi_controller_resume(struct spi_controller *ctlr);
 625
 626/* Calls the driver make to interact with the message queue */
 627extern struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr);
 628extern void spi_finalize_current_message(struct spi_controller *ctlr);
 629extern void spi_finalize_current_transfer(struct spi_controller *ctlr);
 630
 631/* the spi driver core manages memory for the spi_controller classdev */
 632extern struct spi_controller *__spi_alloc_controller(struct device *host,
 633                                                unsigned int size, bool slave);
 634
 635static inline struct spi_controller *spi_alloc_master(struct device *host,
 636                                                      unsigned int size)
 637{
 638        return __spi_alloc_controller(host, size, false);
 639}
 640
 641static inline struct spi_controller *spi_alloc_slave(struct device *host,
 642                                                     unsigned int size)
 643{
 644        if (!IS_ENABLED(CONFIG_SPI_SLAVE))
 645                return NULL;
 646
 647        return __spi_alloc_controller(host, size, true);
 648}
 649
 650extern int spi_register_controller(struct spi_controller *ctlr);
 651extern int devm_spi_register_controller(struct device *dev,
 652                                        struct spi_controller *ctlr);
 653extern void spi_unregister_controller(struct spi_controller *ctlr);
 654
 655extern struct spi_controller *spi_busnum_to_master(u16 busnum);
 656
 657/*
 658 * SPI resource management while processing a SPI message
 659 */
 660
 661typedef void (*spi_res_release_t)(struct spi_controller *ctlr,
 662                                  struct spi_message *msg,
 663                                  void *res);
 664
 665/**
 666 * struct spi_res - spi resource management structure
 667 * @entry:   list entry
 668 * @release: release code called prior to freeing this resource
 669 * @data:    extra data allocated for the specific use-case
 670 *
 671 * this is based on ideas from devres, but focused on life-cycle
 672 * management during spi_message processing
 673 */
 674struct spi_res {
 675        struct list_head        entry;
 676        spi_res_release_t       release;
 677        unsigned long long      data[]; /* guarantee ull alignment */
 678};
 679
 680extern void *spi_res_alloc(struct spi_device *spi,
 681                           spi_res_release_t release,
 682                           size_t size, gfp_t gfp);
 683extern void spi_res_add(struct spi_message *message, void *res);
 684extern void spi_res_free(void *res);
 685
 686extern void spi_res_release(struct spi_controller *ctlr,
 687                            struct spi_message *message);
 688
 689/*---------------------------------------------------------------------------*/
 690
 691/*
 692 * I/O INTERFACE between SPI controller and protocol drivers
 693 *
 694 * Protocol drivers use a queue of spi_messages, each transferring data
 695 * between the controller and memory buffers.
 696 *
 697 * The spi_messages themselves consist of a series of read+write transfer
 698 * segments.  Those segments always read the same number of bits as they
 699 * write; but one or the other is easily ignored by passing a null buffer
 700 * pointer.  (This is unlike most types of I/O API, because SPI hardware
 701 * is full duplex.)
 702 *
 703 * NOTE:  Allocation of spi_transfer and spi_message memory is entirely
 704 * up to the protocol driver, which guarantees the integrity of both (as
 705 * well as the data buffers) for as long as the message is queued.
 706 */
 707
 708/**
 709 * struct spi_transfer - a read/write buffer pair
 710 * @tx_buf: data to be written (dma-safe memory), or NULL
 711 * @rx_buf: data to be read (dma-safe memory), or NULL
 712 * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped
 713 * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped
 714 * @tx_nbits: number of bits used for writing. If 0 the default
 715 *      (SPI_NBITS_SINGLE) is used.
 716 * @rx_nbits: number of bits used for reading. If 0 the default
 717 *      (SPI_NBITS_SINGLE) is used.
 718 * @len: size of rx and tx buffers (in bytes)
 719 * @speed_hz: Select a speed other than the device default for this
 720 *      transfer. If 0 the default (from @spi_device) is used.
 721 * @bits_per_word: select a bits_per_word other than the device default
 722 *      for this transfer. If 0 the default (from @spi_device) is used.
 723 * @cs_change: affects chipselect after this transfer completes
 724 * @delay_usecs: microseconds to delay after this transfer before
 725 *      (optionally) changing the chipselect status, then starting
 726 *      the next transfer or completing this @spi_message.
 727 * @word_delay_usecs: microseconds to inter word delay after each word size
 728 *      (set by bits_per_word) transmission.
 729 * @word_delay: clock cycles to inter word delay after each word size
 730 *      (set by bits_per_word) transmission.
 731 * @transfer_list: transfers are sequenced through @spi_message.transfers
 732 * @tx_sg: Scatterlist for transmit, currently not for client use
 733 * @rx_sg: Scatterlist for receive, currently not for client use
 734 *
 735 * SPI transfers always write the same number of bytes as they read.
 736 * Protocol drivers should always provide @rx_buf and/or @tx_buf.
 737 * In some cases, they may also want to provide DMA addresses for
 738 * the data being transferred; that may reduce overhead, when the
 739 * underlying driver uses dma.
 740 *
 741 * If the transmit buffer is null, zeroes will be shifted out
 742 * while filling @rx_buf.  If the receive buffer is null, the data
 743 * shifted in will be discarded.  Only "len" bytes shift out (or in).
 744 * It's an error to try to shift out a partial word.  (For example, by
 745 * shifting out three bytes with word size of sixteen or twenty bits;
 746 * the former uses two bytes per word, the latter uses four bytes.)
 747 *
 748 * In-memory data values are always in native CPU byte order, translated
 749 * from the wire byte order (big-endian except with SPI_LSB_FIRST).  So
 750 * for example when bits_per_word is sixteen, buffers are 2N bytes long
 751 * (@len = 2N) and hold N sixteen bit words in CPU byte order.
 752 *
 753 * When the word size of the SPI transfer is not a power-of-two multiple
 754 * of eight bits, those in-memory words include extra bits.  In-memory
 755 * words are always seen by protocol drivers as right-justified, so the
 756 * undefined (rx) or unused (tx) bits are always the most significant bits.
 757 *
 758 * All SPI transfers start with the relevant chipselect active.  Normally
 759 * it stays selected until after the last transfer in a message.  Drivers
 760 * can affect the chipselect signal using cs_change.
 761 *
 762 * (i) If the transfer isn't the last one in the message, this flag is
 763 * used to make the chipselect briefly go inactive in the middle of the
 764 * message.  Toggling chipselect in this way may be needed to terminate
 765 * a chip command, letting a single spi_message perform all of group of
 766 * chip transactions together.
 767 *
 768 * (ii) When the transfer is the last one in the message, the chip may
 769 * stay selected until the next transfer.  On multi-device SPI busses
 770 * with nothing blocking messages going to other devices, this is just
 771 * a performance hint; starting a message to another device deselects
 772 * this one.  But in other cases, this can be used to ensure correctness.
 773 * Some devices need protocol transactions to be built from a series of
 774 * spi_message submissions, where the content of one message is determined
 775 * by the results of previous messages and where the whole transaction
 776 * ends when the chipselect goes intactive.
 777 *
 778 * When SPI can transfer in 1x,2x or 4x. It can get this transfer information
 779 * from device through @tx_nbits and @rx_nbits. In Bi-direction, these
 780 * two should both be set. User can set transfer mode with SPI_NBITS_SINGLE(1x)
 781 * SPI_NBITS_DUAL(2x) and SPI_NBITS_QUAD(4x) to support these three transfer.
 782 *
 783 * The code that submits an spi_message (and its spi_transfers)
 784 * to the lower layers is responsible for managing its memory.
 785 * Zero-initialize every field you don't set up explicitly, to
 786 * insulate against future API updates.  After you submit a message
 787 * and its transfers, ignore them until its completion callback.
 788 */
 789struct spi_transfer {
 790        /* it's ok if tx_buf == rx_buf (right?)
 791         * for MicroWire, one buffer must be null
 792         * buffers must work with dma_*map_single() calls, unless
 793         *   spi_message.is_dma_mapped reports a pre-existing mapping
 794         */
 795        const void      *tx_buf;
 796        void            *rx_buf;
 797        unsigned        len;
 798
 799        dma_addr_t      tx_dma;
 800        dma_addr_t      rx_dma;
 801        struct sg_table tx_sg;
 802        struct sg_table rx_sg;
 803
 804        unsigned        cs_change:1;
 805        unsigned        tx_nbits:3;
 806        unsigned        rx_nbits:3;
 807#define SPI_NBITS_SINGLE        0x01 /* 1bit transfer */
 808#define SPI_NBITS_DUAL          0x02 /* 2bits transfer */
 809#define SPI_NBITS_QUAD          0x04 /* 4bits transfer */
 810        u8              bits_per_word;
 811        u8              word_delay_usecs;
 812        u16             delay_usecs;
 813        u32             speed_hz;
 814        u16             word_delay;
 815
 816        struct list_head transfer_list;
 817};
 818
 819/**
 820 * struct spi_message - one multi-segment SPI transaction
 821 * @transfers: list of transfer segments in this transaction
 822 * @spi: SPI device to which the transaction is queued
 823 * @is_dma_mapped: if true, the caller provided both dma and cpu virtual
 824 *      addresses for each transfer buffer
 825 * @complete: called to report transaction completions
 826 * @context: the argument to complete() when it's called
 827 * @frame_length: the total number of bytes in the message
 828 * @actual_length: the total number of bytes that were transferred in all
 829 *      successful segments
 830 * @status: zero for success, else negative errno
 831 * @queue: for use by whichever driver currently owns the message
 832 * @state: for use by whichever driver currently owns the message
 833 * @resources: for resource management when the spi message is processed
 834 *
 835 * A @spi_message is used to execute an atomic sequence of data transfers,
 836 * each represented by a struct spi_transfer.  The sequence is "atomic"
 837 * in the sense that no other spi_message may use that SPI bus until that
 838 * sequence completes.  On some systems, many such sequences can execute as
 839 * as single programmed DMA transfer.  On all systems, these messages are
 840 * queued, and might complete after transactions to other devices.  Messages
 841 * sent to a given spi_device are always executed in FIFO order.
 842 *
 843 * The code that submits an spi_message (and its spi_transfers)
 844 * to the lower layers is responsible for managing its memory.
 845 * Zero-initialize every field you don't set up explicitly, to
 846 * insulate against future API updates.  After you submit a message
 847 * and its transfers, ignore them until its completion callback.
 848 */
 849struct spi_message {
 850        struct list_head        transfers;
 851
 852        struct spi_device       *spi;
 853
 854        unsigned                is_dma_mapped:1;
 855
 856        /* REVISIT:  we might want a flag affecting the behavior of the
 857         * last transfer ... allowing things like "read 16 bit length L"
 858         * immediately followed by "read L bytes".  Basically imposing
 859         * a specific message scheduling algorithm.
 860         *
 861         * Some controller drivers (message-at-a-time queue processing)
 862         * could provide that as their default scheduling algorithm.  But
 863         * others (with multi-message pipelines) could need a flag to
 864         * tell them about such special cases.
 865         */
 866
 867        /* completion is reported through a callback */
 868        void                    (*complete)(void *context);
 869        void                    *context;
 870        unsigned                frame_length;
 871        unsigned                actual_length;
 872        int                     status;
 873
 874        /* for optional use by whatever driver currently owns the
 875         * spi_message ...  between calls to spi_async and then later
 876         * complete(), that's the spi_controller controller driver.
 877         */
 878        struct list_head        queue;
 879        void                    *state;
 880
 881        /* list of spi_res reources when the spi message is processed */
 882        struct list_head        resources;
 883};
 884
 885static inline void spi_message_init_no_memset(struct spi_message *m)
 886{
 887        INIT_LIST_HEAD(&m->transfers);
 888        INIT_LIST_HEAD(&m->resources);
 889}
 890
 891static inline void spi_message_init(struct spi_message *m)
 892{
 893        memset(m, 0, sizeof *m);
 894        spi_message_init_no_memset(m);
 895}
 896
 897static inline void
 898spi_message_add_tail(struct spi_transfer *t, struct spi_message *m)
 899{
 900        list_add_tail(&t->transfer_list, &m->transfers);
 901}
 902
 903static inline void
 904spi_transfer_del(struct spi_transfer *t)
 905{
 906        list_del(&t->transfer_list);
 907}
 908
 909/**
 910 * spi_message_init_with_transfers - Initialize spi_message and append transfers
 911 * @m: spi_message to be initialized
 912 * @xfers: An array of spi transfers
 913 * @num_xfers: Number of items in the xfer array
 914 *
 915 * This function initializes the given spi_message and adds each spi_transfer in
 916 * the given array to the message.
 917 */
 918static inline void
 919spi_message_init_with_transfers(struct spi_message *m,
 920struct spi_transfer *xfers, unsigned int num_xfers)
 921{
 922        unsigned int i;
 923
 924        spi_message_init(m);
 925        for (i = 0; i < num_xfers; ++i)
 926                spi_message_add_tail(&xfers[i], m);
 927}
 928
 929/* It's fine to embed message and transaction structures in other data
 930 * structures so long as you don't free them while they're in use.
 931 */
 932
 933static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags)
 934{
 935        struct spi_message *m;
 936
 937        m = kzalloc(sizeof(struct spi_message)
 938                        + ntrans * sizeof(struct spi_transfer),
 939                        flags);
 940        if (m) {
 941                unsigned i;
 942                struct spi_transfer *t = (struct spi_transfer *)(m + 1);
 943
 944                spi_message_init_no_memset(m);
 945                for (i = 0; i < ntrans; i++, t++)
 946                        spi_message_add_tail(t, m);
 947        }
 948        return m;
 949}
 950
 951static inline void spi_message_free(struct spi_message *m)
 952{
 953        kfree(m);
 954}
 955
 956extern int spi_setup(struct spi_device *spi);
 957extern int spi_async(struct spi_device *spi, struct spi_message *message);
 958extern int spi_async_locked(struct spi_device *spi,
 959                            struct spi_message *message);
 960extern int spi_slave_abort(struct spi_device *spi);
 961
 962static inline size_t
 963spi_max_message_size(struct spi_device *spi)
 964{
 965        struct spi_controller *ctlr = spi->controller;
 966
 967        if (!ctlr->max_message_size)
 968                return SIZE_MAX;
 969        return ctlr->max_message_size(spi);
 970}
 971
 972static inline size_t
 973spi_max_transfer_size(struct spi_device *spi)
 974{
 975        struct spi_controller *ctlr = spi->controller;
 976        size_t tr_max = SIZE_MAX;
 977        size_t msg_max = spi_max_message_size(spi);
 978
 979        if (ctlr->max_transfer_size)
 980                tr_max = ctlr->max_transfer_size(spi);
 981
 982        /* transfer size limit must not be greater than messsage size limit */
 983        return min(tr_max, msg_max);
 984}
 985
 986/*---------------------------------------------------------------------------*/
 987
 988/* SPI transfer replacement methods which make use of spi_res */
 989
 990struct spi_replaced_transfers;
 991typedef void (*spi_replaced_release_t)(struct spi_controller *ctlr,
 992                                       struct spi_message *msg,
 993                                       struct spi_replaced_transfers *res);
 994/**
 995 * struct spi_replaced_transfers - structure describing the spi_transfer
 996 *                                 replacements that have occurred
 997 *                                 so that they can get reverted
 998 * @release:            some extra release code to get executed prior to
 999 *                      relasing this structure
1000 * @extradata:          pointer to some extra data if requested or NULL
1001 * @replaced_transfers: transfers that have been replaced and which need
1002 *                      to get restored
1003 * @replaced_after:     the transfer after which the @replaced_transfers
1004 *                      are to get re-inserted
1005 * @inserted:           number of transfers inserted
1006 * @inserted_transfers: array of spi_transfers of array-size @inserted,
1007 *                      that have been replacing replaced_transfers
1008 *
1009 * note: that @extradata will point to @inserted_transfers[@inserted]
1010 * if some extra allocation is requested, so alignment will be the same
1011 * as for spi_transfers
1012 */
1013struct spi_replaced_transfers {
1014        spi_replaced_release_t release;
1015        void *extradata;
1016        struct list_head replaced_transfers;
1017        struct list_head *replaced_after;
1018        size_t inserted;
1019        struct spi_transfer inserted_transfers[];
1020};
1021
1022extern struct spi_replaced_transfers *spi_replace_transfers(
1023        struct spi_message *msg,
1024        struct spi_transfer *xfer_first,
1025        size_t remove,
1026        size_t insert,
1027        spi_replaced_release_t release,
1028        size_t extradatasize,
1029        gfp_t gfp);
1030
1031/*---------------------------------------------------------------------------*/
1032
1033/* SPI transfer transformation methods */
1034
1035extern int spi_split_transfers_maxsize(struct spi_controller *ctlr,
1036                                       struct spi_message *msg,
1037                                       size_t maxsize,
1038                                       gfp_t gfp);
1039
1040/*---------------------------------------------------------------------------*/
1041
1042/* All these synchronous SPI transfer routines are utilities layered
1043 * over the core async transfer primitive.  Here, "synchronous" means
1044 * they will sleep uninterruptibly until the async transfer completes.
1045 */
1046
1047extern int spi_sync(struct spi_device *spi, struct spi_message *message);
1048extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message);
1049extern int spi_bus_lock(struct spi_controller *ctlr);
1050extern int spi_bus_unlock(struct spi_controller *ctlr);
1051
1052/**
1053 * spi_sync_transfer - synchronous SPI data transfer
1054 * @spi: device with which data will be exchanged
1055 * @xfers: An array of spi_transfers
1056 * @num_xfers: Number of items in the xfer array
1057 * Context: can sleep
1058 *
1059 * Does a synchronous SPI data transfer of the given spi_transfer array.
1060 *
1061 * For more specific semantics see spi_sync().
1062 *
1063 * Return: Return: zero on success, else a negative error code.
1064 */
1065static inline int
1066spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers,
1067        unsigned int num_xfers)
1068{
1069        struct spi_message msg;
1070
1071        spi_message_init_with_transfers(&msg, xfers, num_xfers);
1072
1073        return spi_sync(spi, &msg);
1074}
1075
1076/**
1077 * spi_write - SPI synchronous write
1078 * @spi: device to which data will be written
1079 * @buf: data buffer
1080 * @len: data buffer size
1081 * Context: can sleep
1082 *
1083 * This function writes the buffer @buf.
1084 * Callable only from contexts that can sleep.
1085 *
1086 * Return: zero on success, else a negative error code.
1087 */
1088static inline int
1089spi_write(struct spi_device *spi, const void *buf, size_t len)
1090{
1091        struct spi_transfer     t = {
1092                        .tx_buf         = buf,
1093                        .len            = len,
1094                };
1095
1096        return spi_sync_transfer(spi, &t, 1);
1097}
1098
1099/**
1100 * spi_read - SPI synchronous read
1101 * @spi: device from which data will be read
1102 * @buf: data buffer
1103 * @len: data buffer size
1104 * Context: can sleep
1105 *
1106 * This function reads the buffer @buf.
1107 * Callable only from contexts that can sleep.
1108 *
1109 * Return: zero on success, else a negative error code.
1110 */
1111static inline int
1112spi_read(struct spi_device *spi, void *buf, size_t len)
1113{
1114        struct spi_transfer     t = {
1115                        .rx_buf         = buf,
1116                        .len            = len,
1117                };
1118
1119        return spi_sync_transfer(spi, &t, 1);
1120}
1121
1122/* this copies txbuf and rxbuf data; for small transfers only! */
1123extern int spi_write_then_read(struct spi_device *spi,
1124                const void *txbuf, unsigned n_tx,
1125                void *rxbuf, unsigned n_rx);
1126
1127/**
1128 * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
1129 * @spi: device with which data will be exchanged
1130 * @cmd: command to be written before data is read back
1131 * Context: can sleep
1132 *
1133 * Callable only from contexts that can sleep.
1134 *
1135 * Return: the (unsigned) eight bit number returned by the
1136 * device, or else a negative error code.
1137 */
1138static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd)
1139{
1140        ssize_t                 status;
1141        u8                      result;
1142
1143        status = spi_write_then_read(spi, &cmd, 1, &result, 1);
1144
1145        /* return negative errno or unsigned value */
1146        return (status < 0) ? status : result;
1147}
1148
1149/**
1150 * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read
1151 * @spi: device with which data will be exchanged
1152 * @cmd: command to be written before data is read back
1153 * Context: can sleep
1154 *
1155 * The number is returned in wire-order, which is at least sometimes
1156 * big-endian.
1157 *
1158 * Callable only from contexts that can sleep.
1159 *
1160 * Return: the (unsigned) sixteen bit number returned by the
1161 * device, or else a negative error code.
1162 */
1163static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd)
1164{
1165        ssize_t                 status;
1166        u16                     result;
1167
1168        status = spi_write_then_read(spi, &cmd, 1, &result, 2);
1169
1170        /* return negative errno or unsigned value */
1171        return (status < 0) ? status : result;
1172}
1173
1174/**
1175 * spi_w8r16be - SPI synchronous 8 bit write followed by 16 bit big-endian read
1176 * @spi: device with which data will be exchanged
1177 * @cmd: command to be written before data is read back
1178 * Context: can sleep
1179 *
1180 * This function is similar to spi_w8r16, with the exception that it will
1181 * convert the read 16 bit data word from big-endian to native endianness.
1182 *
1183 * Callable only from contexts that can sleep.
1184 *
1185 * Return: the (unsigned) sixteen bit number returned by the device in cpu
1186 * endianness, or else a negative error code.
1187 */
1188static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd)
1189
1190{
1191        ssize_t status;
1192        __be16 result;
1193
1194        status = spi_write_then_read(spi, &cmd, 1, &result, 2);
1195        if (status < 0)
1196                return status;
1197
1198        return be16_to_cpu(result);
1199}
1200
1201/*---------------------------------------------------------------------------*/
1202
1203/*
1204 * INTERFACE between board init code and SPI infrastructure.
1205 *
1206 * No SPI driver ever sees these SPI device table segments, but
1207 * it's how the SPI core (or adapters that get hotplugged) grows
1208 * the driver model tree.
1209 *
1210 * As a rule, SPI devices can't be probed.  Instead, board init code
1211 * provides a table listing the devices which are present, with enough
1212 * information to bind and set up the device's driver.  There's basic
1213 * support for nonstatic configurations too; enough to handle adding
1214 * parport adapters, or microcontrollers acting as USB-to-SPI bridges.
1215 */
1216
1217/**
1218 * struct spi_board_info - board-specific template for a SPI device
1219 * @modalias: Initializes spi_device.modalias; identifies the driver.
1220 * @platform_data: Initializes spi_device.platform_data; the particular
1221 *      data stored there is driver-specific.
1222 * @properties: Additional device properties for the device.
1223 * @controller_data: Initializes spi_device.controller_data; some
1224 *      controllers need hints about hardware setup, e.g. for DMA.
1225 * @irq: Initializes spi_device.irq; depends on how the board is wired.
1226 * @max_speed_hz: Initializes spi_device.max_speed_hz; based on limits
1227 *      from the chip datasheet and board-specific signal quality issues.
1228 * @bus_num: Identifies which spi_controller parents the spi_device; unused
1229 *      by spi_new_device(), and otherwise depends on board wiring.
1230 * @chip_select: Initializes spi_device.chip_select; depends on how
1231 *      the board is wired.
1232 * @mode: Initializes spi_device.mode; based on the chip datasheet, board
1233 *      wiring (some devices support both 3WIRE and standard modes), and
1234 *      possibly presence of an inverter in the chipselect path.
1235 *
1236 * When adding new SPI devices to the device tree, these structures serve
1237 * as a partial device template.  They hold information which can't always
1238 * be determined by drivers.  Information that probe() can establish (such
1239 * as the default transfer wordsize) is not included here.
1240 *
1241 * These structures are used in two places.  Their primary role is to
1242 * be stored in tables of board-specific device descriptors, which are
1243 * declared early in board initialization and then used (much later) to
1244 * populate a controller's device tree after the that controller's driver
1245 * initializes.  A secondary (and atypical) role is as a parameter to
1246 * spi_new_device() call, which happens after those controller drivers
1247 * are active in some dynamic board configuration models.
1248 */
1249struct spi_board_info {
1250        /* the device name and module name are coupled, like platform_bus;
1251         * "modalias" is normally the driver name.
1252         *
1253         * platform_data goes to spi_device.dev.platform_data,
1254         * controller_data goes to spi_device.controller_data,
1255         * device properties are copied and attached to spi_device,
1256         * irq is copied too
1257         */
1258        char            modalias[SPI_NAME_SIZE];
1259        const void      *platform_data;
1260        const struct property_entry *properties;
1261        void            *controller_data;
1262        int             irq;
1263
1264        /* slower signaling on noisy or low voltage boards */
1265        u32             max_speed_hz;
1266
1267
1268        /* bus_num is board specific and matches the bus_num of some
1269         * spi_controller that will probably be registered later.
1270         *
1271         * chip_select reflects how this chip is wired to that master;
1272         * it's less than num_chipselect.
1273         */
1274        u16             bus_num;
1275        u16             chip_select;
1276
1277        /* mode becomes spi_device.mode, and is essential for chips
1278         * where the default of SPI_CS_HIGH = 0 is wrong.
1279         */
1280        u16             mode;
1281
1282        /* ... may need additional spi_device chip config data here.
1283         * avoid stuff protocol drivers can set; but include stuff
1284         * needed to behave without being bound to a driver:
1285         *  - quirks like clock rate mattering when not selected
1286         */
1287};
1288
1289#ifdef  CONFIG_SPI
1290extern int
1291spi_register_board_info(struct spi_board_info const *info, unsigned n);
1292#else
1293/* board init code may ignore whether SPI is configured or not */
1294static inline int
1295spi_register_board_info(struct spi_board_info const *info, unsigned n)
1296        { return 0; }
1297#endif
1298
1299/* If you're hotplugging an adapter with devices (parport, usb, etc)
1300 * use spi_new_device() to describe each device.  You can also call
1301 * spi_unregister_device() to start making that device vanish, but
1302 * normally that would be handled by spi_unregister_controller().
1303 *
1304 * You can also use spi_alloc_device() and spi_add_device() to use a two
1305 * stage registration sequence for each spi_device.  This gives the caller
1306 * some more control over the spi_device structure before it is registered,
1307 * but requires that caller to initialize fields that would otherwise
1308 * be defined using the board info.
1309 */
1310extern struct spi_device *
1311spi_alloc_device(struct spi_controller *ctlr);
1312
1313extern int
1314spi_add_device(struct spi_device *spi);
1315
1316extern struct spi_device *
1317spi_new_device(struct spi_controller *, struct spi_board_info *);
1318
1319extern void spi_unregister_device(struct spi_device *spi);
1320
1321extern const struct spi_device_id *
1322spi_get_device_id(const struct spi_device *sdev);
1323
1324static inline bool
1325spi_transfer_is_last(struct spi_controller *ctlr, struct spi_transfer *xfer)
1326{
1327        return list_is_last(&xfer->transfer_list, &ctlr->cur_msg->transfers);
1328}
1329
1330/* OF support code */
1331#if IS_ENABLED(CONFIG_OF)
1332
1333/* must call put_device() when done with returned spi_device device */
1334extern struct spi_device *
1335of_find_spi_device_by_node(struct device_node *node);
1336
1337#else
1338
1339static inline struct spi_device *
1340of_find_spi_device_by_node(struct device_node *node)
1341{
1342        return NULL;
1343}
1344
1345#endif /* IS_ENABLED(CONFIG_OF) */
1346
1347/* Compatibility layer */
1348#define spi_master                      spi_controller
1349
1350#define SPI_MASTER_HALF_DUPLEX          SPI_CONTROLLER_HALF_DUPLEX
1351#define SPI_MASTER_NO_RX                SPI_CONTROLLER_NO_RX
1352#define SPI_MASTER_NO_TX                SPI_CONTROLLER_NO_TX
1353#define SPI_MASTER_MUST_RX              SPI_CONTROLLER_MUST_RX
1354#define SPI_MASTER_MUST_TX              SPI_CONTROLLER_MUST_TX
1355
1356#define spi_master_get_devdata(_ctlr)   spi_controller_get_devdata(_ctlr)
1357#define spi_master_set_devdata(_ctlr, _data)    \
1358        spi_controller_set_devdata(_ctlr, _data)
1359#define spi_master_get(_ctlr)           spi_controller_get(_ctlr)
1360#define spi_master_put(_ctlr)           spi_controller_put(_ctlr)
1361#define spi_master_suspend(_ctlr)       spi_controller_suspend(_ctlr)
1362#define spi_master_resume(_ctlr)        spi_controller_resume(_ctlr)
1363
1364#define spi_register_master(_ctlr)      spi_register_controller(_ctlr)
1365#define devm_spi_register_master(_dev, _ctlr) \
1366        devm_spi_register_controller(_dev, _ctlr)
1367#define spi_unregister_master(_ctlr)    spi_unregister_controller(_ctlr)
1368
1369#endif /* __LINUX_SPI_H */
1370