2 * Copyright (C) 2005 David Brownell
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
18 #include <linux/device.h>
19 #include <linux/mod_devicetable.h>
20 #include <linux/slab.h>
21 #include <linux/kthread.h>
22 #include <linux/completion.h>
23 #include <linux/scatterlist.h>
26 struct property_entry
;
27 struct spi_controller
;
29 struct spi_flash_read_message
;
32 * INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
33 * and SPI infrastructure.
35 extern struct bus_type spi_bus_type
;
38 * struct spi_statistics - statistics for spi transfers
39 * @lock: lock protecting this structure
41 * @messages: number of spi-messages handled
42 * @transfers: number of spi_transfers handled
43 * @errors: number of errors during spi_transfer
44 * @timedout: number of timeouts during spi_transfer
46 * @spi_sync: number of times spi_sync is used
47 * @spi_sync_immediate:
48 * number of times spi_sync is executed immediately
49 * in calling context without queuing and scheduling
50 * @spi_async: number of times spi_async is used
52 * @bytes: number of bytes transferred to/from device
53 * @bytes_tx: number of bytes sent to device
54 * @bytes_rx: number of bytes received from device
56 * @transfer_bytes_histo:
57 * transfer bytes histogramm
59 * @transfers_split_maxsize:
60 * number of transfers that have been split because of
63 struct spi_statistics
{
64 spinlock_t lock
; /* lock for the whole structure */
66 unsigned long messages
;
67 unsigned long transfers
;
69 unsigned long timedout
;
71 unsigned long spi_sync
;
72 unsigned long spi_sync_immediate
;
73 unsigned long spi_async
;
75 unsigned long long bytes
;
76 unsigned long long bytes_rx
;
77 unsigned long long bytes_tx
;
79 #define SPI_STATISTICS_HISTO_SIZE 17
80 unsigned long transfer_bytes_histo
[SPI_STATISTICS_HISTO_SIZE
];
82 unsigned long transfers_split_maxsize
;
85 void spi_statistics_add_transfer_stats(struct spi_statistics
*stats
,
86 struct spi_transfer
*xfer
,
87 struct spi_controller
*ctlr
);
89 #define SPI_STATISTICS_ADD_TO_FIELD(stats, field, count) \
91 unsigned long flags; \
92 spin_lock_irqsave(&(stats)->lock, flags); \
93 (stats)->field += count; \
94 spin_unlock_irqrestore(&(stats)->lock, flags); \
97 #define SPI_STATISTICS_INCREMENT_FIELD(stats, field) \
98 SPI_STATISTICS_ADD_TO_FIELD(stats, field, 1)
101 * struct spi_device - Controller side proxy for an SPI slave device
102 * @dev: Driver model representation of the device.
103 * @controller: SPI controller used with the device.
104 * @master: Copy of controller, for backwards compatibility.
105 * @max_speed_hz: Maximum clock rate to be used with this chip
106 * (on this board); may be changed by the device's driver.
107 * The spi_transfer.speed_hz can override this for each transfer.
108 * @chip_select: Chipselect, distinguishing chips handled by @controller.
109 * @mode: The spi mode defines how data is clocked out and in.
110 * This may be changed by the device's driver.
111 * The "active low" default for chipselect mode can be overridden
112 * (by specifying SPI_CS_HIGH) as can the "MSB first" default for
113 * each word in a transfer (by specifying SPI_LSB_FIRST).
114 * @bits_per_word: Data transfers involve one or more words; word sizes
115 * like eight or 12 bits are common. In-memory wordsizes are
116 * powers of two bytes (e.g. 20 bit samples use 32 bits).
117 * This may be changed by the device's driver, or left at the
118 * default (0) indicating protocol words are eight bit bytes.
119 * The spi_transfer.bits_per_word can override this for each transfer.
120 * @irq: Negative, or the number passed to request_irq() to receive
121 * interrupts from this device.
122 * @controller_state: Controller's runtime state
123 * @controller_data: Board-specific definitions for controller, such as
124 * FIFO initialization parameters; from board_info.controller_data
125 * @modalias: Name of the driver to use with this device, or an alias
126 * for that name. This appears in the sysfs "modalias" attribute
127 * for driver coldplugging, and in uevents used for hotplugging
128 * @cs_gpio: gpio number of the chipselect line (optional, -ENOENT when
129 * not using a GPIO line)
131 * @statistics: statistics for the spi_device
133 * A @spi_device is used to interchange data between an SPI slave
134 * (usually a discrete chip) and CPU memory.
136 * In @dev, the platform_data is used to hold information about this
137 * device that's meaningful to the device's protocol driver, but not
138 * to its controller. One example might be an identifier for a chip
139 * variant with slightly different functionality; another might be
140 * information about how this particular board wires the chip's pins.
144 struct spi_controller
*controller
;
145 struct spi_controller
*master
; /* compatibility layer */
150 #define SPI_CPHA 0x01 /* clock phase */
151 #define SPI_CPOL 0x02 /* clock polarity */
152 #define SPI_MODE_0 (0|0) /* (original MicroWire) */
153 #define SPI_MODE_1 (0|SPI_CPHA)
154 #define SPI_MODE_2 (SPI_CPOL|0)
155 #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
156 #define SPI_CS_HIGH 0x04 /* chipselect active high? */
157 #define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
158 #define SPI_3WIRE 0x10 /* SI/SO signals shared */
159 #define SPI_LOOP 0x20 /* loopback mode */
160 #define SPI_NO_CS 0x40 /* 1 dev/bus, no chipselect */
161 #define SPI_READY 0x80 /* slave pulls low to pause */
162 #define SPI_TX_DUAL 0x100 /* transmit with 2 wires */
163 #define SPI_TX_QUAD 0x200 /* transmit with 4 wires */
164 #define SPI_RX_DUAL 0x400 /* receive with 2 wires */
165 #define SPI_RX_QUAD 0x800 /* receive with 4 wires */
167 void *controller_state
;
168 void *controller_data
;
169 char modalias
[SPI_NAME_SIZE
];
170 int cs_gpio
; /* chip select gpio */
173 struct spi_statistics statistics
;
176 * likely need more hooks for more protocol options affecting how
177 * the controller talks to each chip, like:
178 * - memory packing (12 bit samples into low bits, others zeroed)
180 * - drop chipselect after each word
181 * - chipselect delays
186 static inline struct spi_device
*to_spi_device(struct device
*dev
)
188 return dev
? container_of(dev
, struct spi_device
, dev
) : NULL
;
191 /* most drivers won't need to care about device refcounting */
192 static inline struct spi_device
*spi_dev_get(struct spi_device
*spi
)
194 return (spi
&& get_device(&spi
->dev
)) ? spi
: NULL
;
197 static inline void spi_dev_put(struct spi_device
*spi
)
200 put_device(&spi
->dev
);
203 /* ctldata is for the bus_controller driver's runtime state */
204 static inline void *spi_get_ctldata(struct spi_device
*spi
)
206 return spi
->controller_state
;
209 static inline void spi_set_ctldata(struct spi_device
*spi
, void *state
)
211 spi
->controller_state
= state
;
214 /* device driver data */
216 static inline void spi_set_drvdata(struct spi_device
*spi
, void *data
)
218 dev_set_drvdata(&spi
->dev
, data
);
221 static inline void *spi_get_drvdata(struct spi_device
*spi
)
223 return dev_get_drvdata(&spi
->dev
);
230 * struct spi_driver - Host side "protocol" driver
231 * @id_table: List of SPI devices supported by this driver
232 * @probe: Binds this driver to the spi device. Drivers can verify
233 * that the device is actually present, and may need to configure
234 * characteristics (such as bits_per_word) which weren't needed for
235 * the initial configuration done during system setup.
236 * @remove: Unbinds this driver from the spi device
237 * @shutdown: Standard shutdown callback used during system state
238 * transitions such as powerdown/halt and kexec
239 * @driver: SPI device drivers should initialize the name and owner
240 * field of this structure.
242 * This represents the kind of device driver that uses SPI messages to
243 * interact with the hardware at the other end of a SPI link. It's called
244 * a "protocol" driver because it works through messages rather than talking
245 * directly to SPI hardware (which is what the underlying SPI controller
246 * driver does to pass those messages). These protocols are defined in the
247 * specification for the device(s) supported by the driver.
249 * As a rule, those device protocols represent the lowest level interface
250 * supported by a driver, and it will support upper level interfaces too.
251 * Examples of such upper levels include frameworks like MTD, networking,
252 * MMC, RTC, filesystem character device nodes, and hardware monitoring.
255 const struct spi_device_id
*id_table
;
256 int (*probe
)(struct spi_device
*spi
);
257 int (*remove
)(struct spi_device
*spi
);
258 void (*shutdown
)(struct spi_device
*spi
);
259 struct device_driver driver
;
262 static inline struct spi_driver
*to_spi_driver(struct device_driver
*drv
)
264 return drv
? container_of(drv
, struct spi_driver
, driver
) : NULL
;
267 extern int __spi_register_driver(struct module
*owner
, struct spi_driver
*sdrv
);
270 * spi_unregister_driver - reverse effect of spi_register_driver
271 * @sdrv: the driver to unregister
274 static inline void spi_unregister_driver(struct spi_driver
*sdrv
)
277 driver_unregister(&sdrv
->driver
);
280 /* use a define to avoid include chaining to get THIS_MODULE */
281 #define spi_register_driver(driver) \
282 __spi_register_driver(THIS_MODULE, driver)
285 * module_spi_driver() - Helper macro for registering a SPI driver
286 * @__spi_driver: spi_driver struct
288 * Helper macro for SPI drivers which do not do anything special in module
289 * init/exit. This eliminates a lot of boilerplate. Each module may only
290 * use this macro once, and calling it replaces module_init() and module_exit()
292 #define module_spi_driver(__spi_driver) \
293 module_driver(__spi_driver, spi_register_driver, \
294 spi_unregister_driver)
297 * struct spi_controller - interface to SPI master or slave controller
298 * @dev: device interface to this driver
299 * @list: link with the global spi_controller list
300 * @bus_num: board-specific (and often SOC-specific) identifier for a
301 * given SPI controller.
302 * @num_chipselect: chipselects are used to distinguish individual
303 * SPI slaves, and are numbered from zero to num_chipselects.
304 * each slave has a chipselect signal, but it's common that not
305 * every chipselect is connected to a slave.
306 * @dma_alignment: SPI controller constraint on DMA buffers alignment.
307 * @mode_bits: flags understood by this controller driver
308 * @bits_per_word_mask: A mask indicating which values of bits_per_word are
309 * supported by the driver. Bit n indicates that a bits_per_word n+1 is
310 * supported. If set, the SPI core will reject any transfer with an
311 * unsupported bits_per_word. If not set, this value is simply ignored,
312 * and it's up to the individual driver to perform any validation.
313 * @min_speed_hz: Lowest supported transfer speed
314 * @max_speed_hz: Highest supported transfer speed
315 * @flags: other constraints relevant to this driver
316 * @slave: indicates that this is an SPI slave controller
317 * @max_transfer_size: function that returns the max transfer size for
318 * a &spi_device; may be %NULL, so the default %SIZE_MAX will be used.
319 * @max_message_size: function that returns the max message size for
320 * a &spi_device; may be %NULL, so the default %SIZE_MAX will be used.
321 * @io_mutex: mutex for physical bus access
322 * @bus_lock_spinlock: spinlock for SPI bus locking
323 * @bus_lock_mutex: mutex for exclusion of multiple callers
324 * @bus_lock_flag: indicates that the SPI bus is locked for exclusive use
325 * @setup: updates the device mode and clocking records used by a
326 * device's SPI controller; protocol code may call this. This
327 * must fail if an unrecognized or unsupported mode is requested.
328 * It's always safe to call this unless transfers are pending on
329 * the device whose settings are being modified.
330 * @transfer: adds a message to the controller's transfer queue.
331 * @cleanup: frees controller-specific state
332 * @can_dma: determine whether this controller supports DMA
333 * @queued: whether this controller is providing an internal message queue
334 * @kworker: thread struct for message pump
335 * @kworker_task: pointer to task for message pump kworker thread
336 * @pump_messages: work struct for scheduling work to the message pump
337 * @queue_lock: spinlock to syncronise access to message queue
338 * @queue: message queue
339 * @idling: the device is entering idle state
340 * @cur_msg: the currently in-flight message
341 * @cur_msg_prepared: spi_prepare_message was called for the currently
343 * @cur_msg_mapped: message has been mapped for DMA
344 * @xfer_completion: used by core transfer_one_message()
345 * @busy: message pump is busy
346 * @running: message pump is running
347 * @rt: whether this queue is set to run as a realtime task
348 * @auto_runtime_pm: the core should ensure a runtime PM reference is held
349 * while the hardware is prepared, using the parent
350 * device for the spidev
351 * @max_dma_len: Maximum length of a DMA transfer for the device.
352 * @prepare_transfer_hardware: a message will soon arrive from the queue
353 * so the subsystem requests the driver to prepare the transfer hardware
354 * by issuing this call
355 * @transfer_one_message: the subsystem calls the driver to transfer a single
356 * message while queuing transfers that arrive in the meantime. When the
357 * driver is finished with this message, it must call
358 * spi_finalize_current_message() so the subsystem can issue the next
360 * @unprepare_transfer_hardware: there are currently no more messages on the
361 * queue so the subsystem notifies the driver that it may relax the
362 * hardware by issuing this call
363 * @set_cs: set the logic level of the chip select line. May be called
364 * from interrupt context.
365 * @prepare_message: set up the controller to transfer a single message,
366 * for example doing DMA mapping. Called from threaded
368 * @transfer_one: transfer a single spi_transfer.
369 * - return 0 if the transfer is finished,
370 * - return 1 if the transfer is still in progress. When
371 * the driver is finished with this transfer it must
372 * call spi_finalize_current_transfer() so the subsystem
373 * can issue the next transfer. Note: transfer_one and
374 * transfer_one_message are mutually exclusive; when both
375 * are set, the generic subsystem does not call your
376 * transfer_one callback.
377 * @handle_err: the subsystem calls the driver to handle an error that occurs
378 * in the generic implementation of transfer_one_message().
379 * @unprepare_message: undo any work done by prepare_message().
380 * @slave_abort: abort the ongoing transfer request on an SPI slave controller
381 * @spi_flash_read: to support spi-controller hardwares that provide
382 * accelerated interface to read from flash devices.
383 * @spi_flash_can_dma: analogous to can_dma() interface, but for
384 * controllers implementing spi_flash_read.
385 * @flash_read_supported: spi device supports flash read
386 * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
387 * number. Any individual value may be -ENOENT for CS lines that
388 * are not GPIOs (driven by the SPI controller itself).
389 * @statistics: statistics for the spi_controller
390 * @dma_tx: DMA transmit channel
391 * @dma_rx: DMA receive channel
392 * @dummy_rx: dummy receive buffer for full-duplex devices
393 * @dummy_tx: dummy transmit buffer for full-duplex devices
394 * @fw_translate_cs: If the boot firmware uses different numbering scheme
395 * what Linux expects, this optional hook can be used to translate
398 * Each SPI controller can communicate with one or more @spi_device
399 * children. These make a small bus, sharing MOSI, MISO and SCK signals
400 * but not chip select signals. Each device may be configured to use a
401 * different clock rate, since those shared signals are ignored unless
402 * the chip is selected.
404 * The driver for an SPI controller manages access to those devices through
405 * a queue of spi_message transactions, copying data between CPU memory and
406 * an SPI slave device. For each such message it queues, it calls the
407 * message's completion function when the transaction completes.
409 struct spi_controller
{
412 struct list_head list
;
414 /* other than negative (== assign one dynamically), bus_num is fully
415 * board-specific. usually that simplifies to being SOC-specific.
416 * example: one SOC has three SPI controllers, numbered 0..2,
417 * and one board's schematics might show it using SPI-2. software
418 * would normally use bus_num=2 for that controller.
422 /* chipselects will be integral to many controllers; some others
423 * might use board-specific GPIOs.
427 /* some SPI controllers pose alignment requirements on DMAable
428 * buffers; let protocol drivers know about these requirements.
432 /* spi_device.mode flags understood by this controller driver */
435 /* bitmask of supported bits_per_word for transfers */
436 u32 bits_per_word_mask
;
437 #define SPI_BPW_MASK(bits) BIT((bits) - 1)
438 #define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0U : (BIT(bits) - 1))
439 #define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1))
441 /* limits on transfer speed */
445 /* other constraints relevant to this driver */
447 #define SPI_CONTROLLER_HALF_DUPLEX BIT(0) /* can't do full duplex */
448 #define SPI_CONTROLLER_NO_RX BIT(1) /* can't do buffer read */
449 #define SPI_CONTROLLER_NO_TX BIT(2) /* can't do buffer write */
450 #define SPI_CONTROLLER_MUST_RX BIT(3) /* requires rx */
451 #define SPI_CONTROLLER_MUST_TX BIT(4) /* requires tx */
453 #define SPI_MASTER_GPIO_SS BIT(5) /* GPIO CS must select slave */
455 /* flag indicating this is an SPI slave controller */
459 * on some hardware transfer / message size may be constrained
460 * the limit may depend on device transfer settings
462 size_t (*max_transfer_size
)(struct spi_device
*spi
);
463 size_t (*max_message_size
)(struct spi_device
*spi
);
466 struct mutex io_mutex
;
468 /* lock and mutex for SPI bus locking */
469 spinlock_t bus_lock_spinlock
;
470 struct mutex bus_lock_mutex
;
472 /* flag indicating that the SPI bus is locked for exclusive use */
475 /* Setup mode and clock, etc (spi driver may call many times).
477 * IMPORTANT: this may be called when transfers to another
478 * device are active. DO NOT UPDATE SHARED REGISTERS in ways
479 * which could break those transfers.
481 int (*setup
)(struct spi_device
*spi
);
483 /* bidirectional bulk transfers
485 * + The transfer() method may not sleep; its main role is
486 * just to add the message to the queue.
487 * + For now there's no remove-from-queue operation, or
488 * any other request management
489 * + To a given spi_device, message queueing is pure fifo
491 * + The controller's main job is to process its message queue,
492 * selecting a chip (for masters), then transferring data
493 * + If there are multiple spi_device children, the i/o queue
494 * arbitration algorithm is unspecified (round robin, fifo,
495 * priority, reservations, preemption, etc)
497 * + Chipselect stays active during the entire message
498 * (unless modified by spi_transfer.cs_change != 0).
499 * + The message transfers use clock and SPI mode parameters
500 * previously established by setup() for this device
502 int (*transfer
)(struct spi_device
*spi
,
503 struct spi_message
*mesg
);
505 /* called on release() to free memory provided by spi_controller */
506 void (*cleanup
)(struct spi_device
*spi
);
509 * Used to enable core support for DMA handling, if can_dma()
510 * exists and returns true then the transfer will be mapped
511 * prior to transfer_one() being called. The driver should
512 * not modify or store xfer and dma_tx and dma_rx must be set
513 * while the device is prepared.
515 bool (*can_dma
)(struct spi_controller
*ctlr
,
516 struct spi_device
*spi
,
517 struct spi_transfer
*xfer
);
520 * These hooks are for drivers that want to use the generic
521 * controller transfer queueing mechanism. If these are used, the
522 * transfer() function above must NOT be specified by the driver.
523 * Over time we expect SPI drivers to be phased over to this API.
526 struct kthread_worker kworker
;
527 struct task_struct
*kworker_task
;
528 struct kthread_work pump_messages
;
529 spinlock_t queue_lock
;
530 struct list_head queue
;
531 struct spi_message
*cur_msg
;
536 bool auto_runtime_pm
;
537 bool cur_msg_prepared
;
539 struct completion xfer_completion
;
542 int (*prepare_transfer_hardware
)(struct spi_controller
*ctlr
);
543 int (*transfer_one_message
)(struct spi_controller
*ctlr
,
544 struct spi_message
*mesg
);
545 int (*unprepare_transfer_hardware
)(struct spi_controller
*ctlr
);
546 int (*prepare_message
)(struct spi_controller
*ctlr
,
547 struct spi_message
*message
);
548 int (*unprepare_message
)(struct spi_controller
*ctlr
,
549 struct spi_message
*message
);
550 int (*slave_abort
)(struct spi_controller
*ctlr
);
551 int (*spi_flash_read
)(struct spi_device
*spi
,
552 struct spi_flash_read_message
*msg
);
553 bool (*spi_flash_can_dma
)(struct spi_device
*spi
,
554 struct spi_flash_read_message
*msg
);
555 bool (*flash_read_supported
)(struct spi_device
*spi
);
558 * These hooks are for drivers that use a generic implementation
559 * of transfer_one_message() provied by the core.
561 void (*set_cs
)(struct spi_device
*spi
, bool enable
);
562 int (*transfer_one
)(struct spi_controller
*ctlr
, struct spi_device
*spi
,
563 struct spi_transfer
*transfer
);
564 void (*handle_err
)(struct spi_controller
*ctlr
,
565 struct spi_message
*message
);
567 /* gpio chip select */
571 struct spi_statistics statistics
;
573 /* DMA channels for use with core dmaengine helpers */
574 struct dma_chan
*dma_tx
;
575 struct dma_chan
*dma_rx
;
577 /* dummy data for full duplex devices */
581 int (*fw_translate_cs
)(struct spi_controller
*ctlr
, unsigned cs
);
584 static inline void *spi_controller_get_devdata(struct spi_controller
*ctlr
)
586 return dev_get_drvdata(&ctlr
->dev
);
589 static inline void spi_controller_set_devdata(struct spi_controller
*ctlr
,
592 dev_set_drvdata(&ctlr
->dev
, data
);
595 static inline struct spi_controller
*spi_controller_get(struct spi_controller
*ctlr
)
597 if (!ctlr
|| !get_device(&ctlr
->dev
))
602 static inline void spi_controller_put(struct spi_controller
*ctlr
)
605 put_device(&ctlr
->dev
);
608 static inline bool spi_controller_is_slave(struct spi_controller
*ctlr
)
610 return IS_ENABLED(CONFIG_SPI_SLAVE
) && ctlr
->slave
;
613 /* PM calls that need to be issued by the driver */
614 extern int spi_controller_suspend(struct spi_controller
*ctlr
);
615 extern int spi_controller_resume(struct spi_controller
*ctlr
);
617 /* Calls the driver make to interact with the message queue */
618 extern struct spi_message
*spi_get_next_queued_message(struct spi_controller
*ctlr
);
619 extern void spi_finalize_current_message(struct spi_controller
*ctlr
);
620 extern void spi_finalize_current_transfer(struct spi_controller
*ctlr
);
622 /* the spi driver core manages memory for the spi_controller classdev */
623 extern struct spi_controller
*__spi_alloc_controller(struct device
*host
,
624 unsigned int size
, bool slave
);
626 static inline struct spi_controller
*spi_alloc_master(struct device
*host
,
629 return __spi_alloc_controller(host
, size
, false);
632 static inline struct spi_controller
*spi_alloc_slave(struct device
*host
,
635 if (!IS_ENABLED(CONFIG_SPI_SLAVE
))
638 return __spi_alloc_controller(host
, size
, true);
641 extern int spi_register_controller(struct spi_controller
*ctlr
);
642 extern int devm_spi_register_controller(struct device
*dev
,
643 struct spi_controller
*ctlr
);
644 extern void spi_unregister_controller(struct spi_controller
*ctlr
);
646 extern struct spi_controller
*spi_busnum_to_master(u16 busnum
);
649 * SPI resource management while processing a SPI message
652 typedef void (*spi_res_release_t
)(struct spi_controller
*ctlr
,
653 struct spi_message
*msg
,
657 * struct spi_res - spi resource management structure
659 * @release: release code called prior to freeing this resource
660 * @data: extra data allocated for the specific use-case
662 * this is based on ideas from devres, but focused on life-cycle
663 * management during spi_message processing
666 struct list_head entry
;
667 spi_res_release_t release
;
668 unsigned long long data
[]; /* guarantee ull alignment */
671 extern void *spi_res_alloc(struct spi_device
*spi
,
672 spi_res_release_t release
,
673 size_t size
, gfp_t gfp
);
674 extern void spi_res_add(struct spi_message
*message
, void *res
);
675 extern void spi_res_free(void *res
);
677 extern void spi_res_release(struct spi_controller
*ctlr
,
678 struct spi_message
*message
);
680 /*---------------------------------------------------------------------------*/
683 * I/O INTERFACE between SPI controller and protocol drivers
685 * Protocol drivers use a queue of spi_messages, each transferring data
686 * between the controller and memory buffers.
688 * The spi_messages themselves consist of a series of read+write transfer
689 * segments. Those segments always read the same number of bits as they
690 * write; but one or the other is easily ignored by passing a null buffer
691 * pointer. (This is unlike most types of I/O API, because SPI hardware
694 * NOTE: Allocation of spi_transfer and spi_message memory is entirely
695 * up to the protocol driver, which guarantees the integrity of both (as
696 * well as the data buffers) for as long as the message is queued.
700 * struct spi_transfer - a read/write buffer pair
701 * @tx_buf: data to be written (dma-safe memory), or NULL
702 * @rx_buf: data to be read (dma-safe memory), or NULL
703 * @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped
704 * @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped
705 * @tx_nbits: number of bits used for writing. If 0 the default
706 * (SPI_NBITS_SINGLE) is used.
707 * @rx_nbits: number of bits used for reading. If 0 the default
708 * (SPI_NBITS_SINGLE) is used.
709 * @len: size of rx and tx buffers (in bytes)
710 * @speed_hz: Select a speed other than the device default for this
711 * transfer. If 0 the default (from @spi_device) is used.
712 * @bits_per_word: select a bits_per_word other than the device default
713 * for this transfer. If 0 the default (from @spi_device) is used.
714 * @cs_change: affects chipselect after this transfer completes
715 * @delay_usecs: microseconds to delay after this transfer before
716 * (optionally) changing the chipselect status, then starting
717 * the next transfer or completing this @spi_message.
718 * @transfer_list: transfers are sequenced through @spi_message.transfers
719 * @tx_sg: Scatterlist for transmit, currently not for client use
720 * @rx_sg: Scatterlist for receive, currently not for client use
722 * SPI transfers always write the same number of bytes as they read.
723 * Protocol drivers should always provide @rx_buf and/or @tx_buf.
724 * In some cases, they may also want to provide DMA addresses for
725 * the data being transferred; that may reduce overhead, when the
726 * underlying driver uses dma.
728 * If the transmit buffer is null, zeroes will be shifted out
729 * while filling @rx_buf. If the receive buffer is null, the data
730 * shifted in will be discarded. Only "len" bytes shift out (or in).
731 * It's an error to try to shift out a partial word. (For example, by
732 * shifting out three bytes with word size of sixteen or twenty bits;
733 * the former uses two bytes per word, the latter uses four bytes.)
735 * In-memory data values are always in native CPU byte order, translated
736 * from the wire byte order (big-endian except with SPI_LSB_FIRST). So
737 * for example when bits_per_word is sixteen, buffers are 2N bytes long
738 * (@len = 2N) and hold N sixteen bit words in CPU byte order.
740 * When the word size of the SPI transfer is not a power-of-two multiple
741 * of eight bits, those in-memory words include extra bits. In-memory
742 * words are always seen by protocol drivers as right-justified, so the
743 * undefined (rx) or unused (tx) bits are always the most significant bits.
745 * All SPI transfers start with the relevant chipselect active. Normally
746 * it stays selected until after the last transfer in a message. Drivers
747 * can affect the chipselect signal using cs_change.
749 * (i) If the transfer isn't the last one in the message, this flag is
750 * used to make the chipselect briefly go inactive in the middle of the
751 * message. Toggling chipselect in this way may be needed to terminate
752 * a chip command, letting a single spi_message perform all of group of
753 * chip transactions together.
755 * (ii) When the transfer is the last one in the message, the chip may
756 * stay selected until the next transfer. On multi-device SPI busses
757 * with nothing blocking messages going to other devices, this is just
758 * a performance hint; starting a message to another device deselects
759 * this one. But in other cases, this can be used to ensure correctness.
760 * Some devices need protocol transactions to be built from a series of
761 * spi_message submissions, where the content of one message is determined
762 * by the results of previous messages and where the whole transaction
763 * ends when the chipselect goes intactive.
765 * When SPI can transfer in 1x,2x or 4x. It can get this transfer information
766 * from device through @tx_nbits and @rx_nbits. In Bi-direction, these
767 * two should both be set. User can set transfer mode with SPI_NBITS_SINGLE(1x)
768 * SPI_NBITS_DUAL(2x) and SPI_NBITS_QUAD(4x) to support these three transfer.
770 * The code that submits an spi_message (and its spi_transfers)
771 * to the lower layers is responsible for managing its memory.
772 * Zero-initialize every field you don't set up explicitly, to
773 * insulate against future API updates. After you submit a message
774 * and its transfers, ignore them until its completion callback.
776 struct spi_transfer
{
777 /* it's ok if tx_buf == rx_buf (right?)
778 * for MicroWire, one buffer must be null
779 * buffers must work with dma_*map_single() calls, unless
780 * spi_message.is_dma_mapped reports a pre-existing mapping
788 struct sg_table tx_sg
;
789 struct sg_table rx_sg
;
791 unsigned cs_change
:1;
794 #define SPI_NBITS_SINGLE 0x01 /* 1bit transfer */
795 #define SPI_NBITS_DUAL 0x02 /* 2bits transfer */
796 #define SPI_NBITS_QUAD 0x04 /* 4bits transfer */
801 struct list_head transfer_list
;
805 * struct spi_message - one multi-segment SPI transaction
806 * @transfers: list of transfer segments in this transaction
807 * @spi: SPI device to which the transaction is queued
808 * @is_dma_mapped: if true, the caller provided both dma and cpu virtual
809 * addresses for each transfer buffer
810 * @complete: called to report transaction completions
811 * @context: the argument to complete() when it's called
812 * @frame_length: the total number of bytes in the message
813 * @actual_length: the total number of bytes that were transferred in all
814 * successful segments
815 * @status: zero for success, else negative errno
816 * @queue: for use by whichever driver currently owns the message
817 * @state: for use by whichever driver currently owns the message
818 * @resources: for resource management when the spi message is processed
820 * A @spi_message is used to execute an atomic sequence of data transfers,
821 * each represented by a struct spi_transfer. The sequence is "atomic"
822 * in the sense that no other spi_message may use that SPI bus until that
823 * sequence completes. On some systems, many such sequences can execute as
824 * as single programmed DMA transfer. On all systems, these messages are
825 * queued, and might complete after transactions to other devices. Messages
826 * sent to a given spi_device are always executed in FIFO order.
828 * The code that submits an spi_message (and its spi_transfers)
829 * to the lower layers is responsible for managing its memory.
830 * Zero-initialize every field you don't set up explicitly, to
831 * insulate against future API updates. After you submit a message
832 * and its transfers, ignore them until its completion callback.
835 struct list_head transfers
;
837 struct spi_device
*spi
;
839 unsigned is_dma_mapped
:1;
841 /* REVISIT: we might want a flag affecting the behavior of the
842 * last transfer ... allowing things like "read 16 bit length L"
843 * immediately followed by "read L bytes". Basically imposing
844 * a specific message scheduling algorithm.
846 * Some controller drivers (message-at-a-time queue processing)
847 * could provide that as their default scheduling algorithm. But
848 * others (with multi-message pipelines) could need a flag to
849 * tell them about such special cases.
852 /* completion is reported through a callback */
853 void (*complete
)(void *context
);
855 unsigned frame_length
;
856 unsigned actual_length
;
859 /* for optional use by whatever driver currently owns the
860 * spi_message ... between calls to spi_async and then later
861 * complete(), that's the spi_controller controller driver.
863 struct list_head queue
;
866 /* list of spi_res reources when the spi message is processed */
867 struct list_head resources
;
870 static inline void spi_message_init_no_memset(struct spi_message
*m
)
872 INIT_LIST_HEAD(&m
->transfers
);
873 INIT_LIST_HEAD(&m
->resources
);
876 static inline void spi_message_init(struct spi_message
*m
)
878 memset(m
, 0, sizeof *m
);
879 spi_message_init_no_memset(m
);
883 spi_message_add_tail(struct spi_transfer
*t
, struct spi_message
*m
)
885 list_add_tail(&t
->transfer_list
, &m
->transfers
);
889 spi_transfer_del(struct spi_transfer
*t
)
891 list_del(&t
->transfer_list
);
895 * spi_message_init_with_transfers - Initialize spi_message and append transfers
896 * @m: spi_message to be initialized
897 * @xfers: An array of spi transfers
898 * @num_xfers: Number of items in the xfer array
900 * This function initializes the given spi_message and adds each spi_transfer in
901 * the given array to the message.
904 spi_message_init_with_transfers(struct spi_message
*m
,
905 struct spi_transfer
*xfers
, unsigned int num_xfers
)
910 for (i
= 0; i
< num_xfers
; ++i
)
911 spi_message_add_tail(&xfers
[i
], m
);
914 /* It's fine to embed message and transaction structures in other data
915 * structures so long as you don't free them while they're in use.
918 static inline struct spi_message
*spi_message_alloc(unsigned ntrans
, gfp_t flags
)
920 struct spi_message
*m
;
922 m
= kzalloc(sizeof(struct spi_message
)
923 + ntrans
* sizeof(struct spi_transfer
),
927 struct spi_transfer
*t
= (struct spi_transfer
*)(m
+ 1);
929 spi_message_init_no_memset(m
);
930 for (i
= 0; i
< ntrans
; i
++, t
++)
931 spi_message_add_tail(t
, m
);
936 static inline void spi_message_free(struct spi_message
*m
)
941 extern int spi_setup(struct spi_device
*spi
);
942 extern int spi_async(struct spi_device
*spi
, struct spi_message
*message
);
943 extern int spi_async_locked(struct spi_device
*spi
,
944 struct spi_message
*message
);
945 extern int spi_slave_abort(struct spi_device
*spi
);
948 spi_max_message_size(struct spi_device
*spi
)
950 struct spi_controller
*ctlr
= spi
->controller
;
952 if (!ctlr
->max_message_size
)
954 return ctlr
->max_message_size(spi
);
958 spi_max_transfer_size(struct spi_device
*spi
)
960 struct spi_controller
*ctlr
= spi
->controller
;
961 size_t tr_max
= SIZE_MAX
;
962 size_t msg_max
= spi_max_message_size(spi
);
964 if (ctlr
->max_transfer_size
)
965 tr_max
= ctlr
->max_transfer_size(spi
);
967 /* transfer size limit must not be greater than messsage size limit */
968 return min(tr_max
, msg_max
);
971 /*---------------------------------------------------------------------------*/
973 /* SPI transfer replacement methods which make use of spi_res */
975 struct spi_replaced_transfers
;
976 typedef void (*spi_replaced_release_t
)(struct spi_controller
*ctlr
,
977 struct spi_message
*msg
,
978 struct spi_replaced_transfers
*res
);
980 * struct spi_replaced_transfers - structure describing the spi_transfer
981 * replacements that have occurred
982 * so that they can get reverted
983 * @release: some extra release code to get executed prior to
984 * relasing this structure
985 * @extradata: pointer to some extra data if requested or NULL
986 * @replaced_transfers: transfers that have been replaced and which need
988 * @replaced_after: the transfer after which the @replaced_transfers
989 * are to get re-inserted
990 * @inserted: number of transfers inserted
991 * @inserted_transfers: array of spi_transfers of array-size @inserted,
992 * that have been replacing replaced_transfers
994 * note: that @extradata will point to @inserted_transfers[@inserted]
995 * if some extra allocation is requested, so alignment will be the same
996 * as for spi_transfers
998 struct spi_replaced_transfers
{
999 spi_replaced_release_t release
;
1001 struct list_head replaced_transfers
;
1002 struct list_head
*replaced_after
;
1004 struct spi_transfer inserted_transfers
[];
1007 extern struct spi_replaced_transfers
*spi_replace_transfers(
1008 struct spi_message
*msg
,
1009 struct spi_transfer
*xfer_first
,
1012 spi_replaced_release_t release
,
1013 size_t extradatasize
,
1016 /*---------------------------------------------------------------------------*/
1018 /* SPI transfer transformation methods */
1020 extern int spi_split_transfers_maxsize(struct spi_controller
*ctlr
,
1021 struct spi_message
*msg
,
1025 /*---------------------------------------------------------------------------*/
1027 /* All these synchronous SPI transfer routines are utilities layered
1028 * over the core async transfer primitive. Here, "synchronous" means
1029 * they will sleep uninterruptibly until the async transfer completes.
1032 extern int spi_sync(struct spi_device
*spi
, struct spi_message
*message
);
1033 extern int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
);
1034 extern int spi_bus_lock(struct spi_controller
*ctlr
);
1035 extern int spi_bus_unlock(struct spi_controller
*ctlr
);
1038 * spi_sync_transfer - synchronous SPI data transfer
1039 * @spi: device with which data will be exchanged
1040 * @xfers: An array of spi_transfers
1041 * @num_xfers: Number of items in the xfer array
1042 * Context: can sleep
1044 * Does a synchronous SPI data transfer of the given spi_transfer array.
1046 * For more specific semantics see spi_sync().
1048 * Return: Return: zero on success, else a negative error code.
1051 spi_sync_transfer(struct spi_device
*spi
, struct spi_transfer
*xfers
,
1052 unsigned int num_xfers
)
1054 struct spi_message msg
;
1056 spi_message_init_with_transfers(&msg
, xfers
, num_xfers
);
1058 return spi_sync(spi
, &msg
);
1062 * spi_write - SPI synchronous write
1063 * @spi: device to which data will be written
1065 * @len: data buffer size
1066 * Context: can sleep
1068 * This function writes the buffer @buf.
1069 * Callable only from contexts that can sleep.
1071 * Return: zero on success, else a negative error code.
1074 spi_write(struct spi_device
*spi
, const void *buf
, size_t len
)
1076 struct spi_transfer t
= {
1081 return spi_sync_transfer(spi
, &t
, 1);
1085 * spi_read - SPI synchronous read
1086 * @spi: device from which data will be read
1088 * @len: data buffer size
1089 * Context: can sleep
1091 * This function reads the buffer @buf.
1092 * Callable only from contexts that can sleep.
1094 * Return: zero on success, else a negative error code.
1097 spi_read(struct spi_device
*spi
, void *buf
, size_t len
)
1099 struct spi_transfer t
= {
1104 return spi_sync_transfer(spi
, &t
, 1);
1107 /* this copies txbuf and rxbuf data; for small transfers only! */
1108 extern int spi_write_then_read(struct spi_device
*spi
,
1109 const void *txbuf
, unsigned n_tx
,
1110 void *rxbuf
, unsigned n_rx
);
1113 * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
1114 * @spi: device with which data will be exchanged
1115 * @cmd: command to be written before data is read back
1116 * Context: can sleep
1118 * Callable only from contexts that can sleep.
1120 * Return: the (unsigned) eight bit number returned by the
1121 * device, or else a negative error code.
1123 static inline ssize_t
spi_w8r8(struct spi_device
*spi
, u8 cmd
)
1128 status
= spi_write_then_read(spi
, &cmd
, 1, &result
, 1);
1130 /* return negative errno or unsigned value */
1131 return (status
< 0) ? status
: result
;
1135 * spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read
1136 * @spi: device with which data will be exchanged
1137 * @cmd: command to be written before data is read back
1138 * Context: can sleep
1140 * The number is returned in wire-order, which is at least sometimes
1143 * Callable only from contexts that can sleep.
1145 * Return: the (unsigned) sixteen bit number returned by the
1146 * device, or else a negative error code.
1148 static inline ssize_t
spi_w8r16(struct spi_device
*spi
, u8 cmd
)
1153 status
= spi_write_then_read(spi
, &cmd
, 1, &result
, 2);
1155 /* return negative errno or unsigned value */
1156 return (status
< 0) ? status
: result
;
1160 * spi_w8r16be - SPI synchronous 8 bit write followed by 16 bit big-endian read
1161 * @spi: device with which data will be exchanged
1162 * @cmd: command to be written before data is read back
1163 * Context: can sleep
1165 * This function is similar to spi_w8r16, with the exception that it will
1166 * convert the read 16 bit data word from big-endian to native endianness.
1168 * Callable only from contexts that can sleep.
1170 * Return: the (unsigned) sixteen bit number returned by the device in cpu
1171 * endianness, or else a negative error code.
1173 static inline ssize_t
spi_w8r16be(struct spi_device
*spi
, u8 cmd
)
1179 status
= spi_write_then_read(spi
, &cmd
, 1, &result
, 2);
1183 return be16_to_cpu(result
);
1187 * struct spi_flash_read_message - flash specific information for
1188 * spi-masters that provide accelerated flash read interfaces
1189 * @buf: buffer to read data
1190 * @from: offset within the flash from where data is to be read
1191 * @len: length of data to be read
1192 * @retlen: actual length of data read
1193 * @read_opcode: read_opcode to be used to communicate with flash
1194 * @addr_width: number of address bytes
1195 * @dummy_bytes: number of dummy bytes
1196 * @opcode_nbits: number of lines to send opcode
1197 * @addr_nbits: number of lines to send address
1198 * @data_nbits: number of lines for data
1199 * @rx_sg: Scatterlist for receive data read from flash
1200 * @cur_msg_mapped: message has been mapped for DMA
1202 struct spi_flash_read_message
{
1213 struct sg_table rx_sg
;
1214 bool cur_msg_mapped
;
1217 /* SPI core interface for flash read support */
1218 static inline bool spi_flash_read_supported(struct spi_device
*spi
)
1220 return spi
->controller
->spi_flash_read
&&
1221 (!spi
->controller
->flash_read_supported
||
1222 spi
->controller
->flash_read_supported(spi
));
1225 int spi_flash_read(struct spi_device
*spi
,
1226 struct spi_flash_read_message
*msg
);
1228 /*---------------------------------------------------------------------------*/
1231 * INTERFACE between board init code and SPI infrastructure.
1233 * No SPI driver ever sees these SPI device table segments, but
1234 * it's how the SPI core (or adapters that get hotplugged) grows
1235 * the driver model tree.
1237 * As a rule, SPI devices can't be probed. Instead, board init code
1238 * provides a table listing the devices which are present, with enough
1239 * information to bind and set up the device's driver. There's basic
1240 * support for nonstatic configurations too; enough to handle adding
1241 * parport adapters, or microcontrollers acting as USB-to-SPI bridges.
1245 * struct spi_board_info - board-specific template for a SPI device
1246 * @modalias: Initializes spi_device.modalias; identifies the driver.
1247 * @platform_data: Initializes spi_device.platform_data; the particular
1248 * data stored there is driver-specific.
1249 * @properties: Additional device properties for the device.
1250 * @controller_data: Initializes spi_device.controller_data; some
1251 * controllers need hints about hardware setup, e.g. for DMA.
1252 * @irq: Initializes spi_device.irq; depends on how the board is wired.
1253 * @max_speed_hz: Initializes spi_device.max_speed_hz; based on limits
1254 * from the chip datasheet and board-specific signal quality issues.
1255 * @bus_num: Identifies which spi_controller parents the spi_device; unused
1256 * by spi_new_device(), and otherwise depends on board wiring.
1257 * @chip_select: Initializes spi_device.chip_select; depends on how
1258 * the board is wired.
1259 * @mode: Initializes spi_device.mode; based on the chip datasheet, board
1260 * wiring (some devices support both 3WIRE and standard modes), and
1261 * possibly presence of an inverter in the chipselect path.
1263 * When adding new SPI devices to the device tree, these structures serve
1264 * as a partial device template. They hold information which can't always
1265 * be determined by drivers. Information that probe() can establish (such
1266 * as the default transfer wordsize) is not included here.
1268 * These structures are used in two places. Their primary role is to
1269 * be stored in tables of board-specific device descriptors, which are
1270 * declared early in board initialization and then used (much later) to
1271 * populate a controller's device tree after the that controller's driver
1272 * initializes. A secondary (and atypical) role is as a parameter to
1273 * spi_new_device() call, which happens after those controller drivers
1274 * are active in some dynamic board configuration models.
1276 struct spi_board_info
{
1277 /* the device name and module name are coupled, like platform_bus;
1278 * "modalias" is normally the driver name.
1280 * platform_data goes to spi_device.dev.platform_data,
1281 * controller_data goes to spi_device.controller_data,
1282 * device properties are copied and attached to spi_device,
1285 char modalias
[SPI_NAME_SIZE
];
1286 const void *platform_data
;
1287 const struct property_entry
*properties
;
1288 void *controller_data
;
1291 /* slower signaling on noisy or low voltage boards */
1295 /* bus_num is board specific and matches the bus_num of some
1296 * spi_controller that will probably be registered later.
1298 * chip_select reflects how this chip is wired to that master;
1299 * it's less than num_chipselect.
1304 /* mode becomes spi_device.mode, and is essential for chips
1305 * where the default of SPI_CS_HIGH = 0 is wrong.
1309 /* ... may need additional spi_device chip config data here.
1310 * avoid stuff protocol drivers can set; but include stuff
1311 * needed to behave without being bound to a driver:
1312 * - quirks like clock rate mattering when not selected
1318 spi_register_board_info(struct spi_board_info
const *info
, unsigned n
);
1320 /* board init code may ignore whether SPI is configured or not */
1322 spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
1327 /* If you're hotplugging an adapter with devices (parport, usb, etc)
1328 * use spi_new_device() to describe each device. You can also call
1329 * spi_unregister_device() to start making that device vanish, but
1330 * normally that would be handled by spi_unregister_controller().
1332 * You can also use spi_alloc_device() and spi_add_device() to use a two
1333 * stage registration sequence for each spi_device. This gives the caller
1334 * some more control over the spi_device structure before it is registered,
1335 * but requires that caller to initialize fields that would otherwise
1336 * be defined using the board info.
1338 extern struct spi_device
*
1339 spi_alloc_device(struct spi_controller
*ctlr
);
1342 spi_add_device(struct spi_device
*spi
);
1344 extern struct spi_device
*
1345 spi_new_device(struct spi_controller
*, struct spi_board_info
*);
1347 extern void spi_unregister_device(struct spi_device
*spi
);
1349 extern const struct spi_device_id
*
1350 spi_get_device_id(const struct spi_device
*sdev
);
1353 spi_transfer_is_last(struct spi_controller
*ctlr
, struct spi_transfer
*xfer
)
1355 return list_is_last(&xfer
->transfer_list
, &ctlr
->cur_msg
->transfers
);
1359 /* Compatibility layer */
1360 #define spi_master spi_controller
1362 #define SPI_MASTER_HALF_DUPLEX SPI_CONTROLLER_HALF_DUPLEX
1363 #define SPI_MASTER_NO_RX SPI_CONTROLLER_NO_RX
1364 #define SPI_MASTER_NO_TX SPI_CONTROLLER_NO_TX
1365 #define SPI_MASTER_MUST_RX SPI_CONTROLLER_MUST_RX
1366 #define SPI_MASTER_MUST_TX SPI_CONTROLLER_MUST_TX
1368 #define spi_master_get_devdata(_ctlr) spi_controller_get_devdata(_ctlr)
1369 #define spi_master_set_devdata(_ctlr, _data) \
1370 spi_controller_set_devdata(_ctlr, _data)
1371 #define spi_master_get(_ctlr) spi_controller_get(_ctlr)
1372 #define spi_master_put(_ctlr) spi_controller_put(_ctlr)
1373 #define spi_master_suspend(_ctlr) spi_controller_suspend(_ctlr)
1374 #define spi_master_resume(_ctlr) spi_controller_resume(_ctlr)
1376 #define spi_register_master(_ctlr) spi_register_controller(_ctlr)
1377 #define devm_spi_register_master(_dev, _ctlr) \
1378 devm_spi_register_controller(_dev, _ctlr)
1379 #define spi_unregister_master(_ctlr) spi_unregister_controller(_ctlr)
1381 #endif /* __LINUX_SPI_H */