4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/kernel.h>
23 #include <linux/kmod.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/cache.h>
27 #include <linux/mutex.h>
28 #include <linux/of_device.h>
29 #include <linux/of_irq.h>
30 #include <linux/slab.h>
31 #include <linux/mod_devicetable.h>
32 #include <linux/spi/spi.h>
33 #include <linux/of_gpio.h>
34 #include <linux/pm_runtime.h>
35 #include <linux/export.h>
36 #include <linux/sched/rt.h>
37 #include <linux/delay.h>
38 #include <linux/kthread.h>
39 #include <linux/ioport.h>
40 #include <linux/acpi.h>
42 static void spidev_release(struct device
*dev
)
44 struct spi_device
*spi
= to_spi_device(dev
);
46 /* spi masters may cleanup for released devices */
47 if (spi
->master
->cleanup
)
48 spi
->master
->cleanup(spi
);
50 spi_master_put(spi
->master
);
55 modalias_show(struct device
*dev
, struct device_attribute
*a
, char *buf
)
57 const struct spi_device
*spi
= to_spi_device(dev
);
59 return sprintf(buf
, "%s%s\n", SPI_MODULE_PREFIX
, spi
->modalias
);
62 static struct device_attribute spi_dev_attrs
[] = {
67 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
68 * and the sysfs version makes coldplug work too.
71 static const struct spi_device_id
*spi_match_id(const struct spi_device_id
*id
,
72 const struct spi_device
*sdev
)
75 if (!strcmp(sdev
->modalias
, id
->name
))
82 const struct spi_device_id
*spi_get_device_id(const struct spi_device
*sdev
)
84 const struct spi_driver
*sdrv
= to_spi_driver(sdev
->dev
.driver
);
86 return spi_match_id(sdrv
->id_table
, sdev
);
88 EXPORT_SYMBOL_GPL(spi_get_device_id
);
90 static int spi_match_device(struct device
*dev
, struct device_driver
*drv
)
92 const struct spi_device
*spi
= to_spi_device(dev
);
93 const struct spi_driver
*sdrv
= to_spi_driver(drv
);
95 /* Attempt an OF style match */
96 if (of_driver_match_device(dev
, drv
))
100 if (acpi_driver_match_device(dev
, drv
))
104 return !!spi_match_id(sdrv
->id_table
, spi
);
106 return strcmp(spi
->modalias
, drv
->name
) == 0;
109 static int spi_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
111 const struct spi_device
*spi
= to_spi_device(dev
);
113 add_uevent_var(env
, "MODALIAS=%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
117 #ifdef CONFIG_PM_SLEEP
118 static int spi_legacy_suspend(struct device
*dev
, pm_message_t message
)
121 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
123 /* suspend will stop irqs and dma; no more i/o */
126 value
= drv
->suspend(to_spi_device(dev
), message
);
128 dev_dbg(dev
, "... can't suspend\n");
133 static int spi_legacy_resume(struct device
*dev
)
136 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
138 /* resume may restart the i/o queue */
141 value
= drv
->resume(to_spi_device(dev
));
143 dev_dbg(dev
, "... can't resume\n");
148 static int spi_pm_suspend(struct device
*dev
)
150 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
153 return pm_generic_suspend(dev
);
155 return spi_legacy_suspend(dev
, PMSG_SUSPEND
);
158 static int spi_pm_resume(struct device
*dev
)
160 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
163 return pm_generic_resume(dev
);
165 return spi_legacy_resume(dev
);
168 static int spi_pm_freeze(struct device
*dev
)
170 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
173 return pm_generic_freeze(dev
);
175 return spi_legacy_suspend(dev
, PMSG_FREEZE
);
178 static int spi_pm_thaw(struct device
*dev
)
180 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
183 return pm_generic_thaw(dev
);
185 return spi_legacy_resume(dev
);
188 static int spi_pm_poweroff(struct device
*dev
)
190 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
193 return pm_generic_poweroff(dev
);
195 return spi_legacy_suspend(dev
, PMSG_HIBERNATE
);
198 static int spi_pm_restore(struct device
*dev
)
200 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
203 return pm_generic_restore(dev
);
205 return spi_legacy_resume(dev
);
208 #define spi_pm_suspend NULL
209 #define spi_pm_resume NULL
210 #define spi_pm_freeze NULL
211 #define spi_pm_thaw NULL
212 #define spi_pm_poweroff NULL
213 #define spi_pm_restore NULL
216 static const struct dev_pm_ops spi_pm
= {
217 .suspend
= spi_pm_suspend
,
218 .resume
= spi_pm_resume
,
219 .freeze
= spi_pm_freeze
,
221 .poweroff
= spi_pm_poweroff
,
222 .restore
= spi_pm_restore
,
224 pm_generic_runtime_suspend
,
225 pm_generic_runtime_resume
,
226 pm_generic_runtime_idle
230 struct bus_type spi_bus_type
= {
232 .dev_attrs
= spi_dev_attrs
,
233 .match
= spi_match_device
,
234 .uevent
= spi_uevent
,
237 EXPORT_SYMBOL_GPL(spi_bus_type
);
240 static int spi_drv_probe(struct device
*dev
)
242 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
244 return sdrv
->probe(to_spi_device(dev
));
247 static int spi_drv_remove(struct device
*dev
)
249 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
251 return sdrv
->remove(to_spi_device(dev
));
254 static void spi_drv_shutdown(struct device
*dev
)
256 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
258 sdrv
->shutdown(to_spi_device(dev
));
262 * spi_register_driver - register a SPI driver
263 * @sdrv: the driver to register
266 int spi_register_driver(struct spi_driver
*sdrv
)
268 sdrv
->driver
.bus
= &spi_bus_type
;
270 sdrv
->driver
.probe
= spi_drv_probe
;
272 sdrv
->driver
.remove
= spi_drv_remove
;
274 sdrv
->driver
.shutdown
= spi_drv_shutdown
;
275 return driver_register(&sdrv
->driver
);
277 EXPORT_SYMBOL_GPL(spi_register_driver
);
279 /*-------------------------------------------------------------------------*/
281 /* SPI devices should normally not be created by SPI device drivers; that
282 * would make them board-specific. Similarly with SPI master drivers.
283 * Device registration normally goes into like arch/.../mach.../board-YYY.c
284 * with other readonly (flashable) information about mainboard devices.
288 struct list_head list
;
289 struct spi_board_info board_info
;
292 static LIST_HEAD(board_list
);
293 static LIST_HEAD(spi_master_list
);
296 * Used to protect add/del opertion for board_info list and
297 * spi_master list, and their matching process
299 static DEFINE_MUTEX(board_lock
);
302 * spi_alloc_device - Allocate a new SPI device
303 * @master: Controller to which device is connected
306 * Allows a driver to allocate and initialize a spi_device without
307 * registering it immediately. This allows a driver to directly
308 * fill the spi_device with device parameters before calling
309 * spi_add_device() on it.
311 * Caller is responsible to call spi_add_device() on the returned
312 * spi_device structure to add it to the SPI master. If the caller
313 * needs to discard the spi_device without adding it, then it should
314 * call spi_dev_put() on it.
316 * Returns a pointer to the new device, or NULL.
318 struct spi_device
*spi_alloc_device(struct spi_master
*master
)
320 struct spi_device
*spi
;
321 struct device
*dev
= master
->dev
.parent
;
323 if (!spi_master_get(master
))
326 spi
= kzalloc(sizeof *spi
, GFP_KERNEL
);
328 dev_err(dev
, "cannot alloc spi_device\n");
329 spi_master_put(master
);
333 spi
->master
= master
;
334 spi
->dev
.parent
= &master
->dev
;
335 spi
->dev
.bus
= &spi_bus_type
;
336 spi
->dev
.release
= spidev_release
;
337 spi
->cs_gpio
= -EINVAL
;
338 device_initialize(&spi
->dev
);
341 EXPORT_SYMBOL_GPL(spi_alloc_device
);
344 * spi_add_device - Add spi_device allocated with spi_alloc_device
345 * @spi: spi_device to register
347 * Companion function to spi_alloc_device. Devices allocated with
348 * spi_alloc_device can be added onto the spi bus with this function.
350 * Returns 0 on success; negative errno on failure
352 int spi_add_device(struct spi_device
*spi
)
354 static DEFINE_MUTEX(spi_add_lock
);
355 struct spi_master
*master
= spi
->master
;
356 struct device
*dev
= master
->dev
.parent
;
360 /* Chipselects are numbered 0..max; validate. */
361 if (spi
->chip_select
>= master
->num_chipselect
) {
362 dev_err(dev
, "cs%d >= max %d\n",
364 master
->num_chipselect
);
368 /* Set the bus ID string */
369 dev_set_name(&spi
->dev
, "%s.%u", dev_name(&spi
->master
->dev
),
373 /* We need to make sure there's no other device with this
374 * chipselect **BEFORE** we call setup(), else we'll trash
375 * its configuration. Lock against concurrent add() calls.
377 mutex_lock(&spi_add_lock
);
379 d
= bus_find_device_by_name(&spi_bus_type
, NULL
, dev_name(&spi
->dev
));
381 dev_err(dev
, "chipselect %d already in use\n",
388 if (master
->cs_gpios
)
389 spi
->cs_gpio
= master
->cs_gpios
[spi
->chip_select
];
391 /* Drivers may modify this initial i/o setup, but will
392 * normally rely on the device being setup. Devices
393 * using SPI_CS_HIGH can't coexist well otherwise...
395 status
= spi_setup(spi
);
397 dev_err(dev
, "can't setup %s, status %d\n",
398 dev_name(&spi
->dev
), status
);
402 /* Device may be bound to an active driver when this returns */
403 status
= device_add(&spi
->dev
);
405 dev_err(dev
, "can't add %s, status %d\n",
406 dev_name(&spi
->dev
), status
);
408 dev_dbg(dev
, "registered child %s\n", dev_name(&spi
->dev
));
411 mutex_unlock(&spi_add_lock
);
414 EXPORT_SYMBOL_GPL(spi_add_device
);
417 * spi_new_device - instantiate one new SPI device
418 * @master: Controller to which device is connected
419 * @chip: Describes the SPI device
422 * On typical mainboards, this is purely internal; and it's not needed
423 * after board init creates the hard-wired devices. Some development
424 * platforms may not be able to use spi_register_board_info though, and
425 * this is exported so that for example a USB or parport based adapter
426 * driver could add devices (which it would learn about out-of-band).
428 * Returns the new device, or NULL.
430 struct spi_device
*spi_new_device(struct spi_master
*master
,
431 struct spi_board_info
*chip
)
433 struct spi_device
*proxy
;
436 /* NOTE: caller did any chip->bus_num checks necessary.
438 * Also, unless we change the return value convention to use
439 * error-or-pointer (not NULL-or-pointer), troubleshootability
440 * suggests syslogged diagnostics are best here (ugh).
443 proxy
= spi_alloc_device(master
);
447 WARN_ON(strlen(chip
->modalias
) >= sizeof(proxy
->modalias
));
449 proxy
->chip_select
= chip
->chip_select
;
450 proxy
->max_speed_hz
= chip
->max_speed_hz
;
451 proxy
->mode
= chip
->mode
;
452 proxy
->irq
= chip
->irq
;
453 strlcpy(proxy
->modalias
, chip
->modalias
, sizeof(proxy
->modalias
));
454 proxy
->dev
.platform_data
= (void *) chip
->platform_data
;
455 proxy
->controller_data
= chip
->controller_data
;
456 proxy
->controller_state
= NULL
;
458 status
= spi_add_device(proxy
);
466 EXPORT_SYMBOL_GPL(spi_new_device
);
468 static void spi_match_master_to_boardinfo(struct spi_master
*master
,
469 struct spi_board_info
*bi
)
471 struct spi_device
*dev
;
473 if (master
->bus_num
!= bi
->bus_num
)
476 dev
= spi_new_device(master
, bi
);
478 dev_err(master
->dev
.parent
, "can't create new device for %s\n",
483 * spi_register_board_info - register SPI devices for a given board
484 * @info: array of chip descriptors
485 * @n: how many descriptors are provided
488 * Board-specific early init code calls this (probably during arch_initcall)
489 * with segments of the SPI device table. Any device nodes are created later,
490 * after the relevant parent SPI controller (bus_num) is defined. We keep
491 * this table of devices forever, so that reloading a controller driver will
492 * not make Linux forget about these hard-wired devices.
494 * Other code can also call this, e.g. a particular add-on board might provide
495 * SPI devices through its expansion connector, so code initializing that board
496 * would naturally declare its SPI devices.
498 * The board info passed can safely be __initdata ... but be careful of
499 * any embedded pointers (platform_data, etc), they're copied as-is.
501 int spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
503 struct boardinfo
*bi
;
506 bi
= kzalloc(n
* sizeof(*bi
), GFP_KERNEL
);
510 for (i
= 0; i
< n
; i
++, bi
++, info
++) {
511 struct spi_master
*master
;
513 memcpy(&bi
->board_info
, info
, sizeof(*info
));
514 mutex_lock(&board_lock
);
515 list_add_tail(&bi
->list
, &board_list
);
516 list_for_each_entry(master
, &spi_master_list
, list
)
517 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
518 mutex_unlock(&board_lock
);
524 /*-------------------------------------------------------------------------*/
527 * spi_pump_messages - kthread work function which processes spi message queue
528 * @work: pointer to kthread work struct contained in the master struct
530 * This function checks if there is any spi message in the queue that
531 * needs processing and if so call out to the driver to initialize hardware
532 * and transfer each message.
535 static void spi_pump_messages(struct kthread_work
*work
)
537 struct spi_master
*master
=
538 container_of(work
, struct spi_master
, pump_messages
);
540 bool was_busy
= false;
543 /* Lock queue and check for queue work */
544 spin_lock_irqsave(&master
->queue_lock
, flags
);
545 if (list_empty(&master
->queue
) || !master
->running
) {
546 if (master
->busy
&& master
->unprepare_transfer_hardware
) {
547 ret
= master
->unprepare_transfer_hardware(master
);
549 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
550 dev_err(&master
->dev
,
551 "failed to unprepare transfer hardware\n");
555 master
->busy
= false;
556 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
560 /* Make sure we are not already running a message */
561 if (master
->cur_msg
) {
562 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
565 /* Extract head of queue */
567 list_entry(master
->queue
.next
, struct spi_message
, queue
);
569 list_del_init(&master
->cur_msg
->queue
);
574 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
576 if (!was_busy
&& master
->prepare_transfer_hardware
) {
577 ret
= master
->prepare_transfer_hardware(master
);
579 dev_err(&master
->dev
,
580 "failed to prepare transfer hardware\n");
585 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
587 dev_err(&master
->dev
,
588 "failed to transfer one message from queue\n");
593 static int spi_init_queue(struct spi_master
*master
)
595 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
597 INIT_LIST_HEAD(&master
->queue
);
598 spin_lock_init(&master
->queue_lock
);
600 master
->running
= false;
601 master
->busy
= false;
603 init_kthread_worker(&master
->kworker
);
604 master
->kworker_task
= kthread_run(kthread_worker_fn
,
606 dev_name(&master
->dev
));
607 if (IS_ERR(master
->kworker_task
)) {
608 dev_err(&master
->dev
, "failed to create message pump task\n");
611 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
614 * Master config will indicate if this controller should run the
615 * message pump with high (realtime) priority to reduce the transfer
616 * latency on the bus by minimising the delay between a transfer
617 * request and the scheduling of the message pump thread. Without this
618 * setting the message pump thread will remain at default priority.
621 dev_info(&master
->dev
,
622 "will run message pump with realtime priority\n");
623 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
630 * spi_get_next_queued_message() - called by driver to check for queued
632 * @master: the master to check for queued messages
634 * If there are more messages in the queue, the next message is returned from
637 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
639 struct spi_message
*next
;
642 /* get a pointer to the next message, if any */
643 spin_lock_irqsave(&master
->queue_lock
, flags
);
644 if (list_empty(&master
->queue
))
647 next
= list_entry(master
->queue
.next
,
648 struct spi_message
, queue
);
649 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
653 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
656 * spi_finalize_current_message() - the current message is complete
657 * @master: the master to return the message to
659 * Called by the driver to notify the core that the message in the front of the
660 * queue is complete and can be removed from the queue.
662 void spi_finalize_current_message(struct spi_master
*master
)
664 struct spi_message
*mesg
;
667 spin_lock_irqsave(&master
->queue_lock
, flags
);
668 mesg
= master
->cur_msg
;
669 master
->cur_msg
= NULL
;
671 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
672 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
676 mesg
->complete(mesg
->context
);
678 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
680 static int spi_start_queue(struct spi_master
*master
)
684 spin_lock_irqsave(&master
->queue_lock
, flags
);
686 if (master
->running
|| master
->busy
) {
687 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
691 master
->running
= true;
692 master
->cur_msg
= NULL
;
693 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
695 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
700 static int spi_stop_queue(struct spi_master
*master
)
703 unsigned limit
= 500;
706 spin_lock_irqsave(&master
->queue_lock
, flags
);
709 * This is a bit lame, but is optimized for the common execution path.
710 * A wait_queue on the master->busy could be used, but then the common
711 * execution path (pump_messages) would be required to call wake_up or
712 * friends on every SPI message. Do this instead.
714 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
715 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
717 spin_lock_irqsave(&master
->queue_lock
, flags
);
720 if (!list_empty(&master
->queue
) || master
->busy
)
723 master
->running
= false;
725 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
728 dev_warn(&master
->dev
,
729 "could not stop message queue\n");
735 static int spi_destroy_queue(struct spi_master
*master
)
739 ret
= spi_stop_queue(master
);
742 * flush_kthread_worker will block until all work is done.
743 * If the reason that stop_queue timed out is that the work will never
744 * finish, then it does no good to call flush/stop thread, so
748 dev_err(&master
->dev
, "problem destroying queue\n");
752 flush_kthread_worker(&master
->kworker
);
753 kthread_stop(master
->kworker_task
);
759 * spi_queued_transfer - transfer function for queued transfers
760 * @spi: spi device which is requesting transfer
761 * @msg: spi message which is to handled is queued to driver queue
763 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
765 struct spi_master
*master
= spi
->master
;
768 spin_lock_irqsave(&master
->queue_lock
, flags
);
770 if (!master
->running
) {
771 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
774 msg
->actual_length
= 0;
775 msg
->status
= -EINPROGRESS
;
777 list_add_tail(&msg
->queue
, &master
->queue
);
778 if (master
->running
&& !master
->busy
)
779 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
781 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
785 static int spi_master_initialize_queue(struct spi_master
*master
)
789 master
->queued
= true;
790 master
->transfer
= spi_queued_transfer
;
792 /* Initialize and start queue */
793 ret
= spi_init_queue(master
);
795 dev_err(&master
->dev
, "problem initializing queue\n");
798 ret
= spi_start_queue(master
);
800 dev_err(&master
->dev
, "problem starting queue\n");
801 goto err_start_queue
;
808 spi_destroy_queue(master
);
812 /*-------------------------------------------------------------------------*/
814 #if defined(CONFIG_OF)
816 * of_register_spi_devices() - Register child devices onto the SPI bus
817 * @master: Pointer to spi_master device
819 * Registers an spi_device for each child node of master node which has a 'reg'
822 static void of_register_spi_devices(struct spi_master
*master
)
824 struct spi_device
*spi
;
825 struct device_node
*nc
;
827 char modalias
[SPI_NAME_SIZE
+ 4];
831 if (!master
->dev
.of_node
)
834 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
835 /* Alloc an spi_device */
836 spi
= spi_alloc_device(master
);
838 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
844 /* Select device driver */
845 if (of_modalias_node(nc
, spi
->modalias
,
846 sizeof(spi
->modalias
)) < 0) {
847 dev_err(&master
->dev
, "cannot find modalias for %s\n",
854 prop
= of_get_property(nc
, "reg", &len
);
855 if (!prop
|| len
< sizeof(*prop
)) {
856 dev_err(&master
->dev
, "%s has no 'reg' property\n",
861 spi
->chip_select
= be32_to_cpup(prop
);
863 /* Mode (clock phase/polarity/etc.) */
864 if (of_find_property(nc
, "spi-cpha", NULL
))
865 spi
->mode
|= SPI_CPHA
;
866 if (of_find_property(nc
, "spi-cpol", NULL
))
867 spi
->mode
|= SPI_CPOL
;
868 if (of_find_property(nc
, "spi-cs-high", NULL
))
869 spi
->mode
|= SPI_CS_HIGH
;
870 if (of_find_property(nc
, "spi-3wire", NULL
))
871 spi
->mode
|= SPI_3WIRE
;
874 prop
= of_get_property(nc
, "spi-max-frequency", &len
);
875 if (!prop
|| len
< sizeof(*prop
)) {
876 dev_err(&master
->dev
, "%s has no 'spi-max-frequency' property\n",
881 spi
->max_speed_hz
= be32_to_cpup(prop
);
884 spi
->irq
= irq_of_parse_and_map(nc
, 0);
886 /* Store a pointer to the node in the device structure */
888 spi
->dev
.of_node
= nc
;
890 /* Register the new device */
891 snprintf(modalias
, sizeof(modalias
), "%s%s", SPI_MODULE_PREFIX
,
893 request_module(modalias
);
894 rc
= spi_add_device(spi
);
896 dev_err(&master
->dev
, "spi_device register error %s\n",
904 static void of_register_spi_devices(struct spi_master
*master
) { }
908 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
910 struct spi_device
*spi
= data
;
912 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
913 struct acpi_resource_spi_serialbus
*sb
;
915 sb
= &ares
->data
.spi_serial_bus
;
916 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
917 spi
->chip_select
= sb
->device_selection
;
918 spi
->max_speed_hz
= sb
->connection_speed
;
920 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
921 spi
->mode
|= SPI_CPHA
;
922 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
923 spi
->mode
|= SPI_CPOL
;
924 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
925 spi
->mode
|= SPI_CS_HIGH
;
927 } else if (spi
->irq
< 0) {
930 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
934 /* Always tell the ACPI core to skip this resource */
938 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
939 void *data
, void **return_value
)
941 struct spi_master
*master
= data
;
942 struct list_head resource_list
;
943 struct acpi_device
*adev
;
944 struct spi_device
*spi
;
947 if (acpi_bus_get_device(handle
, &adev
))
949 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
952 spi
= spi_alloc_device(master
);
954 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
955 dev_name(&adev
->dev
));
959 ACPI_HANDLE_SET(&spi
->dev
, handle
);
962 INIT_LIST_HEAD(&resource_list
);
963 ret
= acpi_dev_get_resources(adev
, &resource_list
,
964 acpi_spi_add_resource
, spi
);
965 acpi_dev_free_resource_list(&resource_list
);
967 if (ret
< 0 || !spi
->max_speed_hz
) {
972 strlcpy(spi
->modalias
, dev_name(&adev
->dev
), sizeof(spi
->modalias
));
973 if (spi_add_device(spi
)) {
974 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
975 dev_name(&adev
->dev
));
982 static void acpi_register_spi_devices(struct spi_master
*master
)
987 handle
= ACPI_HANDLE(&master
->dev
);
991 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
992 acpi_spi_add_device
, NULL
,
994 if (ACPI_FAILURE(status
))
995 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
998 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
999 #endif /* CONFIG_ACPI */
1001 static void spi_master_release(struct device
*dev
)
1003 struct spi_master
*master
;
1005 master
= container_of(dev
, struct spi_master
, dev
);
1009 static struct class spi_master_class
= {
1010 .name
= "spi_master",
1011 .owner
= THIS_MODULE
,
1012 .dev_release
= spi_master_release
,
1018 * spi_alloc_master - allocate SPI master controller
1019 * @dev: the controller, possibly using the platform_bus
1020 * @size: how much zeroed driver-private data to allocate; the pointer to this
1021 * memory is in the driver_data field of the returned device,
1022 * accessible with spi_master_get_devdata().
1023 * Context: can sleep
1025 * This call is used only by SPI master controller drivers, which are the
1026 * only ones directly touching chip registers. It's how they allocate
1027 * an spi_master structure, prior to calling spi_register_master().
1029 * This must be called from context that can sleep. It returns the SPI
1030 * master structure on success, else NULL.
1032 * The caller is responsible for assigning the bus number and initializing
1033 * the master's methods before calling spi_register_master(); and (after errors
1034 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1037 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1039 struct spi_master
*master
;
1044 master
= kzalloc(size
+ sizeof *master
, GFP_KERNEL
);
1048 device_initialize(&master
->dev
);
1049 master
->bus_num
= -1;
1050 master
->num_chipselect
= 1;
1051 master
->dev
.class = &spi_master_class
;
1052 master
->dev
.parent
= get_device(dev
);
1053 spi_master_set_devdata(master
, &master
[1]);
1057 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1060 static int of_spi_register_master(struct spi_master
*master
)
1063 struct device_node
*np
= master
->dev
.of_node
;
1068 nb
= of_gpio_named_count(np
, "cs-gpios");
1069 master
->num_chipselect
= max(nb
, (int)master
->num_chipselect
);
1074 cs
= devm_kzalloc(&master
->dev
,
1075 sizeof(int) * master
->num_chipselect
,
1077 master
->cs_gpios
= cs
;
1079 if (!master
->cs_gpios
)
1082 for (i
= 0; i
< master
->num_chipselect
; i
++)
1085 for (i
= 0; i
< nb
; i
++)
1086 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1091 static int of_spi_register_master(struct spi_master
*master
)
1098 * spi_register_master - register SPI master controller
1099 * @master: initialized master, originally from spi_alloc_master()
1100 * Context: can sleep
1102 * SPI master controllers connect to their drivers using some non-SPI bus,
1103 * such as the platform bus. The final stage of probe() in that code
1104 * includes calling spi_register_master() to hook up to this SPI bus glue.
1106 * SPI controllers use board specific (often SOC specific) bus numbers,
1107 * and board-specific addressing for SPI devices combines those numbers
1108 * with chip select numbers. Since SPI does not directly support dynamic
1109 * device identification, boards need configuration tables telling which
1110 * chip is at which address.
1112 * This must be called from context that can sleep. It returns zero on
1113 * success, else a negative error code (dropping the master's refcount).
1114 * After a successful return, the caller is responsible for calling
1115 * spi_unregister_master().
1117 int spi_register_master(struct spi_master
*master
)
1119 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1120 struct device
*dev
= master
->dev
.parent
;
1121 struct boardinfo
*bi
;
1122 int status
= -ENODEV
;
1128 status
= of_spi_register_master(master
);
1132 /* even if it's just one always-selected device, there must
1133 * be at least one chipselect
1135 if (master
->num_chipselect
== 0)
1138 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1139 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1141 /* convention: dynamically assigned bus IDs count down from the max */
1142 if (master
->bus_num
< 0) {
1143 /* FIXME switch to an IDR based scheme, something like
1144 * I2C now uses, so we can't run out of "dynamic" IDs
1146 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1150 spin_lock_init(&master
->bus_lock_spinlock
);
1151 mutex_init(&master
->bus_lock_mutex
);
1152 master
->bus_lock_flag
= 0;
1154 /* register the device, then userspace will see it.
1155 * registration fails if the bus ID is in use.
1157 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1158 status
= device_add(&master
->dev
);
1161 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1162 dynamic
? " (dynamic)" : "");
1164 /* If we're using a queued driver, start the queue */
1165 if (master
->transfer
)
1166 dev_info(dev
, "master is unqueued, this is deprecated\n");
1168 status
= spi_master_initialize_queue(master
);
1170 device_unregister(&master
->dev
);
1175 mutex_lock(&board_lock
);
1176 list_add_tail(&master
->list
, &spi_master_list
);
1177 list_for_each_entry(bi
, &board_list
, list
)
1178 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1179 mutex_unlock(&board_lock
);
1181 /* Register devices from the device tree and ACPI */
1182 of_register_spi_devices(master
);
1183 acpi_register_spi_devices(master
);
1187 EXPORT_SYMBOL_GPL(spi_register_master
);
1189 static int __unregister(struct device
*dev
, void *null
)
1191 spi_unregister_device(to_spi_device(dev
));
1196 * spi_unregister_master - unregister SPI master controller
1197 * @master: the master being unregistered
1198 * Context: can sleep
1200 * This call is used only by SPI master controller drivers, which are the
1201 * only ones directly touching chip registers.
1203 * This must be called from context that can sleep.
1205 void spi_unregister_master(struct spi_master
*master
)
1209 if (master
->queued
) {
1210 if (spi_destroy_queue(master
))
1211 dev_err(&master
->dev
, "queue remove failed\n");
1214 mutex_lock(&board_lock
);
1215 list_del(&master
->list
);
1216 mutex_unlock(&board_lock
);
1218 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1219 device_unregister(&master
->dev
);
1221 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1223 int spi_master_suspend(struct spi_master
*master
)
1227 /* Basically no-ops for non-queued masters */
1228 if (!master
->queued
)
1231 ret
= spi_stop_queue(master
);
1233 dev_err(&master
->dev
, "queue stop failed\n");
1237 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1239 int spi_master_resume(struct spi_master
*master
)
1243 if (!master
->queued
)
1246 ret
= spi_start_queue(master
);
1248 dev_err(&master
->dev
, "queue restart failed\n");
1252 EXPORT_SYMBOL_GPL(spi_master_resume
);
1254 static int __spi_master_match(struct device
*dev
, void *data
)
1256 struct spi_master
*m
;
1257 u16
*bus_num
= data
;
1259 m
= container_of(dev
, struct spi_master
, dev
);
1260 return m
->bus_num
== *bus_num
;
1264 * spi_busnum_to_master - look up master associated with bus_num
1265 * @bus_num: the master's bus number
1266 * Context: can sleep
1268 * This call may be used with devices that are registered after
1269 * arch init time. It returns a refcounted pointer to the relevant
1270 * spi_master (which the caller must release), or NULL if there is
1271 * no such master registered.
1273 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1276 struct spi_master
*master
= NULL
;
1278 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1279 __spi_master_match
);
1281 master
= container_of(dev
, struct spi_master
, dev
);
1282 /* reference got in class_find_device */
1285 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1288 /*-------------------------------------------------------------------------*/
1290 /* Core methods for SPI master protocol drivers. Some of the
1291 * other core methods are currently defined as inline functions.
1295 * spi_setup - setup SPI mode and clock rate
1296 * @spi: the device whose settings are being modified
1297 * Context: can sleep, and no requests are queued to the device
1299 * SPI protocol drivers may need to update the transfer mode if the
1300 * device doesn't work with its default. They may likewise need
1301 * to update clock rates or word sizes from initial values. This function
1302 * changes those settings, and must be called from a context that can sleep.
1303 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1304 * effect the next time the device is selected and data is transferred to
1305 * or from it. When this function returns, the spi device is deselected.
1307 * Note that this call will fail if the protocol driver specifies an option
1308 * that the underlying controller or its driver does not support. For
1309 * example, not all hardware supports wire transfers using nine bit words,
1310 * LSB-first wire encoding, or active-high chipselects.
1312 int spi_setup(struct spi_device
*spi
)
1317 /* help drivers fail *cleanly* when they need options
1318 * that aren't supported with their current master
1320 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1322 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1327 if (!spi
->bits_per_word
)
1328 spi
->bits_per_word
= 8;
1330 if (spi
->master
->setup
)
1331 status
= spi
->master
->setup(spi
);
1333 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s"
1334 "%u bits/w, %u Hz max --> %d\n",
1335 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1336 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1337 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1338 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1339 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1340 spi
->bits_per_word
, spi
->max_speed_hz
,
1345 EXPORT_SYMBOL_GPL(spi_setup
);
1347 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1349 struct spi_master
*master
= spi
->master
;
1350 struct spi_transfer
*xfer
;
1352 /* Half-duplex links include original MicroWire, and ones with
1353 * only one data pin like SPI_3WIRE (switches direction) or where
1354 * either MOSI or MISO is missing. They can also be caused by
1355 * software limitations.
1357 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1358 || (spi
->mode
& SPI_3WIRE
)) {
1359 unsigned flags
= master
->flags
;
1361 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1362 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1364 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1366 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1372 * Set transfer bits_per_word and max speed as spi device default if
1373 * it is not set for this transfer.
1375 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1376 if (!xfer
->bits_per_word
)
1377 xfer
->bits_per_word
= spi
->bits_per_word
;
1378 if (!xfer
->speed_hz
)
1379 xfer
->speed_hz
= spi
->max_speed_hz
;
1383 message
->status
= -EINPROGRESS
;
1384 return master
->transfer(spi
, message
);
1388 * spi_async - asynchronous SPI transfer
1389 * @spi: device with which data will be exchanged
1390 * @message: describes the data transfers, including completion callback
1391 * Context: any (irqs may be blocked, etc)
1393 * This call may be used in_irq and other contexts which can't sleep,
1394 * as well as from task contexts which can sleep.
1396 * The completion callback is invoked in a context which can't sleep.
1397 * Before that invocation, the value of message->status is undefined.
1398 * When the callback is issued, message->status holds either zero (to
1399 * indicate complete success) or a negative error code. After that
1400 * callback returns, the driver which issued the transfer request may
1401 * deallocate the associated memory; it's no longer in use by any SPI
1402 * core or controller driver code.
1404 * Note that although all messages to a spi_device are handled in
1405 * FIFO order, messages may go to different devices in other orders.
1406 * Some device might be higher priority, or have various "hard" access
1407 * time requirements, for example.
1409 * On detection of any fault during the transfer, processing of
1410 * the entire message is aborted, and the device is deselected.
1411 * Until returning from the associated message completion callback,
1412 * no other spi_message queued to that device will be processed.
1413 * (This rule applies equally to all the synchronous transfer calls,
1414 * which are wrappers around this core asynchronous primitive.)
1416 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1418 struct spi_master
*master
= spi
->master
;
1420 unsigned long flags
;
1422 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1424 if (master
->bus_lock_flag
)
1427 ret
= __spi_async(spi
, message
);
1429 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1433 EXPORT_SYMBOL_GPL(spi_async
);
1436 * spi_async_locked - version of spi_async with exclusive bus usage
1437 * @spi: device with which data will be exchanged
1438 * @message: describes the data transfers, including completion callback
1439 * Context: any (irqs may be blocked, etc)
1441 * This call may be used in_irq and other contexts which can't sleep,
1442 * as well as from task contexts which can sleep.
1444 * The completion callback is invoked in a context which can't sleep.
1445 * Before that invocation, the value of message->status is undefined.
1446 * When the callback is issued, message->status holds either zero (to
1447 * indicate complete success) or a negative error code. After that
1448 * callback returns, the driver which issued the transfer request may
1449 * deallocate the associated memory; it's no longer in use by any SPI
1450 * core or controller driver code.
1452 * Note that although all messages to a spi_device are handled in
1453 * FIFO order, messages may go to different devices in other orders.
1454 * Some device might be higher priority, or have various "hard" access
1455 * time requirements, for example.
1457 * On detection of any fault during the transfer, processing of
1458 * the entire message is aborted, and the device is deselected.
1459 * Until returning from the associated message completion callback,
1460 * no other spi_message queued to that device will be processed.
1461 * (This rule applies equally to all the synchronous transfer calls,
1462 * which are wrappers around this core asynchronous primitive.)
1464 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
1466 struct spi_master
*master
= spi
->master
;
1468 unsigned long flags
;
1470 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1472 ret
= __spi_async(spi
, message
);
1474 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1479 EXPORT_SYMBOL_GPL(spi_async_locked
);
1482 /*-------------------------------------------------------------------------*/
1484 /* Utility methods for SPI master protocol drivers, layered on
1485 * top of the core. Some other utility methods are defined as
1489 static void spi_complete(void *arg
)
1494 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
1497 DECLARE_COMPLETION_ONSTACK(done
);
1499 struct spi_master
*master
= spi
->master
;
1501 message
->complete
= spi_complete
;
1502 message
->context
= &done
;
1505 mutex_lock(&master
->bus_lock_mutex
);
1507 status
= spi_async_locked(spi
, message
);
1510 mutex_unlock(&master
->bus_lock_mutex
);
1513 wait_for_completion(&done
);
1514 status
= message
->status
;
1516 message
->context
= NULL
;
1521 * spi_sync - blocking/synchronous SPI data transfers
1522 * @spi: device with which data will be exchanged
1523 * @message: describes the data transfers
1524 * Context: can sleep
1526 * This call may only be used from a context that may sleep. The sleep
1527 * is non-interruptible, and has no timeout. Low-overhead controller
1528 * drivers may DMA directly into and out of the message buffers.
1530 * Note that the SPI device's chip select is active during the message,
1531 * and then is normally disabled between messages. Drivers for some
1532 * frequently-used devices may want to minimize costs of selecting a chip,
1533 * by leaving it selected in anticipation that the next message will go
1534 * to the same chip. (That may increase power usage.)
1536 * Also, the caller is guaranteeing that the memory associated with the
1537 * message will not be freed before this call returns.
1539 * It returns zero on success, else a negative error code.
1541 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
1543 return __spi_sync(spi
, message
, 0);
1545 EXPORT_SYMBOL_GPL(spi_sync
);
1548 * spi_sync_locked - version of spi_sync with exclusive bus usage
1549 * @spi: device with which data will be exchanged
1550 * @message: describes the data transfers
1551 * Context: can sleep
1553 * This call may only be used from a context that may sleep. The sleep
1554 * is non-interruptible, and has no timeout. Low-overhead controller
1555 * drivers may DMA directly into and out of the message buffers.
1557 * This call should be used by drivers that require exclusive access to the
1558 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1559 * be released by a spi_bus_unlock call when the exclusive access is over.
1561 * It returns zero on success, else a negative error code.
1563 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
1565 return __spi_sync(spi
, message
, 1);
1567 EXPORT_SYMBOL_GPL(spi_sync_locked
);
1570 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1571 * @master: SPI bus master that should be locked for exclusive bus access
1572 * Context: can sleep
1574 * This call may only be used from a context that may sleep. The sleep
1575 * is non-interruptible, and has no timeout.
1577 * This call should be used by drivers that require exclusive access to the
1578 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1579 * exclusive access is over. Data transfer must be done by spi_sync_locked
1580 * and spi_async_locked calls when the SPI bus lock is held.
1582 * It returns zero on success, else a negative error code.
1584 int spi_bus_lock(struct spi_master
*master
)
1586 unsigned long flags
;
1588 mutex_lock(&master
->bus_lock_mutex
);
1590 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1591 master
->bus_lock_flag
= 1;
1592 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1594 /* mutex remains locked until spi_bus_unlock is called */
1598 EXPORT_SYMBOL_GPL(spi_bus_lock
);
1601 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1602 * @master: SPI bus master that was locked for exclusive bus access
1603 * Context: can sleep
1605 * This call may only be used from a context that may sleep. The sleep
1606 * is non-interruptible, and has no timeout.
1608 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1611 * It returns zero on success, else a negative error code.
1613 int spi_bus_unlock(struct spi_master
*master
)
1615 master
->bus_lock_flag
= 0;
1617 mutex_unlock(&master
->bus_lock_mutex
);
1621 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
1623 /* portable code must never pass more than 32 bytes */
1624 #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1629 * spi_write_then_read - SPI synchronous write followed by read
1630 * @spi: device with which data will be exchanged
1631 * @txbuf: data to be written (need not be dma-safe)
1632 * @n_tx: size of txbuf, in bytes
1633 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1634 * @n_rx: size of rxbuf, in bytes
1635 * Context: can sleep
1637 * This performs a half duplex MicroWire style transaction with the
1638 * device, sending txbuf and then reading rxbuf. The return value
1639 * is zero for success, else a negative errno status code.
1640 * This call may only be used from a context that may sleep.
1642 * Parameters to this routine are always copied using a small buffer;
1643 * portable code should never use this for more than 32 bytes.
1644 * Performance-sensitive or bulk transfer code should instead use
1645 * spi_{async,sync}() calls with dma-safe buffers.
1647 int spi_write_then_read(struct spi_device
*spi
,
1648 const void *txbuf
, unsigned n_tx
,
1649 void *rxbuf
, unsigned n_rx
)
1651 static DEFINE_MUTEX(lock
);
1654 struct spi_message message
;
1655 struct spi_transfer x
[2];
1658 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1659 * copying here, (as a pure convenience thing), but we can
1660 * keep heap costs out of the hot path unless someone else is
1661 * using the pre-allocated buffer or the transfer is too large.
1663 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
1664 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
1665 GFP_KERNEL
| GFP_DMA
);
1672 spi_message_init(&message
);
1673 memset(x
, 0, sizeof x
);
1676 spi_message_add_tail(&x
[0], &message
);
1680 spi_message_add_tail(&x
[1], &message
);
1683 memcpy(local_buf
, txbuf
, n_tx
);
1684 x
[0].tx_buf
= local_buf
;
1685 x
[1].rx_buf
= local_buf
+ n_tx
;
1688 status
= spi_sync(spi
, &message
);
1690 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
1692 if (x
[0].tx_buf
== buf
)
1693 mutex_unlock(&lock
);
1699 EXPORT_SYMBOL_GPL(spi_write_then_read
);
1701 /*-------------------------------------------------------------------------*/
1703 static int __init
spi_init(void)
1707 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
1713 status
= bus_register(&spi_bus_type
);
1717 status
= class_register(&spi_master_class
);
1723 bus_unregister(&spi_bus_type
);
1731 /* board_info is normally registered in arch_initcall(),
1732 * but even essential drivers wait till later
1734 * REVISIT only boardinfo really needs static linking. the rest (device and
1735 * driver registration) _could_ be dynamically linked (modular) ... costs
1736 * include needing to have boardinfo data structures be much more public.
1738 postcore_initcall(spi_init
);