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
,
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
= -ENOENT
;
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
) {
547 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
550 master
->busy
= false;
551 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
552 if (master
->unprepare_transfer_hardware
&&
553 master
->unprepare_transfer_hardware(master
))
554 dev_err(&master
->dev
,
555 "failed to unprepare transfer hardware\n");
559 /* Make sure we are not already running a message */
560 if (master
->cur_msg
) {
561 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
564 /* Extract head of queue */
566 list_entry(master
->queue
.next
, struct spi_message
, queue
);
568 list_del_init(&master
->cur_msg
->queue
);
573 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
575 if (!was_busy
&& master
->prepare_transfer_hardware
) {
576 ret
= master
->prepare_transfer_hardware(master
);
578 dev_err(&master
->dev
,
579 "failed to prepare transfer hardware\n");
584 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
586 dev_err(&master
->dev
,
587 "failed to transfer one message from queue\n");
592 static int spi_init_queue(struct spi_master
*master
)
594 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
596 INIT_LIST_HEAD(&master
->queue
);
597 spin_lock_init(&master
->queue_lock
);
599 master
->running
= false;
600 master
->busy
= false;
602 init_kthread_worker(&master
->kworker
);
603 master
->kworker_task
= kthread_run(kthread_worker_fn
,
604 &master
->kworker
, "%s",
605 dev_name(&master
->dev
));
606 if (IS_ERR(master
->kworker_task
)) {
607 dev_err(&master
->dev
, "failed to create message pump task\n");
610 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
613 * Master config will indicate if this controller should run the
614 * message pump with high (realtime) priority to reduce the transfer
615 * latency on the bus by minimising the delay between a transfer
616 * request and the scheduling of the message pump thread. Without this
617 * setting the message pump thread will remain at default priority.
620 dev_info(&master
->dev
,
621 "will run message pump with realtime priority\n");
622 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
629 * spi_get_next_queued_message() - called by driver to check for queued
631 * @master: the master to check for queued messages
633 * If there are more messages in the queue, the next message is returned from
636 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
638 struct spi_message
*next
;
641 /* get a pointer to the next message, if any */
642 spin_lock_irqsave(&master
->queue_lock
, flags
);
643 if (list_empty(&master
->queue
))
646 next
= list_entry(master
->queue
.next
,
647 struct spi_message
, queue
);
648 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
652 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
655 * spi_finalize_current_message() - the current message is complete
656 * @master: the master to return the message to
658 * Called by the driver to notify the core that the message in the front of the
659 * queue is complete and can be removed from the queue.
661 void spi_finalize_current_message(struct spi_master
*master
)
663 struct spi_message
*mesg
;
666 spin_lock_irqsave(&master
->queue_lock
, flags
);
667 mesg
= master
->cur_msg
;
668 master
->cur_msg
= NULL
;
670 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
671 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
675 mesg
->complete(mesg
->context
);
677 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
679 static int spi_start_queue(struct spi_master
*master
)
683 spin_lock_irqsave(&master
->queue_lock
, flags
);
685 if (master
->running
|| master
->busy
) {
686 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
690 master
->running
= true;
691 master
->cur_msg
= NULL
;
692 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
694 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
699 static int spi_stop_queue(struct spi_master
*master
)
702 unsigned limit
= 500;
705 spin_lock_irqsave(&master
->queue_lock
, flags
);
708 * This is a bit lame, but is optimized for the common execution path.
709 * A wait_queue on the master->busy could be used, but then the common
710 * execution path (pump_messages) would be required to call wake_up or
711 * friends on every SPI message. Do this instead.
713 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
714 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
716 spin_lock_irqsave(&master
->queue_lock
, flags
);
719 if (!list_empty(&master
->queue
) || master
->busy
)
722 master
->running
= false;
724 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
727 dev_warn(&master
->dev
,
728 "could not stop message queue\n");
734 static int spi_destroy_queue(struct spi_master
*master
)
738 ret
= spi_stop_queue(master
);
741 * flush_kthread_worker will block until all work is done.
742 * If the reason that stop_queue timed out is that the work will never
743 * finish, then it does no good to call flush/stop thread, so
747 dev_err(&master
->dev
, "problem destroying queue\n");
751 flush_kthread_worker(&master
->kworker
);
752 kthread_stop(master
->kworker_task
);
758 * spi_queued_transfer - transfer function for queued transfers
759 * @spi: spi device which is requesting transfer
760 * @msg: spi message which is to handled is queued to driver queue
762 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
764 struct spi_master
*master
= spi
->master
;
767 spin_lock_irqsave(&master
->queue_lock
, flags
);
769 if (!master
->running
) {
770 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
773 msg
->actual_length
= 0;
774 msg
->status
= -EINPROGRESS
;
776 list_add_tail(&msg
->queue
, &master
->queue
);
777 if (master
->running
&& !master
->busy
)
778 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
780 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
784 static int spi_master_initialize_queue(struct spi_master
*master
)
788 master
->queued
= true;
789 master
->transfer
= spi_queued_transfer
;
791 /* Initialize and start queue */
792 ret
= spi_init_queue(master
);
794 dev_err(&master
->dev
, "problem initializing queue\n");
797 ret
= spi_start_queue(master
);
799 dev_err(&master
->dev
, "problem starting queue\n");
800 goto err_start_queue
;
807 spi_destroy_queue(master
);
811 /*-------------------------------------------------------------------------*/
813 #if defined(CONFIG_OF)
815 * of_register_spi_devices() - Register child devices onto the SPI bus
816 * @master: Pointer to spi_master device
818 * Registers an spi_device for each child node of master node which has a 'reg'
821 static void of_register_spi_devices(struct spi_master
*master
)
823 struct spi_device
*spi
;
824 struct device_node
*nc
;
826 char modalias
[SPI_NAME_SIZE
+ 4];
830 if (!master
->dev
.of_node
)
833 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
834 /* Alloc an spi_device */
835 spi
= spi_alloc_device(master
);
837 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
843 /* Select device driver */
844 if (of_modalias_node(nc
, spi
->modalias
,
845 sizeof(spi
->modalias
)) < 0) {
846 dev_err(&master
->dev
, "cannot find modalias for %s\n",
853 prop
= of_get_property(nc
, "reg", &len
);
854 if (!prop
|| len
< sizeof(*prop
)) {
855 dev_err(&master
->dev
, "%s has no 'reg' property\n",
860 spi
->chip_select
= be32_to_cpup(prop
);
862 /* Mode (clock phase/polarity/etc.) */
863 if (of_find_property(nc
, "spi-cpha", NULL
))
864 spi
->mode
|= SPI_CPHA
;
865 if (of_find_property(nc
, "spi-cpol", NULL
))
866 spi
->mode
|= SPI_CPOL
;
867 if (of_find_property(nc
, "spi-cs-high", NULL
))
868 spi
->mode
|= SPI_CS_HIGH
;
869 if (of_find_property(nc
, "spi-3wire", NULL
))
870 spi
->mode
|= SPI_3WIRE
;
873 prop
= of_get_property(nc
, "spi-max-frequency", &len
);
874 if (!prop
|| len
< sizeof(*prop
)) {
875 dev_err(&master
->dev
, "%s has no 'spi-max-frequency' property\n",
880 spi
->max_speed_hz
= be32_to_cpup(prop
);
883 spi
->irq
= irq_of_parse_and_map(nc
, 0);
885 /* Store a pointer to the node in the device structure */
887 spi
->dev
.of_node
= nc
;
889 /* Register the new device */
890 snprintf(modalias
, sizeof(modalias
), "%s%s", SPI_MODULE_PREFIX
,
892 request_module(modalias
);
893 rc
= spi_add_device(spi
);
895 dev_err(&master
->dev
, "spi_device register error %s\n",
903 static void of_register_spi_devices(struct spi_master
*master
) { }
907 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
909 struct spi_device
*spi
= data
;
911 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
912 struct acpi_resource_spi_serialbus
*sb
;
914 sb
= &ares
->data
.spi_serial_bus
;
915 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
916 spi
->chip_select
= sb
->device_selection
;
917 spi
->max_speed_hz
= sb
->connection_speed
;
919 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
920 spi
->mode
|= SPI_CPHA
;
921 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
922 spi
->mode
|= SPI_CPOL
;
923 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
924 spi
->mode
|= SPI_CS_HIGH
;
926 } else if (spi
->irq
< 0) {
929 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
933 /* Always tell the ACPI core to skip this resource */
937 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
938 void *data
, void **return_value
)
940 struct spi_master
*master
= data
;
941 struct list_head resource_list
;
942 struct acpi_device
*adev
;
943 struct spi_device
*spi
;
946 if (acpi_bus_get_device(handle
, &adev
))
948 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
951 spi
= spi_alloc_device(master
);
953 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
954 dev_name(&adev
->dev
));
958 ACPI_HANDLE_SET(&spi
->dev
, handle
);
961 INIT_LIST_HEAD(&resource_list
);
962 ret
= acpi_dev_get_resources(adev
, &resource_list
,
963 acpi_spi_add_resource
, spi
);
964 acpi_dev_free_resource_list(&resource_list
);
966 if (ret
< 0 || !spi
->max_speed_hz
) {
971 strlcpy(spi
->modalias
, dev_name(&adev
->dev
), sizeof(spi
->modalias
));
972 if (spi_add_device(spi
)) {
973 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
974 dev_name(&adev
->dev
));
981 static void acpi_register_spi_devices(struct spi_master
*master
)
986 handle
= ACPI_HANDLE(master
->dev
.parent
);
990 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
991 acpi_spi_add_device
, NULL
,
993 if (ACPI_FAILURE(status
))
994 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
997 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
998 #endif /* CONFIG_ACPI */
1000 static void spi_master_release(struct device
*dev
)
1002 struct spi_master
*master
;
1004 master
= container_of(dev
, struct spi_master
, dev
);
1008 static struct class spi_master_class
= {
1009 .name
= "spi_master",
1010 .owner
= THIS_MODULE
,
1011 .dev_release
= spi_master_release
,
1017 * spi_alloc_master - allocate SPI master controller
1018 * @dev: the controller, possibly using the platform_bus
1019 * @size: how much zeroed driver-private data to allocate; the pointer to this
1020 * memory is in the driver_data field of the returned device,
1021 * accessible with spi_master_get_devdata().
1022 * Context: can sleep
1024 * This call is used only by SPI master controller drivers, which are the
1025 * only ones directly touching chip registers. It's how they allocate
1026 * an spi_master structure, prior to calling spi_register_master().
1028 * This must be called from context that can sleep. It returns the SPI
1029 * master structure on success, else NULL.
1031 * The caller is responsible for assigning the bus number and initializing
1032 * the master's methods before calling spi_register_master(); and (after errors
1033 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1036 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1038 struct spi_master
*master
;
1043 master
= kzalloc(size
+ sizeof *master
, GFP_KERNEL
);
1047 device_initialize(&master
->dev
);
1048 master
->bus_num
= -1;
1049 master
->num_chipselect
= 1;
1050 master
->dev
.class = &spi_master_class
;
1051 master
->dev
.parent
= get_device(dev
);
1052 spi_master_set_devdata(master
, &master
[1]);
1056 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1059 static int of_spi_register_master(struct spi_master
*master
)
1062 struct device_node
*np
= master
->dev
.of_node
;
1067 nb
= of_gpio_named_count(np
, "cs-gpios");
1068 master
->num_chipselect
= max(nb
, (int)master
->num_chipselect
);
1070 /* Return error only for an incorrectly formed cs-gpios property */
1071 if (nb
== 0 || nb
== -ENOENT
)
1076 cs
= devm_kzalloc(&master
->dev
,
1077 sizeof(int) * master
->num_chipselect
,
1079 master
->cs_gpios
= cs
;
1081 if (!master
->cs_gpios
)
1084 for (i
= 0; i
< master
->num_chipselect
; i
++)
1087 for (i
= 0; i
< nb
; i
++)
1088 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1093 static int of_spi_register_master(struct spi_master
*master
)
1100 * spi_register_master - register SPI master controller
1101 * @master: initialized master, originally from spi_alloc_master()
1102 * Context: can sleep
1104 * SPI master controllers connect to their drivers using some non-SPI bus,
1105 * such as the platform bus. The final stage of probe() in that code
1106 * includes calling spi_register_master() to hook up to this SPI bus glue.
1108 * SPI controllers use board specific (often SOC specific) bus numbers,
1109 * and board-specific addressing for SPI devices combines those numbers
1110 * with chip select numbers. Since SPI does not directly support dynamic
1111 * device identification, boards need configuration tables telling which
1112 * chip is at which address.
1114 * This must be called from context that can sleep. It returns zero on
1115 * success, else a negative error code (dropping the master's refcount).
1116 * After a successful return, the caller is responsible for calling
1117 * spi_unregister_master().
1119 int spi_register_master(struct spi_master
*master
)
1121 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1122 struct device
*dev
= master
->dev
.parent
;
1123 struct boardinfo
*bi
;
1124 int status
= -ENODEV
;
1130 status
= of_spi_register_master(master
);
1134 /* even if it's just one always-selected device, there must
1135 * be at least one chipselect
1137 if (master
->num_chipselect
== 0)
1140 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1141 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1143 /* convention: dynamically assigned bus IDs count down from the max */
1144 if (master
->bus_num
< 0) {
1145 /* FIXME switch to an IDR based scheme, something like
1146 * I2C now uses, so we can't run out of "dynamic" IDs
1148 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1152 spin_lock_init(&master
->bus_lock_spinlock
);
1153 mutex_init(&master
->bus_lock_mutex
);
1154 master
->bus_lock_flag
= 0;
1156 /* register the device, then userspace will see it.
1157 * registration fails if the bus ID is in use.
1159 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1160 status
= device_add(&master
->dev
);
1163 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1164 dynamic
? " (dynamic)" : "");
1166 /* If we're using a queued driver, start the queue */
1167 if (master
->transfer
)
1168 dev_info(dev
, "master is unqueued, this is deprecated\n");
1170 status
= spi_master_initialize_queue(master
);
1172 device_unregister(&master
->dev
);
1177 mutex_lock(&board_lock
);
1178 list_add_tail(&master
->list
, &spi_master_list
);
1179 list_for_each_entry(bi
, &board_list
, list
)
1180 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1181 mutex_unlock(&board_lock
);
1183 /* Register devices from the device tree and ACPI */
1184 of_register_spi_devices(master
);
1185 acpi_register_spi_devices(master
);
1189 EXPORT_SYMBOL_GPL(spi_register_master
);
1191 static int __unregister(struct device
*dev
, void *null
)
1193 spi_unregister_device(to_spi_device(dev
));
1198 * spi_unregister_master - unregister SPI master controller
1199 * @master: the master being unregistered
1200 * Context: can sleep
1202 * This call is used only by SPI master controller drivers, which are the
1203 * only ones directly touching chip registers.
1205 * This must be called from context that can sleep.
1207 void spi_unregister_master(struct spi_master
*master
)
1211 if (master
->queued
) {
1212 if (spi_destroy_queue(master
))
1213 dev_err(&master
->dev
, "queue remove failed\n");
1216 mutex_lock(&board_lock
);
1217 list_del(&master
->list
);
1218 mutex_unlock(&board_lock
);
1220 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1221 device_unregister(&master
->dev
);
1223 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1225 int spi_master_suspend(struct spi_master
*master
)
1229 /* Basically no-ops for non-queued masters */
1230 if (!master
->queued
)
1233 ret
= spi_stop_queue(master
);
1235 dev_err(&master
->dev
, "queue stop failed\n");
1239 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1241 int spi_master_resume(struct spi_master
*master
)
1245 if (!master
->queued
)
1248 ret
= spi_start_queue(master
);
1250 dev_err(&master
->dev
, "queue restart failed\n");
1254 EXPORT_SYMBOL_GPL(spi_master_resume
);
1256 static int __spi_master_match(struct device
*dev
, const void *data
)
1258 struct spi_master
*m
;
1259 const u16
*bus_num
= data
;
1261 m
= container_of(dev
, struct spi_master
, dev
);
1262 return m
->bus_num
== *bus_num
;
1266 * spi_busnum_to_master - look up master associated with bus_num
1267 * @bus_num: the master's bus number
1268 * Context: can sleep
1270 * This call may be used with devices that are registered after
1271 * arch init time. It returns a refcounted pointer to the relevant
1272 * spi_master (which the caller must release), or NULL if there is
1273 * no such master registered.
1275 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1278 struct spi_master
*master
= NULL
;
1280 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1281 __spi_master_match
);
1283 master
= container_of(dev
, struct spi_master
, dev
);
1284 /* reference got in class_find_device */
1287 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1290 /*-------------------------------------------------------------------------*/
1292 /* Core methods for SPI master protocol drivers. Some of the
1293 * other core methods are currently defined as inline functions.
1297 * spi_setup - setup SPI mode and clock rate
1298 * @spi: the device whose settings are being modified
1299 * Context: can sleep, and no requests are queued to the device
1301 * SPI protocol drivers may need to update the transfer mode if the
1302 * device doesn't work with its default. They may likewise need
1303 * to update clock rates or word sizes from initial values. This function
1304 * changes those settings, and must be called from a context that can sleep.
1305 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1306 * effect the next time the device is selected and data is transferred to
1307 * or from it. When this function returns, the spi device is deselected.
1309 * Note that this call will fail if the protocol driver specifies an option
1310 * that the underlying controller or its driver does not support. For
1311 * example, not all hardware supports wire transfers using nine bit words,
1312 * LSB-first wire encoding, or active-high chipselects.
1314 int spi_setup(struct spi_device
*spi
)
1319 /* help drivers fail *cleanly* when they need options
1320 * that aren't supported with their current master
1322 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1324 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1329 if (!spi
->bits_per_word
)
1330 spi
->bits_per_word
= 8;
1332 if (spi
->master
->setup
)
1333 status
= spi
->master
->setup(spi
);
1335 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s"
1336 "%u bits/w, %u Hz max --> %d\n",
1337 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1338 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1339 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1340 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1341 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1342 spi
->bits_per_word
, spi
->max_speed_hz
,
1347 EXPORT_SYMBOL_GPL(spi_setup
);
1349 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1351 struct spi_master
*master
= spi
->master
;
1352 struct spi_transfer
*xfer
;
1354 /* Half-duplex links include original MicroWire, and ones with
1355 * only one data pin like SPI_3WIRE (switches direction) or where
1356 * either MOSI or MISO is missing. They can also be caused by
1357 * software limitations.
1359 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1360 || (spi
->mode
& SPI_3WIRE
)) {
1361 unsigned flags
= master
->flags
;
1363 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1364 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1366 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1368 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1374 * Set transfer bits_per_word and max speed as spi device default if
1375 * it is not set for this transfer.
1377 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1378 if (!xfer
->bits_per_word
)
1379 xfer
->bits_per_word
= spi
->bits_per_word
;
1380 if (!xfer
->speed_hz
)
1381 xfer
->speed_hz
= spi
->max_speed_hz
;
1382 if (master
->bits_per_word_mask
) {
1383 /* Only 32 bits fit in the mask */
1384 if (xfer
->bits_per_word
> 32)
1386 if (!(master
->bits_per_word_mask
&
1387 BIT(xfer
->bits_per_word
- 1)))
1393 message
->status
= -EINPROGRESS
;
1394 return master
->transfer(spi
, message
);
1398 * spi_async - asynchronous SPI transfer
1399 * @spi: device with which data will be exchanged
1400 * @message: describes the data transfers, including completion callback
1401 * Context: any (irqs may be blocked, etc)
1403 * This call may be used in_irq and other contexts which can't sleep,
1404 * as well as from task contexts which can sleep.
1406 * The completion callback is invoked in a context which can't sleep.
1407 * Before that invocation, the value of message->status is undefined.
1408 * When the callback is issued, message->status holds either zero (to
1409 * indicate complete success) or a negative error code. After that
1410 * callback returns, the driver which issued the transfer request may
1411 * deallocate the associated memory; it's no longer in use by any SPI
1412 * core or controller driver code.
1414 * Note that although all messages to a spi_device are handled in
1415 * FIFO order, messages may go to different devices in other orders.
1416 * Some device might be higher priority, or have various "hard" access
1417 * time requirements, for example.
1419 * On detection of any fault during the transfer, processing of
1420 * the entire message is aborted, and the device is deselected.
1421 * Until returning from the associated message completion callback,
1422 * no other spi_message queued to that device will be processed.
1423 * (This rule applies equally to all the synchronous transfer calls,
1424 * which are wrappers around this core asynchronous primitive.)
1426 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1428 struct spi_master
*master
= spi
->master
;
1430 unsigned long flags
;
1432 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1434 if (master
->bus_lock_flag
)
1437 ret
= __spi_async(spi
, message
);
1439 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1443 EXPORT_SYMBOL_GPL(spi_async
);
1446 * spi_async_locked - version of spi_async with exclusive bus usage
1447 * @spi: device with which data will be exchanged
1448 * @message: describes the data transfers, including completion callback
1449 * Context: any (irqs may be blocked, etc)
1451 * This call may be used in_irq and other contexts which can't sleep,
1452 * as well as from task contexts which can sleep.
1454 * The completion callback is invoked in a context which can't sleep.
1455 * Before that invocation, the value of message->status is undefined.
1456 * When the callback is issued, message->status holds either zero (to
1457 * indicate complete success) or a negative error code. After that
1458 * callback returns, the driver which issued the transfer request may
1459 * deallocate the associated memory; it's no longer in use by any SPI
1460 * core or controller driver code.
1462 * Note that although all messages to a spi_device are handled in
1463 * FIFO order, messages may go to different devices in other orders.
1464 * Some device might be higher priority, or have various "hard" access
1465 * time requirements, for example.
1467 * On detection of any fault during the transfer, processing of
1468 * the entire message is aborted, and the device is deselected.
1469 * Until returning from the associated message completion callback,
1470 * no other spi_message queued to that device will be processed.
1471 * (This rule applies equally to all the synchronous transfer calls,
1472 * which are wrappers around this core asynchronous primitive.)
1474 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
1476 struct spi_master
*master
= spi
->master
;
1478 unsigned long flags
;
1480 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1482 ret
= __spi_async(spi
, message
);
1484 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1489 EXPORT_SYMBOL_GPL(spi_async_locked
);
1492 /*-------------------------------------------------------------------------*/
1494 /* Utility methods for SPI master protocol drivers, layered on
1495 * top of the core. Some other utility methods are defined as
1499 static void spi_complete(void *arg
)
1504 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
1507 DECLARE_COMPLETION_ONSTACK(done
);
1509 struct spi_master
*master
= spi
->master
;
1511 message
->complete
= spi_complete
;
1512 message
->context
= &done
;
1515 mutex_lock(&master
->bus_lock_mutex
);
1517 status
= spi_async_locked(spi
, message
);
1520 mutex_unlock(&master
->bus_lock_mutex
);
1523 wait_for_completion(&done
);
1524 status
= message
->status
;
1526 message
->context
= NULL
;
1531 * spi_sync - blocking/synchronous SPI data transfers
1532 * @spi: device with which data will be exchanged
1533 * @message: describes the data transfers
1534 * Context: can sleep
1536 * This call may only be used from a context that may sleep. The sleep
1537 * is non-interruptible, and has no timeout. Low-overhead controller
1538 * drivers may DMA directly into and out of the message buffers.
1540 * Note that the SPI device's chip select is active during the message,
1541 * and then is normally disabled between messages. Drivers for some
1542 * frequently-used devices may want to minimize costs of selecting a chip,
1543 * by leaving it selected in anticipation that the next message will go
1544 * to the same chip. (That may increase power usage.)
1546 * Also, the caller is guaranteeing that the memory associated with the
1547 * message will not be freed before this call returns.
1549 * It returns zero on success, else a negative error code.
1551 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
1553 return __spi_sync(spi
, message
, 0);
1555 EXPORT_SYMBOL_GPL(spi_sync
);
1558 * spi_sync_locked - version of spi_sync with exclusive bus usage
1559 * @spi: device with which data will be exchanged
1560 * @message: describes the data transfers
1561 * Context: can sleep
1563 * This call may only be used from a context that may sleep. The sleep
1564 * is non-interruptible, and has no timeout. Low-overhead controller
1565 * drivers may DMA directly into and out of the message buffers.
1567 * This call should be used by drivers that require exclusive access to the
1568 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1569 * be released by a spi_bus_unlock call when the exclusive access is over.
1571 * It returns zero on success, else a negative error code.
1573 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
1575 return __spi_sync(spi
, message
, 1);
1577 EXPORT_SYMBOL_GPL(spi_sync_locked
);
1580 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1581 * @master: SPI bus master that should be locked for exclusive bus access
1582 * Context: can sleep
1584 * This call may only be used from a context that may sleep. The sleep
1585 * is non-interruptible, and has no timeout.
1587 * This call should be used by drivers that require exclusive access to the
1588 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1589 * exclusive access is over. Data transfer must be done by spi_sync_locked
1590 * and spi_async_locked calls when the SPI bus lock is held.
1592 * It returns zero on success, else a negative error code.
1594 int spi_bus_lock(struct spi_master
*master
)
1596 unsigned long flags
;
1598 mutex_lock(&master
->bus_lock_mutex
);
1600 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1601 master
->bus_lock_flag
= 1;
1602 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1604 /* mutex remains locked until spi_bus_unlock is called */
1608 EXPORT_SYMBOL_GPL(spi_bus_lock
);
1611 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1612 * @master: SPI bus master that was locked for exclusive bus access
1613 * Context: can sleep
1615 * This call may only be used from a context that may sleep. The sleep
1616 * is non-interruptible, and has no timeout.
1618 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1621 * It returns zero on success, else a negative error code.
1623 int spi_bus_unlock(struct spi_master
*master
)
1625 master
->bus_lock_flag
= 0;
1627 mutex_unlock(&master
->bus_lock_mutex
);
1631 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
1633 /* portable code must never pass more than 32 bytes */
1634 #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1639 * spi_write_then_read - SPI synchronous write followed by read
1640 * @spi: device with which data will be exchanged
1641 * @txbuf: data to be written (need not be dma-safe)
1642 * @n_tx: size of txbuf, in bytes
1643 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1644 * @n_rx: size of rxbuf, in bytes
1645 * Context: can sleep
1647 * This performs a half duplex MicroWire style transaction with the
1648 * device, sending txbuf and then reading rxbuf. The return value
1649 * is zero for success, else a negative errno status code.
1650 * This call may only be used from a context that may sleep.
1652 * Parameters to this routine are always copied using a small buffer;
1653 * portable code should never use this for more than 32 bytes.
1654 * Performance-sensitive or bulk transfer code should instead use
1655 * spi_{async,sync}() calls with dma-safe buffers.
1657 int spi_write_then_read(struct spi_device
*spi
,
1658 const void *txbuf
, unsigned n_tx
,
1659 void *rxbuf
, unsigned n_rx
)
1661 static DEFINE_MUTEX(lock
);
1664 struct spi_message message
;
1665 struct spi_transfer x
[2];
1668 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1669 * copying here, (as a pure convenience thing), but we can
1670 * keep heap costs out of the hot path unless someone else is
1671 * using the pre-allocated buffer or the transfer is too large.
1673 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
1674 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
1675 GFP_KERNEL
| GFP_DMA
);
1682 spi_message_init(&message
);
1683 memset(x
, 0, sizeof x
);
1686 spi_message_add_tail(&x
[0], &message
);
1690 spi_message_add_tail(&x
[1], &message
);
1693 memcpy(local_buf
, txbuf
, n_tx
);
1694 x
[0].tx_buf
= local_buf
;
1695 x
[1].rx_buf
= local_buf
+ n_tx
;
1698 status
= spi_sync(spi
, &message
);
1700 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
1702 if (x
[0].tx_buf
== buf
)
1703 mutex_unlock(&lock
);
1709 EXPORT_SYMBOL_GPL(spi_write_then_read
);
1711 /*-------------------------------------------------------------------------*/
1713 static int __init
spi_init(void)
1717 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
1723 status
= bus_register(&spi_bus_type
);
1727 status
= class_register(&spi_master_class
);
1733 bus_unregister(&spi_bus_type
);
1741 /* board_info is normally registered in arch_initcall(),
1742 * but even essential drivers wait till later
1744 * REVISIT only boardinfo really needs static linking. the rest (device and
1745 * driver registration) _could_ be dynamically linked (modular) ... costs
1746 * include needing to have boardinfo data structures be much more public.
1748 postcore_initcall(spi_init
);