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");
556 if (master
->auto_runtime_pm
) {
557 pm_runtime_mark_last_busy(master
->dev
.parent
);
558 pm_runtime_put_autosuspend(master
->dev
.parent
);
563 /* Make sure we are not already running a message */
564 if (master
->cur_msg
) {
565 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
568 /* Extract head of queue */
570 list_entry(master
->queue
.next
, struct spi_message
, queue
);
572 list_del_init(&master
->cur_msg
->queue
);
577 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
579 if (!was_busy
&& master
->auto_runtime_pm
) {
580 ret
= pm_runtime_get_sync(master
->dev
.parent
);
582 dev_err(&master
->dev
, "Failed to power device: %d\n",
588 if (!was_busy
&& master
->prepare_transfer_hardware
) {
589 ret
= master
->prepare_transfer_hardware(master
);
591 dev_err(&master
->dev
,
592 "failed to prepare transfer hardware\n");
594 if (master
->auto_runtime_pm
)
595 pm_runtime_put(master
->dev
.parent
);
600 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
602 dev_err(&master
->dev
,
603 "failed to transfer one message from queue\n");
608 static int spi_init_queue(struct spi_master
*master
)
610 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
612 INIT_LIST_HEAD(&master
->queue
);
613 spin_lock_init(&master
->queue_lock
);
615 master
->running
= false;
616 master
->busy
= false;
618 init_kthread_worker(&master
->kworker
);
619 master
->kworker_task
= kthread_run(kthread_worker_fn
,
620 &master
->kworker
, "%s",
621 dev_name(&master
->dev
));
622 if (IS_ERR(master
->kworker_task
)) {
623 dev_err(&master
->dev
, "failed to create message pump task\n");
626 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
629 * Master config will indicate if this controller should run the
630 * message pump with high (realtime) priority to reduce the transfer
631 * latency on the bus by minimising the delay between a transfer
632 * request and the scheduling of the message pump thread. Without this
633 * setting the message pump thread will remain at default priority.
636 dev_info(&master
->dev
,
637 "will run message pump with realtime priority\n");
638 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
645 * spi_get_next_queued_message() - called by driver to check for queued
647 * @master: the master to check for queued messages
649 * If there are more messages in the queue, the next message is returned from
652 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
654 struct spi_message
*next
;
657 /* get a pointer to the next message, if any */
658 spin_lock_irqsave(&master
->queue_lock
, flags
);
659 if (list_empty(&master
->queue
))
662 next
= list_entry(master
->queue
.next
,
663 struct spi_message
, queue
);
664 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
668 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
671 * spi_finalize_current_message() - the current message is complete
672 * @master: the master to return the message to
674 * Called by the driver to notify the core that the message in the front of the
675 * queue is complete and can be removed from the queue.
677 void spi_finalize_current_message(struct spi_master
*master
)
679 struct spi_message
*mesg
;
682 spin_lock_irqsave(&master
->queue_lock
, flags
);
683 mesg
= master
->cur_msg
;
684 master
->cur_msg
= NULL
;
686 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
687 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
691 mesg
->complete(mesg
->context
);
693 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
695 static int spi_start_queue(struct spi_master
*master
)
699 spin_lock_irqsave(&master
->queue_lock
, flags
);
701 if (master
->running
|| master
->busy
) {
702 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
706 master
->running
= true;
707 master
->cur_msg
= NULL
;
708 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
710 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
715 static int spi_stop_queue(struct spi_master
*master
)
718 unsigned limit
= 500;
721 spin_lock_irqsave(&master
->queue_lock
, flags
);
724 * This is a bit lame, but is optimized for the common execution path.
725 * A wait_queue on the master->busy could be used, but then the common
726 * execution path (pump_messages) would be required to call wake_up or
727 * friends on every SPI message. Do this instead.
729 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
730 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
732 spin_lock_irqsave(&master
->queue_lock
, flags
);
735 if (!list_empty(&master
->queue
) || master
->busy
)
738 master
->running
= false;
740 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
743 dev_warn(&master
->dev
,
744 "could not stop message queue\n");
750 static int spi_destroy_queue(struct spi_master
*master
)
754 ret
= spi_stop_queue(master
);
757 * flush_kthread_worker will block until all work is done.
758 * If the reason that stop_queue timed out is that the work will never
759 * finish, then it does no good to call flush/stop thread, so
763 dev_err(&master
->dev
, "problem destroying queue\n");
767 flush_kthread_worker(&master
->kworker
);
768 kthread_stop(master
->kworker_task
);
774 * spi_queued_transfer - transfer function for queued transfers
775 * @spi: spi device which is requesting transfer
776 * @msg: spi message which is to handled is queued to driver queue
778 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
780 struct spi_master
*master
= spi
->master
;
783 spin_lock_irqsave(&master
->queue_lock
, flags
);
785 if (!master
->running
) {
786 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
789 msg
->actual_length
= 0;
790 msg
->status
= -EINPROGRESS
;
792 list_add_tail(&msg
->queue
, &master
->queue
);
794 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
796 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
800 static int spi_master_initialize_queue(struct spi_master
*master
)
804 master
->queued
= true;
805 master
->transfer
= spi_queued_transfer
;
807 /* Initialize and start queue */
808 ret
= spi_init_queue(master
);
810 dev_err(&master
->dev
, "problem initializing queue\n");
813 ret
= spi_start_queue(master
);
815 dev_err(&master
->dev
, "problem starting queue\n");
816 goto err_start_queue
;
823 spi_destroy_queue(master
);
827 /*-------------------------------------------------------------------------*/
829 #if defined(CONFIG_OF)
831 * of_register_spi_devices() - Register child devices onto the SPI bus
832 * @master: Pointer to spi_master device
834 * Registers an spi_device for each child node of master node which has a 'reg'
837 static void of_register_spi_devices(struct spi_master
*master
)
839 struct spi_device
*spi
;
840 struct device_node
*nc
;
842 char modalias
[SPI_NAME_SIZE
+ 4];
846 if (!master
->dev
.of_node
)
849 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
850 /* Alloc an spi_device */
851 spi
= spi_alloc_device(master
);
853 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
859 /* Select device driver */
860 if (of_modalias_node(nc
, spi
->modalias
,
861 sizeof(spi
->modalias
)) < 0) {
862 dev_err(&master
->dev
, "cannot find modalias for %s\n",
869 prop
= of_get_property(nc
, "reg", &len
);
870 if (!prop
|| len
< sizeof(*prop
)) {
871 dev_err(&master
->dev
, "%s has no 'reg' property\n",
876 spi
->chip_select
= be32_to_cpup(prop
);
878 /* Mode (clock phase/polarity/etc.) */
879 if (of_find_property(nc
, "spi-cpha", NULL
))
880 spi
->mode
|= SPI_CPHA
;
881 if (of_find_property(nc
, "spi-cpol", NULL
))
882 spi
->mode
|= SPI_CPOL
;
883 if (of_find_property(nc
, "spi-cs-high", NULL
))
884 spi
->mode
|= SPI_CS_HIGH
;
885 if (of_find_property(nc
, "spi-3wire", NULL
))
886 spi
->mode
|= SPI_3WIRE
;
888 /* Device DUAL/QUAD mode */
889 prop
= of_get_property(nc
, "spi-tx-bus-width", &len
);
890 if (prop
&& len
== sizeof(*prop
)) {
891 switch (be32_to_cpup(prop
)) {
892 case SPI_NBITS_SINGLE
:
895 spi
->mode
|= SPI_TX_DUAL
;
898 spi
->mode
|= SPI_TX_QUAD
;
901 dev_err(&master
->dev
,
902 "spi-tx-bus-width %d not supported\n",
909 prop
= of_get_property(nc
, "spi-rx-bus-width", &len
);
910 if (prop
&& len
== sizeof(*prop
)) {
911 switch (be32_to_cpup(prop
)) {
912 case SPI_NBITS_SINGLE
:
915 spi
->mode
|= SPI_RX_DUAL
;
918 spi
->mode
|= SPI_RX_QUAD
;
921 dev_err(&master
->dev
,
922 "spi-rx-bus-width %d not supported\n",
930 prop
= of_get_property(nc
, "spi-max-frequency", &len
);
931 if (!prop
|| len
< sizeof(*prop
)) {
932 dev_err(&master
->dev
, "%s has no 'spi-max-frequency' property\n",
937 spi
->max_speed_hz
= be32_to_cpup(prop
);
940 spi
->irq
= irq_of_parse_and_map(nc
, 0);
942 /* Store a pointer to the node in the device structure */
944 spi
->dev
.of_node
= nc
;
946 /* Register the new device */
947 snprintf(modalias
, sizeof(modalias
), "%s%s", SPI_MODULE_PREFIX
,
949 request_module(modalias
);
950 rc
= spi_add_device(spi
);
952 dev_err(&master
->dev
, "spi_device register error %s\n",
960 static void of_register_spi_devices(struct spi_master
*master
) { }
964 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
966 struct spi_device
*spi
= data
;
968 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
969 struct acpi_resource_spi_serialbus
*sb
;
971 sb
= &ares
->data
.spi_serial_bus
;
972 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
973 spi
->chip_select
= sb
->device_selection
;
974 spi
->max_speed_hz
= sb
->connection_speed
;
976 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
977 spi
->mode
|= SPI_CPHA
;
978 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
979 spi
->mode
|= SPI_CPOL
;
980 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
981 spi
->mode
|= SPI_CS_HIGH
;
983 } else if (spi
->irq
< 0) {
986 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
990 /* Always tell the ACPI core to skip this resource */
994 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
995 void *data
, void **return_value
)
997 struct spi_master
*master
= data
;
998 struct list_head resource_list
;
999 struct acpi_device
*adev
;
1000 struct spi_device
*spi
;
1003 if (acpi_bus_get_device(handle
, &adev
))
1005 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
1008 spi
= spi_alloc_device(master
);
1010 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
1011 dev_name(&adev
->dev
));
1012 return AE_NO_MEMORY
;
1015 ACPI_HANDLE_SET(&spi
->dev
, handle
);
1018 INIT_LIST_HEAD(&resource_list
);
1019 ret
= acpi_dev_get_resources(adev
, &resource_list
,
1020 acpi_spi_add_resource
, spi
);
1021 acpi_dev_free_resource_list(&resource_list
);
1023 if (ret
< 0 || !spi
->max_speed_hz
) {
1028 strlcpy(spi
->modalias
, dev_name(&adev
->dev
), sizeof(spi
->modalias
));
1029 if (spi_add_device(spi
)) {
1030 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
1031 dev_name(&adev
->dev
));
1038 static void acpi_register_spi_devices(struct spi_master
*master
)
1043 handle
= ACPI_HANDLE(master
->dev
.parent
);
1047 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
1048 acpi_spi_add_device
, NULL
,
1050 if (ACPI_FAILURE(status
))
1051 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
1054 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
1055 #endif /* CONFIG_ACPI */
1057 static void spi_master_release(struct device
*dev
)
1059 struct spi_master
*master
;
1061 master
= container_of(dev
, struct spi_master
, dev
);
1065 static struct class spi_master_class
= {
1066 .name
= "spi_master",
1067 .owner
= THIS_MODULE
,
1068 .dev_release
= spi_master_release
,
1074 * spi_alloc_master - allocate SPI master controller
1075 * @dev: the controller, possibly using the platform_bus
1076 * @size: how much zeroed driver-private data to allocate; the pointer to this
1077 * memory is in the driver_data field of the returned device,
1078 * accessible with spi_master_get_devdata().
1079 * Context: can sleep
1081 * This call is used only by SPI master controller drivers, which are the
1082 * only ones directly touching chip registers. It's how they allocate
1083 * an spi_master structure, prior to calling spi_register_master().
1085 * This must be called from context that can sleep. It returns the SPI
1086 * master structure on success, else NULL.
1088 * The caller is responsible for assigning the bus number and initializing
1089 * the master's methods before calling spi_register_master(); and (after errors
1090 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1093 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1095 struct spi_master
*master
;
1100 master
= kzalloc(size
+ sizeof *master
, GFP_KERNEL
);
1104 device_initialize(&master
->dev
);
1105 master
->bus_num
= -1;
1106 master
->num_chipselect
= 1;
1107 master
->dev
.class = &spi_master_class
;
1108 master
->dev
.parent
= get_device(dev
);
1109 spi_master_set_devdata(master
, &master
[1]);
1113 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1116 static int of_spi_register_master(struct spi_master
*master
)
1119 struct device_node
*np
= master
->dev
.of_node
;
1124 nb
= of_gpio_named_count(np
, "cs-gpios");
1125 master
->num_chipselect
= max(nb
, (int)master
->num_chipselect
);
1127 /* Return error only for an incorrectly formed cs-gpios property */
1128 if (nb
== 0 || nb
== -ENOENT
)
1133 cs
= devm_kzalloc(&master
->dev
,
1134 sizeof(int) * master
->num_chipselect
,
1136 master
->cs_gpios
= cs
;
1138 if (!master
->cs_gpios
)
1141 for (i
= 0; i
< master
->num_chipselect
; i
++)
1144 for (i
= 0; i
< nb
; i
++)
1145 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1150 static int of_spi_register_master(struct spi_master
*master
)
1157 * spi_register_master - register SPI master controller
1158 * @master: initialized master, originally from spi_alloc_master()
1159 * Context: can sleep
1161 * SPI master controllers connect to their drivers using some non-SPI bus,
1162 * such as the platform bus. The final stage of probe() in that code
1163 * includes calling spi_register_master() to hook up to this SPI bus glue.
1165 * SPI controllers use board specific (often SOC specific) bus numbers,
1166 * and board-specific addressing for SPI devices combines those numbers
1167 * with chip select numbers. Since SPI does not directly support dynamic
1168 * device identification, boards need configuration tables telling which
1169 * chip is at which address.
1171 * This must be called from context that can sleep. It returns zero on
1172 * success, else a negative error code (dropping the master's refcount).
1173 * After a successful return, the caller is responsible for calling
1174 * spi_unregister_master().
1176 int spi_register_master(struct spi_master
*master
)
1178 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1179 struct device
*dev
= master
->dev
.parent
;
1180 struct boardinfo
*bi
;
1181 int status
= -ENODEV
;
1187 status
= of_spi_register_master(master
);
1191 /* even if it's just one always-selected device, there must
1192 * be at least one chipselect
1194 if (master
->num_chipselect
== 0)
1197 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1198 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1200 /* convention: dynamically assigned bus IDs count down from the max */
1201 if (master
->bus_num
< 0) {
1202 /* FIXME switch to an IDR based scheme, something like
1203 * I2C now uses, so we can't run out of "dynamic" IDs
1205 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1209 spin_lock_init(&master
->bus_lock_spinlock
);
1210 mutex_init(&master
->bus_lock_mutex
);
1211 master
->bus_lock_flag
= 0;
1213 /* register the device, then userspace will see it.
1214 * registration fails if the bus ID is in use.
1216 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1217 status
= device_add(&master
->dev
);
1220 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1221 dynamic
? " (dynamic)" : "");
1223 /* If we're using a queued driver, start the queue */
1224 if (master
->transfer
)
1225 dev_info(dev
, "master is unqueued, this is deprecated\n");
1227 status
= spi_master_initialize_queue(master
);
1229 device_del(&master
->dev
);
1234 mutex_lock(&board_lock
);
1235 list_add_tail(&master
->list
, &spi_master_list
);
1236 list_for_each_entry(bi
, &board_list
, list
)
1237 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1238 mutex_unlock(&board_lock
);
1240 /* Register devices from the device tree and ACPI */
1241 of_register_spi_devices(master
);
1242 acpi_register_spi_devices(master
);
1246 EXPORT_SYMBOL_GPL(spi_register_master
);
1248 static int __unregister(struct device
*dev
, void *null
)
1250 spi_unregister_device(to_spi_device(dev
));
1255 * spi_unregister_master - unregister SPI master controller
1256 * @master: the master being unregistered
1257 * Context: can sleep
1259 * This call is used only by SPI master controller drivers, which are the
1260 * only ones directly touching chip registers.
1262 * This must be called from context that can sleep.
1264 void spi_unregister_master(struct spi_master
*master
)
1268 if (master
->queued
) {
1269 if (spi_destroy_queue(master
))
1270 dev_err(&master
->dev
, "queue remove failed\n");
1273 mutex_lock(&board_lock
);
1274 list_del(&master
->list
);
1275 mutex_unlock(&board_lock
);
1277 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1278 device_unregister(&master
->dev
);
1280 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1282 int spi_master_suspend(struct spi_master
*master
)
1286 /* Basically no-ops for non-queued masters */
1287 if (!master
->queued
)
1290 ret
= spi_stop_queue(master
);
1292 dev_err(&master
->dev
, "queue stop failed\n");
1296 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1298 int spi_master_resume(struct spi_master
*master
)
1302 if (!master
->queued
)
1305 ret
= spi_start_queue(master
);
1307 dev_err(&master
->dev
, "queue restart failed\n");
1311 EXPORT_SYMBOL_GPL(spi_master_resume
);
1313 static int __spi_master_match(struct device
*dev
, const void *data
)
1315 struct spi_master
*m
;
1316 const u16
*bus_num
= data
;
1318 m
= container_of(dev
, struct spi_master
, dev
);
1319 return m
->bus_num
== *bus_num
;
1323 * spi_busnum_to_master - look up master associated with bus_num
1324 * @bus_num: the master's bus number
1325 * Context: can sleep
1327 * This call may be used with devices that are registered after
1328 * arch init time. It returns a refcounted pointer to the relevant
1329 * spi_master (which the caller must release), or NULL if there is
1330 * no such master registered.
1332 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1335 struct spi_master
*master
= NULL
;
1337 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1338 __spi_master_match
);
1340 master
= container_of(dev
, struct spi_master
, dev
);
1341 /* reference got in class_find_device */
1344 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1347 /*-------------------------------------------------------------------------*/
1349 /* Core methods for SPI master protocol drivers. Some of the
1350 * other core methods are currently defined as inline functions.
1354 * spi_setup - setup SPI mode and clock rate
1355 * @spi: the device whose settings are being modified
1356 * Context: can sleep, and no requests are queued to the device
1358 * SPI protocol drivers may need to update the transfer mode if the
1359 * device doesn't work with its default. They may likewise need
1360 * to update clock rates or word sizes from initial values. This function
1361 * changes those settings, and must be called from a context that can sleep.
1362 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1363 * effect the next time the device is selected and data is transferred to
1364 * or from it. When this function returns, the spi device is deselected.
1366 * Note that this call will fail if the protocol driver specifies an option
1367 * that the underlying controller or its driver does not support. For
1368 * example, not all hardware supports wire transfers using nine bit words,
1369 * LSB-first wire encoding, or active-high chipselects.
1371 int spi_setup(struct spi_device
*spi
)
1373 unsigned bad_bits
, ugly_bits
;
1376 /* check mode to prevent that DUAL and QUAD set at the same time
1378 if (((spi
->mode
& SPI_TX_DUAL
) && (spi
->mode
& SPI_TX_QUAD
)) ||
1379 ((spi
->mode
& SPI_RX_DUAL
) && (spi
->mode
& SPI_RX_QUAD
))) {
1381 "setup: can not select dual and quad at the same time\n");
1384 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1386 if ((spi
->mode
& SPI_3WIRE
) && (spi
->mode
&
1387 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
)))
1389 /* help drivers fail *cleanly* when they need options
1390 * that aren't supported with their current master
1392 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1393 ugly_bits
= bad_bits
&
1394 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
);
1397 "setup: ignoring unsupported mode bits %x\n",
1399 spi
->mode
&= ~ugly_bits
;
1400 bad_bits
&= ~ugly_bits
;
1403 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1408 if (!spi
->bits_per_word
)
1409 spi
->bits_per_word
= 8;
1411 if (spi
->master
->setup
)
1412 status
= spi
->master
->setup(spi
);
1414 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s"
1415 "%u bits/w, %u Hz max --> %d\n",
1416 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1417 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1418 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1419 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1420 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1421 spi
->bits_per_word
, spi
->max_speed_hz
,
1426 EXPORT_SYMBOL_GPL(spi_setup
);
1428 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1430 struct spi_master
*master
= spi
->master
;
1431 struct spi_transfer
*xfer
;
1433 if (list_empty(&message
->transfers
))
1435 if (!message
->complete
)
1438 /* Half-duplex links include original MicroWire, and ones with
1439 * only one data pin like SPI_3WIRE (switches direction) or where
1440 * either MOSI or MISO is missing. They can also be caused by
1441 * software limitations.
1443 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1444 || (spi
->mode
& SPI_3WIRE
)) {
1445 unsigned flags
= master
->flags
;
1447 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1448 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1450 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1452 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1458 * Set transfer bits_per_word and max speed as spi device default if
1459 * it is not set for this transfer.
1460 * Set transfer tx_nbits and rx_nbits as single transfer default
1461 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1463 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1464 message
->frame_length
+= xfer
->len
;
1465 if (!xfer
->bits_per_word
)
1466 xfer
->bits_per_word
= spi
->bits_per_word
;
1467 if (!xfer
->speed_hz
) {
1468 xfer
->speed_hz
= spi
->max_speed_hz
;
1469 if (master
->max_speed_hz
&&
1470 xfer
->speed_hz
> master
->max_speed_hz
)
1471 xfer
->speed_hz
= master
->max_speed_hz
;
1474 if (master
->bits_per_word_mask
) {
1475 /* Only 32 bits fit in the mask */
1476 if (xfer
->bits_per_word
> 32)
1478 if (!(master
->bits_per_word_mask
&
1479 BIT(xfer
->bits_per_word
- 1)))
1483 if (xfer
->speed_hz
&& master
->min_speed_hz
&&
1484 xfer
->speed_hz
< master
->min_speed_hz
)
1486 if (xfer
->speed_hz
&& master
->max_speed_hz
&&
1487 xfer
->speed_hz
> master
->max_speed_hz
)
1490 if (xfer
->tx_buf
&& !xfer
->tx_nbits
)
1491 xfer
->tx_nbits
= SPI_NBITS_SINGLE
;
1492 if (xfer
->rx_buf
&& !xfer
->rx_nbits
)
1493 xfer
->rx_nbits
= SPI_NBITS_SINGLE
;
1494 /* check transfer tx/rx_nbits:
1495 * 1. keep the value is not out of single, dual and quad
1496 * 2. keep tx/rx_nbits is contained by mode in spi_device
1497 * 3. if SPI_3WIRE, tx/rx_nbits should be in single
1500 if (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
&&
1501 xfer
->tx_nbits
!= SPI_NBITS_DUAL
&&
1502 xfer
->tx_nbits
!= SPI_NBITS_QUAD
)
1504 if ((xfer
->tx_nbits
== SPI_NBITS_DUAL
) &&
1505 !(spi
->mode
& (SPI_TX_DUAL
| SPI_TX_QUAD
)))
1507 if ((xfer
->tx_nbits
== SPI_NBITS_QUAD
) &&
1508 !(spi
->mode
& SPI_TX_QUAD
))
1510 if ((spi
->mode
& SPI_3WIRE
) &&
1511 (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
))
1514 /* check transfer rx_nbits */
1516 if (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
&&
1517 xfer
->rx_nbits
!= SPI_NBITS_DUAL
&&
1518 xfer
->rx_nbits
!= SPI_NBITS_QUAD
)
1520 if ((xfer
->rx_nbits
== SPI_NBITS_DUAL
) &&
1521 !(spi
->mode
& (SPI_RX_DUAL
| SPI_RX_QUAD
)))
1523 if ((xfer
->rx_nbits
== SPI_NBITS_QUAD
) &&
1524 !(spi
->mode
& SPI_RX_QUAD
))
1526 if ((spi
->mode
& SPI_3WIRE
) &&
1527 (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
))
1533 message
->status
= -EINPROGRESS
;
1534 return master
->transfer(spi
, message
);
1538 * spi_async - asynchronous SPI transfer
1539 * @spi: device with which data will be exchanged
1540 * @message: describes the data transfers, including completion callback
1541 * Context: any (irqs may be blocked, etc)
1543 * This call may be used in_irq and other contexts which can't sleep,
1544 * as well as from task contexts which can sleep.
1546 * The completion callback is invoked in a context which can't sleep.
1547 * Before that invocation, the value of message->status is undefined.
1548 * When the callback is issued, message->status holds either zero (to
1549 * indicate complete success) or a negative error code. After that
1550 * callback returns, the driver which issued the transfer request may
1551 * deallocate the associated memory; it's no longer in use by any SPI
1552 * core or controller driver code.
1554 * Note that although all messages to a spi_device are handled in
1555 * FIFO order, messages may go to different devices in other orders.
1556 * Some device might be higher priority, or have various "hard" access
1557 * time requirements, for example.
1559 * On detection of any fault during the transfer, processing of
1560 * the entire message is aborted, and the device is deselected.
1561 * Until returning from the associated message completion callback,
1562 * no other spi_message queued to that device will be processed.
1563 * (This rule applies equally to all the synchronous transfer calls,
1564 * which are wrappers around this core asynchronous primitive.)
1566 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1568 struct spi_master
*master
= spi
->master
;
1570 unsigned long flags
;
1572 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1574 if (master
->bus_lock_flag
)
1577 ret
= __spi_async(spi
, message
);
1579 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1583 EXPORT_SYMBOL_GPL(spi_async
);
1586 * spi_async_locked - version of spi_async with exclusive bus usage
1587 * @spi: device with which data will be exchanged
1588 * @message: describes the data transfers, including completion callback
1589 * Context: any (irqs may be blocked, etc)
1591 * This call may be used in_irq and other contexts which can't sleep,
1592 * as well as from task contexts which can sleep.
1594 * The completion callback is invoked in a context which can't sleep.
1595 * Before that invocation, the value of message->status is undefined.
1596 * When the callback is issued, message->status holds either zero (to
1597 * indicate complete success) or a negative error code. After that
1598 * callback returns, the driver which issued the transfer request may
1599 * deallocate the associated memory; it's no longer in use by any SPI
1600 * core or controller driver code.
1602 * Note that although all messages to a spi_device are handled in
1603 * FIFO order, messages may go to different devices in other orders.
1604 * Some device might be higher priority, or have various "hard" access
1605 * time requirements, for example.
1607 * On detection of any fault during the transfer, processing of
1608 * the entire message is aborted, and the device is deselected.
1609 * Until returning from the associated message completion callback,
1610 * no other spi_message queued to that device will be processed.
1611 * (This rule applies equally to all the synchronous transfer calls,
1612 * which are wrappers around this core asynchronous primitive.)
1614 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
1616 struct spi_master
*master
= spi
->master
;
1618 unsigned long flags
;
1620 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1622 ret
= __spi_async(spi
, message
);
1624 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1629 EXPORT_SYMBOL_GPL(spi_async_locked
);
1632 /*-------------------------------------------------------------------------*/
1634 /* Utility methods for SPI master protocol drivers, layered on
1635 * top of the core. Some other utility methods are defined as
1639 static void spi_complete(void *arg
)
1644 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
1647 DECLARE_COMPLETION_ONSTACK(done
);
1649 struct spi_master
*master
= spi
->master
;
1651 message
->complete
= spi_complete
;
1652 message
->context
= &done
;
1655 mutex_lock(&master
->bus_lock_mutex
);
1657 status
= spi_async_locked(spi
, message
);
1660 mutex_unlock(&master
->bus_lock_mutex
);
1663 wait_for_completion(&done
);
1664 status
= message
->status
;
1666 message
->context
= NULL
;
1671 * spi_sync - blocking/synchronous SPI data transfers
1672 * @spi: device with which data will be exchanged
1673 * @message: describes the data transfers
1674 * Context: can sleep
1676 * This call may only be used from a context that may sleep. The sleep
1677 * is non-interruptible, and has no timeout. Low-overhead controller
1678 * drivers may DMA directly into and out of the message buffers.
1680 * Note that the SPI device's chip select is active during the message,
1681 * and then is normally disabled between messages. Drivers for some
1682 * frequently-used devices may want to minimize costs of selecting a chip,
1683 * by leaving it selected in anticipation that the next message will go
1684 * to the same chip. (That may increase power usage.)
1686 * Also, the caller is guaranteeing that the memory associated with the
1687 * message will not be freed before this call returns.
1689 * It returns zero on success, else a negative error code.
1691 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
1693 return __spi_sync(spi
, message
, 0);
1695 EXPORT_SYMBOL_GPL(spi_sync
);
1698 * spi_sync_locked - version of spi_sync with exclusive bus usage
1699 * @spi: device with which data will be exchanged
1700 * @message: describes the data transfers
1701 * Context: can sleep
1703 * This call may only be used from a context that may sleep. The sleep
1704 * is non-interruptible, and has no timeout. Low-overhead controller
1705 * drivers may DMA directly into and out of the message buffers.
1707 * This call should be used by drivers that require exclusive access to the
1708 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1709 * be released by a spi_bus_unlock call when the exclusive access is over.
1711 * It returns zero on success, else a negative error code.
1713 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
1715 return __spi_sync(spi
, message
, 1);
1717 EXPORT_SYMBOL_GPL(spi_sync_locked
);
1720 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1721 * @master: SPI bus master that should be locked for exclusive bus access
1722 * Context: can sleep
1724 * This call may only be used from a context that may sleep. The sleep
1725 * is non-interruptible, and has no timeout.
1727 * This call should be used by drivers that require exclusive access to the
1728 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1729 * exclusive access is over. Data transfer must be done by spi_sync_locked
1730 * and spi_async_locked calls when the SPI bus lock is held.
1732 * It returns zero on success, else a negative error code.
1734 int spi_bus_lock(struct spi_master
*master
)
1736 unsigned long flags
;
1738 mutex_lock(&master
->bus_lock_mutex
);
1740 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1741 master
->bus_lock_flag
= 1;
1742 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1744 /* mutex remains locked until spi_bus_unlock is called */
1748 EXPORT_SYMBOL_GPL(spi_bus_lock
);
1751 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1752 * @master: SPI bus master that was locked for exclusive bus access
1753 * Context: can sleep
1755 * This call may only be used from a context that may sleep. The sleep
1756 * is non-interruptible, and has no timeout.
1758 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1761 * It returns zero on success, else a negative error code.
1763 int spi_bus_unlock(struct spi_master
*master
)
1765 master
->bus_lock_flag
= 0;
1767 mutex_unlock(&master
->bus_lock_mutex
);
1771 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
1773 /* portable code must never pass more than 32 bytes */
1774 #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1779 * spi_write_then_read - SPI synchronous write followed by read
1780 * @spi: device with which data will be exchanged
1781 * @txbuf: data to be written (need not be dma-safe)
1782 * @n_tx: size of txbuf, in bytes
1783 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1784 * @n_rx: size of rxbuf, in bytes
1785 * Context: can sleep
1787 * This performs a half duplex MicroWire style transaction with the
1788 * device, sending txbuf and then reading rxbuf. The return value
1789 * is zero for success, else a negative errno status code.
1790 * This call may only be used from a context that may sleep.
1792 * Parameters to this routine are always copied using a small buffer;
1793 * portable code should never use this for more than 32 bytes.
1794 * Performance-sensitive or bulk transfer code should instead use
1795 * spi_{async,sync}() calls with dma-safe buffers.
1797 int spi_write_then_read(struct spi_device
*spi
,
1798 const void *txbuf
, unsigned n_tx
,
1799 void *rxbuf
, unsigned n_rx
)
1801 static DEFINE_MUTEX(lock
);
1804 struct spi_message message
;
1805 struct spi_transfer x
[2];
1808 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1809 * copying here, (as a pure convenience thing), but we can
1810 * keep heap costs out of the hot path unless someone else is
1811 * using the pre-allocated buffer or the transfer is too large.
1813 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
1814 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
1815 GFP_KERNEL
| GFP_DMA
);
1822 spi_message_init(&message
);
1823 memset(x
, 0, sizeof x
);
1826 spi_message_add_tail(&x
[0], &message
);
1830 spi_message_add_tail(&x
[1], &message
);
1833 memcpy(local_buf
, txbuf
, n_tx
);
1834 x
[0].tx_buf
= local_buf
;
1835 x
[1].rx_buf
= local_buf
+ n_tx
;
1838 status
= spi_sync(spi
, &message
);
1840 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
1842 if (x
[0].tx_buf
== buf
)
1843 mutex_unlock(&lock
);
1849 EXPORT_SYMBOL_GPL(spi_write_then_read
);
1851 /*-------------------------------------------------------------------------*/
1853 static int __init
spi_init(void)
1857 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
1863 status
= bus_register(&spi_bus_type
);
1867 status
= class_register(&spi_master_class
);
1873 bus_unregister(&spi_bus_type
);
1881 /* board_info is normally registered in arch_initcall(),
1882 * but even essential drivers wait till later
1884 * REVISIT only boardinfo really needs static linking. the rest (device and
1885 * driver registration) _could_ be dynamically linked (modular) ... costs
1886 * include needing to have boardinfo data structures be much more public.
1888 postcore_initcall(spi_init
);