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/pm_runtime.h>
34 #include <linux/export.h>
35 #include <linux/sched.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
39 static void spidev_release(struct device
*dev
)
41 struct spi_device
*spi
= to_spi_device(dev
);
43 /* spi masters may cleanup for released devices */
44 if (spi
->master
->cleanup
)
45 spi
->master
->cleanup(spi
);
47 spi_master_put(spi
->master
);
52 modalias_show(struct device
*dev
, struct device_attribute
*a
, char *buf
)
54 const struct spi_device
*spi
= to_spi_device(dev
);
56 return sprintf(buf
, "%s\n", spi
->modalias
);
59 static struct device_attribute spi_dev_attrs
[] = {
64 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
65 * and the sysfs version makes coldplug work too.
68 static const struct spi_device_id
*spi_match_id(const struct spi_device_id
*id
,
69 const struct spi_device
*sdev
)
72 if (!strcmp(sdev
->modalias
, id
->name
))
79 const struct spi_device_id
*spi_get_device_id(const struct spi_device
*sdev
)
81 const struct spi_driver
*sdrv
= to_spi_driver(sdev
->dev
.driver
);
83 return spi_match_id(sdrv
->id_table
, sdev
);
85 EXPORT_SYMBOL_GPL(spi_get_device_id
);
87 static int spi_match_device(struct device
*dev
, struct device_driver
*drv
)
89 const struct spi_device
*spi
= to_spi_device(dev
);
90 const struct spi_driver
*sdrv
= to_spi_driver(drv
);
92 /* Attempt an OF style match */
93 if (of_driver_match_device(dev
, drv
))
97 return !!spi_match_id(sdrv
->id_table
, spi
);
99 return strcmp(spi
->modalias
, drv
->name
) == 0;
102 static int spi_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
104 const struct spi_device
*spi
= to_spi_device(dev
);
106 add_uevent_var(env
, "MODALIAS=%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
110 #ifdef CONFIG_PM_SLEEP
111 static int spi_legacy_suspend(struct device
*dev
, pm_message_t message
)
114 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
116 /* suspend will stop irqs and dma; no more i/o */
119 value
= drv
->suspend(to_spi_device(dev
), message
);
121 dev_dbg(dev
, "... can't suspend\n");
126 static int spi_legacy_resume(struct device
*dev
)
129 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
131 /* resume may restart the i/o queue */
134 value
= drv
->resume(to_spi_device(dev
));
136 dev_dbg(dev
, "... can't resume\n");
141 static int spi_pm_suspend(struct device
*dev
)
143 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
146 return pm_generic_suspend(dev
);
148 return spi_legacy_suspend(dev
, PMSG_SUSPEND
);
151 static int spi_pm_resume(struct device
*dev
)
153 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
156 return pm_generic_resume(dev
);
158 return spi_legacy_resume(dev
);
161 static int spi_pm_freeze(struct device
*dev
)
163 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
166 return pm_generic_freeze(dev
);
168 return spi_legacy_suspend(dev
, PMSG_FREEZE
);
171 static int spi_pm_thaw(struct device
*dev
)
173 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
176 return pm_generic_thaw(dev
);
178 return spi_legacy_resume(dev
);
181 static int spi_pm_poweroff(struct device
*dev
)
183 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
186 return pm_generic_poweroff(dev
);
188 return spi_legacy_suspend(dev
, PMSG_HIBERNATE
);
191 static int spi_pm_restore(struct device
*dev
)
193 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
196 return pm_generic_restore(dev
);
198 return spi_legacy_resume(dev
);
201 #define spi_pm_suspend NULL
202 #define spi_pm_resume NULL
203 #define spi_pm_freeze NULL
204 #define spi_pm_thaw NULL
205 #define spi_pm_poweroff NULL
206 #define spi_pm_restore NULL
209 static const struct dev_pm_ops spi_pm
= {
210 .suspend
= spi_pm_suspend
,
211 .resume
= spi_pm_resume
,
212 .freeze
= spi_pm_freeze
,
214 .poweroff
= spi_pm_poweroff
,
215 .restore
= spi_pm_restore
,
217 pm_generic_runtime_suspend
,
218 pm_generic_runtime_resume
,
219 pm_generic_runtime_idle
223 struct bus_type spi_bus_type
= {
225 .dev_attrs
= spi_dev_attrs
,
226 .match
= spi_match_device
,
227 .uevent
= spi_uevent
,
230 EXPORT_SYMBOL_GPL(spi_bus_type
);
233 static int spi_drv_probe(struct device
*dev
)
235 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
237 return sdrv
->probe(to_spi_device(dev
));
240 static int spi_drv_remove(struct device
*dev
)
242 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
244 return sdrv
->remove(to_spi_device(dev
));
247 static void spi_drv_shutdown(struct device
*dev
)
249 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
251 sdrv
->shutdown(to_spi_device(dev
));
255 * spi_register_driver - register a SPI driver
256 * @sdrv: the driver to register
259 int spi_register_driver(struct spi_driver
*sdrv
)
261 sdrv
->driver
.bus
= &spi_bus_type
;
263 sdrv
->driver
.probe
= spi_drv_probe
;
265 sdrv
->driver
.remove
= spi_drv_remove
;
267 sdrv
->driver
.shutdown
= spi_drv_shutdown
;
268 return driver_register(&sdrv
->driver
);
270 EXPORT_SYMBOL_GPL(spi_register_driver
);
272 /*-------------------------------------------------------------------------*/
274 /* SPI devices should normally not be created by SPI device drivers; that
275 * would make them board-specific. Similarly with SPI master drivers.
276 * Device registration normally goes into like arch/.../mach.../board-YYY.c
277 * with other readonly (flashable) information about mainboard devices.
281 struct list_head list
;
282 struct spi_board_info board_info
;
285 static LIST_HEAD(board_list
);
286 static LIST_HEAD(spi_master_list
);
289 * Used to protect add/del opertion for board_info list and
290 * spi_master list, and their matching process
292 static DEFINE_MUTEX(board_lock
);
295 * spi_alloc_device - Allocate a new SPI device
296 * @master: Controller to which device is connected
299 * Allows a driver to allocate and initialize a spi_device without
300 * registering it immediately. This allows a driver to directly
301 * fill the spi_device with device parameters before calling
302 * spi_add_device() on it.
304 * Caller is responsible to call spi_add_device() on the returned
305 * spi_device structure to add it to the SPI master. If the caller
306 * needs to discard the spi_device without adding it, then it should
307 * call spi_dev_put() on it.
309 * Returns a pointer to the new device, or NULL.
311 struct spi_device
*spi_alloc_device(struct spi_master
*master
)
313 struct spi_device
*spi
;
314 struct device
*dev
= master
->dev
.parent
;
316 if (!spi_master_get(master
))
319 spi
= kzalloc(sizeof *spi
, GFP_KERNEL
);
321 dev_err(dev
, "cannot alloc spi_device\n");
322 spi_master_put(master
);
326 spi
->master
= master
;
327 spi
->dev
.parent
= &master
->dev
;
328 spi
->dev
.bus
= &spi_bus_type
;
329 spi
->dev
.release
= spidev_release
;
330 device_initialize(&spi
->dev
);
333 EXPORT_SYMBOL_GPL(spi_alloc_device
);
336 * spi_add_device - Add spi_device allocated with spi_alloc_device
337 * @spi: spi_device to register
339 * Companion function to spi_alloc_device. Devices allocated with
340 * spi_alloc_device can be added onto the spi bus with this function.
342 * Returns 0 on success; negative errno on failure
344 int spi_add_device(struct spi_device
*spi
)
346 static DEFINE_MUTEX(spi_add_lock
);
347 struct device
*dev
= spi
->master
->dev
.parent
;
351 /* Chipselects are numbered 0..max; validate. */
352 if (spi
->chip_select
>= spi
->master
->num_chipselect
) {
353 dev_err(dev
, "cs%d >= max %d\n",
355 spi
->master
->num_chipselect
);
359 /* Set the bus ID string */
360 dev_set_name(&spi
->dev
, "%s.%u", dev_name(&spi
->master
->dev
),
364 /* We need to make sure there's no other device with this
365 * chipselect **BEFORE** we call setup(), else we'll trash
366 * its configuration. Lock against concurrent add() calls.
368 mutex_lock(&spi_add_lock
);
370 d
= bus_find_device_by_name(&spi_bus_type
, NULL
, dev_name(&spi
->dev
));
372 dev_err(dev
, "chipselect %d already in use\n",
379 /* Drivers may modify this initial i/o setup, but will
380 * normally rely on the device being setup. Devices
381 * using SPI_CS_HIGH can't coexist well otherwise...
383 status
= spi_setup(spi
);
385 dev_err(dev
, "can't setup %s, status %d\n",
386 dev_name(&spi
->dev
), status
);
390 /* Device may be bound to an active driver when this returns */
391 status
= device_add(&spi
->dev
);
393 dev_err(dev
, "can't add %s, status %d\n",
394 dev_name(&spi
->dev
), status
);
396 dev_dbg(dev
, "registered child %s\n", dev_name(&spi
->dev
));
399 mutex_unlock(&spi_add_lock
);
402 EXPORT_SYMBOL_GPL(spi_add_device
);
405 * spi_new_device - instantiate one new SPI device
406 * @master: Controller to which device is connected
407 * @chip: Describes the SPI device
410 * On typical mainboards, this is purely internal; and it's not needed
411 * after board init creates the hard-wired devices. Some development
412 * platforms may not be able to use spi_register_board_info though, and
413 * this is exported so that for example a USB or parport based adapter
414 * driver could add devices (which it would learn about out-of-band).
416 * Returns the new device, or NULL.
418 struct spi_device
*spi_new_device(struct spi_master
*master
,
419 struct spi_board_info
*chip
)
421 struct spi_device
*proxy
;
424 /* NOTE: caller did any chip->bus_num checks necessary.
426 * Also, unless we change the return value convention to use
427 * error-or-pointer (not NULL-or-pointer), troubleshootability
428 * suggests syslogged diagnostics are best here (ugh).
431 proxy
= spi_alloc_device(master
);
435 WARN_ON(strlen(chip
->modalias
) >= sizeof(proxy
->modalias
));
437 proxy
->chip_select
= chip
->chip_select
;
438 proxy
->max_speed_hz
= chip
->max_speed_hz
;
439 proxy
->mode
= chip
->mode
;
440 proxy
->irq
= chip
->irq
;
441 strlcpy(proxy
->modalias
, chip
->modalias
, sizeof(proxy
->modalias
));
442 proxy
->dev
.platform_data
= (void *) chip
->platform_data
;
443 proxy
->controller_data
= chip
->controller_data
;
444 proxy
->controller_state
= NULL
;
446 status
= spi_add_device(proxy
);
454 EXPORT_SYMBOL_GPL(spi_new_device
);
456 static void spi_match_master_to_boardinfo(struct spi_master
*master
,
457 struct spi_board_info
*bi
)
459 struct spi_device
*dev
;
461 if (master
->bus_num
!= bi
->bus_num
)
464 dev
= spi_new_device(master
, bi
);
466 dev_err(master
->dev
.parent
, "can't create new device for %s\n",
471 * spi_register_board_info - register SPI devices for a given board
472 * @info: array of chip descriptors
473 * @n: how many descriptors are provided
476 * Board-specific early init code calls this (probably during arch_initcall)
477 * with segments of the SPI device table. Any device nodes are created later,
478 * after the relevant parent SPI controller (bus_num) is defined. We keep
479 * this table of devices forever, so that reloading a controller driver will
480 * not make Linux forget about these hard-wired devices.
482 * Other code can also call this, e.g. a particular add-on board might provide
483 * SPI devices through its expansion connector, so code initializing that board
484 * would naturally declare its SPI devices.
486 * The board info passed can safely be __initdata ... but be careful of
487 * any embedded pointers (platform_data, etc), they're copied as-is.
490 spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
492 struct boardinfo
*bi
;
495 bi
= kzalloc(n
* sizeof(*bi
), GFP_KERNEL
);
499 for (i
= 0; i
< n
; i
++, bi
++, info
++) {
500 struct spi_master
*master
;
502 memcpy(&bi
->board_info
, info
, sizeof(*info
));
503 mutex_lock(&board_lock
);
504 list_add_tail(&bi
->list
, &board_list
);
505 list_for_each_entry(master
, &spi_master_list
, list
)
506 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
507 mutex_unlock(&board_lock
);
513 /*-------------------------------------------------------------------------*/
516 * spi_pump_messages - kthread work function which processes spi message queue
517 * @work: pointer to kthread work struct contained in the master struct
519 * This function checks if there is any spi message in the queue that
520 * needs processing and if so call out to the driver to initialize hardware
521 * and transfer each message.
524 static void spi_pump_messages(struct kthread_work
*work
)
526 struct spi_master
*master
=
527 container_of(work
, struct spi_master
, pump_messages
);
529 bool was_busy
= false;
532 /* Lock queue and check for queue work */
533 spin_lock_irqsave(&master
->queue_lock
, flags
);
534 if (list_empty(&master
->queue
) || !master
->running
) {
535 if (master
->busy
&& master
->unprepare_transfer_hardware
) {
536 ret
= master
->unprepare_transfer_hardware(master
);
538 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
539 dev_err(&master
->dev
,
540 "failed to unprepare transfer hardware\n");
544 master
->busy
= false;
545 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
549 /* Make sure we are not already running a message */
550 if (master
->cur_msg
) {
551 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
554 /* Extract head of queue */
556 list_entry(master
->queue
.next
, struct spi_message
, queue
);
558 list_del_init(&master
->cur_msg
->queue
);
563 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
565 if (!was_busy
&& master
->prepare_transfer_hardware
) {
566 ret
= master
->prepare_transfer_hardware(master
);
568 dev_err(&master
->dev
,
569 "failed to prepare transfer hardware\n");
574 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
576 dev_err(&master
->dev
,
577 "failed to transfer one message from queue\n");
582 static int spi_init_queue(struct spi_master
*master
)
584 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
586 INIT_LIST_HEAD(&master
->queue
);
587 spin_lock_init(&master
->queue_lock
);
589 master
->running
= false;
590 master
->busy
= false;
592 init_kthread_worker(&master
->kworker
);
593 master
->kworker_task
= kthread_run(kthread_worker_fn
,
595 dev_name(&master
->dev
));
596 if (IS_ERR(master
->kworker_task
)) {
597 dev_err(&master
->dev
, "failed to create message pump task\n");
600 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
603 * Master config will indicate if this controller should run the
604 * message pump with high (realtime) priority to reduce the transfer
605 * latency on the bus by minimising the delay between a transfer
606 * request and the scheduling of the message pump thread. Without this
607 * setting the message pump thread will remain at default priority.
610 dev_info(&master
->dev
,
611 "will run message pump with realtime priority\n");
612 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
619 * spi_get_next_queued_message() - called by driver to check for queued
621 * @master: the master to check for queued messages
623 * If there are more messages in the queue, the next message is returned from
626 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
628 struct spi_message
*next
;
631 /* get a pointer to the next message, if any */
632 spin_lock_irqsave(&master
->queue_lock
, flags
);
633 if (list_empty(&master
->queue
))
636 next
= list_entry(master
->queue
.next
,
637 struct spi_message
, queue
);
638 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
642 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
645 * spi_finalize_current_message() - the current message is complete
646 * @master: the master to return the message to
648 * Called by the driver to notify the core that the message in the front of the
649 * queue is complete and can be removed from the queue.
651 void spi_finalize_current_message(struct spi_master
*master
)
653 struct spi_message
*mesg
;
656 spin_lock_irqsave(&master
->queue_lock
, flags
);
657 mesg
= master
->cur_msg
;
658 master
->cur_msg
= NULL
;
660 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
661 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
665 mesg
->complete(mesg
->context
);
667 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
669 static int spi_start_queue(struct spi_master
*master
)
673 spin_lock_irqsave(&master
->queue_lock
, flags
);
675 if (master
->running
|| master
->busy
) {
676 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
680 master
->running
= true;
681 master
->cur_msg
= NULL
;
682 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
684 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
689 static int spi_stop_queue(struct spi_master
*master
)
692 unsigned limit
= 500;
695 spin_lock_irqsave(&master
->queue_lock
, flags
);
698 * This is a bit lame, but is optimized for the common execution path.
699 * A wait_queue on the master->busy could be used, but then the common
700 * execution path (pump_messages) would be required to call wake_up or
701 * friends on every SPI message. Do this instead.
703 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
704 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
706 spin_lock_irqsave(&master
->queue_lock
, flags
);
709 if (!list_empty(&master
->queue
) || master
->busy
)
712 master
->running
= false;
714 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
717 dev_warn(&master
->dev
,
718 "could not stop message queue\n");
724 static int spi_destroy_queue(struct spi_master
*master
)
728 ret
= spi_stop_queue(master
);
731 * flush_kthread_worker will block until all work is done.
732 * If the reason that stop_queue timed out is that the work will never
733 * finish, then it does no good to call flush/stop thread, so
737 dev_err(&master
->dev
, "problem destroying queue\n");
741 flush_kthread_worker(&master
->kworker
);
742 kthread_stop(master
->kworker_task
);
748 * spi_queued_transfer - transfer function for queued transfers
749 * @spi: spi device which is requesting transfer
750 * @msg: spi message which is to handled is queued to driver queue
752 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
754 struct spi_master
*master
= spi
->master
;
757 spin_lock_irqsave(&master
->queue_lock
, flags
);
759 if (!master
->running
) {
760 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
763 msg
->actual_length
= 0;
764 msg
->status
= -EINPROGRESS
;
766 list_add_tail(&msg
->queue
, &master
->queue
);
767 if (master
->running
&& !master
->busy
)
768 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
770 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
774 static int spi_master_initialize_queue(struct spi_master
*master
)
778 master
->queued
= true;
779 master
->transfer
= spi_queued_transfer
;
781 /* Initialize and start queue */
782 ret
= spi_init_queue(master
);
784 dev_err(&master
->dev
, "problem initializing queue\n");
787 ret
= spi_start_queue(master
);
789 dev_err(&master
->dev
, "problem starting queue\n");
790 goto err_start_queue
;
797 spi_destroy_queue(master
);
801 /*-------------------------------------------------------------------------*/
803 #if defined(CONFIG_OF) && !defined(CONFIG_SPARC)
805 * of_register_spi_devices() - Register child devices onto the SPI bus
806 * @master: Pointer to spi_master device
808 * Registers an spi_device for each child node of master node which has a 'reg'
811 static void of_register_spi_devices(struct spi_master
*master
)
813 struct spi_device
*spi
;
814 struct device_node
*nc
;
819 if (!master
->dev
.of_node
)
822 for_each_child_of_node(master
->dev
.of_node
, nc
) {
823 /* Alloc an spi_device */
824 spi
= spi_alloc_device(master
);
826 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
832 /* Select device driver */
833 if (of_modalias_node(nc
, spi
->modalias
,
834 sizeof(spi
->modalias
)) < 0) {
835 dev_err(&master
->dev
, "cannot find modalias for %s\n",
842 prop
= of_get_property(nc
, "reg", &len
);
843 if (!prop
|| len
< sizeof(*prop
)) {
844 dev_err(&master
->dev
, "%s has no 'reg' property\n",
849 spi
->chip_select
= be32_to_cpup(prop
);
851 /* Mode (clock phase/polarity/etc.) */
852 if (of_find_property(nc
, "spi-cpha", NULL
))
853 spi
->mode
|= SPI_CPHA
;
854 if (of_find_property(nc
, "spi-cpol", NULL
))
855 spi
->mode
|= SPI_CPOL
;
856 if (of_find_property(nc
, "spi-cs-high", NULL
))
857 spi
->mode
|= SPI_CS_HIGH
;
860 prop
= of_get_property(nc
, "spi-max-frequency", &len
);
861 if (!prop
|| len
< sizeof(*prop
)) {
862 dev_err(&master
->dev
, "%s has no 'spi-max-frequency' property\n",
867 spi
->max_speed_hz
= be32_to_cpup(prop
);
870 spi
->irq
= irq_of_parse_and_map(nc
, 0);
872 /* Store a pointer to the node in the device structure */
874 spi
->dev
.of_node
= nc
;
876 /* Register the new device */
877 request_module(spi
->modalias
);
878 rc
= spi_add_device(spi
);
880 dev_err(&master
->dev
, "spi_device register error %s\n",
888 static void of_register_spi_devices(struct spi_master
*master
) { }
891 static void spi_master_release(struct device
*dev
)
893 struct spi_master
*master
;
895 master
= container_of(dev
, struct spi_master
, dev
);
899 static struct class spi_master_class
= {
900 .name
= "spi_master",
901 .owner
= THIS_MODULE
,
902 .dev_release
= spi_master_release
,
908 * spi_alloc_master - allocate SPI master controller
909 * @dev: the controller, possibly using the platform_bus
910 * @size: how much zeroed driver-private data to allocate; the pointer to this
911 * memory is in the driver_data field of the returned device,
912 * accessible with spi_master_get_devdata().
915 * This call is used only by SPI master controller drivers, which are the
916 * only ones directly touching chip registers. It's how they allocate
917 * an spi_master structure, prior to calling spi_register_master().
919 * This must be called from context that can sleep. It returns the SPI
920 * master structure on success, else NULL.
922 * The caller is responsible for assigning the bus number and initializing
923 * the master's methods before calling spi_register_master(); and (after errors
924 * adding the device) calling spi_master_put() and kfree() to prevent a memory
927 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
929 struct spi_master
*master
;
934 master
= kzalloc(size
+ sizeof *master
, GFP_KERNEL
);
938 device_initialize(&master
->dev
);
939 master
->bus_num
= -1;
940 master
->num_chipselect
= 1;
941 master
->dev
.class = &spi_master_class
;
942 master
->dev
.parent
= get_device(dev
);
943 spi_master_set_devdata(master
, &master
[1]);
947 EXPORT_SYMBOL_GPL(spi_alloc_master
);
950 * spi_register_master - register SPI master controller
951 * @master: initialized master, originally from spi_alloc_master()
954 * SPI master controllers connect to their drivers using some non-SPI bus,
955 * such as the platform bus. The final stage of probe() in that code
956 * includes calling spi_register_master() to hook up to this SPI bus glue.
958 * SPI controllers use board specific (often SOC specific) bus numbers,
959 * and board-specific addressing for SPI devices combines those numbers
960 * with chip select numbers. Since SPI does not directly support dynamic
961 * device identification, boards need configuration tables telling which
962 * chip is at which address.
964 * This must be called from context that can sleep. It returns zero on
965 * success, else a negative error code (dropping the master's refcount).
966 * After a successful return, the caller is responsible for calling
967 * spi_unregister_master().
969 int spi_register_master(struct spi_master
*master
)
971 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
972 struct device
*dev
= master
->dev
.parent
;
973 struct boardinfo
*bi
;
974 int status
= -ENODEV
;
980 /* even if it's just one always-selected device, there must
981 * be at least one chipselect
983 if (master
->num_chipselect
== 0)
986 /* convention: dynamically assigned bus IDs count down from the max */
987 if (master
->bus_num
< 0) {
988 /* FIXME switch to an IDR based scheme, something like
989 * I2C now uses, so we can't run out of "dynamic" IDs
991 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
995 spin_lock_init(&master
->bus_lock_spinlock
);
996 mutex_init(&master
->bus_lock_mutex
);
997 master
->bus_lock_flag
= 0;
999 /* register the device, then userspace will see it.
1000 * registration fails if the bus ID is in use.
1002 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1003 status
= device_add(&master
->dev
);
1006 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1007 dynamic
? " (dynamic)" : "");
1009 /* If we're using a queued driver, start the queue */
1010 if (master
->transfer
)
1011 dev_info(dev
, "master is unqueued, this is deprecated\n");
1013 status
= spi_master_initialize_queue(master
);
1015 device_unregister(&master
->dev
);
1020 mutex_lock(&board_lock
);
1021 list_add_tail(&master
->list
, &spi_master_list
);
1022 list_for_each_entry(bi
, &board_list
, list
)
1023 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1024 mutex_unlock(&board_lock
);
1026 /* Register devices from the device tree */
1027 of_register_spi_devices(master
);
1031 EXPORT_SYMBOL_GPL(spi_register_master
);
1033 static int __unregister(struct device
*dev
, void *null
)
1035 spi_unregister_device(to_spi_device(dev
));
1040 * spi_unregister_master - unregister SPI master controller
1041 * @master: the master being unregistered
1042 * Context: can sleep
1044 * This call is used only by SPI master controller drivers, which are the
1045 * only ones directly touching chip registers.
1047 * This must be called from context that can sleep.
1049 void spi_unregister_master(struct spi_master
*master
)
1053 if (master
->queued
) {
1054 if (spi_destroy_queue(master
))
1055 dev_err(&master
->dev
, "queue remove failed\n");
1058 mutex_lock(&board_lock
);
1059 list_del(&master
->list
);
1060 mutex_unlock(&board_lock
);
1062 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1063 device_unregister(&master
->dev
);
1065 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1067 int spi_master_suspend(struct spi_master
*master
)
1071 /* Basically no-ops for non-queued masters */
1072 if (!master
->queued
)
1075 ret
= spi_stop_queue(master
);
1077 dev_err(&master
->dev
, "queue stop failed\n");
1081 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1083 int spi_master_resume(struct spi_master
*master
)
1087 if (!master
->queued
)
1090 ret
= spi_start_queue(master
);
1092 dev_err(&master
->dev
, "queue restart failed\n");
1096 EXPORT_SYMBOL_GPL(spi_master_resume
);
1098 static int __spi_master_match(struct device
*dev
, void *data
)
1100 struct spi_master
*m
;
1101 u16
*bus_num
= data
;
1103 m
= container_of(dev
, struct spi_master
, dev
);
1104 return m
->bus_num
== *bus_num
;
1108 * spi_busnum_to_master - look up master associated with bus_num
1109 * @bus_num: the master's bus number
1110 * Context: can sleep
1112 * This call may be used with devices that are registered after
1113 * arch init time. It returns a refcounted pointer to the relevant
1114 * spi_master (which the caller must release), or NULL if there is
1115 * no such master registered.
1117 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1120 struct spi_master
*master
= NULL
;
1122 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1123 __spi_master_match
);
1125 master
= container_of(dev
, struct spi_master
, dev
);
1126 /* reference got in class_find_device */
1129 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1132 /*-------------------------------------------------------------------------*/
1134 /* Core methods for SPI master protocol drivers. Some of the
1135 * other core methods are currently defined as inline functions.
1139 * spi_setup - setup SPI mode and clock rate
1140 * @spi: the device whose settings are being modified
1141 * Context: can sleep, and no requests are queued to the device
1143 * SPI protocol drivers may need to update the transfer mode if the
1144 * device doesn't work with its default. They may likewise need
1145 * to update clock rates or word sizes from initial values. This function
1146 * changes those settings, and must be called from a context that can sleep.
1147 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1148 * effect the next time the device is selected and data is transferred to
1149 * or from it. When this function returns, the spi device is deselected.
1151 * Note that this call will fail if the protocol driver specifies an option
1152 * that the underlying controller or its driver does not support. For
1153 * example, not all hardware supports wire transfers using nine bit words,
1154 * LSB-first wire encoding, or active-high chipselects.
1156 int spi_setup(struct spi_device
*spi
)
1161 /* help drivers fail *cleanly* when they need options
1162 * that aren't supported with their current master
1164 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1166 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1171 if (!spi
->bits_per_word
)
1172 spi
->bits_per_word
= 8;
1174 status
= spi
->master
->setup(spi
);
1176 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s"
1177 "%u bits/w, %u Hz max --> %d\n",
1178 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1179 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1180 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1181 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1182 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1183 spi
->bits_per_word
, spi
->max_speed_hz
,
1188 EXPORT_SYMBOL_GPL(spi_setup
);
1190 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1192 struct spi_master
*master
= spi
->master
;
1194 /* Half-duplex links include original MicroWire, and ones with
1195 * only one data pin like SPI_3WIRE (switches direction) or where
1196 * either MOSI or MISO is missing. They can also be caused by
1197 * software limitations.
1199 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1200 || (spi
->mode
& SPI_3WIRE
)) {
1201 struct spi_transfer
*xfer
;
1202 unsigned flags
= master
->flags
;
1204 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1205 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1207 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1209 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1215 message
->status
= -EINPROGRESS
;
1216 return master
->transfer(spi
, message
);
1220 * spi_async - asynchronous SPI transfer
1221 * @spi: device with which data will be exchanged
1222 * @message: describes the data transfers, including completion callback
1223 * Context: any (irqs may be blocked, etc)
1225 * This call may be used in_irq and other contexts which can't sleep,
1226 * as well as from task contexts which can sleep.
1228 * The completion callback is invoked in a context which can't sleep.
1229 * Before that invocation, the value of message->status is undefined.
1230 * When the callback is issued, message->status holds either zero (to
1231 * indicate complete success) or a negative error code. After that
1232 * callback returns, the driver which issued the transfer request may
1233 * deallocate the associated memory; it's no longer in use by any SPI
1234 * core or controller driver code.
1236 * Note that although all messages to a spi_device are handled in
1237 * FIFO order, messages may go to different devices in other orders.
1238 * Some device might be higher priority, or have various "hard" access
1239 * time requirements, for example.
1241 * On detection of any fault during the transfer, processing of
1242 * the entire message is aborted, and the device is deselected.
1243 * Until returning from the associated message completion callback,
1244 * no other spi_message queued to that device will be processed.
1245 * (This rule applies equally to all the synchronous transfer calls,
1246 * which are wrappers around this core asynchronous primitive.)
1248 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1250 struct spi_master
*master
= spi
->master
;
1252 unsigned long flags
;
1254 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1256 if (master
->bus_lock_flag
)
1259 ret
= __spi_async(spi
, message
);
1261 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1265 EXPORT_SYMBOL_GPL(spi_async
);
1268 * spi_async_locked - version of spi_async with exclusive bus usage
1269 * @spi: device with which data will be exchanged
1270 * @message: describes the data transfers, including completion callback
1271 * Context: any (irqs may be blocked, etc)
1273 * This call may be used in_irq and other contexts which can't sleep,
1274 * as well as from task contexts which can sleep.
1276 * The completion callback is invoked in a context which can't sleep.
1277 * Before that invocation, the value of message->status is undefined.
1278 * When the callback is issued, message->status holds either zero (to
1279 * indicate complete success) or a negative error code. After that
1280 * callback returns, the driver which issued the transfer request may
1281 * deallocate the associated memory; it's no longer in use by any SPI
1282 * core or controller driver code.
1284 * Note that although all messages to a spi_device are handled in
1285 * FIFO order, messages may go to different devices in other orders.
1286 * Some device might be higher priority, or have various "hard" access
1287 * time requirements, for example.
1289 * On detection of any fault during the transfer, processing of
1290 * the entire message is aborted, and the device is deselected.
1291 * Until returning from the associated message completion callback,
1292 * no other spi_message queued to that device will be processed.
1293 * (This rule applies equally to all the synchronous transfer calls,
1294 * which are wrappers around this core asynchronous primitive.)
1296 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
1298 struct spi_master
*master
= spi
->master
;
1300 unsigned long flags
;
1302 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1304 ret
= __spi_async(spi
, message
);
1306 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1311 EXPORT_SYMBOL_GPL(spi_async_locked
);
1314 /*-------------------------------------------------------------------------*/
1316 /* Utility methods for SPI master protocol drivers, layered on
1317 * top of the core. Some other utility methods are defined as
1321 static void spi_complete(void *arg
)
1326 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
1329 DECLARE_COMPLETION_ONSTACK(done
);
1331 struct spi_master
*master
= spi
->master
;
1333 message
->complete
= spi_complete
;
1334 message
->context
= &done
;
1337 mutex_lock(&master
->bus_lock_mutex
);
1339 status
= spi_async_locked(spi
, message
);
1342 mutex_unlock(&master
->bus_lock_mutex
);
1345 wait_for_completion(&done
);
1346 status
= message
->status
;
1348 message
->context
= NULL
;
1353 * spi_sync - blocking/synchronous SPI data transfers
1354 * @spi: device with which data will be exchanged
1355 * @message: describes the data transfers
1356 * Context: can sleep
1358 * This call may only be used from a context that may sleep. The sleep
1359 * is non-interruptible, and has no timeout. Low-overhead controller
1360 * drivers may DMA directly into and out of the message buffers.
1362 * Note that the SPI device's chip select is active during the message,
1363 * and then is normally disabled between messages. Drivers for some
1364 * frequently-used devices may want to minimize costs of selecting a chip,
1365 * by leaving it selected in anticipation that the next message will go
1366 * to the same chip. (That may increase power usage.)
1368 * Also, the caller is guaranteeing that the memory associated with the
1369 * message will not be freed before this call returns.
1371 * It returns zero on success, else a negative error code.
1373 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
1375 return __spi_sync(spi
, message
, 0);
1377 EXPORT_SYMBOL_GPL(spi_sync
);
1380 * spi_sync_locked - version of spi_sync with exclusive bus usage
1381 * @spi: device with which data will be exchanged
1382 * @message: describes the data transfers
1383 * Context: can sleep
1385 * This call may only be used from a context that may sleep. The sleep
1386 * is non-interruptible, and has no timeout. Low-overhead controller
1387 * drivers may DMA directly into and out of the message buffers.
1389 * This call should be used by drivers that require exclusive access to the
1390 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1391 * be released by a spi_bus_unlock call when the exclusive access is over.
1393 * It returns zero on success, else a negative error code.
1395 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
1397 return __spi_sync(spi
, message
, 1);
1399 EXPORT_SYMBOL_GPL(spi_sync_locked
);
1402 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1403 * @master: SPI bus master that should be locked for exclusive bus access
1404 * Context: can sleep
1406 * This call may only be used from a context that may sleep. The sleep
1407 * is non-interruptible, and has no timeout.
1409 * This call should be used by drivers that require exclusive access to the
1410 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1411 * exclusive access is over. Data transfer must be done by spi_sync_locked
1412 * and spi_async_locked calls when the SPI bus lock is held.
1414 * It returns zero on success, else a negative error code.
1416 int spi_bus_lock(struct spi_master
*master
)
1418 unsigned long flags
;
1420 mutex_lock(&master
->bus_lock_mutex
);
1422 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1423 master
->bus_lock_flag
= 1;
1424 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1426 /* mutex remains locked until spi_bus_unlock is called */
1430 EXPORT_SYMBOL_GPL(spi_bus_lock
);
1433 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1434 * @master: SPI bus master that was locked for exclusive bus access
1435 * Context: can sleep
1437 * This call may only be used from a context that may sleep. The sleep
1438 * is non-interruptible, and has no timeout.
1440 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1443 * It returns zero on success, else a negative error code.
1445 int spi_bus_unlock(struct spi_master
*master
)
1447 master
->bus_lock_flag
= 0;
1449 mutex_unlock(&master
->bus_lock_mutex
);
1453 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
1455 /* portable code must never pass more than 32 bytes */
1456 #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1461 * spi_write_then_read - SPI synchronous write followed by read
1462 * @spi: device with which data will be exchanged
1463 * @txbuf: data to be written (need not be dma-safe)
1464 * @n_tx: size of txbuf, in bytes
1465 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1466 * @n_rx: size of rxbuf, in bytes
1467 * Context: can sleep
1469 * This performs a half duplex MicroWire style transaction with the
1470 * device, sending txbuf and then reading rxbuf. The return value
1471 * is zero for success, else a negative errno status code.
1472 * This call may only be used from a context that may sleep.
1474 * Parameters to this routine are always copied using a small buffer;
1475 * portable code should never use this for more than 32 bytes.
1476 * Performance-sensitive or bulk transfer code should instead use
1477 * spi_{async,sync}() calls with dma-safe buffers.
1479 int spi_write_then_read(struct spi_device
*spi
,
1480 const void *txbuf
, unsigned n_tx
,
1481 void *rxbuf
, unsigned n_rx
)
1483 static DEFINE_MUTEX(lock
);
1486 struct spi_message message
;
1487 struct spi_transfer x
[2];
1490 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
1491 * (as a pure convenience thing), but we can keep heap costs
1492 * out of the hot path ...
1494 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
)
1497 spi_message_init(&message
);
1498 memset(x
, 0, sizeof x
);
1501 spi_message_add_tail(&x
[0], &message
);
1505 spi_message_add_tail(&x
[1], &message
);
1508 /* ... unless someone else is using the pre-allocated buffer */
1509 if (!mutex_trylock(&lock
)) {
1510 local_buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
1516 memcpy(local_buf
, txbuf
, n_tx
);
1517 x
[0].tx_buf
= local_buf
;
1518 x
[1].rx_buf
= local_buf
+ n_tx
;
1521 status
= spi_sync(spi
, &message
);
1523 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
1525 if (x
[0].tx_buf
== buf
)
1526 mutex_unlock(&lock
);
1532 EXPORT_SYMBOL_GPL(spi_write_then_read
);
1534 /*-------------------------------------------------------------------------*/
1536 static int __init
spi_init(void)
1540 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
1546 status
= bus_register(&spi_bus_type
);
1550 status
= class_register(&spi_master_class
);
1556 bus_unregister(&spi_bus_type
);
1564 /* board_info is normally registered in arch_initcall(),
1565 * but even essential drivers wait till later
1567 * REVISIT only boardinfo really needs static linking. the rest (device and
1568 * driver registration) _could_ be dynamically linked (modular) ... costs
1569 * include needing to have boardinfo data structures be much more public.
1571 postcore_initcall(spi_init
);