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 #define CREATE_TRACE_POINTS
43 #include <trace/events/spi.h>
45 static void spidev_release(struct device
*dev
)
47 struct spi_device
*spi
= to_spi_device(dev
);
49 /* spi masters may cleanup for released devices */
50 if (spi
->master
->cleanup
)
51 spi
->master
->cleanup(spi
);
53 spi_master_put(spi
->master
);
58 modalias_show(struct device
*dev
, struct device_attribute
*a
, char *buf
)
60 const struct spi_device
*spi
= to_spi_device(dev
);
62 return sprintf(buf
, "%s%s\n", SPI_MODULE_PREFIX
, spi
->modalias
);
64 static DEVICE_ATTR_RO(modalias
);
66 static struct attribute
*spi_dev_attrs
[] = {
67 &dev_attr_modalias
.attr
,
70 ATTRIBUTE_GROUPS(spi_dev
);
72 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
73 * and the sysfs version makes coldplug work too.
76 static const struct spi_device_id
*spi_match_id(const struct spi_device_id
*id
,
77 const struct spi_device
*sdev
)
80 if (!strcmp(sdev
->modalias
, id
->name
))
87 const struct spi_device_id
*spi_get_device_id(const struct spi_device
*sdev
)
89 const struct spi_driver
*sdrv
= to_spi_driver(sdev
->dev
.driver
);
91 return spi_match_id(sdrv
->id_table
, sdev
);
93 EXPORT_SYMBOL_GPL(spi_get_device_id
);
95 static int spi_match_device(struct device
*dev
, struct device_driver
*drv
)
97 const struct spi_device
*spi
= to_spi_device(dev
);
98 const struct spi_driver
*sdrv
= to_spi_driver(drv
);
100 /* Attempt an OF style match */
101 if (of_driver_match_device(dev
, drv
))
105 if (acpi_driver_match_device(dev
, drv
))
109 return !!spi_match_id(sdrv
->id_table
, spi
);
111 return strcmp(spi
->modalias
, drv
->name
) == 0;
114 static int spi_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
116 const struct spi_device
*spi
= to_spi_device(dev
);
118 add_uevent_var(env
, "MODALIAS=%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
122 #ifdef CONFIG_PM_SLEEP
123 static int spi_legacy_suspend(struct device
*dev
, pm_message_t message
)
126 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
128 /* suspend will stop irqs and dma; no more i/o */
131 value
= drv
->suspend(to_spi_device(dev
), message
);
133 dev_dbg(dev
, "... can't suspend\n");
138 static int spi_legacy_resume(struct device
*dev
)
141 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
143 /* resume may restart the i/o queue */
146 value
= drv
->resume(to_spi_device(dev
));
148 dev_dbg(dev
, "... can't resume\n");
153 static int spi_pm_suspend(struct device
*dev
)
155 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
158 return pm_generic_suspend(dev
);
160 return spi_legacy_suspend(dev
, PMSG_SUSPEND
);
163 static int spi_pm_resume(struct device
*dev
)
165 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
168 return pm_generic_resume(dev
);
170 return spi_legacy_resume(dev
);
173 static int spi_pm_freeze(struct device
*dev
)
175 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
178 return pm_generic_freeze(dev
);
180 return spi_legacy_suspend(dev
, PMSG_FREEZE
);
183 static int spi_pm_thaw(struct device
*dev
)
185 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
188 return pm_generic_thaw(dev
);
190 return spi_legacy_resume(dev
);
193 static int spi_pm_poweroff(struct device
*dev
)
195 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
198 return pm_generic_poweroff(dev
);
200 return spi_legacy_suspend(dev
, PMSG_HIBERNATE
);
203 static int spi_pm_restore(struct device
*dev
)
205 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
208 return pm_generic_restore(dev
);
210 return spi_legacy_resume(dev
);
213 #define spi_pm_suspend NULL
214 #define spi_pm_resume NULL
215 #define spi_pm_freeze NULL
216 #define spi_pm_thaw NULL
217 #define spi_pm_poweroff NULL
218 #define spi_pm_restore NULL
221 static const struct dev_pm_ops spi_pm
= {
222 .suspend
= spi_pm_suspend
,
223 .resume
= spi_pm_resume
,
224 .freeze
= spi_pm_freeze
,
226 .poweroff
= spi_pm_poweroff
,
227 .restore
= spi_pm_restore
,
229 pm_generic_runtime_suspend
,
230 pm_generic_runtime_resume
,
235 struct bus_type spi_bus_type
= {
237 .dev_groups
= spi_dev_groups
,
238 .match
= spi_match_device
,
239 .uevent
= spi_uevent
,
242 EXPORT_SYMBOL_GPL(spi_bus_type
);
245 static int spi_drv_probe(struct device
*dev
)
247 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
248 struct spi_device
*spi
= to_spi_device(dev
);
251 acpi_dev_pm_attach(&spi
->dev
, true);
252 ret
= sdrv
->probe(spi
);
254 acpi_dev_pm_detach(&spi
->dev
, true);
259 static int spi_drv_remove(struct device
*dev
)
261 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
262 struct spi_device
*spi
= to_spi_device(dev
);
265 ret
= sdrv
->remove(spi
);
266 acpi_dev_pm_detach(&spi
->dev
, true);
271 static void spi_drv_shutdown(struct device
*dev
)
273 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
275 sdrv
->shutdown(to_spi_device(dev
));
279 * spi_register_driver - register a SPI driver
280 * @sdrv: the driver to register
283 int spi_register_driver(struct spi_driver
*sdrv
)
285 sdrv
->driver
.bus
= &spi_bus_type
;
287 sdrv
->driver
.probe
= spi_drv_probe
;
289 sdrv
->driver
.remove
= spi_drv_remove
;
291 sdrv
->driver
.shutdown
= spi_drv_shutdown
;
292 return driver_register(&sdrv
->driver
);
294 EXPORT_SYMBOL_GPL(spi_register_driver
);
296 /*-------------------------------------------------------------------------*/
298 /* SPI devices should normally not be created by SPI device drivers; that
299 * would make them board-specific. Similarly with SPI master drivers.
300 * Device registration normally goes into like arch/.../mach.../board-YYY.c
301 * with other readonly (flashable) information about mainboard devices.
305 struct list_head list
;
306 struct spi_board_info board_info
;
309 static LIST_HEAD(board_list
);
310 static LIST_HEAD(spi_master_list
);
313 * Used to protect add/del opertion for board_info list and
314 * spi_master list, and their matching process
316 static DEFINE_MUTEX(board_lock
);
319 * spi_alloc_device - Allocate a new SPI device
320 * @master: Controller to which device is connected
323 * Allows a driver to allocate and initialize a spi_device without
324 * registering it immediately. This allows a driver to directly
325 * fill the spi_device with device parameters before calling
326 * spi_add_device() on it.
328 * Caller is responsible to call spi_add_device() on the returned
329 * spi_device structure to add it to the SPI master. If the caller
330 * needs to discard the spi_device without adding it, then it should
331 * call spi_dev_put() on it.
333 * Returns a pointer to the new device, or NULL.
335 struct spi_device
*spi_alloc_device(struct spi_master
*master
)
337 struct spi_device
*spi
;
338 struct device
*dev
= master
->dev
.parent
;
340 if (!spi_master_get(master
))
343 spi
= kzalloc(sizeof(*spi
), GFP_KERNEL
);
345 dev_err(dev
, "cannot alloc spi_device\n");
346 spi_master_put(master
);
350 spi
->master
= master
;
351 spi
->dev
.parent
= &master
->dev
;
352 spi
->dev
.bus
= &spi_bus_type
;
353 spi
->dev
.release
= spidev_release
;
354 spi
->cs_gpio
= -ENOENT
;
355 device_initialize(&spi
->dev
);
358 EXPORT_SYMBOL_GPL(spi_alloc_device
);
360 static void spi_dev_set_name(struct spi_device
*spi
)
362 struct acpi_device
*adev
= ACPI_COMPANION(&spi
->dev
);
365 dev_set_name(&spi
->dev
, "spi-%s", acpi_dev_name(adev
));
369 dev_set_name(&spi
->dev
, "%s.%u", dev_name(&spi
->master
->dev
),
374 * spi_add_device - Add spi_device allocated with spi_alloc_device
375 * @spi: spi_device to register
377 * Companion function to spi_alloc_device. Devices allocated with
378 * spi_alloc_device can be added onto the spi bus with this function.
380 * Returns 0 on success; negative errno on failure
382 int spi_add_device(struct spi_device
*spi
)
384 static DEFINE_MUTEX(spi_add_lock
);
385 struct spi_master
*master
= spi
->master
;
386 struct device
*dev
= master
->dev
.parent
;
390 /* Chipselects are numbered 0..max; validate. */
391 if (spi
->chip_select
>= master
->num_chipselect
) {
392 dev_err(dev
, "cs%d >= max %d\n",
394 master
->num_chipselect
);
398 /* Set the bus ID string */
399 spi_dev_set_name(spi
);
401 /* We need to make sure there's no other device with this
402 * chipselect **BEFORE** we call setup(), else we'll trash
403 * its configuration. Lock against concurrent add() calls.
405 mutex_lock(&spi_add_lock
);
407 d
= bus_find_device_by_name(&spi_bus_type
, NULL
, dev_name(&spi
->dev
));
409 dev_err(dev
, "chipselect %d already in use\n",
416 if (master
->cs_gpios
)
417 spi
->cs_gpio
= master
->cs_gpios
[spi
->chip_select
];
419 /* Drivers may modify this initial i/o setup, but will
420 * normally rely on the device being setup. Devices
421 * using SPI_CS_HIGH can't coexist well otherwise...
423 status
= spi_setup(spi
);
425 dev_err(dev
, "can't setup %s, status %d\n",
426 dev_name(&spi
->dev
), status
);
430 /* Device may be bound to an active driver when this returns */
431 status
= device_add(&spi
->dev
);
433 dev_err(dev
, "can't add %s, status %d\n",
434 dev_name(&spi
->dev
), status
);
436 dev_dbg(dev
, "registered child %s\n", dev_name(&spi
->dev
));
439 mutex_unlock(&spi_add_lock
);
442 EXPORT_SYMBOL_GPL(spi_add_device
);
445 * spi_new_device - instantiate one new SPI device
446 * @master: Controller to which device is connected
447 * @chip: Describes the SPI device
450 * On typical mainboards, this is purely internal; and it's not needed
451 * after board init creates the hard-wired devices. Some development
452 * platforms may not be able to use spi_register_board_info though, and
453 * this is exported so that for example a USB or parport based adapter
454 * driver could add devices (which it would learn about out-of-band).
456 * Returns the new device, or NULL.
458 struct spi_device
*spi_new_device(struct spi_master
*master
,
459 struct spi_board_info
*chip
)
461 struct spi_device
*proxy
;
464 /* NOTE: caller did any chip->bus_num checks necessary.
466 * Also, unless we change the return value convention to use
467 * error-or-pointer (not NULL-or-pointer), troubleshootability
468 * suggests syslogged diagnostics are best here (ugh).
471 proxy
= spi_alloc_device(master
);
475 WARN_ON(strlen(chip
->modalias
) >= sizeof(proxy
->modalias
));
477 proxy
->chip_select
= chip
->chip_select
;
478 proxy
->max_speed_hz
= chip
->max_speed_hz
;
479 proxy
->mode
= chip
->mode
;
480 proxy
->irq
= chip
->irq
;
481 strlcpy(proxy
->modalias
, chip
->modalias
, sizeof(proxy
->modalias
));
482 proxy
->dev
.platform_data
= (void *) chip
->platform_data
;
483 proxy
->controller_data
= chip
->controller_data
;
484 proxy
->controller_state
= NULL
;
486 status
= spi_add_device(proxy
);
494 EXPORT_SYMBOL_GPL(spi_new_device
);
496 static void spi_match_master_to_boardinfo(struct spi_master
*master
,
497 struct spi_board_info
*bi
)
499 struct spi_device
*dev
;
501 if (master
->bus_num
!= bi
->bus_num
)
504 dev
= spi_new_device(master
, bi
);
506 dev_err(master
->dev
.parent
, "can't create new device for %s\n",
511 * spi_register_board_info - register SPI devices for a given board
512 * @info: array of chip descriptors
513 * @n: how many descriptors are provided
516 * Board-specific early init code calls this (probably during arch_initcall)
517 * with segments of the SPI device table. Any device nodes are created later,
518 * after the relevant parent SPI controller (bus_num) is defined. We keep
519 * this table of devices forever, so that reloading a controller driver will
520 * not make Linux forget about these hard-wired devices.
522 * Other code can also call this, e.g. a particular add-on board might provide
523 * SPI devices through its expansion connector, so code initializing that board
524 * would naturally declare its SPI devices.
526 * The board info passed can safely be __initdata ... but be careful of
527 * any embedded pointers (platform_data, etc), they're copied as-is.
529 int spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
531 struct boardinfo
*bi
;
534 bi
= kzalloc(n
* sizeof(*bi
), GFP_KERNEL
);
538 for (i
= 0; i
< n
; i
++, bi
++, info
++) {
539 struct spi_master
*master
;
541 memcpy(&bi
->board_info
, info
, sizeof(*info
));
542 mutex_lock(&board_lock
);
543 list_add_tail(&bi
->list
, &board_list
);
544 list_for_each_entry(master
, &spi_master_list
, list
)
545 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
546 mutex_unlock(&board_lock
);
552 /*-------------------------------------------------------------------------*/
554 static void spi_set_cs(struct spi_device
*spi
, bool enable
)
556 if (spi
->mode
& SPI_CS_HIGH
)
559 if (spi
->cs_gpio
>= 0)
560 gpio_set_value(spi
->cs_gpio
, !enable
);
561 else if (spi
->master
->set_cs
)
562 spi
->master
->set_cs(spi
, !enable
);
566 * spi_transfer_one_message - Default implementation of transfer_one_message()
568 * This is a standard implementation of transfer_one_message() for
569 * drivers which impelment a transfer_one() operation. It provides
570 * standard handling of delays and chip select management.
572 static int spi_transfer_one_message(struct spi_master
*master
,
573 struct spi_message
*msg
)
575 struct spi_transfer
*xfer
;
577 bool keep_cs
= false;
580 spi_set_cs(msg
->spi
, true);
582 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
583 trace_spi_transfer_start(msg
, xfer
);
585 reinit_completion(&master
->xfer_completion
);
587 ret
= master
->transfer_one(master
, msg
->spi
, xfer
);
589 dev_err(&msg
->spi
->dev
,
590 "SPI transfer failed: %d\n", ret
);
595 wait_for_completion(&master
->xfer_completion
);
597 trace_spi_transfer_stop(msg
, xfer
);
599 if (msg
->status
!= -EINPROGRESS
)
602 if (xfer
->delay_usecs
)
603 udelay(xfer
->delay_usecs
);
605 if (xfer
->cs_change
) {
606 if (list_is_last(&xfer
->transfer_list
,
611 spi_set_cs(msg
->spi
, cur_cs
);
615 msg
->actual_length
+= xfer
->len
;
619 if (ret
!= 0 || !keep_cs
)
620 spi_set_cs(msg
->spi
, false);
622 if (msg
->status
== -EINPROGRESS
)
625 spi_finalize_current_message(master
);
631 * spi_finalize_current_transfer - report completion of a transfer
633 * Called by SPI drivers using the core transfer_one_message()
634 * implementation to notify it that the current interrupt driven
635 * transfer has finised and the next one may be scheduled.
637 void spi_finalize_current_transfer(struct spi_master
*master
)
639 complete(&master
->xfer_completion
);
641 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer
);
644 * spi_pump_messages - kthread work function which processes spi message queue
645 * @work: pointer to kthread work struct contained in the master struct
647 * This function checks if there is any spi message in the queue that
648 * needs processing and if so call out to the driver to initialize hardware
649 * and transfer each message.
652 static void spi_pump_messages(struct kthread_work
*work
)
654 struct spi_master
*master
=
655 container_of(work
, struct spi_master
, pump_messages
);
657 bool was_busy
= false;
660 /* Lock queue and check for queue work */
661 spin_lock_irqsave(&master
->queue_lock
, flags
);
662 if (list_empty(&master
->queue
) || !master
->running
) {
664 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
667 master
->busy
= false;
668 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
669 if (master
->unprepare_transfer_hardware
&&
670 master
->unprepare_transfer_hardware(master
))
671 dev_err(&master
->dev
,
672 "failed to unprepare transfer hardware\n");
673 if (master
->auto_runtime_pm
) {
674 pm_runtime_mark_last_busy(master
->dev
.parent
);
675 pm_runtime_put_autosuspend(master
->dev
.parent
);
677 trace_spi_master_idle(master
);
681 /* Make sure we are not already running a message */
682 if (master
->cur_msg
) {
683 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
686 /* Extract head of queue */
688 list_entry(master
->queue
.next
, struct spi_message
, queue
);
690 list_del_init(&master
->cur_msg
->queue
);
695 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
697 if (!was_busy
&& master
->auto_runtime_pm
) {
698 ret
= pm_runtime_get_sync(master
->dev
.parent
);
700 dev_err(&master
->dev
, "Failed to power device: %d\n",
707 trace_spi_master_busy(master
);
709 if (!was_busy
&& master
->prepare_transfer_hardware
) {
710 ret
= master
->prepare_transfer_hardware(master
);
712 dev_err(&master
->dev
,
713 "failed to prepare transfer hardware\n");
715 if (master
->auto_runtime_pm
)
716 pm_runtime_put(master
->dev
.parent
);
721 trace_spi_message_start(master
->cur_msg
);
723 if (master
->prepare_message
) {
724 ret
= master
->prepare_message(master
, master
->cur_msg
);
726 dev_err(&master
->dev
,
727 "failed to prepare message: %d\n", ret
);
728 master
->cur_msg
->status
= ret
;
729 spi_finalize_current_message(master
);
732 master
->cur_msg_prepared
= true;
735 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
737 dev_err(&master
->dev
,
738 "failed to transfer one message from queue\n");
743 static int spi_init_queue(struct spi_master
*master
)
745 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
747 INIT_LIST_HEAD(&master
->queue
);
748 spin_lock_init(&master
->queue_lock
);
750 master
->running
= false;
751 master
->busy
= false;
753 init_kthread_worker(&master
->kworker
);
754 master
->kworker_task
= kthread_run(kthread_worker_fn
,
755 &master
->kworker
, "%s",
756 dev_name(&master
->dev
));
757 if (IS_ERR(master
->kworker_task
)) {
758 dev_err(&master
->dev
, "failed to create message pump task\n");
761 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
764 * Master config will indicate if this controller should run the
765 * message pump with high (realtime) priority to reduce the transfer
766 * latency on the bus by minimising the delay between a transfer
767 * request and the scheduling of the message pump thread. Without this
768 * setting the message pump thread will remain at default priority.
771 dev_info(&master
->dev
,
772 "will run message pump with realtime priority\n");
773 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
780 * spi_get_next_queued_message() - called by driver to check for queued
782 * @master: the master to check for queued messages
784 * If there are more messages in the queue, the next message is returned from
787 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
789 struct spi_message
*next
;
792 /* get a pointer to the next message, if any */
793 spin_lock_irqsave(&master
->queue_lock
, flags
);
794 if (list_empty(&master
->queue
))
797 next
= list_entry(master
->queue
.next
,
798 struct spi_message
, queue
);
799 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
803 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
806 * spi_finalize_current_message() - the current message is complete
807 * @master: the master to return the message to
809 * Called by the driver to notify the core that the message in the front of the
810 * queue is complete and can be removed from the queue.
812 void spi_finalize_current_message(struct spi_master
*master
)
814 struct spi_message
*mesg
;
818 spin_lock_irqsave(&master
->queue_lock
, flags
);
819 mesg
= master
->cur_msg
;
820 master
->cur_msg
= NULL
;
822 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
823 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
825 if (master
->cur_msg_prepared
&& master
->unprepare_message
) {
826 ret
= master
->unprepare_message(master
, mesg
);
828 dev_err(&master
->dev
,
829 "failed to unprepare message: %d\n", ret
);
832 master
->cur_msg_prepared
= false;
836 mesg
->complete(mesg
->context
);
838 trace_spi_message_done(mesg
);
840 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
842 static int spi_start_queue(struct spi_master
*master
)
846 spin_lock_irqsave(&master
->queue_lock
, flags
);
848 if (master
->running
|| master
->busy
) {
849 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
853 master
->running
= true;
854 master
->cur_msg
= NULL
;
855 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
857 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
862 static int spi_stop_queue(struct spi_master
*master
)
865 unsigned limit
= 500;
868 spin_lock_irqsave(&master
->queue_lock
, flags
);
871 * This is a bit lame, but is optimized for the common execution path.
872 * A wait_queue on the master->busy could be used, but then the common
873 * execution path (pump_messages) would be required to call wake_up or
874 * friends on every SPI message. Do this instead.
876 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
877 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
879 spin_lock_irqsave(&master
->queue_lock
, flags
);
882 if (!list_empty(&master
->queue
) || master
->busy
)
885 master
->running
= false;
887 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
890 dev_warn(&master
->dev
,
891 "could not stop message queue\n");
897 static int spi_destroy_queue(struct spi_master
*master
)
901 ret
= spi_stop_queue(master
);
904 * flush_kthread_worker will block until all work is done.
905 * If the reason that stop_queue timed out is that the work will never
906 * finish, then it does no good to call flush/stop thread, so
910 dev_err(&master
->dev
, "problem destroying queue\n");
914 flush_kthread_worker(&master
->kworker
);
915 kthread_stop(master
->kworker_task
);
921 * spi_queued_transfer - transfer function for queued transfers
922 * @spi: spi device which is requesting transfer
923 * @msg: spi message which is to handled is queued to driver queue
925 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
927 struct spi_master
*master
= spi
->master
;
930 spin_lock_irqsave(&master
->queue_lock
, flags
);
932 if (!master
->running
) {
933 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
936 msg
->actual_length
= 0;
937 msg
->status
= -EINPROGRESS
;
939 list_add_tail(&msg
->queue
, &master
->queue
);
941 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
943 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
947 static int spi_master_initialize_queue(struct spi_master
*master
)
951 master
->queued
= true;
952 master
->transfer
= spi_queued_transfer
;
953 if (!master
->transfer_one_message
)
954 master
->transfer_one_message
= spi_transfer_one_message
;
956 /* Initialize and start queue */
957 ret
= spi_init_queue(master
);
959 dev_err(&master
->dev
, "problem initializing queue\n");
962 ret
= spi_start_queue(master
);
964 dev_err(&master
->dev
, "problem starting queue\n");
965 goto err_start_queue
;
972 spi_destroy_queue(master
);
976 /*-------------------------------------------------------------------------*/
978 #if defined(CONFIG_OF)
980 * of_register_spi_devices() - Register child devices onto the SPI bus
981 * @master: Pointer to spi_master device
983 * Registers an spi_device for each child node of master node which has a 'reg'
986 static void of_register_spi_devices(struct spi_master
*master
)
988 struct spi_device
*spi
;
989 struct device_node
*nc
;
993 if (!master
->dev
.of_node
)
996 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
997 /* Alloc an spi_device */
998 spi
= spi_alloc_device(master
);
1000 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
1006 /* Select device driver */
1007 if (of_modalias_node(nc
, spi
->modalias
,
1008 sizeof(spi
->modalias
)) < 0) {
1009 dev_err(&master
->dev
, "cannot find modalias for %s\n",
1015 /* Device address */
1016 rc
= of_property_read_u32(nc
, "reg", &value
);
1018 dev_err(&master
->dev
, "%s has no valid 'reg' property (%d)\n",
1023 spi
->chip_select
= value
;
1025 /* Mode (clock phase/polarity/etc.) */
1026 if (of_find_property(nc
, "spi-cpha", NULL
))
1027 spi
->mode
|= SPI_CPHA
;
1028 if (of_find_property(nc
, "spi-cpol", NULL
))
1029 spi
->mode
|= SPI_CPOL
;
1030 if (of_find_property(nc
, "spi-cs-high", NULL
))
1031 spi
->mode
|= SPI_CS_HIGH
;
1032 if (of_find_property(nc
, "spi-3wire", NULL
))
1033 spi
->mode
|= SPI_3WIRE
;
1035 /* Device DUAL/QUAD mode */
1036 if (!of_property_read_u32(nc
, "spi-tx-bus-width", &value
)) {
1041 spi
->mode
|= SPI_TX_DUAL
;
1044 spi
->mode
|= SPI_TX_QUAD
;
1047 dev_err(&master
->dev
,
1048 "spi-tx-bus-width %d not supported\n",
1055 if (!of_property_read_u32(nc
, "spi-rx-bus-width", &value
)) {
1060 spi
->mode
|= SPI_RX_DUAL
;
1063 spi
->mode
|= SPI_RX_QUAD
;
1066 dev_err(&master
->dev
,
1067 "spi-rx-bus-width %d not supported\n",
1075 rc
= of_property_read_u32(nc
, "spi-max-frequency", &value
);
1077 dev_err(&master
->dev
, "%s has no valid 'spi-max-frequency' property (%d)\n",
1082 spi
->max_speed_hz
= value
;
1085 spi
->irq
= irq_of_parse_and_map(nc
, 0);
1087 /* Store a pointer to the node in the device structure */
1089 spi
->dev
.of_node
= nc
;
1091 /* Register the new device */
1092 request_module("%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
1093 rc
= spi_add_device(spi
);
1095 dev_err(&master
->dev
, "spi_device register error %s\n",
1103 static void of_register_spi_devices(struct spi_master
*master
) { }
1107 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
1109 struct spi_device
*spi
= data
;
1111 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
1112 struct acpi_resource_spi_serialbus
*sb
;
1114 sb
= &ares
->data
.spi_serial_bus
;
1115 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
1116 spi
->chip_select
= sb
->device_selection
;
1117 spi
->max_speed_hz
= sb
->connection_speed
;
1119 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
1120 spi
->mode
|= SPI_CPHA
;
1121 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
1122 spi
->mode
|= SPI_CPOL
;
1123 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
1124 spi
->mode
|= SPI_CS_HIGH
;
1126 } else if (spi
->irq
< 0) {
1129 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
1133 /* Always tell the ACPI core to skip this resource */
1137 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
1138 void *data
, void **return_value
)
1140 struct spi_master
*master
= data
;
1141 struct list_head resource_list
;
1142 struct acpi_device
*adev
;
1143 struct spi_device
*spi
;
1146 if (acpi_bus_get_device(handle
, &adev
))
1148 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
1151 spi
= spi_alloc_device(master
);
1153 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
1154 dev_name(&adev
->dev
));
1155 return AE_NO_MEMORY
;
1158 ACPI_COMPANION_SET(&spi
->dev
, adev
);
1161 INIT_LIST_HEAD(&resource_list
);
1162 ret
= acpi_dev_get_resources(adev
, &resource_list
,
1163 acpi_spi_add_resource
, spi
);
1164 acpi_dev_free_resource_list(&resource_list
);
1166 if (ret
< 0 || !spi
->max_speed_hz
) {
1171 adev
->power
.flags
.ignore_parent
= true;
1172 strlcpy(spi
->modalias
, acpi_device_hid(adev
), sizeof(spi
->modalias
));
1173 if (spi_add_device(spi
)) {
1174 adev
->power
.flags
.ignore_parent
= false;
1175 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
1176 dev_name(&adev
->dev
));
1183 static void acpi_register_spi_devices(struct spi_master
*master
)
1188 handle
= ACPI_HANDLE(master
->dev
.parent
);
1192 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
1193 acpi_spi_add_device
, NULL
,
1195 if (ACPI_FAILURE(status
))
1196 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
1199 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
1200 #endif /* CONFIG_ACPI */
1202 static void spi_master_release(struct device
*dev
)
1204 struct spi_master
*master
;
1206 master
= container_of(dev
, struct spi_master
, dev
);
1210 static struct class spi_master_class
= {
1211 .name
= "spi_master",
1212 .owner
= THIS_MODULE
,
1213 .dev_release
= spi_master_release
,
1219 * spi_alloc_master - allocate SPI master controller
1220 * @dev: the controller, possibly using the platform_bus
1221 * @size: how much zeroed driver-private data to allocate; the pointer to this
1222 * memory is in the driver_data field of the returned device,
1223 * accessible with spi_master_get_devdata().
1224 * Context: can sleep
1226 * This call is used only by SPI master controller drivers, which are the
1227 * only ones directly touching chip registers. It's how they allocate
1228 * an spi_master structure, prior to calling spi_register_master().
1230 * This must be called from context that can sleep. It returns the SPI
1231 * master structure on success, else NULL.
1233 * The caller is responsible for assigning the bus number and initializing
1234 * the master's methods before calling spi_register_master(); and (after errors
1235 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1238 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1240 struct spi_master
*master
;
1245 master
= kzalloc(size
+ sizeof(*master
), GFP_KERNEL
);
1249 device_initialize(&master
->dev
);
1250 master
->bus_num
= -1;
1251 master
->num_chipselect
= 1;
1252 master
->dev
.class = &spi_master_class
;
1253 master
->dev
.parent
= get_device(dev
);
1254 spi_master_set_devdata(master
, &master
[1]);
1258 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1261 static int of_spi_register_master(struct spi_master
*master
)
1264 struct device_node
*np
= master
->dev
.of_node
;
1269 nb
= of_gpio_named_count(np
, "cs-gpios");
1270 master
->num_chipselect
= max_t(int, nb
, master
->num_chipselect
);
1272 /* Return error only for an incorrectly formed cs-gpios property */
1273 if (nb
== 0 || nb
== -ENOENT
)
1278 cs
= devm_kzalloc(&master
->dev
,
1279 sizeof(int) * master
->num_chipselect
,
1281 master
->cs_gpios
= cs
;
1283 if (!master
->cs_gpios
)
1286 for (i
= 0; i
< master
->num_chipselect
; i
++)
1289 for (i
= 0; i
< nb
; i
++)
1290 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1295 static int of_spi_register_master(struct spi_master
*master
)
1302 * spi_register_master - register SPI master controller
1303 * @master: initialized master, originally from spi_alloc_master()
1304 * Context: can sleep
1306 * SPI master controllers connect to their drivers using some non-SPI bus,
1307 * such as the platform bus. The final stage of probe() in that code
1308 * includes calling spi_register_master() to hook up to this SPI bus glue.
1310 * SPI controllers use board specific (often SOC specific) bus numbers,
1311 * and board-specific addressing for SPI devices combines those numbers
1312 * with chip select numbers. Since SPI does not directly support dynamic
1313 * device identification, boards need configuration tables telling which
1314 * chip is at which address.
1316 * This must be called from context that can sleep. It returns zero on
1317 * success, else a negative error code (dropping the master's refcount).
1318 * After a successful return, the caller is responsible for calling
1319 * spi_unregister_master().
1321 int spi_register_master(struct spi_master
*master
)
1323 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1324 struct device
*dev
= master
->dev
.parent
;
1325 struct boardinfo
*bi
;
1326 int status
= -ENODEV
;
1332 status
= of_spi_register_master(master
);
1336 /* even if it's just one always-selected device, there must
1337 * be at least one chipselect
1339 if (master
->num_chipselect
== 0)
1342 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1343 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1345 /* convention: dynamically assigned bus IDs count down from the max */
1346 if (master
->bus_num
< 0) {
1347 /* FIXME switch to an IDR based scheme, something like
1348 * I2C now uses, so we can't run out of "dynamic" IDs
1350 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1354 spin_lock_init(&master
->bus_lock_spinlock
);
1355 mutex_init(&master
->bus_lock_mutex
);
1356 master
->bus_lock_flag
= 0;
1357 init_completion(&master
->xfer_completion
);
1359 /* register the device, then userspace will see it.
1360 * registration fails if the bus ID is in use.
1362 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1363 status
= device_add(&master
->dev
);
1366 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1367 dynamic
? " (dynamic)" : "");
1369 /* If we're using a queued driver, start the queue */
1370 if (master
->transfer
)
1371 dev_info(dev
, "master is unqueued, this is deprecated\n");
1373 status
= spi_master_initialize_queue(master
);
1375 device_del(&master
->dev
);
1380 mutex_lock(&board_lock
);
1381 list_add_tail(&master
->list
, &spi_master_list
);
1382 list_for_each_entry(bi
, &board_list
, list
)
1383 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1384 mutex_unlock(&board_lock
);
1386 /* Register devices from the device tree and ACPI */
1387 of_register_spi_devices(master
);
1388 acpi_register_spi_devices(master
);
1392 EXPORT_SYMBOL_GPL(spi_register_master
);
1394 static void devm_spi_unregister(struct device
*dev
, void *res
)
1396 spi_unregister_master(*(struct spi_master
**)res
);
1400 * dev_spi_register_master - register managed SPI master controller
1401 * @dev: device managing SPI master
1402 * @master: initialized master, originally from spi_alloc_master()
1403 * Context: can sleep
1405 * Register a SPI device as with spi_register_master() which will
1406 * automatically be unregister
1408 int devm_spi_register_master(struct device
*dev
, struct spi_master
*master
)
1410 struct spi_master
**ptr
;
1413 ptr
= devres_alloc(devm_spi_unregister
, sizeof(*ptr
), GFP_KERNEL
);
1417 ret
= spi_register_master(master
);
1420 devres_add(dev
, ptr
);
1427 EXPORT_SYMBOL_GPL(devm_spi_register_master
);
1429 static int __unregister(struct device
*dev
, void *null
)
1431 spi_unregister_device(to_spi_device(dev
));
1436 * spi_unregister_master - unregister SPI master controller
1437 * @master: the master being unregistered
1438 * Context: can sleep
1440 * This call is used only by SPI master controller drivers, which are the
1441 * only ones directly touching chip registers.
1443 * This must be called from context that can sleep.
1445 void spi_unregister_master(struct spi_master
*master
)
1449 if (master
->queued
) {
1450 if (spi_destroy_queue(master
))
1451 dev_err(&master
->dev
, "queue remove failed\n");
1454 mutex_lock(&board_lock
);
1455 list_del(&master
->list
);
1456 mutex_unlock(&board_lock
);
1458 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1459 device_unregister(&master
->dev
);
1461 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1463 int spi_master_suspend(struct spi_master
*master
)
1467 /* Basically no-ops for non-queued masters */
1468 if (!master
->queued
)
1471 ret
= spi_stop_queue(master
);
1473 dev_err(&master
->dev
, "queue stop failed\n");
1477 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1479 int spi_master_resume(struct spi_master
*master
)
1483 if (!master
->queued
)
1486 ret
= spi_start_queue(master
);
1488 dev_err(&master
->dev
, "queue restart failed\n");
1492 EXPORT_SYMBOL_GPL(spi_master_resume
);
1494 static int __spi_master_match(struct device
*dev
, const void *data
)
1496 struct spi_master
*m
;
1497 const u16
*bus_num
= data
;
1499 m
= container_of(dev
, struct spi_master
, dev
);
1500 return m
->bus_num
== *bus_num
;
1504 * spi_busnum_to_master - look up master associated with bus_num
1505 * @bus_num: the master's bus number
1506 * Context: can sleep
1508 * This call may be used with devices that are registered after
1509 * arch init time. It returns a refcounted pointer to the relevant
1510 * spi_master (which the caller must release), or NULL if there is
1511 * no such master registered.
1513 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1516 struct spi_master
*master
= NULL
;
1518 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1519 __spi_master_match
);
1521 master
= container_of(dev
, struct spi_master
, dev
);
1522 /* reference got in class_find_device */
1525 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1528 /*-------------------------------------------------------------------------*/
1530 /* Core methods for SPI master protocol drivers. Some of the
1531 * other core methods are currently defined as inline functions.
1535 * spi_setup - setup SPI mode and clock rate
1536 * @spi: the device whose settings are being modified
1537 * Context: can sleep, and no requests are queued to the device
1539 * SPI protocol drivers may need to update the transfer mode if the
1540 * device doesn't work with its default. They may likewise need
1541 * to update clock rates or word sizes from initial values. This function
1542 * changes those settings, and must be called from a context that can sleep.
1543 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1544 * effect the next time the device is selected and data is transferred to
1545 * or from it. When this function returns, the spi device is deselected.
1547 * Note that this call will fail if the protocol driver specifies an option
1548 * that the underlying controller or its driver does not support. For
1549 * example, not all hardware supports wire transfers using nine bit words,
1550 * LSB-first wire encoding, or active-high chipselects.
1552 int spi_setup(struct spi_device
*spi
)
1557 /* check mode to prevent that DUAL and QUAD set at the same time
1559 if (((spi
->mode
& SPI_TX_DUAL
) && (spi
->mode
& SPI_TX_QUAD
)) ||
1560 ((spi
->mode
& SPI_RX_DUAL
) && (spi
->mode
& SPI_RX_QUAD
))) {
1562 "setup: can not select dual and quad at the same time\n");
1565 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1567 if ((spi
->mode
& SPI_3WIRE
) && (spi
->mode
&
1568 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
)))
1570 /* help drivers fail *cleanly* when they need options
1571 * that aren't supported with their current master
1573 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1575 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1580 if (!spi
->bits_per_word
)
1581 spi
->bits_per_word
= 8;
1583 if (spi
->master
->setup
)
1584 status
= spi
->master
->setup(spi
);
1586 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1587 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1588 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1589 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1590 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1591 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1592 spi
->bits_per_word
, spi
->max_speed_hz
,
1597 EXPORT_SYMBOL_GPL(spi_setup
);
1599 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1601 struct spi_master
*master
= spi
->master
;
1602 struct spi_transfer
*xfer
;
1606 trace_spi_message_submit(message
);
1608 if (list_empty(&message
->transfers
))
1610 if (!message
->complete
)
1613 /* Half-duplex links include original MicroWire, and ones with
1614 * only one data pin like SPI_3WIRE (switches direction) or where
1615 * either MOSI or MISO is missing. They can also be caused by
1616 * software limitations.
1618 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1619 || (spi
->mode
& SPI_3WIRE
)) {
1620 unsigned flags
= master
->flags
;
1622 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1623 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1625 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1627 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1633 * Set transfer bits_per_word and max speed as spi device default if
1634 * it is not set for this transfer.
1635 * Set transfer tx_nbits and rx_nbits as single transfer default
1636 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1638 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1639 message
->frame_length
+= xfer
->len
;
1640 if (!xfer
->bits_per_word
)
1641 xfer
->bits_per_word
= spi
->bits_per_word
;
1642 if (!xfer
->speed_hz
) {
1643 xfer
->speed_hz
= spi
->max_speed_hz
;
1644 if (master
->max_speed_hz
&&
1645 xfer
->speed_hz
> master
->max_speed_hz
)
1646 xfer
->speed_hz
= master
->max_speed_hz
;
1649 if (master
->bits_per_word_mask
) {
1650 /* Only 32 bits fit in the mask */
1651 if (xfer
->bits_per_word
> 32)
1653 if (!(master
->bits_per_word_mask
&
1654 BIT(xfer
->bits_per_word
- 1)))
1658 if (xfer
->speed_hz
&& master
->min_speed_hz
&&
1659 xfer
->speed_hz
< master
->min_speed_hz
)
1661 if (xfer
->speed_hz
&& master
->max_speed_hz
&&
1662 xfer
->speed_hz
> master
->max_speed_hz
)
1665 if (xfer
->tx_buf
&& !xfer
->tx_nbits
)
1666 xfer
->tx_nbits
= SPI_NBITS_SINGLE
;
1667 if (xfer
->rx_buf
&& !xfer
->rx_nbits
)
1668 xfer
->rx_nbits
= SPI_NBITS_SINGLE
;
1669 /* check transfer tx/rx_nbits:
1670 * 1. keep the value is not out of single, dual and quad
1671 * 2. keep tx/rx_nbits is contained by mode in spi_device
1672 * 3. if SPI_3WIRE, tx/rx_nbits should be in single
1675 if (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
&&
1676 xfer
->tx_nbits
!= SPI_NBITS_DUAL
&&
1677 xfer
->tx_nbits
!= SPI_NBITS_QUAD
)
1679 if ((xfer
->tx_nbits
== SPI_NBITS_DUAL
) &&
1680 !(spi
->mode
& (SPI_TX_DUAL
| SPI_TX_QUAD
)))
1682 if ((xfer
->tx_nbits
== SPI_NBITS_QUAD
) &&
1683 !(spi
->mode
& SPI_TX_QUAD
))
1685 if ((spi
->mode
& SPI_3WIRE
) &&
1686 (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
))
1689 /* check transfer rx_nbits */
1691 if (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
&&
1692 xfer
->rx_nbits
!= SPI_NBITS_DUAL
&&
1693 xfer
->rx_nbits
!= SPI_NBITS_QUAD
)
1695 if ((xfer
->rx_nbits
== SPI_NBITS_DUAL
) &&
1696 !(spi
->mode
& (SPI_RX_DUAL
| SPI_RX_QUAD
)))
1698 if ((xfer
->rx_nbits
== SPI_NBITS_QUAD
) &&
1699 !(spi
->mode
& SPI_RX_QUAD
))
1701 if ((spi
->mode
& SPI_3WIRE
) &&
1702 (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
))
1707 message
->status
= -EINPROGRESS
;
1708 return master
->transfer(spi
, message
);
1712 * spi_async - asynchronous SPI transfer
1713 * @spi: device with which data will be exchanged
1714 * @message: describes the data transfers, including completion callback
1715 * Context: any (irqs may be blocked, etc)
1717 * This call may be used in_irq and other contexts which can't sleep,
1718 * as well as from task contexts which can sleep.
1720 * The completion callback is invoked in a context which can't sleep.
1721 * Before that invocation, the value of message->status is undefined.
1722 * When the callback is issued, message->status holds either zero (to
1723 * indicate complete success) or a negative error code. After that
1724 * callback returns, the driver which issued the transfer request may
1725 * deallocate the associated memory; it's no longer in use by any SPI
1726 * core or controller driver code.
1728 * Note that although all messages to a spi_device are handled in
1729 * FIFO order, messages may go to different devices in other orders.
1730 * Some device might be higher priority, or have various "hard" access
1731 * time requirements, for example.
1733 * On detection of any fault during the transfer, processing of
1734 * the entire message is aborted, and the device is deselected.
1735 * Until returning from the associated message completion callback,
1736 * no other spi_message queued to that device will be processed.
1737 * (This rule applies equally to all the synchronous transfer calls,
1738 * which are wrappers around this core asynchronous primitive.)
1740 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1742 struct spi_master
*master
= spi
->master
;
1744 unsigned long flags
;
1746 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1748 if (master
->bus_lock_flag
)
1751 ret
= __spi_async(spi
, message
);
1753 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1757 EXPORT_SYMBOL_GPL(spi_async
);
1760 * spi_async_locked - version of spi_async with exclusive bus usage
1761 * @spi: device with which data will be exchanged
1762 * @message: describes the data transfers, including completion callback
1763 * Context: any (irqs may be blocked, etc)
1765 * This call may be used in_irq and other contexts which can't sleep,
1766 * as well as from task contexts which can sleep.
1768 * The completion callback is invoked in a context which can't sleep.
1769 * Before that invocation, the value of message->status is undefined.
1770 * When the callback is issued, message->status holds either zero (to
1771 * indicate complete success) or a negative error code. After that
1772 * callback returns, the driver which issued the transfer request may
1773 * deallocate the associated memory; it's no longer in use by any SPI
1774 * core or controller driver code.
1776 * Note that although all messages to a spi_device are handled in
1777 * FIFO order, messages may go to different devices in other orders.
1778 * Some device might be higher priority, or have various "hard" access
1779 * time requirements, for example.
1781 * On detection of any fault during the transfer, processing of
1782 * the entire message is aborted, and the device is deselected.
1783 * Until returning from the associated message completion callback,
1784 * no other spi_message queued to that device will be processed.
1785 * (This rule applies equally to all the synchronous transfer calls,
1786 * which are wrappers around this core asynchronous primitive.)
1788 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
1790 struct spi_master
*master
= spi
->master
;
1792 unsigned long flags
;
1794 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1796 ret
= __spi_async(spi
, message
);
1798 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1803 EXPORT_SYMBOL_GPL(spi_async_locked
);
1806 /*-------------------------------------------------------------------------*/
1808 /* Utility methods for SPI master protocol drivers, layered on
1809 * top of the core. Some other utility methods are defined as
1813 static void spi_complete(void *arg
)
1818 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
1821 DECLARE_COMPLETION_ONSTACK(done
);
1823 struct spi_master
*master
= spi
->master
;
1825 message
->complete
= spi_complete
;
1826 message
->context
= &done
;
1829 mutex_lock(&master
->bus_lock_mutex
);
1831 status
= spi_async_locked(spi
, message
);
1834 mutex_unlock(&master
->bus_lock_mutex
);
1837 wait_for_completion(&done
);
1838 status
= message
->status
;
1840 message
->context
= NULL
;
1845 * spi_sync - blocking/synchronous SPI data transfers
1846 * @spi: device with which data will be exchanged
1847 * @message: describes the data transfers
1848 * Context: can sleep
1850 * This call may only be used from a context that may sleep. The sleep
1851 * is non-interruptible, and has no timeout. Low-overhead controller
1852 * drivers may DMA directly into and out of the message buffers.
1854 * Note that the SPI device's chip select is active during the message,
1855 * and then is normally disabled between messages. Drivers for some
1856 * frequently-used devices may want to minimize costs of selecting a chip,
1857 * by leaving it selected in anticipation that the next message will go
1858 * to the same chip. (That may increase power usage.)
1860 * Also, the caller is guaranteeing that the memory associated with the
1861 * message will not be freed before this call returns.
1863 * It returns zero on success, else a negative error code.
1865 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
1867 return __spi_sync(spi
, message
, 0);
1869 EXPORT_SYMBOL_GPL(spi_sync
);
1872 * spi_sync_locked - version of spi_sync with exclusive bus usage
1873 * @spi: device with which data will be exchanged
1874 * @message: describes the data transfers
1875 * Context: can sleep
1877 * This call may only be used from a context that may sleep. The sleep
1878 * is non-interruptible, and has no timeout. Low-overhead controller
1879 * drivers may DMA directly into and out of the message buffers.
1881 * This call should be used by drivers that require exclusive access to the
1882 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1883 * be released by a spi_bus_unlock call when the exclusive access is over.
1885 * It returns zero on success, else a negative error code.
1887 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
1889 return __spi_sync(spi
, message
, 1);
1891 EXPORT_SYMBOL_GPL(spi_sync_locked
);
1894 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1895 * @master: SPI bus master that should be locked for exclusive bus access
1896 * Context: can sleep
1898 * This call may only be used from a context that may sleep. The sleep
1899 * is non-interruptible, and has no timeout.
1901 * This call should be used by drivers that require exclusive access to the
1902 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1903 * exclusive access is over. Data transfer must be done by spi_sync_locked
1904 * and spi_async_locked calls when the SPI bus lock is held.
1906 * It returns zero on success, else a negative error code.
1908 int spi_bus_lock(struct spi_master
*master
)
1910 unsigned long flags
;
1912 mutex_lock(&master
->bus_lock_mutex
);
1914 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
1915 master
->bus_lock_flag
= 1;
1916 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
1918 /* mutex remains locked until spi_bus_unlock is called */
1922 EXPORT_SYMBOL_GPL(spi_bus_lock
);
1925 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1926 * @master: SPI bus master that was locked for exclusive bus access
1927 * Context: can sleep
1929 * This call may only be used from a context that may sleep. The sleep
1930 * is non-interruptible, and has no timeout.
1932 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1935 * It returns zero on success, else a negative error code.
1937 int spi_bus_unlock(struct spi_master
*master
)
1939 master
->bus_lock_flag
= 0;
1941 mutex_unlock(&master
->bus_lock_mutex
);
1945 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
1947 /* portable code must never pass more than 32 bytes */
1948 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
1953 * spi_write_then_read - SPI synchronous write followed by read
1954 * @spi: device with which data will be exchanged
1955 * @txbuf: data to be written (need not be dma-safe)
1956 * @n_tx: size of txbuf, in bytes
1957 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1958 * @n_rx: size of rxbuf, in bytes
1959 * Context: can sleep
1961 * This performs a half duplex MicroWire style transaction with the
1962 * device, sending txbuf and then reading rxbuf. The return value
1963 * is zero for success, else a negative errno status code.
1964 * This call may only be used from a context that may sleep.
1966 * Parameters to this routine are always copied using a small buffer;
1967 * portable code should never use this for more than 32 bytes.
1968 * Performance-sensitive or bulk transfer code should instead use
1969 * spi_{async,sync}() calls with dma-safe buffers.
1971 int spi_write_then_read(struct spi_device
*spi
,
1972 const void *txbuf
, unsigned n_tx
,
1973 void *rxbuf
, unsigned n_rx
)
1975 static DEFINE_MUTEX(lock
);
1978 struct spi_message message
;
1979 struct spi_transfer x
[2];
1982 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1983 * copying here, (as a pure convenience thing), but we can
1984 * keep heap costs out of the hot path unless someone else is
1985 * using the pre-allocated buffer or the transfer is too large.
1987 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
1988 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
1989 GFP_KERNEL
| GFP_DMA
);
1996 spi_message_init(&message
);
1997 memset(x
, 0, sizeof(x
));
2000 spi_message_add_tail(&x
[0], &message
);
2004 spi_message_add_tail(&x
[1], &message
);
2007 memcpy(local_buf
, txbuf
, n_tx
);
2008 x
[0].tx_buf
= local_buf
;
2009 x
[1].rx_buf
= local_buf
+ n_tx
;
2012 status
= spi_sync(spi
, &message
);
2014 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
2016 if (x
[0].tx_buf
== buf
)
2017 mutex_unlock(&lock
);
2023 EXPORT_SYMBOL_GPL(spi_write_then_read
);
2025 /*-------------------------------------------------------------------------*/
2027 static int __init
spi_init(void)
2031 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
2037 status
= bus_register(&spi_bus_type
);
2041 status
= class_register(&spi_master_class
);
2047 bus_unregister(&spi_bus_type
);
2055 /* board_info is normally registered in arch_initcall(),
2056 * but even essential drivers wait till later
2058 * REVISIT only boardinfo really needs static linking. the rest (device and
2059 * driver registration) _could_ be dynamically linked (modular) ... costs
2060 * include needing to have boardinfo data structures be much more public.
2062 postcore_initcall(spi_init
);