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);
63 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
67 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
69 static DEVICE_ATTR_RO(modalias);
71 static struct attribute *spi_dev_attrs[] = {
72 &dev_attr_modalias.attr,
75 ATTRIBUTE_GROUPS(spi_dev);
77 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
78 * and the sysfs version makes coldplug work too.
81 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
82 const struct spi_device *sdev)
85 if (!strcmp(sdev->modalias, id->name))
92 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
94 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
96 return spi_match_id(sdrv->id_table, sdev);
98 EXPORT_SYMBOL_GPL(spi_get_device_id);
100 static int spi_match_device(struct device *dev, struct device_driver *drv)
102 const struct spi_device *spi = to_spi_device(dev);
103 const struct spi_driver *sdrv = to_spi_driver(drv);
105 /* Attempt an OF style match */
106 if (of_driver_match_device(dev, drv))
110 if (acpi_driver_match_device(dev, drv))
114 return !!spi_match_id(sdrv->id_table, spi);
116 return strcmp(spi->modalias, drv->name) == 0;
119 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
121 const struct spi_device *spi = to_spi_device(dev);
124 rc = acpi_device_uevent_modalias(dev, env);
128 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
132 #ifdef CONFIG_PM_SLEEP
133 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
136 struct spi_driver *drv = to_spi_driver(dev->driver);
138 /* suspend will stop irqs and dma; no more i/o */
141 value = drv->suspend(to_spi_device(dev), message);
143 dev_dbg(dev, "... can't suspend\n");
148 static int spi_legacy_resume(struct device *dev)
151 struct spi_driver *drv = to_spi_driver(dev->driver);
153 /* resume may restart the i/o queue */
156 value = drv->resume(to_spi_device(dev));
158 dev_dbg(dev, "... can't resume\n");
163 static int spi_pm_suspend(struct device *dev)
165 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
168 return pm_generic_suspend(dev);
170 return spi_legacy_suspend(dev, PMSG_SUSPEND);
173 static int spi_pm_resume(struct device *dev)
175 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
178 return pm_generic_resume(dev);
180 return spi_legacy_resume(dev);
183 static int spi_pm_freeze(struct device *dev)
185 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
188 return pm_generic_freeze(dev);
190 return spi_legacy_suspend(dev, PMSG_FREEZE);
193 static int spi_pm_thaw(struct device *dev)
195 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
198 return pm_generic_thaw(dev);
200 return spi_legacy_resume(dev);
203 static int spi_pm_poweroff(struct device *dev)
205 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
208 return pm_generic_poweroff(dev);
210 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
213 static int spi_pm_restore(struct device *dev)
215 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
218 return pm_generic_restore(dev);
220 return spi_legacy_resume(dev);
223 #define spi_pm_suspend NULL
224 #define spi_pm_resume NULL
225 #define spi_pm_freeze NULL
226 #define spi_pm_thaw NULL
227 #define spi_pm_poweroff NULL
228 #define spi_pm_restore NULL
231 static const struct dev_pm_ops spi_pm = {
232 .suspend = spi_pm_suspend,
233 .resume = spi_pm_resume,
234 .freeze = spi_pm_freeze,
236 .poweroff = spi_pm_poweroff,
237 .restore = spi_pm_restore,
239 pm_generic_runtime_suspend,
240 pm_generic_runtime_resume,
245 struct bus_type spi_bus_type = {
247 .dev_groups = spi_dev_groups,
248 .match = spi_match_device,
249 .uevent = spi_uevent,
252 EXPORT_SYMBOL_GPL(spi_bus_type);
255 static int spi_drv_probe(struct device *dev)
257 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
260 acpi_dev_pm_attach(dev, true);
261 ret = sdrv->probe(to_spi_device(dev));
263 acpi_dev_pm_detach(dev, true);
268 static int spi_drv_remove(struct device *dev)
270 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
273 ret = sdrv->remove(to_spi_device(dev));
274 acpi_dev_pm_detach(dev, true);
279 static void spi_drv_shutdown(struct device *dev)
281 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
283 sdrv->shutdown(to_spi_device(dev));
287 * spi_register_driver - register a SPI driver
288 * @sdrv: the driver to register
291 int spi_register_driver(struct spi_driver *sdrv)
293 sdrv->driver.bus = &spi_bus_type;
295 sdrv->driver.probe = spi_drv_probe;
297 sdrv->driver.remove = spi_drv_remove;
299 sdrv->driver.shutdown = spi_drv_shutdown;
300 return driver_register(&sdrv->driver);
302 EXPORT_SYMBOL_GPL(spi_register_driver);
304 /*-------------------------------------------------------------------------*/
306 /* SPI devices should normally not be created by SPI device drivers; that
307 * would make them board-specific. Similarly with SPI master drivers.
308 * Device registration normally goes into like arch/.../mach.../board-YYY.c
309 * with other readonly (flashable) information about mainboard devices.
313 struct list_head list;
314 struct spi_board_info board_info;
317 static LIST_HEAD(board_list);
318 static LIST_HEAD(spi_master_list);
321 * Used to protect add/del opertion for board_info list and
322 * spi_master list, and their matching process
324 static DEFINE_MUTEX(board_lock);
327 * spi_alloc_device - Allocate a new SPI device
328 * @master: Controller to which device is connected
331 * Allows a driver to allocate and initialize a spi_device without
332 * registering it immediately. This allows a driver to directly
333 * fill the spi_device with device parameters before calling
334 * spi_add_device() on it.
336 * Caller is responsible to call spi_add_device() on the returned
337 * spi_device structure to add it to the SPI master. If the caller
338 * needs to discard the spi_device without adding it, then it should
339 * call spi_dev_put() on it.
341 * Returns a pointer to the new device, or NULL.
343 struct spi_device *spi_alloc_device(struct spi_master *master)
345 struct spi_device *spi;
346 struct device *dev = master->dev.parent;
348 if (!spi_master_get(master))
351 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
353 dev_err(dev, "cannot alloc spi_device\n");
354 spi_master_put(master);
358 spi->master = master;
359 spi->dev.parent = &master->dev;
360 spi->dev.bus = &spi_bus_type;
361 spi->dev.release = spidev_release;
362 spi->cs_gpio = -ENOENT;
363 device_initialize(&spi->dev);
366 EXPORT_SYMBOL_GPL(spi_alloc_device);
368 static void spi_dev_set_name(struct spi_device *spi)
370 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
373 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
377 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
381 static int spi_dev_check(struct device *dev, void *data)
383 struct spi_device *spi = to_spi_device(dev);
384 struct spi_device *new_spi = data;
386 if (spi->master == new_spi->master &&
387 spi->chip_select == new_spi->chip_select)
393 * spi_add_device - Add spi_device allocated with spi_alloc_device
394 * @spi: spi_device to register
396 * Companion function to spi_alloc_device. Devices allocated with
397 * spi_alloc_device can be added onto the spi bus with this function.
399 * Returns 0 on success; negative errno on failure
401 int spi_add_device(struct spi_device *spi)
403 static DEFINE_MUTEX(spi_add_lock);
404 struct spi_master *master = spi->master;
405 struct device *dev = master->dev.parent;
408 /* Chipselects are numbered 0..max; validate. */
409 if (spi->chip_select >= master->num_chipselect) {
410 dev_err(dev, "cs%d >= max %d\n",
412 master->num_chipselect);
416 /* Set the bus ID string */
417 spi_dev_set_name(spi);
419 /* We need to make sure there's no other device with this
420 * chipselect **BEFORE** we call setup(), else we'll trash
421 * its configuration. Lock against concurrent add() calls.
423 mutex_lock(&spi_add_lock);
425 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
427 dev_err(dev, "chipselect %d already in use\n",
432 if (master->cs_gpios)
433 spi->cs_gpio = master->cs_gpios[spi->chip_select];
435 /* Drivers may modify this initial i/o setup, but will
436 * normally rely on the device being setup. Devices
437 * using SPI_CS_HIGH can't coexist well otherwise...
439 status = spi_setup(spi);
441 dev_err(dev, "can't setup %s, status %d\n",
442 dev_name(&spi->dev), status);
446 /* Device may be bound to an active driver when this returns */
447 status = device_add(&spi->dev);
449 dev_err(dev, "can't add %s, status %d\n",
450 dev_name(&spi->dev), status);
452 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
455 mutex_unlock(&spi_add_lock);
458 EXPORT_SYMBOL_GPL(spi_add_device);
461 * spi_new_device - instantiate one new SPI device
462 * @master: Controller to which device is connected
463 * @chip: Describes the SPI device
466 * On typical mainboards, this is purely internal; and it's not needed
467 * after board init creates the hard-wired devices. Some development
468 * platforms may not be able to use spi_register_board_info though, and
469 * this is exported so that for example a USB or parport based adapter
470 * driver could add devices (which it would learn about out-of-band).
472 * Returns the new device, or NULL.
474 struct spi_device *spi_new_device(struct spi_master *master,
475 struct spi_board_info *chip)
477 struct spi_device *proxy;
480 /* NOTE: caller did any chip->bus_num checks necessary.
482 * Also, unless we change the return value convention to use
483 * error-or-pointer (not NULL-or-pointer), troubleshootability
484 * suggests syslogged diagnostics are best here (ugh).
487 proxy = spi_alloc_device(master);
491 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
493 proxy->chip_select = chip->chip_select;
494 proxy->max_speed_hz = chip->max_speed_hz;
495 proxy->mode = chip->mode;
496 proxy->irq = chip->irq;
497 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
498 proxy->dev.platform_data = (void *) chip->platform_data;
499 proxy->controller_data = chip->controller_data;
500 proxy->controller_state = NULL;
502 status = spi_add_device(proxy);
510 EXPORT_SYMBOL_GPL(spi_new_device);
512 static void spi_match_master_to_boardinfo(struct spi_master *master,
513 struct spi_board_info *bi)
515 struct spi_device *dev;
517 if (master->bus_num != bi->bus_num)
520 dev = spi_new_device(master, bi);
522 dev_err(master->dev.parent, "can't create new device for %s\n",
527 * spi_register_board_info - register SPI devices for a given board
528 * @info: array of chip descriptors
529 * @n: how many descriptors are provided
532 * Board-specific early init code calls this (probably during arch_initcall)
533 * with segments of the SPI device table. Any device nodes are created later,
534 * after the relevant parent SPI controller (bus_num) is defined. We keep
535 * this table of devices forever, so that reloading a controller driver will
536 * not make Linux forget about these hard-wired devices.
538 * Other code can also call this, e.g. a particular add-on board might provide
539 * SPI devices through its expansion connector, so code initializing that board
540 * would naturally declare its SPI devices.
542 * The board info passed can safely be __initdata ... but be careful of
543 * any embedded pointers (platform_data, etc), they're copied as-is.
545 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
547 struct boardinfo *bi;
550 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
554 for (i = 0; i < n; i++, bi++, info++) {
555 struct spi_master *master;
557 memcpy(&bi->board_info, info, sizeof(*info));
558 mutex_lock(&board_lock);
559 list_add_tail(&bi->list, &board_list);
560 list_for_each_entry(master, &spi_master_list, list)
561 spi_match_master_to_boardinfo(master, &bi->board_info);
562 mutex_unlock(&board_lock);
568 /*-------------------------------------------------------------------------*/
570 static void spi_set_cs(struct spi_device *spi, bool enable)
572 if (spi->mode & SPI_CS_HIGH)
575 if (spi->cs_gpio >= 0)
576 gpio_set_value(spi->cs_gpio, !enable);
577 else if (spi->master->set_cs)
578 spi->master->set_cs(spi, !enable);
582 * spi_transfer_one_message - Default implementation of transfer_one_message()
584 * This is a standard implementation of transfer_one_message() for
585 * drivers which impelment a transfer_one() operation. It provides
586 * standard handling of delays and chip select management.
588 static int spi_transfer_one_message(struct spi_master *master,
589 struct spi_message *msg)
591 struct spi_transfer *xfer;
592 bool keep_cs = false;
595 spi_set_cs(msg->spi, true);
597 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
598 trace_spi_transfer_start(msg, xfer);
600 reinit_completion(&master->xfer_completion);
602 ret = master->transfer_one(master, msg->spi, xfer);
604 dev_err(&msg->spi->dev,
605 "SPI transfer failed: %d\n", ret);
611 wait_for_completion(&master->xfer_completion);
614 trace_spi_transfer_stop(msg, xfer);
616 if (msg->status != -EINPROGRESS)
619 if (xfer->delay_usecs)
620 udelay(xfer->delay_usecs);
622 if (xfer->cs_change) {
623 if (list_is_last(&xfer->transfer_list,
627 spi_set_cs(msg->spi, false);
629 spi_set_cs(msg->spi, true);
633 msg->actual_length += xfer->len;
637 if (ret != 0 || !keep_cs)
638 spi_set_cs(msg->spi, false);
640 if (msg->status == -EINPROGRESS)
643 spi_finalize_current_message(master);
649 * spi_finalize_current_transfer - report completion of a transfer
651 * Called by SPI drivers using the core transfer_one_message()
652 * implementation to notify it that the current interrupt driven
653 * transfer has finished and the next one may be scheduled.
655 void spi_finalize_current_transfer(struct spi_master *master)
657 complete(&master->xfer_completion);
659 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
662 * spi_pump_messages - kthread work function which processes spi message queue
663 * @work: pointer to kthread work struct contained in the master struct
665 * This function checks if there is any spi message in the queue that
666 * needs processing and if so call out to the driver to initialize hardware
667 * and transfer each message.
670 static void spi_pump_messages(struct kthread_work *work)
672 struct spi_master *master =
673 container_of(work, struct spi_master, pump_messages);
675 bool was_busy = false;
678 /* Lock queue and check for queue work */
679 spin_lock_irqsave(&master->queue_lock, flags);
680 if (list_empty(&master->queue) || !master->running) {
682 spin_unlock_irqrestore(&master->queue_lock, flags);
685 master->busy = false;
686 spin_unlock_irqrestore(&master->queue_lock, flags);
687 if (master->unprepare_transfer_hardware &&
688 master->unprepare_transfer_hardware(master))
689 dev_err(&master->dev,
690 "failed to unprepare transfer hardware\n");
691 if (master->auto_runtime_pm) {
692 pm_runtime_mark_last_busy(master->dev.parent);
693 pm_runtime_put_autosuspend(master->dev.parent);
695 trace_spi_master_idle(master);
699 /* Make sure we are not already running a message */
700 if (master->cur_msg) {
701 spin_unlock_irqrestore(&master->queue_lock, flags);
704 /* Extract head of queue */
706 list_first_entry(&master->queue, struct spi_message, queue);
708 list_del_init(&master->cur_msg->queue);
713 spin_unlock_irqrestore(&master->queue_lock, flags);
715 if (!was_busy && master->auto_runtime_pm) {
716 ret = pm_runtime_get_sync(master->dev.parent);
718 dev_err(&master->dev, "Failed to power device: %d\n",
725 trace_spi_master_busy(master);
727 if (!was_busy && master->prepare_transfer_hardware) {
728 ret = master->prepare_transfer_hardware(master);
730 dev_err(&master->dev,
731 "failed to prepare transfer hardware\n");
733 if (master->auto_runtime_pm)
734 pm_runtime_put(master->dev.parent);
739 trace_spi_message_start(master->cur_msg);
741 if (master->prepare_message) {
742 ret = master->prepare_message(master, master->cur_msg);
744 dev_err(&master->dev,
745 "failed to prepare message: %d\n", ret);
746 master->cur_msg->status = ret;
747 spi_finalize_current_message(master);
750 master->cur_msg_prepared = true;
753 ret = master->transfer_one_message(master, master->cur_msg);
755 dev_err(&master->dev,
756 "failed to transfer one message from queue\n");
761 static int spi_init_queue(struct spi_master *master)
763 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
765 INIT_LIST_HEAD(&master->queue);
766 spin_lock_init(&master->queue_lock);
768 master->running = false;
769 master->busy = false;
771 init_kthread_worker(&master->kworker);
772 master->kworker_task = kthread_run(kthread_worker_fn,
773 &master->kworker, "%s",
774 dev_name(&master->dev));
775 if (IS_ERR(master->kworker_task)) {
776 dev_err(&master->dev, "failed to create message pump task\n");
779 init_kthread_work(&master->pump_messages, spi_pump_messages);
782 * Master config will indicate if this controller should run the
783 * message pump with high (realtime) priority to reduce the transfer
784 * latency on the bus by minimising the delay between a transfer
785 * request and the scheduling of the message pump thread. Without this
786 * setting the message pump thread will remain at default priority.
789 dev_info(&master->dev,
790 "will run message pump with realtime priority\n");
791 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
798 * spi_get_next_queued_message() - called by driver to check for queued
800 * @master: the master to check for queued messages
802 * If there are more messages in the queue, the next message is returned from
805 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
807 struct spi_message *next;
810 /* get a pointer to the next message, if any */
811 spin_lock_irqsave(&master->queue_lock, flags);
812 next = list_first_entry_or_null(&master->queue, struct spi_message,
814 spin_unlock_irqrestore(&master->queue_lock, flags);
818 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
821 * spi_finalize_current_message() - the current message is complete
822 * @master: the master to return the message to
824 * Called by the driver to notify the core that the message in the front of the
825 * queue is complete and can be removed from the queue.
827 void spi_finalize_current_message(struct spi_master *master)
829 struct spi_message *mesg;
833 spin_lock_irqsave(&master->queue_lock, flags);
834 mesg = master->cur_msg;
835 master->cur_msg = NULL;
837 queue_kthread_work(&master->kworker, &master->pump_messages);
838 spin_unlock_irqrestore(&master->queue_lock, flags);
840 if (master->cur_msg_prepared && master->unprepare_message) {
841 ret = master->unprepare_message(master, mesg);
843 dev_err(&master->dev,
844 "failed to unprepare message: %d\n", ret);
847 master->cur_msg_prepared = false;
851 mesg->complete(mesg->context);
853 trace_spi_message_done(mesg);
855 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
857 static int spi_start_queue(struct spi_master *master)
861 spin_lock_irqsave(&master->queue_lock, flags);
863 if (master->running || master->busy) {
864 spin_unlock_irqrestore(&master->queue_lock, flags);
868 master->running = true;
869 master->cur_msg = NULL;
870 spin_unlock_irqrestore(&master->queue_lock, flags);
872 queue_kthread_work(&master->kworker, &master->pump_messages);
877 static int spi_stop_queue(struct spi_master *master)
880 unsigned limit = 500;
883 spin_lock_irqsave(&master->queue_lock, flags);
886 * This is a bit lame, but is optimized for the common execution path.
887 * A wait_queue on the master->busy could be used, but then the common
888 * execution path (pump_messages) would be required to call wake_up or
889 * friends on every SPI message. Do this instead.
891 while ((!list_empty(&master->queue) || master->busy) && limit--) {
892 spin_unlock_irqrestore(&master->queue_lock, flags);
893 usleep_range(10000, 11000);
894 spin_lock_irqsave(&master->queue_lock, flags);
897 if (!list_empty(&master->queue) || master->busy)
900 master->running = false;
902 spin_unlock_irqrestore(&master->queue_lock, flags);
905 dev_warn(&master->dev,
906 "could not stop message queue\n");
912 static int spi_destroy_queue(struct spi_master *master)
916 ret = spi_stop_queue(master);
919 * flush_kthread_worker will block until all work is done.
920 * If the reason that stop_queue timed out is that the work will never
921 * finish, then it does no good to call flush/stop thread, so
925 dev_err(&master->dev, "problem destroying queue\n");
929 flush_kthread_worker(&master->kworker);
930 kthread_stop(master->kworker_task);
936 * spi_queued_transfer - transfer function for queued transfers
937 * @spi: spi device which is requesting transfer
938 * @msg: spi message which is to handled is queued to driver queue
940 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
942 struct spi_master *master = spi->master;
945 spin_lock_irqsave(&master->queue_lock, flags);
947 if (!master->running) {
948 spin_unlock_irqrestore(&master->queue_lock, flags);
951 msg->actual_length = 0;
952 msg->status = -EINPROGRESS;
954 list_add_tail(&msg->queue, &master->queue);
956 queue_kthread_work(&master->kworker, &master->pump_messages);
958 spin_unlock_irqrestore(&master->queue_lock, flags);
962 static int spi_master_initialize_queue(struct spi_master *master)
966 master->queued = true;
967 master->transfer = spi_queued_transfer;
968 if (!master->transfer_one_message)
969 master->transfer_one_message = spi_transfer_one_message;
971 /* Initialize and start queue */
972 ret = spi_init_queue(master);
974 dev_err(&master->dev, "problem initializing queue\n");
977 ret = spi_start_queue(master);
979 dev_err(&master->dev, "problem starting queue\n");
980 goto err_start_queue;
987 spi_destroy_queue(master);
991 /*-------------------------------------------------------------------------*/
993 #if defined(CONFIG_OF)
995 * of_register_spi_devices() - Register child devices onto the SPI bus
996 * @master: Pointer to spi_master device
998 * Registers an spi_device for each child node of master node which has a 'reg'
1001 static void of_register_spi_devices(struct spi_master *master)
1003 struct spi_device *spi;
1004 struct device_node *nc;
1008 if (!master->dev.of_node)
1011 for_each_available_child_of_node(master->dev.of_node, nc) {
1012 /* Alloc an spi_device */
1013 spi = spi_alloc_device(master);
1015 dev_err(&master->dev, "spi_device alloc error for %s\n",
1021 /* Select device driver */
1022 if (of_modalias_node(nc, spi->modalias,
1023 sizeof(spi->modalias)) < 0) {
1024 dev_err(&master->dev, "cannot find modalias for %s\n",
1030 /* Device address */
1031 rc = of_property_read_u32(nc, "reg", &value);
1033 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1038 spi->chip_select = value;
1040 /* Mode (clock phase/polarity/etc.) */
1041 if (of_find_property(nc, "spi-cpha", NULL))
1042 spi->mode |= SPI_CPHA;
1043 if (of_find_property(nc, "spi-cpol", NULL))
1044 spi->mode |= SPI_CPOL;
1045 if (of_find_property(nc, "spi-cs-high", NULL))
1046 spi->mode |= SPI_CS_HIGH;
1047 if (of_find_property(nc, "spi-3wire", NULL))
1048 spi->mode |= SPI_3WIRE;
1050 /* Device DUAL/QUAD mode */
1051 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1056 spi->mode |= SPI_TX_DUAL;
1059 spi->mode |= SPI_TX_QUAD;
1062 dev_err(&master->dev,
1063 "spi-tx-bus-width %d not supported\n",
1070 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1075 spi->mode |= SPI_RX_DUAL;
1078 spi->mode |= SPI_RX_QUAD;
1081 dev_err(&master->dev,
1082 "spi-rx-bus-width %d not supported\n",
1090 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1092 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1097 spi->max_speed_hz = value;
1100 spi->irq = irq_of_parse_and_map(nc, 0);
1102 /* Store a pointer to the node in the device structure */
1104 spi->dev.of_node = nc;
1106 /* Register the new device */
1107 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1108 rc = spi_add_device(spi);
1110 dev_err(&master->dev, "spi_device register error %s\n",
1118 static void of_register_spi_devices(struct spi_master *master) { }
1122 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1124 struct spi_device *spi = data;
1126 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1127 struct acpi_resource_spi_serialbus *sb;
1129 sb = &ares->data.spi_serial_bus;
1130 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1131 spi->chip_select = sb->device_selection;
1132 spi->max_speed_hz = sb->connection_speed;
1134 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1135 spi->mode |= SPI_CPHA;
1136 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1137 spi->mode |= SPI_CPOL;
1138 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1139 spi->mode |= SPI_CS_HIGH;
1141 } else if (spi->irq < 0) {
1144 if (acpi_dev_resource_interrupt(ares, 0, &r))
1148 /* Always tell the ACPI core to skip this resource */
1152 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1153 void *data, void **return_value)
1155 struct spi_master *master = data;
1156 struct list_head resource_list;
1157 struct acpi_device *adev;
1158 struct spi_device *spi;
1161 if (acpi_bus_get_device(handle, &adev))
1163 if (acpi_bus_get_status(adev) || !adev->status.present)
1166 spi = spi_alloc_device(master);
1168 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1169 dev_name(&adev->dev));
1170 return AE_NO_MEMORY;
1173 ACPI_COMPANION_SET(&spi->dev, adev);
1176 INIT_LIST_HEAD(&resource_list);
1177 ret = acpi_dev_get_resources(adev, &resource_list,
1178 acpi_spi_add_resource, spi);
1179 acpi_dev_free_resource_list(&resource_list);
1181 if (ret < 0 || !spi->max_speed_hz) {
1186 adev->power.flags.ignore_parent = true;
1187 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1188 if (spi_add_device(spi)) {
1189 adev->power.flags.ignore_parent = false;
1190 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1191 dev_name(&adev->dev));
1198 static void acpi_register_spi_devices(struct spi_master *master)
1203 handle = ACPI_HANDLE(master->dev.parent);
1207 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1208 acpi_spi_add_device, NULL,
1210 if (ACPI_FAILURE(status))
1211 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1214 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1215 #endif /* CONFIG_ACPI */
1217 static void spi_master_release(struct device *dev)
1219 struct spi_master *master;
1221 master = container_of(dev, struct spi_master, dev);
1225 static struct class spi_master_class = {
1226 .name = "spi_master",
1227 .owner = THIS_MODULE,
1228 .dev_release = spi_master_release,
1234 * spi_alloc_master - allocate SPI master controller
1235 * @dev: the controller, possibly using the platform_bus
1236 * @size: how much zeroed driver-private data to allocate; the pointer to this
1237 * memory is in the driver_data field of the returned device,
1238 * accessible with spi_master_get_devdata().
1239 * Context: can sleep
1241 * This call is used only by SPI master controller drivers, which are the
1242 * only ones directly touching chip registers. It's how they allocate
1243 * an spi_master structure, prior to calling spi_register_master().
1245 * This must be called from context that can sleep. It returns the SPI
1246 * master structure on success, else NULL.
1248 * The caller is responsible for assigning the bus number and initializing
1249 * the master's methods before calling spi_register_master(); and (after errors
1250 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1253 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1255 struct spi_master *master;
1260 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1264 device_initialize(&master->dev);
1265 master->bus_num = -1;
1266 master->num_chipselect = 1;
1267 master->dev.class = &spi_master_class;
1268 master->dev.parent = get_device(dev);
1269 spi_master_set_devdata(master, &master[1]);
1273 EXPORT_SYMBOL_GPL(spi_alloc_master);
1276 static int of_spi_register_master(struct spi_master *master)
1279 struct device_node *np = master->dev.of_node;
1284 nb = of_gpio_named_count(np, "cs-gpios");
1285 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1287 /* Return error only for an incorrectly formed cs-gpios property */
1288 if (nb == 0 || nb == -ENOENT)
1293 cs = devm_kzalloc(&master->dev,
1294 sizeof(int) * master->num_chipselect,
1296 master->cs_gpios = cs;
1298 if (!master->cs_gpios)
1301 for (i = 0; i < master->num_chipselect; i++)
1304 for (i = 0; i < nb; i++)
1305 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1310 static int of_spi_register_master(struct spi_master *master)
1317 * spi_register_master - register SPI master controller
1318 * @master: initialized master, originally from spi_alloc_master()
1319 * Context: can sleep
1321 * SPI master controllers connect to their drivers using some non-SPI bus,
1322 * such as the platform bus. The final stage of probe() in that code
1323 * includes calling spi_register_master() to hook up to this SPI bus glue.
1325 * SPI controllers use board specific (often SOC specific) bus numbers,
1326 * and board-specific addressing for SPI devices combines those numbers
1327 * with chip select numbers. Since SPI does not directly support dynamic
1328 * device identification, boards need configuration tables telling which
1329 * chip is at which address.
1331 * This must be called from context that can sleep. It returns zero on
1332 * success, else a negative error code (dropping the master's refcount).
1333 * After a successful return, the caller is responsible for calling
1334 * spi_unregister_master().
1336 int spi_register_master(struct spi_master *master)
1338 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1339 struct device *dev = master->dev.parent;
1340 struct boardinfo *bi;
1341 int status = -ENODEV;
1347 status = of_spi_register_master(master);
1351 /* even if it's just one always-selected device, there must
1352 * be at least one chipselect
1354 if (master->num_chipselect == 0)
1357 if ((master->bus_num < 0) && master->dev.of_node)
1358 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1360 /* convention: dynamically assigned bus IDs count down from the max */
1361 if (master->bus_num < 0) {
1362 /* FIXME switch to an IDR based scheme, something like
1363 * I2C now uses, so we can't run out of "dynamic" IDs
1365 master->bus_num = atomic_dec_return(&dyn_bus_id);
1369 spin_lock_init(&master->bus_lock_spinlock);
1370 mutex_init(&master->bus_lock_mutex);
1371 master->bus_lock_flag = 0;
1372 init_completion(&master->xfer_completion);
1374 /* register the device, then userspace will see it.
1375 * registration fails if the bus ID is in use.
1377 dev_set_name(&master->dev, "spi%u", master->bus_num);
1378 status = device_add(&master->dev);
1381 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1382 dynamic ? " (dynamic)" : "");
1384 /* If we're using a queued driver, start the queue */
1385 if (master->transfer)
1386 dev_info(dev, "master is unqueued, this is deprecated\n");
1388 status = spi_master_initialize_queue(master);
1390 device_del(&master->dev);
1395 mutex_lock(&board_lock);
1396 list_add_tail(&master->list, &spi_master_list);
1397 list_for_each_entry(bi, &board_list, list)
1398 spi_match_master_to_boardinfo(master, &bi->board_info);
1399 mutex_unlock(&board_lock);
1401 /* Register devices from the device tree and ACPI */
1402 of_register_spi_devices(master);
1403 acpi_register_spi_devices(master);
1407 EXPORT_SYMBOL_GPL(spi_register_master);
1409 static void devm_spi_unregister(struct device *dev, void *res)
1411 spi_unregister_master(*(struct spi_master **)res);
1415 * dev_spi_register_master - register managed SPI master controller
1416 * @dev: device managing SPI master
1417 * @master: initialized master, originally from spi_alloc_master()
1418 * Context: can sleep
1420 * Register a SPI device as with spi_register_master() which will
1421 * automatically be unregister
1423 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1425 struct spi_master **ptr;
1428 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1432 ret = spi_register_master(master);
1435 devres_add(dev, ptr);
1442 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1444 static int __unregister(struct device *dev, void *null)
1446 spi_unregister_device(to_spi_device(dev));
1451 * spi_unregister_master - unregister SPI master controller
1452 * @master: the master being unregistered
1453 * Context: can sleep
1455 * This call is used only by SPI master controller drivers, which are the
1456 * only ones directly touching chip registers.
1458 * This must be called from context that can sleep.
1460 void spi_unregister_master(struct spi_master *master)
1464 if (master->queued) {
1465 if (spi_destroy_queue(master))
1466 dev_err(&master->dev, "queue remove failed\n");
1469 mutex_lock(&board_lock);
1470 list_del(&master->list);
1471 mutex_unlock(&board_lock);
1473 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1474 device_unregister(&master->dev);
1476 EXPORT_SYMBOL_GPL(spi_unregister_master);
1478 int spi_master_suspend(struct spi_master *master)
1482 /* Basically no-ops for non-queued masters */
1483 if (!master->queued)
1486 ret = spi_stop_queue(master);
1488 dev_err(&master->dev, "queue stop failed\n");
1492 EXPORT_SYMBOL_GPL(spi_master_suspend);
1494 int spi_master_resume(struct spi_master *master)
1498 if (!master->queued)
1501 ret = spi_start_queue(master);
1503 dev_err(&master->dev, "queue restart failed\n");
1507 EXPORT_SYMBOL_GPL(spi_master_resume);
1509 static int __spi_master_match(struct device *dev, const void *data)
1511 struct spi_master *m;
1512 const u16 *bus_num = data;
1514 m = container_of(dev, struct spi_master, dev);
1515 return m->bus_num == *bus_num;
1519 * spi_busnum_to_master - look up master associated with bus_num
1520 * @bus_num: the master's bus number
1521 * Context: can sleep
1523 * This call may be used with devices that are registered after
1524 * arch init time. It returns a refcounted pointer to the relevant
1525 * spi_master (which the caller must release), or NULL if there is
1526 * no such master registered.
1528 struct spi_master *spi_busnum_to_master(u16 bus_num)
1531 struct spi_master *master = NULL;
1533 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1534 __spi_master_match);
1536 master = container_of(dev, struct spi_master, dev);
1537 /* reference got in class_find_device */
1540 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1543 /*-------------------------------------------------------------------------*/
1545 /* Core methods for SPI master protocol drivers. Some of the
1546 * other core methods are currently defined as inline functions.
1550 * spi_setup - setup SPI mode and clock rate
1551 * @spi: the device whose settings are being modified
1552 * Context: can sleep, and no requests are queued to the device
1554 * SPI protocol drivers may need to update the transfer mode if the
1555 * device doesn't work with its default. They may likewise need
1556 * to update clock rates or word sizes from initial values. This function
1557 * changes those settings, and must be called from a context that can sleep.
1558 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1559 * effect the next time the device is selected and data is transferred to
1560 * or from it. When this function returns, the spi device is deselected.
1562 * Note that this call will fail if the protocol driver specifies an option
1563 * that the underlying controller or its driver does not support. For
1564 * example, not all hardware supports wire transfers using nine bit words,
1565 * LSB-first wire encoding, or active-high chipselects.
1567 int spi_setup(struct spi_device *spi)
1572 /* check mode to prevent that DUAL and QUAD set at the same time
1574 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1575 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1577 "setup: can not select dual and quad at the same time\n");
1580 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1582 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1583 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1585 /* help drivers fail *cleanly* when they need options
1586 * that aren't supported with their current master
1588 bad_bits = spi->mode & ~spi->master->mode_bits;
1590 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1595 if (!spi->bits_per_word)
1596 spi->bits_per_word = 8;
1598 if (spi->master->setup)
1599 status = spi->master->setup(spi);
1601 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1602 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1603 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1604 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1605 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1606 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1607 spi->bits_per_word, spi->max_speed_hz,
1612 EXPORT_SYMBOL_GPL(spi_setup);
1614 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1616 struct spi_master *master = spi->master;
1617 struct spi_transfer *xfer;
1620 if (list_empty(&message->transfers))
1623 /* Half-duplex links include original MicroWire, and ones with
1624 * only one data pin like SPI_3WIRE (switches direction) or where
1625 * either MOSI or MISO is missing. They can also be caused by
1626 * software limitations.
1628 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1629 || (spi->mode & SPI_3WIRE)) {
1630 unsigned flags = master->flags;
1632 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1633 if (xfer->rx_buf && xfer->tx_buf)
1635 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1637 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1643 * Set transfer bits_per_word and max speed as spi device default if
1644 * it is not set for this transfer.
1645 * Set transfer tx_nbits and rx_nbits as single transfer default
1646 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1648 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1649 message->frame_length += xfer->len;
1650 if (!xfer->bits_per_word)
1651 xfer->bits_per_word = spi->bits_per_word;
1653 if (!xfer->speed_hz)
1654 xfer->speed_hz = spi->max_speed_hz;
1656 if (master->max_speed_hz &&
1657 xfer->speed_hz > master->max_speed_hz)
1658 xfer->speed_hz = master->max_speed_hz;
1660 if (master->bits_per_word_mask) {
1661 /* Only 32 bits fit in the mask */
1662 if (xfer->bits_per_word > 32)
1664 if (!(master->bits_per_word_mask &
1665 BIT(xfer->bits_per_word - 1)))
1670 * SPI transfer length should be multiple of SPI word size
1671 * where SPI word size should be power-of-two multiple
1673 if (xfer->bits_per_word <= 8)
1675 else if (xfer->bits_per_word <= 16)
1680 /* No partial transfers accepted */
1681 if (xfer->len % w_size)
1684 if (xfer->speed_hz && master->min_speed_hz &&
1685 xfer->speed_hz < master->min_speed_hz)
1688 if (xfer->tx_buf && !xfer->tx_nbits)
1689 xfer->tx_nbits = SPI_NBITS_SINGLE;
1690 if (xfer->rx_buf && !xfer->rx_nbits)
1691 xfer->rx_nbits = SPI_NBITS_SINGLE;
1692 /* check transfer tx/rx_nbits:
1693 * 1. check the value matches one of single, dual and quad
1694 * 2. check tx/rx_nbits match the mode in spi_device
1697 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1698 xfer->tx_nbits != SPI_NBITS_DUAL &&
1699 xfer->tx_nbits != SPI_NBITS_QUAD)
1701 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1702 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1704 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1705 !(spi->mode & SPI_TX_QUAD))
1708 /* check transfer rx_nbits */
1710 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1711 xfer->rx_nbits != SPI_NBITS_DUAL &&
1712 xfer->rx_nbits != SPI_NBITS_QUAD)
1714 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1715 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1717 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1718 !(spi->mode & SPI_RX_QUAD))
1723 message->status = -EINPROGRESS;
1728 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1730 struct spi_master *master = spi->master;
1734 trace_spi_message_submit(message);
1736 return master->transfer(spi, message);
1740 * spi_async - asynchronous SPI transfer
1741 * @spi: device with which data will be exchanged
1742 * @message: describes the data transfers, including completion callback
1743 * Context: any (irqs may be blocked, etc)
1745 * This call may be used in_irq and other contexts which can't sleep,
1746 * as well as from task contexts which can sleep.
1748 * The completion callback is invoked in a context which can't sleep.
1749 * Before that invocation, the value of message->status is undefined.
1750 * When the callback is issued, message->status holds either zero (to
1751 * indicate complete success) or a negative error code. After that
1752 * callback returns, the driver which issued the transfer request may
1753 * deallocate the associated memory; it's no longer in use by any SPI
1754 * core or controller driver code.
1756 * Note that although all messages to a spi_device are handled in
1757 * FIFO order, messages may go to different devices in other orders.
1758 * Some device might be higher priority, or have various "hard" access
1759 * time requirements, for example.
1761 * On detection of any fault during the transfer, processing of
1762 * the entire message is aborted, and the device is deselected.
1763 * Until returning from the associated message completion callback,
1764 * no other spi_message queued to that device will be processed.
1765 * (This rule applies equally to all the synchronous transfer calls,
1766 * which are wrappers around this core asynchronous primitive.)
1768 int spi_async(struct spi_device *spi, struct spi_message *message)
1770 struct spi_master *master = spi->master;
1772 unsigned long flags;
1774 ret = __spi_validate(spi, message);
1778 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1780 if (master->bus_lock_flag)
1783 ret = __spi_async(spi, message);
1785 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1789 EXPORT_SYMBOL_GPL(spi_async);
1792 * spi_async_locked - version of spi_async with exclusive bus usage
1793 * @spi: device with which data will be exchanged
1794 * @message: describes the data transfers, including completion callback
1795 * Context: any (irqs may be blocked, etc)
1797 * This call may be used in_irq and other contexts which can't sleep,
1798 * as well as from task contexts which can sleep.
1800 * The completion callback is invoked in a context which can't sleep.
1801 * Before that invocation, the value of message->status is undefined.
1802 * When the callback is issued, message->status holds either zero (to
1803 * indicate complete success) or a negative error code. After that
1804 * callback returns, the driver which issued the transfer request may
1805 * deallocate the associated memory; it's no longer in use by any SPI
1806 * core or controller driver code.
1808 * Note that although all messages to a spi_device are handled in
1809 * FIFO order, messages may go to different devices in other orders.
1810 * Some device might be higher priority, or have various "hard" access
1811 * time requirements, for example.
1813 * On detection of any fault during the transfer, processing of
1814 * the entire message is aborted, and the device is deselected.
1815 * Until returning from the associated message completion callback,
1816 * no other spi_message queued to that device will be processed.
1817 * (This rule applies equally to all the synchronous transfer calls,
1818 * which are wrappers around this core asynchronous primitive.)
1820 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1822 struct spi_master *master = spi->master;
1824 unsigned long flags;
1826 ret = __spi_validate(spi, message);
1830 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1832 ret = __spi_async(spi, message);
1834 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1839 EXPORT_SYMBOL_GPL(spi_async_locked);
1842 /*-------------------------------------------------------------------------*/
1844 /* Utility methods for SPI master protocol drivers, layered on
1845 * top of the core. Some other utility methods are defined as
1849 static void spi_complete(void *arg)
1854 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1857 DECLARE_COMPLETION_ONSTACK(done);
1859 struct spi_master *master = spi->master;
1861 message->complete = spi_complete;
1862 message->context = &done;
1865 mutex_lock(&master->bus_lock_mutex);
1867 status = spi_async_locked(spi, message);
1870 mutex_unlock(&master->bus_lock_mutex);
1873 wait_for_completion(&done);
1874 status = message->status;
1876 message->context = NULL;
1881 * spi_sync - blocking/synchronous SPI data transfers
1882 * @spi: device with which data will be exchanged
1883 * @message: describes the data transfers
1884 * Context: can sleep
1886 * This call may only be used from a context that may sleep. The sleep
1887 * is non-interruptible, and has no timeout. Low-overhead controller
1888 * drivers may DMA directly into and out of the message buffers.
1890 * Note that the SPI device's chip select is active during the message,
1891 * and then is normally disabled between messages. Drivers for some
1892 * frequently-used devices may want to minimize costs of selecting a chip,
1893 * by leaving it selected in anticipation that the next message will go
1894 * to the same chip. (That may increase power usage.)
1896 * Also, the caller is guaranteeing that the memory associated with the
1897 * message will not be freed before this call returns.
1899 * It returns zero on success, else a negative error code.
1901 int spi_sync(struct spi_device *spi, struct spi_message *message)
1903 return __spi_sync(spi, message, 0);
1905 EXPORT_SYMBOL_GPL(spi_sync);
1908 * spi_sync_locked - version of spi_sync with exclusive bus usage
1909 * @spi: device with which data will be exchanged
1910 * @message: describes the data transfers
1911 * Context: can sleep
1913 * This call may only be used from a context that may sleep. The sleep
1914 * is non-interruptible, and has no timeout. Low-overhead controller
1915 * drivers may DMA directly into and out of the message buffers.
1917 * This call should be used by drivers that require exclusive access to the
1918 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1919 * be released by a spi_bus_unlock call when the exclusive access is over.
1921 * It returns zero on success, else a negative error code.
1923 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1925 return __spi_sync(spi, message, 1);
1927 EXPORT_SYMBOL_GPL(spi_sync_locked);
1930 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1931 * @master: SPI bus master that should be locked for exclusive bus access
1932 * Context: can sleep
1934 * This call may only be used from a context that may sleep. The sleep
1935 * is non-interruptible, and has no timeout.
1937 * This call should be used by drivers that require exclusive access to the
1938 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1939 * exclusive access is over. Data transfer must be done by spi_sync_locked
1940 * and spi_async_locked calls when the SPI bus lock is held.
1942 * It returns zero on success, else a negative error code.
1944 int spi_bus_lock(struct spi_master *master)
1946 unsigned long flags;
1948 mutex_lock(&master->bus_lock_mutex);
1950 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1951 master->bus_lock_flag = 1;
1952 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1954 /* mutex remains locked until spi_bus_unlock is called */
1958 EXPORT_SYMBOL_GPL(spi_bus_lock);
1961 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1962 * @master: SPI bus master that was locked for exclusive bus access
1963 * Context: can sleep
1965 * This call may only be used from a context that may sleep. The sleep
1966 * is non-interruptible, and has no timeout.
1968 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1971 * It returns zero on success, else a negative error code.
1973 int spi_bus_unlock(struct spi_master *master)
1975 master->bus_lock_flag = 0;
1977 mutex_unlock(&master->bus_lock_mutex);
1981 EXPORT_SYMBOL_GPL(spi_bus_unlock);
1983 /* portable code must never pass more than 32 bytes */
1984 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
1989 * spi_write_then_read - SPI synchronous write followed by read
1990 * @spi: device with which data will be exchanged
1991 * @txbuf: data to be written (need not be dma-safe)
1992 * @n_tx: size of txbuf, in bytes
1993 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1994 * @n_rx: size of rxbuf, in bytes
1995 * Context: can sleep
1997 * This performs a half duplex MicroWire style transaction with the
1998 * device, sending txbuf and then reading rxbuf. The return value
1999 * is zero for success, else a negative errno status code.
2000 * This call may only be used from a context that may sleep.
2002 * Parameters to this routine are always copied using a small buffer;
2003 * portable code should never use this for more than 32 bytes.
2004 * Performance-sensitive or bulk transfer code should instead use
2005 * spi_{async,sync}() calls with dma-safe buffers.
2007 int spi_write_then_read(struct spi_device *spi,
2008 const void *txbuf, unsigned n_tx,
2009 void *rxbuf, unsigned n_rx)
2011 static DEFINE_MUTEX(lock);
2014 struct spi_message message;
2015 struct spi_transfer x[2];
2018 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2019 * copying here, (as a pure convenience thing), but we can
2020 * keep heap costs out of the hot path unless someone else is
2021 * using the pre-allocated buffer or the transfer is too large.
2023 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2024 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2025 GFP_KERNEL | GFP_DMA);
2032 spi_message_init(&message);
2033 memset(x, 0, sizeof(x));
2036 spi_message_add_tail(&x[0], &message);
2040 spi_message_add_tail(&x[1], &message);
2043 memcpy(local_buf, txbuf, n_tx);
2044 x[0].tx_buf = local_buf;
2045 x[1].rx_buf = local_buf + n_tx;
2048 status = spi_sync(spi, &message);
2050 memcpy(rxbuf, x[1].rx_buf, n_rx);
2052 if (x[0].tx_buf == buf)
2053 mutex_unlock(&lock);
2059 EXPORT_SYMBOL_GPL(spi_write_then_read);
2061 /*-------------------------------------------------------------------------*/
2063 static int __init spi_init(void)
2067 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2073 status = bus_register(&spi_bus_type);
2077 status = class_register(&spi_master_class);
2083 bus_unregister(&spi_bus_type);
2091 /* board_info is normally registered in arch_initcall(),
2092 * but even essential drivers wait till later
2094 * REVISIT only boardinfo really needs static linking. the rest (device and
2095 * driver registration) _could_ be dynamically linked (modular) ... costs
2096 * include needing to have boardinfo data structures be much more public.
2098 postcore_initcall(spi_init);