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);
65 static struct device_attribute spi_dev_attrs[] = {
70 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
71 * and the sysfs version makes coldplug work too.
74 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
75 const struct spi_device *sdev)
78 if (!strcmp(sdev->modalias, id->name))
85 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
87 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
89 return spi_match_id(sdrv->id_table, sdev);
91 EXPORT_SYMBOL_GPL(spi_get_device_id);
93 static int spi_match_device(struct device *dev, struct device_driver *drv)
95 const struct spi_device *spi = to_spi_device(dev);
96 const struct spi_driver *sdrv = to_spi_driver(drv);
98 /* Attempt an OF style match */
99 if (of_driver_match_device(dev, drv))
103 if (acpi_driver_match_device(dev, drv))
107 return !!spi_match_id(sdrv->id_table, spi);
109 return strcmp(spi->modalias, drv->name) == 0;
112 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
114 const struct spi_device *spi = to_spi_device(dev);
116 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
120 #ifdef CONFIG_PM_SLEEP
121 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
124 struct spi_driver *drv = to_spi_driver(dev->driver);
126 /* suspend will stop irqs and dma; no more i/o */
129 value = drv->suspend(to_spi_device(dev), message);
131 dev_dbg(dev, "... can't suspend\n");
136 static int spi_legacy_resume(struct device *dev)
139 struct spi_driver *drv = to_spi_driver(dev->driver);
141 /* resume may restart the i/o queue */
144 value = drv->resume(to_spi_device(dev));
146 dev_dbg(dev, "... can't resume\n");
151 static int spi_pm_suspend(struct device *dev)
153 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
156 return pm_generic_suspend(dev);
158 return spi_legacy_suspend(dev, PMSG_SUSPEND);
161 static int spi_pm_resume(struct device *dev)
163 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
166 return pm_generic_resume(dev);
168 return spi_legacy_resume(dev);
171 static int spi_pm_freeze(struct device *dev)
173 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
176 return pm_generic_freeze(dev);
178 return spi_legacy_suspend(dev, PMSG_FREEZE);
181 static int spi_pm_thaw(struct device *dev)
183 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
186 return pm_generic_thaw(dev);
188 return spi_legacy_resume(dev);
191 static int spi_pm_poweroff(struct device *dev)
193 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
196 return pm_generic_poweroff(dev);
198 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
201 static int spi_pm_restore(struct device *dev)
203 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
206 return pm_generic_restore(dev);
208 return spi_legacy_resume(dev);
211 #define spi_pm_suspend NULL
212 #define spi_pm_resume NULL
213 #define spi_pm_freeze NULL
214 #define spi_pm_thaw NULL
215 #define spi_pm_poweroff NULL
216 #define spi_pm_restore NULL
219 static const struct dev_pm_ops spi_pm = {
220 .suspend = spi_pm_suspend,
221 .resume = spi_pm_resume,
222 .freeze = spi_pm_freeze,
224 .poweroff = spi_pm_poweroff,
225 .restore = spi_pm_restore,
227 pm_generic_runtime_suspend,
228 pm_generic_runtime_resume,
233 struct bus_type spi_bus_type = {
235 .dev_attrs = spi_dev_attrs,
236 .match = spi_match_device,
237 .uevent = spi_uevent,
240 EXPORT_SYMBOL_GPL(spi_bus_type);
243 static int spi_drv_probe(struct device *dev)
245 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
247 return sdrv->probe(to_spi_device(dev));
250 static int spi_drv_remove(struct device *dev)
252 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
254 return sdrv->remove(to_spi_device(dev));
257 static void spi_drv_shutdown(struct device *dev)
259 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
261 sdrv->shutdown(to_spi_device(dev));
265 * spi_register_driver - register a SPI driver
266 * @sdrv: the driver to register
269 int spi_register_driver(struct spi_driver *sdrv)
271 sdrv->driver.bus = &spi_bus_type;
273 sdrv->driver.probe = spi_drv_probe;
275 sdrv->driver.remove = spi_drv_remove;
277 sdrv->driver.shutdown = spi_drv_shutdown;
278 return driver_register(&sdrv->driver);
280 EXPORT_SYMBOL_GPL(spi_register_driver);
282 /*-------------------------------------------------------------------------*/
284 /* SPI devices should normally not be created by SPI device drivers; that
285 * would make them board-specific. Similarly with SPI master drivers.
286 * Device registration normally goes into like arch/.../mach.../board-YYY.c
287 * with other readonly (flashable) information about mainboard devices.
291 struct list_head list;
292 struct spi_board_info board_info;
295 static LIST_HEAD(board_list);
296 static LIST_HEAD(spi_master_list);
299 * Used to protect add/del opertion for board_info list and
300 * spi_master list, and their matching process
302 static DEFINE_MUTEX(board_lock);
305 * spi_alloc_device - Allocate a new SPI device
306 * @master: Controller to which device is connected
309 * Allows a driver to allocate and initialize a spi_device without
310 * registering it immediately. This allows a driver to directly
311 * fill the spi_device with device parameters before calling
312 * spi_add_device() on it.
314 * Caller is responsible to call spi_add_device() on the returned
315 * spi_device structure to add it to the SPI master. If the caller
316 * needs to discard the spi_device without adding it, then it should
317 * call spi_dev_put() on it.
319 * Returns a pointer to the new device, or NULL.
321 struct spi_device *spi_alloc_device(struct spi_master *master)
323 struct spi_device *spi;
324 struct device *dev = master->dev.parent;
326 if (!spi_master_get(master))
329 spi = kzalloc(sizeof *spi, GFP_KERNEL);
331 dev_err(dev, "cannot alloc spi_device\n");
332 spi_master_put(master);
336 spi->master = master;
337 spi->dev.parent = &master->dev;
338 spi->dev.bus = &spi_bus_type;
339 spi->dev.release = spidev_release;
340 spi->cs_gpio = -ENOENT;
341 device_initialize(&spi->dev);
344 EXPORT_SYMBOL_GPL(spi_alloc_device);
347 * spi_add_device - Add spi_device allocated with spi_alloc_device
348 * @spi: spi_device to register
350 * Companion function to spi_alloc_device. Devices allocated with
351 * spi_alloc_device can be added onto the spi bus with this function.
353 * Returns 0 on success; negative errno on failure
355 int spi_add_device(struct spi_device *spi)
357 static DEFINE_MUTEX(spi_add_lock);
358 struct spi_master *master = spi->master;
359 struct device *dev = master->dev.parent;
363 /* Chipselects are numbered 0..max; validate. */
364 if (spi->chip_select >= master->num_chipselect) {
365 dev_err(dev, "cs%d >= max %d\n",
367 master->num_chipselect);
371 /* Set the bus ID string */
372 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
376 /* We need to make sure there's no other device with this
377 * chipselect **BEFORE** we call setup(), else we'll trash
378 * its configuration. Lock against concurrent add() calls.
380 mutex_lock(&spi_add_lock);
382 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
384 dev_err(dev, "chipselect %d already in use\n",
391 if (master->cs_gpios)
392 spi->cs_gpio = master->cs_gpios[spi->chip_select];
394 /* Drivers may modify this initial i/o setup, but will
395 * normally rely on the device being setup. Devices
396 * using SPI_CS_HIGH can't coexist well otherwise...
398 status = spi_setup(spi);
400 dev_err(dev, "can't setup %s, status %d\n",
401 dev_name(&spi->dev), status);
405 /* Device may be bound to an active driver when this returns */
406 status = device_add(&spi->dev);
408 dev_err(dev, "can't add %s, status %d\n",
409 dev_name(&spi->dev), status);
411 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
414 mutex_unlock(&spi_add_lock);
417 EXPORT_SYMBOL_GPL(spi_add_device);
420 * spi_new_device - instantiate one new SPI device
421 * @master: Controller to which device is connected
422 * @chip: Describes the SPI device
425 * On typical mainboards, this is purely internal; and it's not needed
426 * after board init creates the hard-wired devices. Some development
427 * platforms may not be able to use spi_register_board_info though, and
428 * this is exported so that for example a USB or parport based adapter
429 * driver could add devices (which it would learn about out-of-band).
431 * Returns the new device, or NULL.
433 struct spi_device *spi_new_device(struct spi_master *master,
434 struct spi_board_info *chip)
436 struct spi_device *proxy;
439 /* NOTE: caller did any chip->bus_num checks necessary.
441 * Also, unless we change the return value convention to use
442 * error-or-pointer (not NULL-or-pointer), troubleshootability
443 * suggests syslogged diagnostics are best here (ugh).
446 proxy = spi_alloc_device(master);
450 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
452 proxy->chip_select = chip->chip_select;
453 proxy->max_speed_hz = chip->max_speed_hz;
454 proxy->mode = chip->mode;
455 proxy->irq = chip->irq;
456 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
457 proxy->dev.platform_data = (void *) chip->platform_data;
458 proxy->controller_data = chip->controller_data;
459 proxy->controller_state = NULL;
461 status = spi_add_device(proxy);
469 EXPORT_SYMBOL_GPL(spi_new_device);
471 static void spi_match_master_to_boardinfo(struct spi_master *master,
472 struct spi_board_info *bi)
474 struct spi_device *dev;
476 if (master->bus_num != bi->bus_num)
479 dev = spi_new_device(master, bi);
481 dev_err(master->dev.parent, "can't create new device for %s\n",
486 * spi_register_board_info - register SPI devices for a given board
487 * @info: array of chip descriptors
488 * @n: how many descriptors are provided
491 * Board-specific early init code calls this (probably during arch_initcall)
492 * with segments of the SPI device table. Any device nodes are created later,
493 * after the relevant parent SPI controller (bus_num) is defined. We keep
494 * this table of devices forever, so that reloading a controller driver will
495 * not make Linux forget about these hard-wired devices.
497 * Other code can also call this, e.g. a particular add-on board might provide
498 * SPI devices through its expansion connector, so code initializing that board
499 * would naturally declare its SPI devices.
501 * The board info passed can safely be __initdata ... but be careful of
502 * any embedded pointers (platform_data, etc), they're copied as-is.
504 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
506 struct boardinfo *bi;
509 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
513 for (i = 0; i < n; i++, bi++, info++) {
514 struct spi_master *master;
516 memcpy(&bi->board_info, info, sizeof(*info));
517 mutex_lock(&board_lock);
518 list_add_tail(&bi->list, &board_list);
519 list_for_each_entry(master, &spi_master_list, list)
520 spi_match_master_to_boardinfo(master, &bi->board_info);
521 mutex_unlock(&board_lock);
527 /*-------------------------------------------------------------------------*/
529 static void spi_set_cs(struct spi_device *spi, bool enable)
531 if (spi->mode & SPI_CS_HIGH)
534 if (spi->cs_gpio >= 0)
535 gpio_set_value(spi->cs_gpio, !enable);
536 else if (spi->master->set_cs)
537 spi->master->set_cs(spi, !enable);
541 * spi_transfer_one_message - Default implementation of transfer_one_message()
543 * This is a standard implementation of transfer_one_message() for
544 * drivers which impelment a transfer_one() operation. It provides
545 * standard handling of delays and chip select management.
547 static int spi_transfer_one_message(struct spi_master *master,
548 struct spi_message *msg)
550 struct spi_transfer *xfer;
552 bool keep_cs = false;
555 spi_set_cs(msg->spi, true);
557 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
558 trace_spi_transfer_start(msg, xfer);
560 INIT_COMPLETION(master->xfer_completion);
562 ret = master->transfer_one(master, msg->spi, xfer);
564 dev_err(&msg->spi->dev,
565 "SPI transfer failed: %d\n", ret);
570 wait_for_completion(&master->xfer_completion);
572 trace_spi_transfer_stop(msg, xfer);
574 if (msg->status != -EINPROGRESS)
577 if (xfer->delay_usecs)
578 udelay(xfer->delay_usecs);
580 if (xfer->cs_change) {
581 if (list_is_last(&xfer->transfer_list,
586 spi_set_cs(msg->spi, cur_cs);
590 msg->actual_length += xfer->len;
594 if (ret != 0 || !keep_cs)
595 spi_set_cs(msg->spi, false);
597 if (msg->status == -EINPROGRESS)
600 spi_finalize_current_message(master);
606 * spi_finalize_current_transfer - report completion of a transfer
608 * Called by SPI drivers using the core transfer_one_message()
609 * implementation to notify it that the current interrupt driven
610 * transfer has finised and the next one may be scheduled.
612 void spi_finalize_current_transfer(struct spi_master *master)
614 complete(&master->xfer_completion);
616 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
619 * spi_pump_messages - kthread work function which processes spi message queue
620 * @work: pointer to kthread work struct contained in the master struct
622 * This function checks if there is any spi message in the queue that
623 * needs processing and if so call out to the driver to initialize hardware
624 * and transfer each message.
627 static void spi_pump_messages(struct kthread_work *work)
629 struct spi_master *master =
630 container_of(work, struct spi_master, pump_messages);
632 bool was_busy = false;
635 /* Lock queue and check for queue work */
636 spin_lock_irqsave(&master->queue_lock, flags);
637 if (list_empty(&master->queue) || !master->running) {
639 spin_unlock_irqrestore(&master->queue_lock, flags);
642 master->busy = false;
643 spin_unlock_irqrestore(&master->queue_lock, flags);
644 if (master->unprepare_transfer_hardware &&
645 master->unprepare_transfer_hardware(master))
646 dev_err(&master->dev,
647 "failed to unprepare transfer hardware\n");
648 if (master->auto_runtime_pm) {
649 pm_runtime_mark_last_busy(master->dev.parent);
650 pm_runtime_put_autosuspend(master->dev.parent);
652 trace_spi_master_idle(master);
656 /* Make sure we are not already running a message */
657 if (master->cur_msg) {
658 spin_unlock_irqrestore(&master->queue_lock, flags);
661 /* Extract head of queue */
663 list_entry(master->queue.next, struct spi_message, queue);
665 list_del_init(&master->cur_msg->queue);
670 spin_unlock_irqrestore(&master->queue_lock, flags);
672 if (!was_busy && master->auto_runtime_pm) {
673 ret = pm_runtime_get_sync(master->dev.parent);
675 dev_err(&master->dev, "Failed to power device: %d\n",
682 trace_spi_master_busy(master);
684 if (!was_busy && master->prepare_transfer_hardware) {
685 ret = master->prepare_transfer_hardware(master);
687 dev_err(&master->dev,
688 "failed to prepare transfer hardware\n");
690 if (master->auto_runtime_pm)
691 pm_runtime_put(master->dev.parent);
696 trace_spi_message_start(master->cur_msg);
698 if (master->prepare_message) {
699 ret = master->prepare_message(master, master->cur_msg);
701 dev_err(&master->dev,
702 "failed to prepare message: %d\n", ret);
703 master->cur_msg->status = ret;
704 spi_finalize_current_message(master);
707 master->cur_msg_prepared = true;
710 ret = master->transfer_one_message(master, master->cur_msg);
712 dev_err(&master->dev,
713 "failed to transfer one message from queue\n");
718 static int spi_init_queue(struct spi_master *master)
720 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
722 INIT_LIST_HEAD(&master->queue);
723 spin_lock_init(&master->queue_lock);
725 master->running = false;
726 master->busy = false;
728 init_kthread_worker(&master->kworker);
729 master->kworker_task = kthread_run(kthread_worker_fn,
730 &master->kworker, "%s",
731 dev_name(&master->dev));
732 if (IS_ERR(master->kworker_task)) {
733 dev_err(&master->dev, "failed to create message pump task\n");
736 init_kthread_work(&master->pump_messages, spi_pump_messages);
739 * Master config will indicate if this controller should run the
740 * message pump with high (realtime) priority to reduce the transfer
741 * latency on the bus by minimising the delay between a transfer
742 * request and the scheduling of the message pump thread. Without this
743 * setting the message pump thread will remain at default priority.
746 dev_info(&master->dev,
747 "will run message pump with realtime priority\n");
748 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
755 * spi_get_next_queued_message() - called by driver to check for queued
757 * @master: the master to check for queued messages
759 * If there are more messages in the queue, the next message is returned from
762 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
764 struct spi_message *next;
767 /* get a pointer to the next message, if any */
768 spin_lock_irqsave(&master->queue_lock, flags);
769 if (list_empty(&master->queue))
772 next = list_entry(master->queue.next,
773 struct spi_message, queue);
774 spin_unlock_irqrestore(&master->queue_lock, flags);
778 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
781 * spi_finalize_current_message() - the current message is complete
782 * @master: the master to return the message to
784 * Called by the driver to notify the core that the message in the front of the
785 * queue is complete and can be removed from the queue.
787 void spi_finalize_current_message(struct spi_master *master)
789 struct spi_message *mesg;
793 spin_lock_irqsave(&master->queue_lock, flags);
794 mesg = master->cur_msg;
795 master->cur_msg = NULL;
797 queue_kthread_work(&master->kworker, &master->pump_messages);
798 spin_unlock_irqrestore(&master->queue_lock, flags);
800 if (master->cur_msg_prepared && master->unprepare_message) {
801 ret = master->unprepare_message(master, mesg);
803 dev_err(&master->dev,
804 "failed to unprepare message: %d\n", ret);
807 master->cur_msg_prepared = false;
811 mesg->complete(mesg->context);
813 trace_spi_message_done(mesg);
815 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
817 static int spi_start_queue(struct spi_master *master)
821 spin_lock_irqsave(&master->queue_lock, flags);
823 if (master->running || master->busy) {
824 spin_unlock_irqrestore(&master->queue_lock, flags);
828 master->running = true;
829 master->cur_msg = NULL;
830 spin_unlock_irqrestore(&master->queue_lock, flags);
832 queue_kthread_work(&master->kworker, &master->pump_messages);
837 static int spi_stop_queue(struct spi_master *master)
840 unsigned limit = 500;
843 spin_lock_irqsave(&master->queue_lock, flags);
846 * This is a bit lame, but is optimized for the common execution path.
847 * A wait_queue on the master->busy could be used, but then the common
848 * execution path (pump_messages) would be required to call wake_up or
849 * friends on every SPI message. Do this instead.
851 while ((!list_empty(&master->queue) || master->busy) && limit--) {
852 spin_unlock_irqrestore(&master->queue_lock, flags);
854 spin_lock_irqsave(&master->queue_lock, flags);
857 if (!list_empty(&master->queue) || master->busy)
860 master->running = false;
862 spin_unlock_irqrestore(&master->queue_lock, flags);
865 dev_warn(&master->dev,
866 "could not stop message queue\n");
872 static int spi_destroy_queue(struct spi_master *master)
876 ret = spi_stop_queue(master);
879 * flush_kthread_worker will block until all work is done.
880 * If the reason that stop_queue timed out is that the work will never
881 * finish, then it does no good to call flush/stop thread, so
885 dev_err(&master->dev, "problem destroying queue\n");
889 flush_kthread_worker(&master->kworker);
890 kthread_stop(master->kworker_task);
896 * spi_queued_transfer - transfer function for queued transfers
897 * @spi: spi device which is requesting transfer
898 * @msg: spi message which is to handled is queued to driver queue
900 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
902 struct spi_master *master = spi->master;
905 spin_lock_irqsave(&master->queue_lock, flags);
907 if (!master->running) {
908 spin_unlock_irqrestore(&master->queue_lock, flags);
911 msg->actual_length = 0;
912 msg->status = -EINPROGRESS;
914 list_add_tail(&msg->queue, &master->queue);
916 queue_kthread_work(&master->kworker, &master->pump_messages);
918 spin_unlock_irqrestore(&master->queue_lock, flags);
922 static int spi_master_initialize_queue(struct spi_master *master)
926 master->queued = true;
927 master->transfer = spi_queued_transfer;
928 if (!master->transfer_one_message)
929 master->transfer_one_message = spi_transfer_one_message;
931 /* Initialize and start queue */
932 ret = spi_init_queue(master);
934 dev_err(&master->dev, "problem initializing queue\n");
937 ret = spi_start_queue(master);
939 dev_err(&master->dev, "problem starting queue\n");
940 goto err_start_queue;
947 spi_destroy_queue(master);
951 /*-------------------------------------------------------------------------*/
953 #if defined(CONFIG_OF)
955 * of_register_spi_devices() - Register child devices onto the SPI bus
956 * @master: Pointer to spi_master device
958 * Registers an spi_device for each child node of master node which has a 'reg'
961 static void of_register_spi_devices(struct spi_master *master)
963 struct spi_device *spi;
964 struct device_node *nc;
966 char modalias[SPI_NAME_SIZE + 4];
970 if (!master->dev.of_node)
973 for_each_available_child_of_node(master->dev.of_node, nc) {
974 /* Alloc an spi_device */
975 spi = spi_alloc_device(master);
977 dev_err(&master->dev, "spi_device alloc error for %s\n",
983 /* Select device driver */
984 if (of_modalias_node(nc, spi->modalias,
985 sizeof(spi->modalias)) < 0) {
986 dev_err(&master->dev, "cannot find modalias for %s\n",
993 prop = of_get_property(nc, "reg", &len);
994 if (!prop || len < sizeof(*prop)) {
995 dev_err(&master->dev, "%s has no 'reg' property\n",
1000 spi->chip_select = be32_to_cpup(prop);
1002 /* Mode (clock phase/polarity/etc.) */
1003 if (of_find_property(nc, "spi-cpha", NULL))
1004 spi->mode |= SPI_CPHA;
1005 if (of_find_property(nc, "spi-cpol", NULL))
1006 spi->mode |= SPI_CPOL;
1007 if (of_find_property(nc, "spi-cs-high", NULL))
1008 spi->mode |= SPI_CS_HIGH;
1009 if (of_find_property(nc, "spi-3wire", NULL))
1010 spi->mode |= SPI_3WIRE;
1012 /* Device DUAL/QUAD mode */
1013 prop = of_get_property(nc, "spi-tx-bus-width", &len);
1014 if (prop && len == sizeof(*prop)) {
1015 switch (be32_to_cpup(prop)) {
1016 case SPI_NBITS_SINGLE:
1018 case SPI_NBITS_DUAL:
1019 spi->mode |= SPI_TX_DUAL;
1021 case SPI_NBITS_QUAD:
1022 spi->mode |= SPI_TX_QUAD;
1025 dev_err(&master->dev,
1026 "spi-tx-bus-width %d not supported\n",
1027 be32_to_cpup(prop));
1033 prop = of_get_property(nc, "spi-rx-bus-width", &len);
1034 if (prop && len == sizeof(*prop)) {
1035 switch (be32_to_cpup(prop)) {
1036 case SPI_NBITS_SINGLE:
1038 case SPI_NBITS_DUAL:
1039 spi->mode |= SPI_RX_DUAL;
1041 case SPI_NBITS_QUAD:
1042 spi->mode |= SPI_RX_QUAD;
1045 dev_err(&master->dev,
1046 "spi-rx-bus-width %d not supported\n",
1047 be32_to_cpup(prop));
1054 prop = of_get_property(nc, "spi-max-frequency", &len);
1055 if (!prop || len < sizeof(*prop)) {
1056 dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
1061 spi->max_speed_hz = be32_to_cpup(prop);
1064 spi->irq = irq_of_parse_and_map(nc, 0);
1066 /* Store a pointer to the node in the device structure */
1068 spi->dev.of_node = nc;
1070 /* Register the new device */
1071 snprintf(modalias, sizeof(modalias), "%s%s", SPI_MODULE_PREFIX,
1073 request_module(modalias);
1074 rc = spi_add_device(spi);
1076 dev_err(&master->dev, "spi_device register error %s\n",
1084 static void of_register_spi_devices(struct spi_master *master) { }
1088 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1090 struct spi_device *spi = data;
1092 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1093 struct acpi_resource_spi_serialbus *sb;
1095 sb = &ares->data.spi_serial_bus;
1096 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1097 spi->chip_select = sb->device_selection;
1098 spi->max_speed_hz = sb->connection_speed;
1100 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1101 spi->mode |= SPI_CPHA;
1102 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1103 spi->mode |= SPI_CPOL;
1104 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1105 spi->mode |= SPI_CS_HIGH;
1107 } else if (spi->irq < 0) {
1110 if (acpi_dev_resource_interrupt(ares, 0, &r))
1114 /* Always tell the ACPI core to skip this resource */
1118 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1119 void *data, void **return_value)
1121 struct spi_master *master = data;
1122 struct list_head resource_list;
1123 struct acpi_device *adev;
1124 struct spi_device *spi;
1127 if (acpi_bus_get_device(handle, &adev))
1129 if (acpi_bus_get_status(adev) || !adev->status.present)
1132 spi = spi_alloc_device(master);
1134 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1135 dev_name(&adev->dev));
1136 return AE_NO_MEMORY;
1139 ACPI_HANDLE_SET(&spi->dev, handle);
1142 INIT_LIST_HEAD(&resource_list);
1143 ret = acpi_dev_get_resources(adev, &resource_list,
1144 acpi_spi_add_resource, spi);
1145 acpi_dev_free_resource_list(&resource_list);
1147 if (ret < 0 || !spi->max_speed_hz) {
1152 strlcpy(spi->modalias, dev_name(&adev->dev), sizeof(spi->modalias));
1153 if (spi_add_device(spi)) {
1154 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1155 dev_name(&adev->dev));
1162 static void acpi_register_spi_devices(struct spi_master *master)
1167 handle = ACPI_HANDLE(master->dev.parent);
1171 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1172 acpi_spi_add_device, NULL,
1174 if (ACPI_FAILURE(status))
1175 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1178 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1179 #endif /* CONFIG_ACPI */
1181 static void spi_master_release(struct device *dev)
1183 struct spi_master *master;
1185 master = container_of(dev, struct spi_master, dev);
1189 static struct class spi_master_class = {
1190 .name = "spi_master",
1191 .owner = THIS_MODULE,
1192 .dev_release = spi_master_release,
1198 * spi_alloc_master - allocate SPI master controller
1199 * @dev: the controller, possibly using the platform_bus
1200 * @size: how much zeroed driver-private data to allocate; the pointer to this
1201 * memory is in the driver_data field of the returned device,
1202 * accessible with spi_master_get_devdata().
1203 * Context: can sleep
1205 * This call is used only by SPI master controller drivers, which are the
1206 * only ones directly touching chip registers. It's how they allocate
1207 * an spi_master structure, prior to calling spi_register_master().
1209 * This must be called from context that can sleep. It returns the SPI
1210 * master structure on success, else NULL.
1212 * The caller is responsible for assigning the bus number and initializing
1213 * the master's methods before calling spi_register_master(); and (after errors
1214 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1217 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1219 struct spi_master *master;
1224 master = kzalloc(size + sizeof *master, GFP_KERNEL);
1228 device_initialize(&master->dev);
1229 master->bus_num = -1;
1230 master->num_chipselect = 1;
1231 master->dev.class = &spi_master_class;
1232 master->dev.parent = get_device(dev);
1233 spi_master_set_devdata(master, &master[1]);
1237 EXPORT_SYMBOL_GPL(spi_alloc_master);
1240 static int of_spi_register_master(struct spi_master *master)
1243 struct device_node *np = master->dev.of_node;
1248 nb = of_gpio_named_count(np, "cs-gpios");
1249 master->num_chipselect = max(nb, (int)master->num_chipselect);
1251 /* Return error only for an incorrectly formed cs-gpios property */
1252 if (nb == 0 || nb == -ENOENT)
1257 cs = devm_kzalloc(&master->dev,
1258 sizeof(int) * master->num_chipselect,
1260 master->cs_gpios = cs;
1262 if (!master->cs_gpios)
1265 for (i = 0; i < master->num_chipselect; i++)
1268 for (i = 0; i < nb; i++)
1269 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1274 static int of_spi_register_master(struct spi_master *master)
1281 * spi_register_master - register SPI master controller
1282 * @master: initialized master, originally from spi_alloc_master()
1283 * Context: can sleep
1285 * SPI master controllers connect to their drivers using some non-SPI bus,
1286 * such as the platform bus. The final stage of probe() in that code
1287 * includes calling spi_register_master() to hook up to this SPI bus glue.
1289 * SPI controllers use board specific (often SOC specific) bus numbers,
1290 * and board-specific addressing for SPI devices combines those numbers
1291 * with chip select numbers. Since SPI does not directly support dynamic
1292 * device identification, boards need configuration tables telling which
1293 * chip is at which address.
1295 * This must be called from context that can sleep. It returns zero on
1296 * success, else a negative error code (dropping the master's refcount).
1297 * After a successful return, the caller is responsible for calling
1298 * spi_unregister_master().
1300 int spi_register_master(struct spi_master *master)
1302 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1303 struct device *dev = master->dev.parent;
1304 struct boardinfo *bi;
1305 int status = -ENODEV;
1311 status = of_spi_register_master(master);
1315 /* even if it's just one always-selected device, there must
1316 * be at least one chipselect
1318 if (master->num_chipselect == 0)
1321 if ((master->bus_num < 0) && master->dev.of_node)
1322 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1324 /* convention: dynamically assigned bus IDs count down from the max */
1325 if (master->bus_num < 0) {
1326 /* FIXME switch to an IDR based scheme, something like
1327 * I2C now uses, so we can't run out of "dynamic" IDs
1329 master->bus_num = atomic_dec_return(&dyn_bus_id);
1333 spin_lock_init(&master->bus_lock_spinlock);
1334 mutex_init(&master->bus_lock_mutex);
1335 master->bus_lock_flag = 0;
1336 init_completion(&master->xfer_completion);
1338 /* register the device, then userspace will see it.
1339 * registration fails if the bus ID is in use.
1341 dev_set_name(&master->dev, "spi%u", master->bus_num);
1342 status = device_add(&master->dev);
1345 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1346 dynamic ? " (dynamic)" : "");
1348 /* If we're using a queued driver, start the queue */
1349 if (master->transfer)
1350 dev_info(dev, "master is unqueued, this is deprecated\n");
1352 status = spi_master_initialize_queue(master);
1354 device_del(&master->dev);
1359 mutex_lock(&board_lock);
1360 list_add_tail(&master->list, &spi_master_list);
1361 list_for_each_entry(bi, &board_list, list)
1362 spi_match_master_to_boardinfo(master, &bi->board_info);
1363 mutex_unlock(&board_lock);
1365 /* Register devices from the device tree and ACPI */
1366 of_register_spi_devices(master);
1367 acpi_register_spi_devices(master);
1371 EXPORT_SYMBOL_GPL(spi_register_master);
1373 static void devm_spi_unregister(struct device *dev, void *res)
1375 spi_unregister_master(*(struct spi_master **)res);
1379 * dev_spi_register_master - register managed SPI master controller
1380 * @dev: device managing SPI master
1381 * @master: initialized master, originally from spi_alloc_master()
1382 * Context: can sleep
1384 * Register a SPI device as with spi_register_master() which will
1385 * automatically be unregister
1387 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1389 struct spi_master **ptr;
1392 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1396 ret = spi_register_master(master);
1399 devres_add(dev, ptr);
1406 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1408 static int __unregister(struct device *dev, void *null)
1410 spi_unregister_device(to_spi_device(dev));
1415 * spi_unregister_master - unregister SPI master controller
1416 * @master: the master being unregistered
1417 * Context: can sleep
1419 * This call is used only by SPI master controller drivers, which are the
1420 * only ones directly touching chip registers.
1422 * This must be called from context that can sleep.
1424 void spi_unregister_master(struct spi_master *master)
1428 if (master->queued) {
1429 if (spi_destroy_queue(master))
1430 dev_err(&master->dev, "queue remove failed\n");
1433 mutex_lock(&board_lock);
1434 list_del(&master->list);
1435 mutex_unlock(&board_lock);
1437 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1438 device_unregister(&master->dev);
1440 EXPORT_SYMBOL_GPL(spi_unregister_master);
1442 int spi_master_suspend(struct spi_master *master)
1446 /* Basically no-ops for non-queued masters */
1447 if (!master->queued)
1450 ret = spi_stop_queue(master);
1452 dev_err(&master->dev, "queue stop failed\n");
1456 EXPORT_SYMBOL_GPL(spi_master_suspend);
1458 int spi_master_resume(struct spi_master *master)
1462 if (!master->queued)
1465 ret = spi_start_queue(master);
1467 dev_err(&master->dev, "queue restart failed\n");
1471 EXPORT_SYMBOL_GPL(spi_master_resume);
1473 static int __spi_master_match(struct device *dev, const void *data)
1475 struct spi_master *m;
1476 const u16 *bus_num = data;
1478 m = container_of(dev, struct spi_master, dev);
1479 return m->bus_num == *bus_num;
1483 * spi_busnum_to_master - look up master associated with bus_num
1484 * @bus_num: the master's bus number
1485 * Context: can sleep
1487 * This call may be used with devices that are registered after
1488 * arch init time. It returns a refcounted pointer to the relevant
1489 * spi_master (which the caller must release), or NULL if there is
1490 * no such master registered.
1492 struct spi_master *spi_busnum_to_master(u16 bus_num)
1495 struct spi_master *master = NULL;
1497 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1498 __spi_master_match);
1500 master = container_of(dev, struct spi_master, dev);
1501 /* reference got in class_find_device */
1504 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1507 /*-------------------------------------------------------------------------*/
1509 /* Core methods for SPI master protocol drivers. Some of the
1510 * other core methods are currently defined as inline functions.
1514 * spi_setup - setup SPI mode and clock rate
1515 * @spi: the device whose settings are being modified
1516 * Context: can sleep, and no requests are queued to the device
1518 * SPI protocol drivers may need to update the transfer mode if the
1519 * device doesn't work with its default. They may likewise need
1520 * to update clock rates or word sizes from initial values. This function
1521 * changes those settings, and must be called from a context that can sleep.
1522 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1523 * effect the next time the device is selected and data is transferred to
1524 * or from it. When this function returns, the spi device is deselected.
1526 * Note that this call will fail if the protocol driver specifies an option
1527 * that the underlying controller or its driver does not support. For
1528 * example, not all hardware supports wire transfers using nine bit words,
1529 * LSB-first wire encoding, or active-high chipselects.
1531 int spi_setup(struct spi_device *spi)
1536 /* check mode to prevent that DUAL and QUAD set at the same time
1538 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1539 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1541 "setup: can not select dual and quad at the same time\n");
1544 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1546 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1547 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1549 /* help drivers fail *cleanly* when they need options
1550 * that aren't supported with their current master
1552 bad_bits = spi->mode & ~spi->master->mode_bits;
1554 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1559 if (!spi->bits_per_word)
1560 spi->bits_per_word = 8;
1562 if (spi->master->setup)
1563 status = spi->master->setup(spi);
1565 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
1566 "%u bits/w, %u Hz max --> %d\n",
1567 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1568 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1569 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1570 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1571 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1572 spi->bits_per_word, spi->max_speed_hz,
1577 EXPORT_SYMBOL_GPL(spi_setup);
1579 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1581 struct spi_master *master = spi->master;
1582 struct spi_transfer *xfer;
1586 trace_spi_message_submit(message);
1588 if (list_empty(&message->transfers))
1590 if (!message->complete)
1593 /* Half-duplex links include original MicroWire, and ones with
1594 * only one data pin like SPI_3WIRE (switches direction) or where
1595 * either MOSI or MISO is missing. They can also be caused by
1596 * software limitations.
1598 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1599 || (spi->mode & SPI_3WIRE)) {
1600 unsigned flags = master->flags;
1602 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1603 if (xfer->rx_buf && xfer->tx_buf)
1605 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1607 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1613 * Set transfer bits_per_word and max speed as spi device default if
1614 * it is not set for this transfer.
1615 * Set transfer tx_nbits and rx_nbits as single transfer default
1616 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1618 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1619 message->frame_length += xfer->len;
1620 if (!xfer->bits_per_word)
1621 xfer->bits_per_word = spi->bits_per_word;
1622 if (!xfer->speed_hz) {
1623 xfer->speed_hz = spi->max_speed_hz;
1624 if (master->max_speed_hz &&
1625 xfer->speed_hz > master->max_speed_hz)
1626 xfer->speed_hz = master->max_speed_hz;
1629 if (master->bits_per_word_mask) {
1630 /* Only 32 bits fit in the mask */
1631 if (xfer->bits_per_word > 32)
1633 if (!(master->bits_per_word_mask &
1634 BIT(xfer->bits_per_word - 1)))
1638 if (xfer->speed_hz && master->min_speed_hz &&
1639 xfer->speed_hz < master->min_speed_hz)
1641 if (xfer->speed_hz && master->max_speed_hz &&
1642 xfer->speed_hz > master->max_speed_hz)
1645 if (xfer->tx_buf && !xfer->tx_nbits)
1646 xfer->tx_nbits = SPI_NBITS_SINGLE;
1647 if (xfer->rx_buf && !xfer->rx_nbits)
1648 xfer->rx_nbits = SPI_NBITS_SINGLE;
1649 /* check transfer tx/rx_nbits:
1650 * 1. keep the value is not out of single, dual and quad
1651 * 2. keep tx/rx_nbits is contained by mode in spi_device
1652 * 3. if SPI_3WIRE, tx/rx_nbits should be in single
1655 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1656 xfer->tx_nbits != SPI_NBITS_DUAL &&
1657 xfer->tx_nbits != SPI_NBITS_QUAD)
1659 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1660 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1662 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1663 !(spi->mode & SPI_TX_QUAD))
1665 if ((spi->mode & SPI_3WIRE) &&
1666 (xfer->tx_nbits != SPI_NBITS_SINGLE))
1669 /* check transfer rx_nbits */
1671 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1672 xfer->rx_nbits != SPI_NBITS_DUAL &&
1673 xfer->rx_nbits != SPI_NBITS_QUAD)
1675 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1676 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1678 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1679 !(spi->mode & SPI_RX_QUAD))
1681 if ((spi->mode & SPI_3WIRE) &&
1682 (xfer->rx_nbits != SPI_NBITS_SINGLE))
1687 message->status = -EINPROGRESS;
1688 return master->transfer(spi, message);
1692 * spi_async - asynchronous SPI transfer
1693 * @spi: device with which data will be exchanged
1694 * @message: describes the data transfers, including completion callback
1695 * Context: any (irqs may be blocked, etc)
1697 * This call may be used in_irq and other contexts which can't sleep,
1698 * as well as from task contexts which can sleep.
1700 * The completion callback is invoked in a context which can't sleep.
1701 * Before that invocation, the value of message->status is undefined.
1702 * When the callback is issued, message->status holds either zero (to
1703 * indicate complete success) or a negative error code. After that
1704 * callback returns, the driver which issued the transfer request may
1705 * deallocate the associated memory; it's no longer in use by any SPI
1706 * core or controller driver code.
1708 * Note that although all messages to a spi_device are handled in
1709 * FIFO order, messages may go to different devices in other orders.
1710 * Some device might be higher priority, or have various "hard" access
1711 * time requirements, for example.
1713 * On detection of any fault during the transfer, processing of
1714 * the entire message is aborted, and the device is deselected.
1715 * Until returning from the associated message completion callback,
1716 * no other spi_message queued to that device will be processed.
1717 * (This rule applies equally to all the synchronous transfer calls,
1718 * which are wrappers around this core asynchronous primitive.)
1720 int spi_async(struct spi_device *spi, struct spi_message *message)
1722 struct spi_master *master = spi->master;
1724 unsigned long flags;
1726 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1728 if (master->bus_lock_flag)
1731 ret = __spi_async(spi, message);
1733 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1737 EXPORT_SYMBOL_GPL(spi_async);
1740 * spi_async_locked - version of spi_async with exclusive bus usage
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_locked(struct spi_device *spi, struct spi_message *message)
1770 struct spi_master *master = spi->master;
1772 unsigned long flags;
1774 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1776 ret = __spi_async(spi, message);
1778 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1783 EXPORT_SYMBOL_GPL(spi_async_locked);
1786 /*-------------------------------------------------------------------------*/
1788 /* Utility methods for SPI master protocol drivers, layered on
1789 * top of the core. Some other utility methods are defined as
1793 static void spi_complete(void *arg)
1798 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1801 DECLARE_COMPLETION_ONSTACK(done);
1803 struct spi_master *master = spi->master;
1805 message->complete = spi_complete;
1806 message->context = &done;
1809 mutex_lock(&master->bus_lock_mutex);
1811 status = spi_async_locked(spi, message);
1814 mutex_unlock(&master->bus_lock_mutex);
1817 wait_for_completion(&done);
1818 status = message->status;
1820 message->context = NULL;
1825 * spi_sync - blocking/synchronous SPI data transfers
1826 * @spi: device with which data will be exchanged
1827 * @message: describes the data transfers
1828 * Context: can sleep
1830 * This call may only be used from a context that may sleep. The sleep
1831 * is non-interruptible, and has no timeout. Low-overhead controller
1832 * drivers may DMA directly into and out of the message buffers.
1834 * Note that the SPI device's chip select is active during the message,
1835 * and then is normally disabled between messages. Drivers for some
1836 * frequently-used devices may want to minimize costs of selecting a chip,
1837 * by leaving it selected in anticipation that the next message will go
1838 * to the same chip. (That may increase power usage.)
1840 * Also, the caller is guaranteeing that the memory associated with the
1841 * message will not be freed before this call returns.
1843 * It returns zero on success, else a negative error code.
1845 int spi_sync(struct spi_device *spi, struct spi_message *message)
1847 return __spi_sync(spi, message, 0);
1849 EXPORT_SYMBOL_GPL(spi_sync);
1852 * spi_sync_locked - version of spi_sync with exclusive bus usage
1853 * @spi: device with which data will be exchanged
1854 * @message: describes the data transfers
1855 * Context: can sleep
1857 * This call may only be used from a context that may sleep. The sleep
1858 * is non-interruptible, and has no timeout. Low-overhead controller
1859 * drivers may DMA directly into and out of the message buffers.
1861 * This call should be used by drivers that require exclusive access to the
1862 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1863 * be released by a spi_bus_unlock call when the exclusive access is over.
1865 * It returns zero on success, else a negative error code.
1867 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1869 return __spi_sync(spi, message, 1);
1871 EXPORT_SYMBOL_GPL(spi_sync_locked);
1874 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1875 * @master: SPI bus master that should be locked for exclusive bus access
1876 * Context: can sleep
1878 * This call may only be used from a context that may sleep. The sleep
1879 * is non-interruptible, and has no timeout.
1881 * This call should be used by drivers that require exclusive access to the
1882 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1883 * exclusive access is over. Data transfer must be done by spi_sync_locked
1884 * and spi_async_locked calls when the SPI bus lock is held.
1886 * It returns zero on success, else a negative error code.
1888 int spi_bus_lock(struct spi_master *master)
1890 unsigned long flags;
1892 mutex_lock(&master->bus_lock_mutex);
1894 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1895 master->bus_lock_flag = 1;
1896 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1898 /* mutex remains locked until spi_bus_unlock is called */
1902 EXPORT_SYMBOL_GPL(spi_bus_lock);
1905 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1906 * @master: SPI bus master that was locked for exclusive bus access
1907 * Context: can sleep
1909 * This call may only be used from a context that may sleep. The sleep
1910 * is non-interruptible, and has no timeout.
1912 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1915 * It returns zero on success, else a negative error code.
1917 int spi_bus_unlock(struct spi_master *master)
1919 master->bus_lock_flag = 0;
1921 mutex_unlock(&master->bus_lock_mutex);
1925 EXPORT_SYMBOL_GPL(spi_bus_unlock);
1927 /* portable code must never pass more than 32 bytes */
1928 #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1933 * spi_write_then_read - SPI synchronous write followed by read
1934 * @spi: device with which data will be exchanged
1935 * @txbuf: data to be written (need not be dma-safe)
1936 * @n_tx: size of txbuf, in bytes
1937 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1938 * @n_rx: size of rxbuf, in bytes
1939 * Context: can sleep
1941 * This performs a half duplex MicroWire style transaction with the
1942 * device, sending txbuf and then reading rxbuf. The return value
1943 * is zero for success, else a negative errno status code.
1944 * This call may only be used from a context that may sleep.
1946 * Parameters to this routine are always copied using a small buffer;
1947 * portable code should never use this for more than 32 bytes.
1948 * Performance-sensitive or bulk transfer code should instead use
1949 * spi_{async,sync}() calls with dma-safe buffers.
1951 int spi_write_then_read(struct spi_device *spi,
1952 const void *txbuf, unsigned n_tx,
1953 void *rxbuf, unsigned n_rx)
1955 static DEFINE_MUTEX(lock);
1958 struct spi_message message;
1959 struct spi_transfer x[2];
1962 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1963 * copying here, (as a pure convenience thing), but we can
1964 * keep heap costs out of the hot path unless someone else is
1965 * using the pre-allocated buffer or the transfer is too large.
1967 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
1968 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
1969 GFP_KERNEL | GFP_DMA);
1976 spi_message_init(&message);
1977 memset(x, 0, sizeof x);
1980 spi_message_add_tail(&x[0], &message);
1984 spi_message_add_tail(&x[1], &message);
1987 memcpy(local_buf, txbuf, n_tx);
1988 x[0].tx_buf = local_buf;
1989 x[1].rx_buf = local_buf + n_tx;
1992 status = spi_sync(spi, &message);
1994 memcpy(rxbuf, x[1].rx_buf, n_rx);
1996 if (x[0].tx_buf == buf)
1997 mutex_unlock(&lock);
2003 EXPORT_SYMBOL_GPL(spi_write_then_read);
2005 /*-------------------------------------------------------------------------*/
2007 static int __init spi_init(void)
2011 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2017 status = bus_register(&spi_bus_type);
2021 status = class_register(&spi_master_class);
2027 bus_unregister(&spi_bus_type);
2035 /* board_info is normally registered in arch_initcall(),
2036 * but even essential drivers wait till later
2038 * REVISIT only boardinfo really needs static linking. the rest (device and
2039 * driver registration) _could_ be dynamically linked (modular) ... costs
2040 * include needing to have boardinfo data structures be much more public.
2042 postcore_initcall(spi_init);