4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/kernel.h>
23 #include <linux/kmod.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/cache.h>
27 #include <linux/mutex.h>
28 #include <linux/of_device.h>
29 #include <linux/of_irq.h>
30 #include <linux/slab.h>
31 #include <linux/mod_devicetable.h>
32 #include <linux/spi/spi.h>
33 #include <linux/of_gpio.h>
34 #include <linux/pm_runtime.h>
35 #include <linux/export.h>
36 #include <linux/sched/rt.h>
37 #include <linux/delay.h>
38 #include <linux/kthread.h>
39 #include <linux/ioport.h>
40 #include <linux/acpi.h>
42 #define CREATE_TRACE_POINTS
43 #include <trace/events/spi.h>
45 static void spidev_release(struct device *dev)
47 struct spi_device *spi = to_spi_device(dev);
49 /* spi masters may cleanup for released devices */
50 if (spi->master->cleanup)
51 spi->master->cleanup(spi);
53 spi_master_put(spi->master);
58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
60 const struct spi_device *spi = to_spi_device(dev);
62 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
64 static DEVICE_ATTR_RO(modalias);
66 static struct attribute *spi_dev_attrs[] = {
67 &dev_attr_modalias.attr,
70 ATTRIBUTE_GROUPS(spi_dev);
72 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
73 * and the sysfs version makes coldplug work too.
76 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
77 const struct spi_device *sdev)
80 if (!strcmp(sdev->modalias, id->name))
87 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
89 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
91 return spi_match_id(sdrv->id_table, sdev);
93 EXPORT_SYMBOL_GPL(spi_get_device_id);
95 static int spi_match_device(struct device *dev, struct device_driver *drv)
97 const struct spi_device *spi = to_spi_device(dev);
98 const struct spi_driver *sdrv = to_spi_driver(drv);
100 /* Attempt an OF style match */
101 if (of_driver_match_device(dev, drv))
105 if (acpi_driver_match_device(dev, drv))
109 return !!spi_match_id(sdrv->id_table, spi);
111 return strcmp(spi->modalias, drv->name) == 0;
114 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
116 const struct spi_device *spi = to_spi_device(dev);
118 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
122 #ifdef CONFIG_PM_SLEEP
123 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
126 struct spi_driver *drv = to_spi_driver(dev->driver);
128 /* suspend will stop irqs and dma; no more i/o */
131 value = drv->suspend(to_spi_device(dev), message);
133 dev_dbg(dev, "... can't suspend\n");
138 static int spi_legacy_resume(struct device *dev)
141 struct spi_driver *drv = to_spi_driver(dev->driver);
143 /* resume may restart the i/o queue */
146 value = drv->resume(to_spi_device(dev));
148 dev_dbg(dev, "... can't resume\n");
153 static int spi_pm_suspend(struct device *dev)
155 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
158 return pm_generic_suspend(dev);
160 return spi_legacy_suspend(dev, PMSG_SUSPEND);
163 static int spi_pm_resume(struct device *dev)
165 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
168 return pm_generic_resume(dev);
170 return spi_legacy_resume(dev);
173 static int spi_pm_freeze(struct device *dev)
175 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
178 return pm_generic_freeze(dev);
180 return spi_legacy_suspend(dev, PMSG_FREEZE);
183 static int spi_pm_thaw(struct device *dev)
185 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
188 return pm_generic_thaw(dev);
190 return spi_legacy_resume(dev);
193 static int spi_pm_poweroff(struct device *dev)
195 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
198 return pm_generic_poweroff(dev);
200 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
203 static int spi_pm_restore(struct device *dev)
205 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
208 return pm_generic_restore(dev);
210 return spi_legacy_resume(dev);
213 #define spi_pm_suspend NULL
214 #define spi_pm_resume NULL
215 #define spi_pm_freeze NULL
216 #define spi_pm_thaw NULL
217 #define spi_pm_poweroff NULL
218 #define spi_pm_restore NULL
221 static const struct dev_pm_ops spi_pm = {
222 .suspend = spi_pm_suspend,
223 .resume = spi_pm_resume,
224 .freeze = spi_pm_freeze,
226 .poweroff = spi_pm_poweroff,
227 .restore = spi_pm_restore,
229 pm_generic_runtime_suspend,
230 pm_generic_runtime_resume,
235 struct bus_type spi_bus_type = {
237 .dev_groups = spi_dev_groups,
238 .match = spi_match_device,
239 .uevent = spi_uevent,
242 EXPORT_SYMBOL_GPL(spi_bus_type);
245 static int spi_drv_probe(struct device *dev)
247 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
248 struct spi_device *spi = to_spi_device(dev);
251 acpi_dev_pm_attach(&spi->dev, true);
252 ret = sdrv->probe(spi);
254 acpi_dev_pm_detach(&spi->dev, true);
259 static int spi_drv_remove(struct device *dev)
261 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
262 struct spi_device *spi = to_spi_device(dev);
265 ret = sdrv->remove(spi);
266 acpi_dev_pm_detach(&spi->dev, true);
271 static void spi_drv_shutdown(struct device *dev)
273 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
275 sdrv->shutdown(to_spi_device(dev));
279 * spi_register_driver - register a SPI driver
280 * @sdrv: the driver to register
283 int spi_register_driver(struct spi_driver *sdrv)
285 sdrv->driver.bus = &spi_bus_type;
287 sdrv->driver.probe = spi_drv_probe;
289 sdrv->driver.remove = spi_drv_remove;
291 sdrv->driver.shutdown = spi_drv_shutdown;
292 return driver_register(&sdrv->driver);
294 EXPORT_SYMBOL_GPL(spi_register_driver);
296 /*-------------------------------------------------------------------------*/
298 /* SPI devices should normally not be created by SPI device drivers; that
299 * would make them board-specific. Similarly with SPI master drivers.
300 * Device registration normally goes into like arch/.../mach.../board-YYY.c
301 * with other readonly (flashable) information about mainboard devices.
305 struct list_head list;
306 struct spi_board_info board_info;
309 static LIST_HEAD(board_list);
310 static LIST_HEAD(spi_master_list);
313 * Used to protect add/del opertion for board_info list and
314 * spi_master list, and their matching process
316 static DEFINE_MUTEX(board_lock);
319 * spi_alloc_device - Allocate a new SPI device
320 * @master: Controller to which device is connected
323 * Allows a driver to allocate and initialize a spi_device without
324 * registering it immediately. This allows a driver to directly
325 * fill the spi_device with device parameters before calling
326 * spi_add_device() on it.
328 * Caller is responsible to call spi_add_device() on the returned
329 * spi_device structure to add it to the SPI master. If the caller
330 * needs to discard the spi_device without adding it, then it should
331 * call spi_dev_put() on it.
333 * Returns a pointer to the new device, or NULL.
335 struct spi_device *spi_alloc_device(struct spi_master *master)
337 struct spi_device *spi;
338 struct device *dev = master->dev.parent;
340 if (!spi_master_get(master))
343 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
345 dev_err(dev, "cannot alloc spi_device\n");
346 spi_master_put(master);
350 spi->master = master;
351 spi->dev.parent = &master->dev;
352 spi->dev.bus = &spi_bus_type;
353 spi->dev.release = spidev_release;
354 spi->cs_gpio = -ENOENT;
355 device_initialize(&spi->dev);
358 EXPORT_SYMBOL_GPL(spi_alloc_device);
360 static void spi_dev_set_name(struct spi_device *spi)
362 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
365 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
369 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
373 static int spi_dev_check(struct device *dev, void *data)
375 struct spi_device *spi = to_spi_device(dev);
376 struct spi_device *new_spi = data;
378 if (spi->master == new_spi->master &&
379 spi->chip_select == new_spi->chip_select)
385 * spi_add_device - Add spi_device allocated with spi_alloc_device
386 * @spi: spi_device to register
388 * Companion function to spi_alloc_device. Devices allocated with
389 * spi_alloc_device can be added onto the spi bus with this function.
391 * Returns 0 on success; negative errno on failure
393 int spi_add_device(struct spi_device *spi)
395 static DEFINE_MUTEX(spi_add_lock);
396 struct spi_master *master = spi->master;
397 struct device *dev = master->dev.parent;
400 /* Chipselects are numbered 0..max; validate. */
401 if (spi->chip_select >= master->num_chipselect) {
402 dev_err(dev, "cs%d >= max %d\n",
404 master->num_chipselect);
408 /* Set the bus ID string */
409 spi_dev_set_name(spi);
411 /* We need to make sure there's no other device with this
412 * chipselect **BEFORE** we call setup(), else we'll trash
413 * its configuration. Lock against concurrent add() calls.
415 mutex_lock(&spi_add_lock);
417 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
419 dev_err(dev, "chipselect %d already in use\n",
424 if (master->cs_gpios)
425 spi->cs_gpio = master->cs_gpios[spi->chip_select];
427 /* Drivers may modify this initial i/o setup, but will
428 * normally rely on the device being setup. Devices
429 * using SPI_CS_HIGH can't coexist well otherwise...
431 status = spi_setup(spi);
433 dev_err(dev, "can't setup %s, status %d\n",
434 dev_name(&spi->dev), status);
438 /* Device may be bound to an active driver when this returns */
439 status = device_add(&spi->dev);
441 dev_err(dev, "can't add %s, status %d\n",
442 dev_name(&spi->dev), status);
444 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
447 mutex_unlock(&spi_add_lock);
450 EXPORT_SYMBOL_GPL(spi_add_device);
453 * spi_new_device - instantiate one new SPI device
454 * @master: Controller to which device is connected
455 * @chip: Describes the SPI device
458 * On typical mainboards, this is purely internal; and it's not needed
459 * after board init creates the hard-wired devices. Some development
460 * platforms may not be able to use spi_register_board_info though, and
461 * this is exported so that for example a USB or parport based adapter
462 * driver could add devices (which it would learn about out-of-band).
464 * Returns the new device, or NULL.
466 struct spi_device *spi_new_device(struct spi_master *master,
467 struct spi_board_info *chip)
469 struct spi_device *proxy;
472 /* NOTE: caller did any chip->bus_num checks necessary.
474 * Also, unless we change the return value convention to use
475 * error-or-pointer (not NULL-or-pointer), troubleshootability
476 * suggests syslogged diagnostics are best here (ugh).
479 proxy = spi_alloc_device(master);
483 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
485 proxy->chip_select = chip->chip_select;
486 proxy->max_speed_hz = chip->max_speed_hz;
487 proxy->mode = chip->mode;
488 proxy->irq = chip->irq;
489 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
490 proxy->dev.platform_data = (void *) chip->platform_data;
491 proxy->controller_data = chip->controller_data;
492 proxy->controller_state = NULL;
494 status = spi_add_device(proxy);
502 EXPORT_SYMBOL_GPL(spi_new_device);
504 static void spi_match_master_to_boardinfo(struct spi_master *master,
505 struct spi_board_info *bi)
507 struct spi_device *dev;
509 if (master->bus_num != bi->bus_num)
512 dev = spi_new_device(master, bi);
514 dev_err(master->dev.parent, "can't create new device for %s\n",
519 * spi_register_board_info - register SPI devices for a given board
520 * @info: array of chip descriptors
521 * @n: how many descriptors are provided
524 * Board-specific early init code calls this (probably during arch_initcall)
525 * with segments of the SPI device table. Any device nodes are created later,
526 * after the relevant parent SPI controller (bus_num) is defined. We keep
527 * this table of devices forever, so that reloading a controller driver will
528 * not make Linux forget about these hard-wired devices.
530 * Other code can also call this, e.g. a particular add-on board might provide
531 * SPI devices through its expansion connector, so code initializing that board
532 * would naturally declare its SPI devices.
534 * The board info passed can safely be __initdata ... but be careful of
535 * any embedded pointers (platform_data, etc), they're copied as-is.
537 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
539 struct boardinfo *bi;
542 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
546 for (i = 0; i < n; i++, bi++, info++) {
547 struct spi_master *master;
549 memcpy(&bi->board_info, info, sizeof(*info));
550 mutex_lock(&board_lock);
551 list_add_tail(&bi->list, &board_list);
552 list_for_each_entry(master, &spi_master_list, list)
553 spi_match_master_to_boardinfo(master, &bi->board_info);
554 mutex_unlock(&board_lock);
560 /*-------------------------------------------------------------------------*/
562 static void spi_set_cs(struct spi_device *spi, bool enable)
564 if (spi->mode & SPI_CS_HIGH)
567 if (spi->cs_gpio >= 0)
568 gpio_set_value(spi->cs_gpio, !enable);
569 else if (spi->master->set_cs)
570 spi->master->set_cs(spi, !enable);
574 * spi_transfer_one_message - Default implementation of transfer_one_message()
576 * This is a standard implementation of transfer_one_message() for
577 * drivers which impelment a transfer_one() operation. It provides
578 * standard handling of delays and chip select management.
580 static int spi_transfer_one_message(struct spi_master *master,
581 struct spi_message *msg)
583 struct spi_transfer *xfer;
585 bool keep_cs = false;
588 spi_set_cs(msg->spi, true);
590 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
591 trace_spi_transfer_start(msg, xfer);
593 reinit_completion(&master->xfer_completion);
595 ret = master->transfer_one(master, msg->spi, xfer);
597 dev_err(&msg->spi->dev,
598 "SPI transfer failed: %d\n", ret);
604 wait_for_completion(&master->xfer_completion);
607 trace_spi_transfer_stop(msg, xfer);
609 if (msg->status != -EINPROGRESS)
612 if (xfer->delay_usecs)
613 udelay(xfer->delay_usecs);
615 if (xfer->cs_change) {
616 if (list_is_last(&xfer->transfer_list,
621 spi_set_cs(msg->spi, cur_cs);
625 msg->actual_length += xfer->len;
629 if (ret != 0 || !keep_cs)
630 spi_set_cs(msg->spi, false);
632 if (msg->status == -EINPROGRESS)
635 spi_finalize_current_message(master);
641 * spi_finalize_current_transfer - report completion of a transfer
643 * Called by SPI drivers using the core transfer_one_message()
644 * implementation to notify it that the current interrupt driven
645 * transfer has finished and the next one may be scheduled.
647 void spi_finalize_current_transfer(struct spi_master *master)
649 complete(&master->xfer_completion);
651 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
654 * spi_pump_messages - kthread work function which processes spi message queue
655 * @work: pointer to kthread work struct contained in the master struct
657 * This function checks if there is any spi message in the queue that
658 * needs processing and if so call out to the driver to initialize hardware
659 * and transfer each message.
662 static void spi_pump_messages(struct kthread_work *work)
664 struct spi_master *master =
665 container_of(work, struct spi_master, pump_messages);
667 bool was_busy = false;
670 /* Lock queue and check for queue work */
671 spin_lock_irqsave(&master->queue_lock, flags);
672 if (list_empty(&master->queue) || !master->running) {
674 spin_unlock_irqrestore(&master->queue_lock, flags);
677 master->busy = false;
678 spin_unlock_irqrestore(&master->queue_lock, flags);
679 if (master->unprepare_transfer_hardware &&
680 master->unprepare_transfer_hardware(master))
681 dev_err(&master->dev,
682 "failed to unprepare transfer hardware\n");
683 if (master->auto_runtime_pm) {
684 pm_runtime_mark_last_busy(master->dev.parent);
685 pm_runtime_put_autosuspend(master->dev.parent);
687 trace_spi_master_idle(master);
691 /* Make sure we are not already running a message */
692 if (master->cur_msg) {
693 spin_unlock_irqrestore(&master->queue_lock, flags);
696 /* Extract head of queue */
698 list_first_entry(&master->queue, struct spi_message, queue);
700 list_del_init(&master->cur_msg->queue);
705 spin_unlock_irqrestore(&master->queue_lock, flags);
707 if (!was_busy && master->auto_runtime_pm) {
708 ret = pm_runtime_get_sync(master->dev.parent);
710 dev_err(&master->dev, "Failed to power device: %d\n",
717 trace_spi_master_busy(master);
719 if (!was_busy && master->prepare_transfer_hardware) {
720 ret = master->prepare_transfer_hardware(master);
722 dev_err(&master->dev,
723 "failed to prepare transfer hardware\n");
725 if (master->auto_runtime_pm)
726 pm_runtime_put(master->dev.parent);
731 trace_spi_message_start(master->cur_msg);
733 if (master->prepare_message) {
734 ret = master->prepare_message(master, master->cur_msg);
736 dev_err(&master->dev,
737 "failed to prepare message: %d\n", ret);
738 master->cur_msg->status = ret;
739 spi_finalize_current_message(master);
742 master->cur_msg_prepared = true;
745 ret = master->transfer_one_message(master, master->cur_msg);
747 dev_err(&master->dev,
748 "failed to transfer one message from queue\n");
753 static int spi_init_queue(struct spi_master *master)
755 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
757 INIT_LIST_HEAD(&master->queue);
758 spin_lock_init(&master->queue_lock);
760 master->running = false;
761 master->busy = false;
763 init_kthread_worker(&master->kworker);
764 master->kworker_task = kthread_run(kthread_worker_fn,
765 &master->kworker, "%s",
766 dev_name(&master->dev));
767 if (IS_ERR(master->kworker_task)) {
768 dev_err(&master->dev, "failed to create message pump task\n");
771 init_kthread_work(&master->pump_messages, spi_pump_messages);
774 * Master config will indicate if this controller should run the
775 * message pump with high (realtime) priority to reduce the transfer
776 * latency on the bus by minimising the delay between a transfer
777 * request and the scheduling of the message pump thread. Without this
778 * setting the message pump thread will remain at default priority.
781 dev_info(&master->dev,
782 "will run message pump with realtime priority\n");
783 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
790 * spi_get_next_queued_message() - called by driver to check for queued
792 * @master: the master to check for queued messages
794 * If there are more messages in the queue, the next message is returned from
797 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
799 struct spi_message *next;
802 /* get a pointer to the next message, if any */
803 spin_lock_irqsave(&master->queue_lock, flags);
804 next = list_first_entry_or_null(&master->queue, struct spi_message,
806 spin_unlock_irqrestore(&master->queue_lock, flags);
810 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
813 * spi_finalize_current_message() - the current message is complete
814 * @master: the master to return the message to
816 * Called by the driver to notify the core that the message in the front of the
817 * queue is complete and can be removed from the queue.
819 void spi_finalize_current_message(struct spi_master *master)
821 struct spi_message *mesg;
825 spin_lock_irqsave(&master->queue_lock, flags);
826 mesg = master->cur_msg;
827 master->cur_msg = NULL;
829 queue_kthread_work(&master->kworker, &master->pump_messages);
830 spin_unlock_irqrestore(&master->queue_lock, flags);
832 if (master->cur_msg_prepared && master->unprepare_message) {
833 ret = master->unprepare_message(master, mesg);
835 dev_err(&master->dev,
836 "failed to unprepare message: %d\n", ret);
839 master->cur_msg_prepared = false;
843 mesg->complete(mesg->context);
845 trace_spi_message_done(mesg);
847 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
849 static int spi_start_queue(struct spi_master *master)
853 spin_lock_irqsave(&master->queue_lock, flags);
855 if (master->running || master->busy) {
856 spin_unlock_irqrestore(&master->queue_lock, flags);
860 master->running = true;
861 master->cur_msg = NULL;
862 spin_unlock_irqrestore(&master->queue_lock, flags);
864 queue_kthread_work(&master->kworker, &master->pump_messages);
869 static int spi_stop_queue(struct spi_master *master)
872 unsigned limit = 500;
875 spin_lock_irqsave(&master->queue_lock, flags);
878 * This is a bit lame, but is optimized for the common execution path.
879 * A wait_queue on the master->busy could be used, but then the common
880 * execution path (pump_messages) would be required to call wake_up or
881 * friends on every SPI message. Do this instead.
883 while ((!list_empty(&master->queue) || master->busy) && limit--) {
884 spin_unlock_irqrestore(&master->queue_lock, flags);
886 spin_lock_irqsave(&master->queue_lock, flags);
889 if (!list_empty(&master->queue) || master->busy)
892 master->running = false;
894 spin_unlock_irqrestore(&master->queue_lock, flags);
897 dev_warn(&master->dev,
898 "could not stop message queue\n");
904 static int spi_destroy_queue(struct spi_master *master)
908 ret = spi_stop_queue(master);
911 * flush_kthread_worker will block until all work is done.
912 * If the reason that stop_queue timed out is that the work will never
913 * finish, then it does no good to call flush/stop thread, so
917 dev_err(&master->dev, "problem destroying queue\n");
921 flush_kthread_worker(&master->kworker);
922 kthread_stop(master->kworker_task);
928 * spi_queued_transfer - transfer function for queued transfers
929 * @spi: spi device which is requesting transfer
930 * @msg: spi message which is to handled is queued to driver queue
932 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
934 struct spi_master *master = spi->master;
937 spin_lock_irqsave(&master->queue_lock, flags);
939 if (!master->running) {
940 spin_unlock_irqrestore(&master->queue_lock, flags);
943 msg->actual_length = 0;
944 msg->status = -EINPROGRESS;
946 list_add_tail(&msg->queue, &master->queue);
948 queue_kthread_work(&master->kworker, &master->pump_messages);
950 spin_unlock_irqrestore(&master->queue_lock, flags);
954 static int spi_master_initialize_queue(struct spi_master *master)
958 master->queued = true;
959 master->transfer = spi_queued_transfer;
960 if (!master->transfer_one_message)
961 master->transfer_one_message = spi_transfer_one_message;
963 /* Initialize and start queue */
964 ret = spi_init_queue(master);
966 dev_err(&master->dev, "problem initializing queue\n");
969 ret = spi_start_queue(master);
971 dev_err(&master->dev, "problem starting queue\n");
972 goto err_start_queue;
979 spi_destroy_queue(master);
983 /*-------------------------------------------------------------------------*/
985 #if defined(CONFIG_OF)
987 * of_register_spi_devices() - Register child devices onto the SPI bus
988 * @master: Pointer to spi_master device
990 * Registers an spi_device for each child node of master node which has a 'reg'
993 static void of_register_spi_devices(struct spi_master *master)
995 struct spi_device *spi;
996 struct device_node *nc;
1000 if (!master->dev.of_node)
1003 for_each_available_child_of_node(master->dev.of_node, nc) {
1004 /* Alloc an spi_device */
1005 spi = spi_alloc_device(master);
1007 dev_err(&master->dev, "spi_device alloc error for %s\n",
1013 /* Select device driver */
1014 if (of_modalias_node(nc, spi->modalias,
1015 sizeof(spi->modalias)) < 0) {
1016 dev_err(&master->dev, "cannot find modalias for %s\n",
1022 /* Device address */
1023 rc = of_property_read_u32(nc, "reg", &value);
1025 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1030 spi->chip_select = value;
1032 /* Mode (clock phase/polarity/etc.) */
1033 if (of_find_property(nc, "spi-cpha", NULL))
1034 spi->mode |= SPI_CPHA;
1035 if (of_find_property(nc, "spi-cpol", NULL))
1036 spi->mode |= SPI_CPOL;
1037 if (of_find_property(nc, "spi-cs-high", NULL))
1038 spi->mode |= SPI_CS_HIGH;
1039 if (of_find_property(nc, "spi-3wire", NULL))
1040 spi->mode |= SPI_3WIRE;
1042 /* Device DUAL/QUAD mode */
1043 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1048 spi->mode |= SPI_TX_DUAL;
1051 spi->mode |= SPI_TX_QUAD;
1054 dev_err(&master->dev,
1055 "spi-tx-bus-width %d not supported\n",
1062 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1067 spi->mode |= SPI_RX_DUAL;
1070 spi->mode |= SPI_RX_QUAD;
1073 dev_err(&master->dev,
1074 "spi-rx-bus-width %d not supported\n",
1082 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1084 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1089 spi->max_speed_hz = value;
1092 spi->irq = irq_of_parse_and_map(nc, 0);
1094 /* Store a pointer to the node in the device structure */
1096 spi->dev.of_node = nc;
1098 /* Register the new device */
1099 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1100 rc = spi_add_device(spi);
1102 dev_err(&master->dev, "spi_device register error %s\n",
1110 static void of_register_spi_devices(struct spi_master *master) { }
1114 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1116 struct spi_device *spi = data;
1118 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1119 struct acpi_resource_spi_serialbus *sb;
1121 sb = &ares->data.spi_serial_bus;
1122 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1123 spi->chip_select = sb->device_selection;
1124 spi->max_speed_hz = sb->connection_speed;
1126 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1127 spi->mode |= SPI_CPHA;
1128 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1129 spi->mode |= SPI_CPOL;
1130 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1131 spi->mode |= SPI_CS_HIGH;
1133 } else if (spi->irq < 0) {
1136 if (acpi_dev_resource_interrupt(ares, 0, &r))
1140 /* Always tell the ACPI core to skip this resource */
1144 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1145 void *data, void **return_value)
1147 struct spi_master *master = data;
1148 struct list_head resource_list;
1149 struct acpi_device *adev;
1150 struct spi_device *spi;
1153 if (acpi_bus_get_device(handle, &adev))
1155 if (acpi_bus_get_status(adev) || !adev->status.present)
1158 spi = spi_alloc_device(master);
1160 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1161 dev_name(&adev->dev));
1162 return AE_NO_MEMORY;
1165 ACPI_COMPANION_SET(&spi->dev, adev);
1168 INIT_LIST_HEAD(&resource_list);
1169 ret = acpi_dev_get_resources(adev, &resource_list,
1170 acpi_spi_add_resource, spi);
1171 acpi_dev_free_resource_list(&resource_list);
1173 if (ret < 0 || !spi->max_speed_hz) {
1178 adev->power.flags.ignore_parent = true;
1179 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1180 if (spi_add_device(spi)) {
1181 adev->power.flags.ignore_parent = false;
1182 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1183 dev_name(&adev->dev));
1190 static void acpi_register_spi_devices(struct spi_master *master)
1195 handle = ACPI_HANDLE(master->dev.parent);
1199 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1200 acpi_spi_add_device, NULL,
1202 if (ACPI_FAILURE(status))
1203 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1206 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1207 #endif /* CONFIG_ACPI */
1209 static void spi_master_release(struct device *dev)
1211 struct spi_master *master;
1213 master = container_of(dev, struct spi_master, dev);
1217 static struct class spi_master_class = {
1218 .name = "spi_master",
1219 .owner = THIS_MODULE,
1220 .dev_release = spi_master_release,
1226 * spi_alloc_master - allocate SPI master controller
1227 * @dev: the controller, possibly using the platform_bus
1228 * @size: how much zeroed driver-private data to allocate; the pointer to this
1229 * memory is in the driver_data field of the returned device,
1230 * accessible with spi_master_get_devdata().
1231 * Context: can sleep
1233 * This call is used only by SPI master controller drivers, which are the
1234 * only ones directly touching chip registers. It's how they allocate
1235 * an spi_master structure, prior to calling spi_register_master().
1237 * This must be called from context that can sleep. It returns the SPI
1238 * master structure on success, else NULL.
1240 * The caller is responsible for assigning the bus number and initializing
1241 * the master's methods before calling spi_register_master(); and (after errors
1242 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1245 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1247 struct spi_master *master;
1252 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1256 device_initialize(&master->dev);
1257 master->bus_num = -1;
1258 master->num_chipselect = 1;
1259 master->dev.class = &spi_master_class;
1260 master->dev.parent = get_device(dev);
1261 spi_master_set_devdata(master, &master[1]);
1265 EXPORT_SYMBOL_GPL(spi_alloc_master);
1268 static int of_spi_register_master(struct spi_master *master)
1271 struct device_node *np = master->dev.of_node;
1276 nb = of_gpio_named_count(np, "cs-gpios");
1277 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1279 /* Return error only for an incorrectly formed cs-gpios property */
1280 if (nb == 0 || nb == -ENOENT)
1285 cs = devm_kzalloc(&master->dev,
1286 sizeof(int) * master->num_chipselect,
1288 master->cs_gpios = cs;
1290 if (!master->cs_gpios)
1293 for (i = 0; i < master->num_chipselect; i++)
1296 for (i = 0; i < nb; i++)
1297 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1302 static int of_spi_register_master(struct spi_master *master)
1309 * spi_register_master - register SPI master controller
1310 * @master: initialized master, originally from spi_alloc_master()
1311 * Context: can sleep
1313 * SPI master controllers connect to their drivers using some non-SPI bus,
1314 * such as the platform bus. The final stage of probe() in that code
1315 * includes calling spi_register_master() to hook up to this SPI bus glue.
1317 * SPI controllers use board specific (often SOC specific) bus numbers,
1318 * and board-specific addressing for SPI devices combines those numbers
1319 * with chip select numbers. Since SPI does not directly support dynamic
1320 * device identification, boards need configuration tables telling which
1321 * chip is at which address.
1323 * This must be called from context that can sleep. It returns zero on
1324 * success, else a negative error code (dropping the master's refcount).
1325 * After a successful return, the caller is responsible for calling
1326 * spi_unregister_master().
1328 int spi_register_master(struct spi_master *master)
1330 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1331 struct device *dev = master->dev.parent;
1332 struct boardinfo *bi;
1333 int status = -ENODEV;
1339 status = of_spi_register_master(master);
1343 /* even if it's just one always-selected device, there must
1344 * be at least one chipselect
1346 if (master->num_chipselect == 0)
1349 if ((master->bus_num < 0) && master->dev.of_node)
1350 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1352 /* convention: dynamically assigned bus IDs count down from the max */
1353 if (master->bus_num < 0) {
1354 /* FIXME switch to an IDR based scheme, something like
1355 * I2C now uses, so we can't run out of "dynamic" IDs
1357 master->bus_num = atomic_dec_return(&dyn_bus_id);
1361 spin_lock_init(&master->bus_lock_spinlock);
1362 mutex_init(&master->bus_lock_mutex);
1363 master->bus_lock_flag = 0;
1364 init_completion(&master->xfer_completion);
1366 /* register the device, then userspace will see it.
1367 * registration fails if the bus ID is in use.
1369 dev_set_name(&master->dev, "spi%u", master->bus_num);
1370 status = device_add(&master->dev);
1373 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1374 dynamic ? " (dynamic)" : "");
1376 /* If we're using a queued driver, start the queue */
1377 if (master->transfer)
1378 dev_info(dev, "master is unqueued, this is deprecated\n");
1380 status = spi_master_initialize_queue(master);
1382 device_del(&master->dev);
1387 mutex_lock(&board_lock);
1388 list_add_tail(&master->list, &spi_master_list);
1389 list_for_each_entry(bi, &board_list, list)
1390 spi_match_master_to_boardinfo(master, &bi->board_info);
1391 mutex_unlock(&board_lock);
1393 /* Register devices from the device tree and ACPI */
1394 of_register_spi_devices(master);
1395 acpi_register_spi_devices(master);
1399 EXPORT_SYMBOL_GPL(spi_register_master);
1401 static void devm_spi_unregister(struct device *dev, void *res)
1403 spi_unregister_master(*(struct spi_master **)res);
1407 * dev_spi_register_master - register managed SPI master controller
1408 * @dev: device managing SPI master
1409 * @master: initialized master, originally from spi_alloc_master()
1410 * Context: can sleep
1412 * Register a SPI device as with spi_register_master() which will
1413 * automatically be unregister
1415 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1417 struct spi_master **ptr;
1420 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1424 ret = spi_register_master(master);
1427 devres_add(dev, ptr);
1434 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1436 static int __unregister(struct device *dev, void *null)
1438 spi_unregister_device(to_spi_device(dev));
1443 * spi_unregister_master - unregister SPI master controller
1444 * @master: the master being unregistered
1445 * Context: can sleep
1447 * This call is used only by SPI master controller drivers, which are the
1448 * only ones directly touching chip registers.
1450 * This must be called from context that can sleep.
1452 void spi_unregister_master(struct spi_master *master)
1456 if (master->queued) {
1457 if (spi_destroy_queue(master))
1458 dev_err(&master->dev, "queue remove failed\n");
1461 mutex_lock(&board_lock);
1462 list_del(&master->list);
1463 mutex_unlock(&board_lock);
1465 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1466 device_unregister(&master->dev);
1468 EXPORT_SYMBOL_GPL(spi_unregister_master);
1470 int spi_master_suspend(struct spi_master *master)
1474 /* Basically no-ops for non-queued masters */
1475 if (!master->queued)
1478 ret = spi_stop_queue(master);
1480 dev_err(&master->dev, "queue stop failed\n");
1484 EXPORT_SYMBOL_GPL(spi_master_suspend);
1486 int spi_master_resume(struct spi_master *master)
1490 if (!master->queued)
1493 ret = spi_start_queue(master);
1495 dev_err(&master->dev, "queue restart failed\n");
1499 EXPORT_SYMBOL_GPL(spi_master_resume);
1501 static int __spi_master_match(struct device *dev, const void *data)
1503 struct spi_master *m;
1504 const u16 *bus_num = data;
1506 m = container_of(dev, struct spi_master, dev);
1507 return m->bus_num == *bus_num;
1511 * spi_busnum_to_master - look up master associated with bus_num
1512 * @bus_num: the master's bus number
1513 * Context: can sleep
1515 * This call may be used with devices that are registered after
1516 * arch init time. It returns a refcounted pointer to the relevant
1517 * spi_master (which the caller must release), or NULL if there is
1518 * no such master registered.
1520 struct spi_master *spi_busnum_to_master(u16 bus_num)
1523 struct spi_master *master = NULL;
1525 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1526 __spi_master_match);
1528 master = container_of(dev, struct spi_master, dev);
1529 /* reference got in class_find_device */
1532 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1535 /*-------------------------------------------------------------------------*/
1537 /* Core methods for SPI master protocol drivers. Some of the
1538 * other core methods are currently defined as inline functions.
1542 * spi_setup - setup SPI mode and clock rate
1543 * @spi: the device whose settings are being modified
1544 * Context: can sleep, and no requests are queued to the device
1546 * SPI protocol drivers may need to update the transfer mode if the
1547 * device doesn't work with its default. They may likewise need
1548 * to update clock rates or word sizes from initial values. This function
1549 * changes those settings, and must be called from a context that can sleep.
1550 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1551 * effect the next time the device is selected and data is transferred to
1552 * or from it. When this function returns, the spi device is deselected.
1554 * Note that this call will fail if the protocol driver specifies an option
1555 * that the underlying controller or its driver does not support. For
1556 * example, not all hardware supports wire transfers using nine bit words,
1557 * LSB-first wire encoding, or active-high chipselects.
1559 int spi_setup(struct spi_device *spi)
1564 /* check mode to prevent that DUAL and QUAD set at the same time
1566 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1567 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1569 "setup: can not select dual and quad at the same time\n");
1572 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1574 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1575 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1577 /* help drivers fail *cleanly* when they need options
1578 * that aren't supported with their current master
1580 bad_bits = spi->mode & ~spi->master->mode_bits;
1582 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1587 if (!spi->bits_per_word)
1588 spi->bits_per_word = 8;
1590 if (spi->master->setup)
1591 status = spi->master->setup(spi);
1593 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1594 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1595 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1596 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1597 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1598 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1599 spi->bits_per_word, spi->max_speed_hz,
1604 EXPORT_SYMBOL_GPL(spi_setup);
1606 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1608 struct spi_master *master = spi->master;
1609 struct spi_transfer *xfer;
1611 if (list_empty(&message->transfers))
1613 if (!message->complete)
1616 /* Half-duplex links include original MicroWire, and ones with
1617 * only one data pin like SPI_3WIRE (switches direction) or where
1618 * either MOSI or MISO is missing. They can also be caused by
1619 * software limitations.
1621 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1622 || (spi->mode & SPI_3WIRE)) {
1623 unsigned flags = master->flags;
1625 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1626 if (xfer->rx_buf && xfer->tx_buf)
1628 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1630 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1636 * Set transfer bits_per_word and max speed as spi device default if
1637 * it is not set for this transfer.
1638 * Set transfer tx_nbits and rx_nbits as single transfer default
1639 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1641 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1642 message->frame_length += xfer->len;
1643 if (!xfer->bits_per_word)
1644 xfer->bits_per_word = spi->bits_per_word;
1645 if (!xfer->speed_hz) {
1646 xfer->speed_hz = spi->max_speed_hz;
1647 if (master->max_speed_hz &&
1648 xfer->speed_hz > master->max_speed_hz)
1649 xfer->speed_hz = master->max_speed_hz;
1652 if (master->bits_per_word_mask) {
1653 /* Only 32 bits fit in the mask */
1654 if (xfer->bits_per_word > 32)
1656 if (!(master->bits_per_word_mask &
1657 BIT(xfer->bits_per_word - 1)))
1661 if (xfer->speed_hz && master->min_speed_hz &&
1662 xfer->speed_hz < master->min_speed_hz)
1664 if (xfer->speed_hz && master->max_speed_hz &&
1665 xfer->speed_hz > master->max_speed_hz)
1668 if (xfer->tx_buf && !xfer->tx_nbits)
1669 xfer->tx_nbits = SPI_NBITS_SINGLE;
1670 if (xfer->rx_buf && !xfer->rx_nbits)
1671 xfer->rx_nbits = SPI_NBITS_SINGLE;
1672 /* check transfer tx/rx_nbits:
1673 * 1. check the value matches one of single, dual and quad
1674 * 2. check tx/rx_nbits match the mode in spi_device
1677 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1678 xfer->tx_nbits != SPI_NBITS_DUAL &&
1679 xfer->tx_nbits != SPI_NBITS_QUAD)
1681 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1682 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1684 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1685 !(spi->mode & SPI_TX_QUAD))
1688 /* check transfer rx_nbits */
1690 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1691 xfer->rx_nbits != SPI_NBITS_DUAL &&
1692 xfer->rx_nbits != SPI_NBITS_QUAD)
1694 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1695 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1697 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1698 !(spi->mode & SPI_RX_QUAD))
1703 message->status = -EINPROGRESS;
1708 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1710 struct spi_master *master = spi->master;
1714 trace_spi_message_submit(message);
1716 return master->transfer(spi, message);
1720 * spi_async - asynchronous SPI transfer
1721 * @spi: device with which data will be exchanged
1722 * @message: describes the data transfers, including completion callback
1723 * Context: any (irqs may be blocked, etc)
1725 * This call may be used in_irq and other contexts which can't sleep,
1726 * as well as from task contexts which can sleep.
1728 * The completion callback is invoked in a context which can't sleep.
1729 * Before that invocation, the value of message->status is undefined.
1730 * When the callback is issued, message->status holds either zero (to
1731 * indicate complete success) or a negative error code. After that
1732 * callback returns, the driver which issued the transfer request may
1733 * deallocate the associated memory; it's no longer in use by any SPI
1734 * core or controller driver code.
1736 * Note that although all messages to a spi_device are handled in
1737 * FIFO order, messages may go to different devices in other orders.
1738 * Some device might be higher priority, or have various "hard" access
1739 * time requirements, for example.
1741 * On detection of any fault during the transfer, processing of
1742 * the entire message is aborted, and the device is deselected.
1743 * Until returning from the associated message completion callback,
1744 * no other spi_message queued to that device will be processed.
1745 * (This rule applies equally to all the synchronous transfer calls,
1746 * which are wrappers around this core asynchronous primitive.)
1748 int spi_async(struct spi_device *spi, struct spi_message *message)
1750 struct spi_master *master = spi->master;
1752 unsigned long flags;
1754 ret = __spi_validate(spi, message);
1758 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1760 if (master->bus_lock_flag)
1763 ret = __spi_async(spi, message);
1765 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1769 EXPORT_SYMBOL_GPL(spi_async);
1772 * spi_async_locked - version of spi_async with exclusive bus usage
1773 * @spi: device with which data will be exchanged
1774 * @message: describes the data transfers, including completion callback
1775 * Context: any (irqs may be blocked, etc)
1777 * This call may be used in_irq and other contexts which can't sleep,
1778 * as well as from task contexts which can sleep.
1780 * The completion callback is invoked in a context which can't sleep.
1781 * Before that invocation, the value of message->status is undefined.
1782 * When the callback is issued, message->status holds either zero (to
1783 * indicate complete success) or a negative error code. After that
1784 * callback returns, the driver which issued the transfer request may
1785 * deallocate the associated memory; it's no longer in use by any SPI
1786 * core or controller driver code.
1788 * Note that although all messages to a spi_device are handled in
1789 * FIFO order, messages may go to different devices in other orders.
1790 * Some device might be higher priority, or have various "hard" access
1791 * time requirements, for example.
1793 * On detection of any fault during the transfer, processing of
1794 * the entire message is aborted, and the device is deselected.
1795 * Until returning from the associated message completion callback,
1796 * no other spi_message queued to that device will be processed.
1797 * (This rule applies equally to all the synchronous transfer calls,
1798 * which are wrappers around this core asynchronous primitive.)
1800 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1802 struct spi_master *master = spi->master;
1804 unsigned long flags;
1806 ret = __spi_validate(spi, message);
1810 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1812 ret = __spi_async(spi, message);
1814 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1819 EXPORT_SYMBOL_GPL(spi_async_locked);
1822 /*-------------------------------------------------------------------------*/
1824 /* Utility methods for SPI master protocol drivers, layered on
1825 * top of the core. Some other utility methods are defined as
1829 static void spi_complete(void *arg)
1834 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1837 DECLARE_COMPLETION_ONSTACK(done);
1839 struct spi_master *master = spi->master;
1841 message->complete = spi_complete;
1842 message->context = &done;
1845 mutex_lock(&master->bus_lock_mutex);
1847 status = spi_async_locked(spi, message);
1850 mutex_unlock(&master->bus_lock_mutex);
1853 wait_for_completion(&done);
1854 status = message->status;
1856 message->context = NULL;
1861 * spi_sync - blocking/synchronous SPI data transfers
1862 * @spi: device with which data will be exchanged
1863 * @message: describes the data transfers
1864 * Context: can sleep
1866 * This call may only be used from a context that may sleep. The sleep
1867 * is non-interruptible, and has no timeout. Low-overhead controller
1868 * drivers may DMA directly into and out of the message buffers.
1870 * Note that the SPI device's chip select is active during the message,
1871 * and then is normally disabled between messages. Drivers for some
1872 * frequently-used devices may want to minimize costs of selecting a chip,
1873 * by leaving it selected in anticipation that the next message will go
1874 * to the same chip. (That may increase power usage.)
1876 * Also, the caller is guaranteeing that the memory associated with the
1877 * message will not be freed before this call returns.
1879 * It returns zero on success, else a negative error code.
1881 int spi_sync(struct spi_device *spi, struct spi_message *message)
1883 return __spi_sync(spi, message, 0);
1885 EXPORT_SYMBOL_GPL(spi_sync);
1888 * spi_sync_locked - version of spi_sync with exclusive bus usage
1889 * @spi: device with which data will be exchanged
1890 * @message: describes the data transfers
1891 * Context: can sleep
1893 * This call may only be used from a context that may sleep. The sleep
1894 * is non-interruptible, and has no timeout. Low-overhead controller
1895 * drivers may DMA directly into and out of the message buffers.
1897 * This call should be used by drivers that require exclusive access to the
1898 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1899 * be released by a spi_bus_unlock call when the exclusive access is over.
1901 * It returns zero on success, else a negative error code.
1903 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1905 return __spi_sync(spi, message, 1);
1907 EXPORT_SYMBOL_GPL(spi_sync_locked);
1910 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1911 * @master: SPI bus master that should be locked for exclusive bus access
1912 * Context: can sleep
1914 * This call may only be used from a context that may sleep. The sleep
1915 * is non-interruptible, and has no timeout.
1917 * This call should be used by drivers that require exclusive access to the
1918 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1919 * exclusive access is over. Data transfer must be done by spi_sync_locked
1920 * and spi_async_locked calls when the SPI bus lock is held.
1922 * It returns zero on success, else a negative error code.
1924 int spi_bus_lock(struct spi_master *master)
1926 unsigned long flags;
1928 mutex_lock(&master->bus_lock_mutex);
1930 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1931 master->bus_lock_flag = 1;
1932 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1934 /* mutex remains locked until spi_bus_unlock is called */
1938 EXPORT_SYMBOL_GPL(spi_bus_lock);
1941 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1942 * @master: SPI bus master that was locked for exclusive bus access
1943 * Context: can sleep
1945 * This call may only be used from a context that may sleep. The sleep
1946 * is non-interruptible, and has no timeout.
1948 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1951 * It returns zero on success, else a negative error code.
1953 int spi_bus_unlock(struct spi_master *master)
1955 master->bus_lock_flag = 0;
1957 mutex_unlock(&master->bus_lock_mutex);
1961 EXPORT_SYMBOL_GPL(spi_bus_unlock);
1963 /* portable code must never pass more than 32 bytes */
1964 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
1969 * spi_write_then_read - SPI synchronous write followed by read
1970 * @spi: device with which data will be exchanged
1971 * @txbuf: data to be written (need not be dma-safe)
1972 * @n_tx: size of txbuf, in bytes
1973 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1974 * @n_rx: size of rxbuf, in bytes
1975 * Context: can sleep
1977 * This performs a half duplex MicroWire style transaction with the
1978 * device, sending txbuf and then reading rxbuf. The return value
1979 * is zero for success, else a negative errno status code.
1980 * This call may only be used from a context that may sleep.
1982 * Parameters to this routine are always copied using a small buffer;
1983 * portable code should never use this for more than 32 bytes.
1984 * Performance-sensitive or bulk transfer code should instead use
1985 * spi_{async,sync}() calls with dma-safe buffers.
1987 int spi_write_then_read(struct spi_device *spi,
1988 const void *txbuf, unsigned n_tx,
1989 void *rxbuf, unsigned n_rx)
1991 static DEFINE_MUTEX(lock);
1994 struct spi_message message;
1995 struct spi_transfer x[2];
1998 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1999 * copying here, (as a pure convenience thing), but we can
2000 * keep heap costs out of the hot path unless someone else is
2001 * using the pre-allocated buffer or the transfer is too large.
2003 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2004 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2005 GFP_KERNEL | GFP_DMA);
2012 spi_message_init(&message);
2013 memset(x, 0, sizeof(x));
2016 spi_message_add_tail(&x[0], &message);
2020 spi_message_add_tail(&x[1], &message);
2023 memcpy(local_buf, txbuf, n_tx);
2024 x[0].tx_buf = local_buf;
2025 x[1].rx_buf = local_buf + n_tx;
2028 status = spi_sync(spi, &message);
2030 memcpy(rxbuf, x[1].rx_buf, n_rx);
2032 if (x[0].tx_buf == buf)
2033 mutex_unlock(&lock);
2039 EXPORT_SYMBOL_GPL(spi_write_then_read);
2041 /*-------------------------------------------------------------------------*/
2043 static int __init spi_init(void)
2047 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2053 status = bus_register(&spi_bus_type);
2057 status = class_register(&spi_master_class);
2063 bus_unregister(&spi_bus_type);
2071 /* board_info is normally registered in arch_initcall(),
2072 * but even essential drivers wait till later
2074 * REVISIT only boardinfo really needs static linking. the rest (device and
2075 * driver registration) _could_ be dynamically linked (modular) ... costs
2076 * include needing to have boardinfo data structures be much more public.
2078 postcore_initcall(spi_init);