4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/kernel.h>
23 #include <linux/kmod.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/cache.h>
27 #include <linux/mutex.h>
28 #include <linux/of_device.h>
29 #include <linux/of_irq.h>
30 #include <linux/slab.h>
31 #include <linux/mod_devicetable.h>
32 #include <linux/spi/spi.h>
33 #include <linux/of_gpio.h>
34 #include <linux/pm_runtime.h>
35 #include <linux/export.h>
36 #include <linux/sched/rt.h>
37 #include <linux/delay.h>
38 #include <linux/kthread.h>
39 #include <linux/ioport.h>
40 #include <linux/acpi.h>
42 #define CREATE_TRACE_POINTS
43 #include <trace/events/spi.h>
45 static void spidev_release(struct device *dev)
47 struct spi_device *spi = to_spi_device(dev);
49 /* spi masters may cleanup for released devices */
50 if (spi->master->cleanup)
51 spi->master->cleanup(spi);
53 spi_master_put(spi->master);
58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
60 const struct spi_device *spi = to_spi_device(dev);
63 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
67 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
69 static DEVICE_ATTR_RO(modalias);
71 static struct attribute *spi_dev_attrs[] = {
72 &dev_attr_modalias.attr,
75 ATTRIBUTE_GROUPS(spi_dev);
77 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
78 * and the sysfs version makes coldplug work too.
81 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
82 const struct spi_device *sdev)
85 if (!strcmp(sdev->modalias, id->name))
92 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
94 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
96 return spi_match_id(sdrv->id_table, sdev);
98 EXPORT_SYMBOL_GPL(spi_get_device_id);
100 static int spi_match_device(struct device *dev, struct device_driver *drv)
102 const struct spi_device *spi = to_spi_device(dev);
103 const struct spi_driver *sdrv = to_spi_driver(drv);
105 /* Attempt an OF style match */
106 if (of_driver_match_device(dev, drv))
110 if (acpi_driver_match_device(dev, drv))
114 return !!spi_match_id(sdrv->id_table, spi);
116 return strcmp(spi->modalias, drv->name) == 0;
119 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
121 const struct spi_device *spi = to_spi_device(dev);
124 rc = acpi_device_uevent_modalias(dev, env);
128 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
132 #ifdef CONFIG_PM_SLEEP
133 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
136 struct spi_driver *drv = to_spi_driver(dev->driver);
138 /* suspend will stop irqs and dma; no more i/o */
141 value = drv->suspend(to_spi_device(dev), message);
143 dev_dbg(dev, "... can't suspend\n");
148 static int spi_legacy_resume(struct device *dev)
151 struct spi_driver *drv = to_spi_driver(dev->driver);
153 /* resume may restart the i/o queue */
156 value = drv->resume(to_spi_device(dev));
158 dev_dbg(dev, "... can't resume\n");
163 static int spi_pm_suspend(struct device *dev)
165 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
168 return pm_generic_suspend(dev);
170 return spi_legacy_suspend(dev, PMSG_SUSPEND);
173 static int spi_pm_resume(struct device *dev)
175 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
178 return pm_generic_resume(dev);
180 return spi_legacy_resume(dev);
183 static int spi_pm_freeze(struct device *dev)
185 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
188 return pm_generic_freeze(dev);
190 return spi_legacy_suspend(dev, PMSG_FREEZE);
193 static int spi_pm_thaw(struct device *dev)
195 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
198 return pm_generic_thaw(dev);
200 return spi_legacy_resume(dev);
203 static int spi_pm_poweroff(struct device *dev)
205 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
208 return pm_generic_poweroff(dev);
210 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
213 static int spi_pm_restore(struct device *dev)
215 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
218 return pm_generic_restore(dev);
220 return spi_legacy_resume(dev);
223 #define spi_pm_suspend NULL
224 #define spi_pm_resume NULL
225 #define spi_pm_freeze NULL
226 #define spi_pm_thaw NULL
227 #define spi_pm_poweroff NULL
228 #define spi_pm_restore NULL
231 static const struct dev_pm_ops spi_pm = {
232 .suspend = spi_pm_suspend,
233 .resume = spi_pm_resume,
234 .freeze = spi_pm_freeze,
236 .poweroff = spi_pm_poweroff,
237 .restore = spi_pm_restore,
239 pm_generic_runtime_suspend,
240 pm_generic_runtime_resume,
245 struct bus_type spi_bus_type = {
247 .dev_groups = spi_dev_groups,
248 .match = spi_match_device,
249 .uevent = spi_uevent,
252 EXPORT_SYMBOL_GPL(spi_bus_type);
255 static int spi_drv_probe(struct device *dev)
257 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
258 struct spi_device *spi = to_spi_device(dev);
261 acpi_dev_pm_attach(&spi->dev, true);
262 ret = sdrv->probe(spi);
264 acpi_dev_pm_detach(&spi->dev, true);
269 static int spi_drv_remove(struct device *dev)
271 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
272 struct spi_device *spi = to_spi_device(dev);
275 ret = sdrv->remove(spi);
276 acpi_dev_pm_detach(&spi->dev, true);
281 static void spi_drv_shutdown(struct device *dev)
283 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
285 sdrv->shutdown(to_spi_device(dev));
289 * spi_register_driver - register a SPI driver
290 * @sdrv: the driver to register
293 int spi_register_driver(struct spi_driver *sdrv)
295 sdrv->driver.bus = &spi_bus_type;
297 sdrv->driver.probe = spi_drv_probe;
299 sdrv->driver.remove = spi_drv_remove;
301 sdrv->driver.shutdown = spi_drv_shutdown;
302 return driver_register(&sdrv->driver);
304 EXPORT_SYMBOL_GPL(spi_register_driver);
306 /*-------------------------------------------------------------------------*/
308 /* SPI devices should normally not be created by SPI device drivers; that
309 * would make them board-specific. Similarly with SPI master drivers.
310 * Device registration normally goes into like arch/.../mach.../board-YYY.c
311 * with other readonly (flashable) information about mainboard devices.
315 struct list_head list;
316 struct spi_board_info board_info;
319 static LIST_HEAD(board_list);
320 static LIST_HEAD(spi_master_list);
323 * Used to protect add/del opertion for board_info list and
324 * spi_master list, and their matching process
326 static DEFINE_MUTEX(board_lock);
329 * spi_alloc_device - Allocate a new SPI device
330 * @master: Controller to which device is connected
333 * Allows a driver to allocate and initialize a spi_device without
334 * registering it immediately. This allows a driver to directly
335 * fill the spi_device with device parameters before calling
336 * spi_add_device() on it.
338 * Caller is responsible to call spi_add_device() on the returned
339 * spi_device structure to add it to the SPI master. If the caller
340 * needs to discard the spi_device without adding it, then it should
341 * call spi_dev_put() on it.
343 * Returns a pointer to the new device, or NULL.
345 struct spi_device *spi_alloc_device(struct spi_master *master)
347 struct spi_device *spi;
348 struct device *dev = master->dev.parent;
350 if (!spi_master_get(master))
353 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
355 dev_err(dev, "cannot alloc spi_device\n");
356 spi_master_put(master);
360 spi->master = master;
361 spi->dev.parent = &master->dev;
362 spi->dev.bus = &spi_bus_type;
363 spi->dev.release = spidev_release;
364 spi->cs_gpio = -ENOENT;
365 device_initialize(&spi->dev);
368 EXPORT_SYMBOL_GPL(spi_alloc_device);
370 static void spi_dev_set_name(struct spi_device *spi)
372 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
375 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
379 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
384 * spi_add_device - Add spi_device allocated with spi_alloc_device
385 * @spi: spi_device to register
387 * Companion function to spi_alloc_device. Devices allocated with
388 * spi_alloc_device can be added onto the spi bus with this function.
390 * Returns 0 on success; negative errno on failure
392 int spi_add_device(struct spi_device *spi)
394 static DEFINE_MUTEX(spi_add_lock);
395 struct spi_master *master = spi->master;
396 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 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
419 dev_err(dev, "chipselect %d already in use\n",
426 if (master->cs_gpios)
427 spi->cs_gpio = master->cs_gpios[spi->chip_select];
429 /* Drivers may modify this initial i/o setup, but will
430 * normally rely on the device being setup. Devices
431 * using SPI_CS_HIGH can't coexist well otherwise...
433 status = spi_setup(spi);
435 dev_err(dev, "can't setup %s, status %d\n",
436 dev_name(&spi->dev), status);
440 /* Device may be bound to an active driver when this returns */
441 status = device_add(&spi->dev);
443 dev_err(dev, "can't add %s, status %d\n",
444 dev_name(&spi->dev), status);
446 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
449 mutex_unlock(&spi_add_lock);
452 EXPORT_SYMBOL_GPL(spi_add_device);
455 * spi_new_device - instantiate one new SPI device
456 * @master: Controller to which device is connected
457 * @chip: Describes the SPI device
460 * On typical mainboards, this is purely internal; and it's not needed
461 * after board init creates the hard-wired devices. Some development
462 * platforms may not be able to use spi_register_board_info though, and
463 * this is exported so that for example a USB or parport based adapter
464 * driver could add devices (which it would learn about out-of-band).
466 * Returns the new device, or NULL.
468 struct spi_device *spi_new_device(struct spi_master *master,
469 struct spi_board_info *chip)
471 struct spi_device *proxy;
474 /* NOTE: caller did any chip->bus_num checks necessary.
476 * Also, unless we change the return value convention to use
477 * error-or-pointer (not NULL-or-pointer), troubleshootability
478 * suggests syslogged diagnostics are best here (ugh).
481 proxy = spi_alloc_device(master);
485 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
487 proxy->chip_select = chip->chip_select;
488 proxy->max_speed_hz = chip->max_speed_hz;
489 proxy->mode = chip->mode;
490 proxy->irq = chip->irq;
491 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
492 proxy->dev.platform_data = (void *) chip->platform_data;
493 proxy->controller_data = chip->controller_data;
494 proxy->controller_state = NULL;
496 status = spi_add_device(proxy);
504 EXPORT_SYMBOL_GPL(spi_new_device);
506 static void spi_match_master_to_boardinfo(struct spi_master *master,
507 struct spi_board_info *bi)
509 struct spi_device *dev;
511 if (master->bus_num != bi->bus_num)
514 dev = spi_new_device(master, bi);
516 dev_err(master->dev.parent, "can't create new device for %s\n",
521 * spi_register_board_info - register SPI devices for a given board
522 * @info: array of chip descriptors
523 * @n: how many descriptors are provided
526 * Board-specific early init code calls this (probably during arch_initcall)
527 * with segments of the SPI device table. Any device nodes are created later,
528 * after the relevant parent SPI controller (bus_num) is defined. We keep
529 * this table of devices forever, so that reloading a controller driver will
530 * not make Linux forget about these hard-wired devices.
532 * Other code can also call this, e.g. a particular add-on board might provide
533 * SPI devices through its expansion connector, so code initializing that board
534 * would naturally declare its SPI devices.
536 * The board info passed can safely be __initdata ... but be careful of
537 * any embedded pointers (platform_data, etc), they're copied as-is.
539 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
541 struct boardinfo *bi;
544 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
548 for (i = 0; i < n; i++, bi++, info++) {
549 struct spi_master *master;
551 memcpy(&bi->board_info, info, sizeof(*info));
552 mutex_lock(&board_lock);
553 list_add_tail(&bi->list, &board_list);
554 list_for_each_entry(master, &spi_master_list, list)
555 spi_match_master_to_boardinfo(master, &bi->board_info);
556 mutex_unlock(&board_lock);
562 /*-------------------------------------------------------------------------*/
564 static void spi_set_cs(struct spi_device *spi, bool enable)
566 if (spi->mode & SPI_CS_HIGH)
569 if (spi->cs_gpio >= 0)
570 gpio_set_value(spi->cs_gpio, !enable);
571 else if (spi->master->set_cs)
572 spi->master->set_cs(spi, !enable);
576 * spi_transfer_one_message - Default implementation of transfer_one_message()
578 * This is a standard implementation of transfer_one_message() for
579 * drivers which impelment a transfer_one() operation. It provides
580 * standard handling of delays and chip select management.
582 static int spi_transfer_one_message(struct spi_master *master,
583 struct spi_message *msg)
585 struct spi_transfer *xfer;
587 bool keep_cs = false;
590 spi_set_cs(msg->spi, true);
592 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
593 trace_spi_transfer_start(msg, xfer);
595 reinit_completion(&master->xfer_completion);
597 ret = master->transfer_one(master, msg->spi, xfer);
599 dev_err(&msg->spi->dev,
600 "SPI transfer failed: %d\n", ret);
605 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 finised 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_entry(master->queue.next, 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 if (list_empty(&master->queue))
807 next = list_entry(master->queue.next,
808 struct spi_message, queue);
809 spin_unlock_irqrestore(&master->queue_lock, flags);
813 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
816 * spi_finalize_current_message() - the current message is complete
817 * @master: the master to return the message to
819 * Called by the driver to notify the core that the message in the front of the
820 * queue is complete and can be removed from the queue.
822 void spi_finalize_current_message(struct spi_master *master)
824 struct spi_message *mesg;
828 spin_lock_irqsave(&master->queue_lock, flags);
829 mesg = master->cur_msg;
830 master->cur_msg = NULL;
832 queue_kthread_work(&master->kworker, &master->pump_messages);
833 spin_unlock_irqrestore(&master->queue_lock, flags);
835 if (master->cur_msg_prepared && master->unprepare_message) {
836 ret = master->unprepare_message(master, mesg);
838 dev_err(&master->dev,
839 "failed to unprepare message: %d\n", ret);
842 master->cur_msg_prepared = false;
846 mesg->complete(mesg->context);
848 trace_spi_message_done(mesg);
850 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
852 static int spi_start_queue(struct spi_master *master)
856 spin_lock_irqsave(&master->queue_lock, flags);
858 if (master->running || master->busy) {
859 spin_unlock_irqrestore(&master->queue_lock, flags);
863 master->running = true;
864 master->cur_msg = NULL;
865 spin_unlock_irqrestore(&master->queue_lock, flags);
867 queue_kthread_work(&master->kworker, &master->pump_messages);
872 static int spi_stop_queue(struct spi_master *master)
875 unsigned limit = 500;
878 spin_lock_irqsave(&master->queue_lock, flags);
881 * This is a bit lame, but is optimized for the common execution path.
882 * A wait_queue on the master->busy could be used, but then the common
883 * execution path (pump_messages) would be required to call wake_up or
884 * friends on every SPI message. Do this instead.
886 while ((!list_empty(&master->queue) || master->busy) && limit--) {
887 spin_unlock_irqrestore(&master->queue_lock, flags);
889 spin_lock_irqsave(&master->queue_lock, flags);
892 if (!list_empty(&master->queue) || master->busy)
895 master->running = false;
897 spin_unlock_irqrestore(&master->queue_lock, flags);
900 dev_warn(&master->dev,
901 "could not stop message queue\n");
907 static int spi_destroy_queue(struct spi_master *master)
911 ret = spi_stop_queue(master);
914 * flush_kthread_worker will block until all work is done.
915 * If the reason that stop_queue timed out is that the work will never
916 * finish, then it does no good to call flush/stop thread, so
920 dev_err(&master->dev, "problem destroying queue\n");
924 flush_kthread_worker(&master->kworker);
925 kthread_stop(master->kworker_task);
931 * spi_queued_transfer - transfer function for queued transfers
932 * @spi: spi device which is requesting transfer
933 * @msg: spi message which is to handled is queued to driver queue
935 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
937 struct spi_master *master = spi->master;
940 spin_lock_irqsave(&master->queue_lock, flags);
942 if (!master->running) {
943 spin_unlock_irqrestore(&master->queue_lock, flags);
946 msg->actual_length = 0;
947 msg->status = -EINPROGRESS;
949 list_add_tail(&msg->queue, &master->queue);
951 queue_kthread_work(&master->kworker, &master->pump_messages);
953 spin_unlock_irqrestore(&master->queue_lock, flags);
957 static int spi_master_initialize_queue(struct spi_master *master)
961 master->queued = true;
962 master->transfer = spi_queued_transfer;
963 if (!master->transfer_one_message)
964 master->transfer_one_message = spi_transfer_one_message;
966 /* Initialize and start queue */
967 ret = spi_init_queue(master);
969 dev_err(&master->dev, "problem initializing queue\n");
972 ret = spi_start_queue(master);
974 dev_err(&master->dev, "problem starting queue\n");
975 goto err_start_queue;
982 spi_destroy_queue(master);
986 /*-------------------------------------------------------------------------*/
988 #if defined(CONFIG_OF)
990 * of_register_spi_devices() - Register child devices onto the SPI bus
991 * @master: Pointer to spi_master device
993 * Registers an spi_device for each child node of master node which has a 'reg'
996 static void of_register_spi_devices(struct spi_master *master)
998 struct spi_device *spi;
999 struct device_node *nc;
1003 if (!master->dev.of_node)
1006 for_each_available_child_of_node(master->dev.of_node, nc) {
1007 /* Alloc an spi_device */
1008 spi = spi_alloc_device(master);
1010 dev_err(&master->dev, "spi_device alloc error for %s\n",
1016 /* Select device driver */
1017 if (of_modalias_node(nc, spi->modalias,
1018 sizeof(spi->modalias)) < 0) {
1019 dev_err(&master->dev, "cannot find modalias for %s\n",
1025 /* Device address */
1026 rc = of_property_read_u32(nc, "reg", &value);
1028 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1033 spi->chip_select = value;
1035 /* Mode (clock phase/polarity/etc.) */
1036 if (of_find_property(nc, "spi-cpha", NULL))
1037 spi->mode |= SPI_CPHA;
1038 if (of_find_property(nc, "spi-cpol", NULL))
1039 spi->mode |= SPI_CPOL;
1040 if (of_find_property(nc, "spi-cs-high", NULL))
1041 spi->mode |= SPI_CS_HIGH;
1042 if (of_find_property(nc, "spi-3wire", NULL))
1043 spi->mode |= SPI_3WIRE;
1045 /* Device DUAL/QUAD mode */
1046 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1051 spi->mode |= SPI_TX_DUAL;
1054 spi->mode |= SPI_TX_QUAD;
1057 dev_err(&master->dev,
1058 "spi-tx-bus-width %d not supported\n",
1065 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1070 spi->mode |= SPI_RX_DUAL;
1073 spi->mode |= SPI_RX_QUAD;
1076 dev_err(&master->dev,
1077 "spi-rx-bus-width %d not supported\n",
1085 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1087 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1092 spi->max_speed_hz = value;
1095 spi->irq = irq_of_parse_and_map(nc, 0);
1097 /* Store a pointer to the node in the device structure */
1099 spi->dev.of_node = nc;
1101 /* Register the new device */
1102 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1103 rc = spi_add_device(spi);
1105 dev_err(&master->dev, "spi_device register error %s\n",
1113 static void of_register_spi_devices(struct spi_master *master) { }
1117 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1119 struct spi_device *spi = data;
1121 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1122 struct acpi_resource_spi_serialbus *sb;
1124 sb = &ares->data.spi_serial_bus;
1125 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1126 spi->chip_select = sb->device_selection;
1127 spi->max_speed_hz = sb->connection_speed;
1129 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1130 spi->mode |= SPI_CPHA;
1131 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1132 spi->mode |= SPI_CPOL;
1133 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1134 spi->mode |= SPI_CS_HIGH;
1136 } else if (spi->irq < 0) {
1139 if (acpi_dev_resource_interrupt(ares, 0, &r))
1143 /* Always tell the ACPI core to skip this resource */
1147 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1148 void *data, void **return_value)
1150 struct spi_master *master = data;
1151 struct list_head resource_list;
1152 struct acpi_device *adev;
1153 struct spi_device *spi;
1156 if (acpi_bus_get_device(handle, &adev))
1158 if (acpi_bus_get_status(adev) || !adev->status.present)
1161 spi = spi_alloc_device(master);
1163 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1164 dev_name(&adev->dev));
1165 return AE_NO_MEMORY;
1168 ACPI_COMPANION_SET(&spi->dev, adev);
1171 INIT_LIST_HEAD(&resource_list);
1172 ret = acpi_dev_get_resources(adev, &resource_list,
1173 acpi_spi_add_resource, spi);
1174 acpi_dev_free_resource_list(&resource_list);
1176 if (ret < 0 || !spi->max_speed_hz) {
1181 adev->power.flags.ignore_parent = true;
1182 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1183 if (spi_add_device(spi)) {
1184 adev->power.flags.ignore_parent = false;
1185 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1186 dev_name(&adev->dev));
1193 static void acpi_register_spi_devices(struct spi_master *master)
1198 handle = ACPI_HANDLE(master->dev.parent);
1202 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1203 acpi_spi_add_device, NULL,
1205 if (ACPI_FAILURE(status))
1206 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1209 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1210 #endif /* CONFIG_ACPI */
1212 static void spi_master_release(struct device *dev)
1214 struct spi_master *master;
1216 master = container_of(dev, struct spi_master, dev);
1220 static struct class spi_master_class = {
1221 .name = "spi_master",
1222 .owner = THIS_MODULE,
1223 .dev_release = spi_master_release,
1229 * spi_alloc_master - allocate SPI master controller
1230 * @dev: the controller, possibly using the platform_bus
1231 * @size: how much zeroed driver-private data to allocate; the pointer to this
1232 * memory is in the driver_data field of the returned device,
1233 * accessible with spi_master_get_devdata().
1234 * Context: can sleep
1236 * This call is used only by SPI master controller drivers, which are the
1237 * only ones directly touching chip registers. It's how they allocate
1238 * an spi_master structure, prior to calling spi_register_master().
1240 * This must be called from context that can sleep. It returns the SPI
1241 * master structure on success, else NULL.
1243 * The caller is responsible for assigning the bus number and initializing
1244 * the master's methods before calling spi_register_master(); and (after errors
1245 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1248 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1250 struct spi_master *master;
1255 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1259 device_initialize(&master->dev);
1260 master->bus_num = -1;
1261 master->num_chipselect = 1;
1262 master->dev.class = &spi_master_class;
1263 master->dev.parent = get_device(dev);
1264 spi_master_set_devdata(master, &master[1]);
1268 EXPORT_SYMBOL_GPL(spi_alloc_master);
1271 static int of_spi_register_master(struct spi_master *master)
1274 struct device_node *np = master->dev.of_node;
1279 nb = of_gpio_named_count(np, "cs-gpios");
1280 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1282 /* Return error only for an incorrectly formed cs-gpios property */
1283 if (nb == 0 || nb == -ENOENT)
1288 cs = devm_kzalloc(&master->dev,
1289 sizeof(int) * master->num_chipselect,
1291 master->cs_gpios = cs;
1293 if (!master->cs_gpios)
1296 for (i = 0; i < master->num_chipselect; i++)
1299 for (i = 0; i < nb; i++)
1300 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1305 static int of_spi_register_master(struct spi_master *master)
1312 * spi_register_master - register SPI master controller
1313 * @master: initialized master, originally from spi_alloc_master()
1314 * Context: can sleep
1316 * SPI master controllers connect to their drivers using some non-SPI bus,
1317 * such as the platform bus. The final stage of probe() in that code
1318 * includes calling spi_register_master() to hook up to this SPI bus glue.
1320 * SPI controllers use board specific (often SOC specific) bus numbers,
1321 * and board-specific addressing for SPI devices combines those numbers
1322 * with chip select numbers. Since SPI does not directly support dynamic
1323 * device identification, boards need configuration tables telling which
1324 * chip is at which address.
1326 * This must be called from context that can sleep. It returns zero on
1327 * success, else a negative error code (dropping the master's refcount).
1328 * After a successful return, the caller is responsible for calling
1329 * spi_unregister_master().
1331 int spi_register_master(struct spi_master *master)
1333 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1334 struct device *dev = master->dev.parent;
1335 struct boardinfo *bi;
1336 int status = -ENODEV;
1342 status = of_spi_register_master(master);
1346 /* even if it's just one always-selected device, there must
1347 * be at least one chipselect
1349 if (master->num_chipselect == 0)
1352 if ((master->bus_num < 0) && master->dev.of_node)
1353 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1355 /* convention: dynamically assigned bus IDs count down from the max */
1356 if (master->bus_num < 0) {
1357 /* FIXME switch to an IDR based scheme, something like
1358 * I2C now uses, so we can't run out of "dynamic" IDs
1360 master->bus_num = atomic_dec_return(&dyn_bus_id);
1364 spin_lock_init(&master->bus_lock_spinlock);
1365 mutex_init(&master->bus_lock_mutex);
1366 master->bus_lock_flag = 0;
1367 init_completion(&master->xfer_completion);
1369 /* register the device, then userspace will see it.
1370 * registration fails if the bus ID is in use.
1372 dev_set_name(&master->dev, "spi%u", master->bus_num);
1373 status = device_add(&master->dev);
1376 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1377 dynamic ? " (dynamic)" : "");
1379 /* If we're using a queued driver, start the queue */
1380 if (master->transfer)
1381 dev_info(dev, "master is unqueued, this is deprecated\n");
1383 status = spi_master_initialize_queue(master);
1385 device_del(&master->dev);
1390 mutex_lock(&board_lock);
1391 list_add_tail(&master->list, &spi_master_list);
1392 list_for_each_entry(bi, &board_list, list)
1393 spi_match_master_to_boardinfo(master, &bi->board_info);
1394 mutex_unlock(&board_lock);
1396 /* Register devices from the device tree and ACPI */
1397 of_register_spi_devices(master);
1398 acpi_register_spi_devices(master);
1402 EXPORT_SYMBOL_GPL(spi_register_master);
1404 static void devm_spi_unregister(struct device *dev, void *res)
1406 spi_unregister_master(*(struct spi_master **)res);
1410 * dev_spi_register_master - register managed SPI master controller
1411 * @dev: device managing SPI master
1412 * @master: initialized master, originally from spi_alloc_master()
1413 * Context: can sleep
1415 * Register a SPI device as with spi_register_master() which will
1416 * automatically be unregister
1418 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1420 struct spi_master **ptr;
1423 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1427 ret = spi_register_master(master);
1430 devres_add(dev, ptr);
1437 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1439 static int __unregister(struct device *dev, void *null)
1441 spi_unregister_device(to_spi_device(dev));
1446 * spi_unregister_master - unregister SPI master controller
1447 * @master: the master being unregistered
1448 * Context: can sleep
1450 * This call is used only by SPI master controller drivers, which are the
1451 * only ones directly touching chip registers.
1453 * This must be called from context that can sleep.
1455 void spi_unregister_master(struct spi_master *master)
1459 if (master->queued) {
1460 if (spi_destroy_queue(master))
1461 dev_err(&master->dev, "queue remove failed\n");
1464 mutex_lock(&board_lock);
1465 list_del(&master->list);
1466 mutex_unlock(&board_lock);
1468 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1469 device_unregister(&master->dev);
1471 EXPORT_SYMBOL_GPL(spi_unregister_master);
1473 int spi_master_suspend(struct spi_master *master)
1477 /* Basically no-ops for non-queued masters */
1478 if (!master->queued)
1481 ret = spi_stop_queue(master);
1483 dev_err(&master->dev, "queue stop failed\n");
1487 EXPORT_SYMBOL_GPL(spi_master_suspend);
1489 int spi_master_resume(struct spi_master *master)
1493 if (!master->queued)
1496 ret = spi_start_queue(master);
1498 dev_err(&master->dev, "queue restart failed\n");
1502 EXPORT_SYMBOL_GPL(spi_master_resume);
1504 static int __spi_master_match(struct device *dev, const void *data)
1506 struct spi_master *m;
1507 const u16 *bus_num = data;
1509 m = container_of(dev, struct spi_master, dev);
1510 return m->bus_num == *bus_num;
1514 * spi_busnum_to_master - look up master associated with bus_num
1515 * @bus_num: the master's bus number
1516 * Context: can sleep
1518 * This call may be used with devices that are registered after
1519 * arch init time. It returns a refcounted pointer to the relevant
1520 * spi_master (which the caller must release), or NULL if there is
1521 * no such master registered.
1523 struct spi_master *spi_busnum_to_master(u16 bus_num)
1526 struct spi_master *master = NULL;
1528 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1529 __spi_master_match);
1531 master = container_of(dev, struct spi_master, dev);
1532 /* reference got in class_find_device */
1535 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1538 /*-------------------------------------------------------------------------*/
1540 /* Core methods for SPI master protocol drivers. Some of the
1541 * other core methods are currently defined as inline functions.
1545 * spi_setup - setup SPI mode and clock rate
1546 * @spi: the device whose settings are being modified
1547 * Context: can sleep, and no requests are queued to the device
1549 * SPI protocol drivers may need to update the transfer mode if the
1550 * device doesn't work with its default. They may likewise need
1551 * to update clock rates or word sizes from initial values. This function
1552 * changes those settings, and must be called from a context that can sleep.
1553 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1554 * effect the next time the device is selected and data is transferred to
1555 * or from it. When this function returns, the spi device is deselected.
1557 * Note that this call will fail if the protocol driver specifies an option
1558 * that the underlying controller or its driver does not support. For
1559 * example, not all hardware supports wire transfers using nine bit words,
1560 * LSB-first wire encoding, or active-high chipselects.
1562 int spi_setup(struct spi_device *spi)
1567 /* check mode to prevent that DUAL and QUAD set at the same time
1569 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1570 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1572 "setup: can not select dual and quad at the same time\n");
1575 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1577 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1578 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1580 /* help drivers fail *cleanly* when they need options
1581 * that aren't supported with their current master
1583 bad_bits = spi->mode & ~spi->master->mode_bits;
1585 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1590 if (!spi->bits_per_word)
1591 spi->bits_per_word = 8;
1593 if (spi->master->setup)
1594 status = spi->master->setup(spi);
1596 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1597 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1598 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1599 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1600 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1601 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1602 spi->bits_per_word, spi->max_speed_hz,
1607 EXPORT_SYMBOL_GPL(spi_setup);
1609 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1611 struct spi_master *master = spi->master;
1612 struct spi_transfer *xfer;
1616 trace_spi_message_submit(message);
1618 if (list_empty(&message->transfers))
1620 if (!message->complete)
1623 /* Half-duplex links include original MicroWire, and ones with
1624 * only one data pin like SPI_3WIRE (switches direction) or where
1625 * either MOSI or MISO is missing. They can also be caused by
1626 * software limitations.
1628 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1629 || (spi->mode & SPI_3WIRE)) {
1630 unsigned flags = master->flags;
1632 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1633 if (xfer->rx_buf && xfer->tx_buf)
1635 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1637 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1643 * Set transfer bits_per_word and max speed as spi device default if
1644 * it is not set for this transfer.
1645 * Set transfer tx_nbits and rx_nbits as single transfer default
1646 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1648 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1649 message->frame_length += xfer->len;
1650 if (!xfer->bits_per_word)
1651 xfer->bits_per_word = spi->bits_per_word;
1652 if (!xfer->speed_hz) {
1653 xfer->speed_hz = spi->max_speed_hz;
1654 if (master->max_speed_hz &&
1655 xfer->speed_hz > master->max_speed_hz)
1656 xfer->speed_hz = master->max_speed_hz;
1659 if (master->bits_per_word_mask) {
1660 /* Only 32 bits fit in the mask */
1661 if (xfer->bits_per_word > 32)
1663 if (!(master->bits_per_word_mask &
1664 BIT(xfer->bits_per_word - 1)))
1668 if (xfer->speed_hz && master->min_speed_hz &&
1669 xfer->speed_hz < master->min_speed_hz)
1671 if (xfer->speed_hz && master->max_speed_hz &&
1672 xfer->speed_hz > master->max_speed_hz)
1675 if (xfer->tx_buf && !xfer->tx_nbits)
1676 xfer->tx_nbits = SPI_NBITS_SINGLE;
1677 if (xfer->rx_buf && !xfer->rx_nbits)
1678 xfer->rx_nbits = SPI_NBITS_SINGLE;
1679 /* check transfer tx/rx_nbits:
1680 * 1. keep the value is not out of single, dual and quad
1681 * 2. keep tx/rx_nbits is contained by mode in spi_device
1682 * 3. if SPI_3WIRE, tx/rx_nbits should be in single
1685 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1686 xfer->tx_nbits != SPI_NBITS_DUAL &&
1687 xfer->tx_nbits != SPI_NBITS_QUAD)
1689 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1690 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1692 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1693 !(spi->mode & SPI_TX_QUAD))
1695 if ((spi->mode & SPI_3WIRE) &&
1696 (xfer->tx_nbits != SPI_NBITS_SINGLE))
1699 /* check transfer rx_nbits */
1701 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1702 xfer->rx_nbits != SPI_NBITS_DUAL &&
1703 xfer->rx_nbits != SPI_NBITS_QUAD)
1705 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1706 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1708 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1709 !(spi->mode & SPI_RX_QUAD))
1711 if ((spi->mode & SPI_3WIRE) &&
1712 (xfer->rx_nbits != SPI_NBITS_SINGLE))
1717 message->status = -EINPROGRESS;
1718 return master->transfer(spi, message);
1722 * spi_async - asynchronous SPI transfer
1723 * @spi: device with which data will be exchanged
1724 * @message: describes the data transfers, including completion callback
1725 * Context: any (irqs may be blocked, etc)
1727 * This call may be used in_irq and other contexts which can't sleep,
1728 * as well as from task contexts which can sleep.
1730 * The completion callback is invoked in a context which can't sleep.
1731 * Before that invocation, the value of message->status is undefined.
1732 * When the callback is issued, message->status holds either zero (to
1733 * indicate complete success) or a negative error code. After that
1734 * callback returns, the driver which issued the transfer request may
1735 * deallocate the associated memory; it's no longer in use by any SPI
1736 * core or controller driver code.
1738 * Note that although all messages to a spi_device are handled in
1739 * FIFO order, messages may go to different devices in other orders.
1740 * Some device might be higher priority, or have various "hard" access
1741 * time requirements, for example.
1743 * On detection of any fault during the transfer, processing of
1744 * the entire message is aborted, and the device is deselected.
1745 * Until returning from the associated message completion callback,
1746 * no other spi_message queued to that device will be processed.
1747 * (This rule applies equally to all the synchronous transfer calls,
1748 * which are wrappers around this core asynchronous primitive.)
1750 int spi_async(struct spi_device *spi, struct spi_message *message)
1752 struct spi_master *master = spi->master;
1754 unsigned long flags;
1756 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1758 if (master->bus_lock_flag)
1761 ret = __spi_async(spi, message);
1763 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1767 EXPORT_SYMBOL_GPL(spi_async);
1770 * spi_async_locked - version of spi_async with exclusive bus usage
1771 * @spi: device with which data will be exchanged
1772 * @message: describes the data transfers, including completion callback
1773 * Context: any (irqs may be blocked, etc)
1775 * This call may be used in_irq and other contexts which can't sleep,
1776 * as well as from task contexts which can sleep.
1778 * The completion callback is invoked in a context which can't sleep.
1779 * Before that invocation, the value of message->status is undefined.
1780 * When the callback is issued, message->status holds either zero (to
1781 * indicate complete success) or a negative error code. After that
1782 * callback returns, the driver which issued the transfer request may
1783 * deallocate the associated memory; it's no longer in use by any SPI
1784 * core or controller driver code.
1786 * Note that although all messages to a spi_device are handled in
1787 * FIFO order, messages may go to different devices in other orders.
1788 * Some device might be higher priority, or have various "hard" access
1789 * time requirements, for example.
1791 * On detection of any fault during the transfer, processing of
1792 * the entire message is aborted, and the device is deselected.
1793 * Until returning from the associated message completion callback,
1794 * no other spi_message queued to that device will be processed.
1795 * (This rule applies equally to all the synchronous transfer calls,
1796 * which are wrappers around this core asynchronous primitive.)
1798 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1800 struct spi_master *master = spi->master;
1802 unsigned long flags;
1804 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1806 ret = __spi_async(spi, message);
1808 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1813 EXPORT_SYMBOL_GPL(spi_async_locked);
1816 /*-------------------------------------------------------------------------*/
1818 /* Utility methods for SPI master protocol drivers, layered on
1819 * top of the core. Some other utility methods are defined as
1823 static void spi_complete(void *arg)
1828 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1831 DECLARE_COMPLETION_ONSTACK(done);
1833 struct spi_master *master = spi->master;
1835 message->complete = spi_complete;
1836 message->context = &done;
1839 mutex_lock(&master->bus_lock_mutex);
1841 status = spi_async_locked(spi, message);
1844 mutex_unlock(&master->bus_lock_mutex);
1847 wait_for_completion(&done);
1848 status = message->status;
1850 message->context = NULL;
1855 * spi_sync - blocking/synchronous SPI data transfers
1856 * @spi: device with which data will be exchanged
1857 * @message: describes the data transfers
1858 * Context: can sleep
1860 * This call may only be used from a context that may sleep. The sleep
1861 * is non-interruptible, and has no timeout. Low-overhead controller
1862 * drivers may DMA directly into and out of the message buffers.
1864 * Note that the SPI device's chip select is active during the message,
1865 * and then is normally disabled between messages. Drivers for some
1866 * frequently-used devices may want to minimize costs of selecting a chip,
1867 * by leaving it selected in anticipation that the next message will go
1868 * to the same chip. (That may increase power usage.)
1870 * Also, the caller is guaranteeing that the memory associated with the
1871 * message will not be freed before this call returns.
1873 * It returns zero on success, else a negative error code.
1875 int spi_sync(struct spi_device *spi, struct spi_message *message)
1877 return __spi_sync(spi, message, 0);
1879 EXPORT_SYMBOL_GPL(spi_sync);
1882 * spi_sync_locked - version of spi_sync with exclusive bus usage
1883 * @spi: device with which data will be exchanged
1884 * @message: describes the data transfers
1885 * Context: can sleep
1887 * This call may only be used from a context that may sleep. The sleep
1888 * is non-interruptible, and has no timeout. Low-overhead controller
1889 * drivers may DMA directly into and out of the message buffers.
1891 * This call should be used by drivers that require exclusive access to the
1892 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1893 * be released by a spi_bus_unlock call when the exclusive access is over.
1895 * It returns zero on success, else a negative error code.
1897 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1899 return __spi_sync(spi, message, 1);
1901 EXPORT_SYMBOL_GPL(spi_sync_locked);
1904 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1905 * @master: SPI bus master that should be locked for exclusive bus access
1906 * Context: can sleep
1908 * This call may only be used from a context that may sleep. The sleep
1909 * is non-interruptible, and has no timeout.
1911 * This call should be used by drivers that require exclusive access to the
1912 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1913 * exclusive access is over. Data transfer must be done by spi_sync_locked
1914 * and spi_async_locked calls when the SPI bus lock is held.
1916 * It returns zero on success, else a negative error code.
1918 int spi_bus_lock(struct spi_master *master)
1920 unsigned long flags;
1922 mutex_lock(&master->bus_lock_mutex);
1924 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1925 master->bus_lock_flag = 1;
1926 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1928 /* mutex remains locked until spi_bus_unlock is called */
1932 EXPORT_SYMBOL_GPL(spi_bus_lock);
1935 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1936 * @master: SPI bus master that was locked for exclusive bus access
1937 * Context: can sleep
1939 * This call may only be used from a context that may sleep. The sleep
1940 * is non-interruptible, and has no timeout.
1942 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1945 * It returns zero on success, else a negative error code.
1947 int spi_bus_unlock(struct spi_master *master)
1949 master->bus_lock_flag = 0;
1951 mutex_unlock(&master->bus_lock_mutex);
1955 EXPORT_SYMBOL_GPL(spi_bus_unlock);
1957 /* portable code must never pass more than 32 bytes */
1958 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
1963 * spi_write_then_read - SPI synchronous write followed by read
1964 * @spi: device with which data will be exchanged
1965 * @txbuf: data to be written (need not be dma-safe)
1966 * @n_tx: size of txbuf, in bytes
1967 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1968 * @n_rx: size of rxbuf, in bytes
1969 * Context: can sleep
1971 * This performs a half duplex MicroWire style transaction with the
1972 * device, sending txbuf and then reading rxbuf. The return value
1973 * is zero for success, else a negative errno status code.
1974 * This call may only be used from a context that may sleep.
1976 * Parameters to this routine are always copied using a small buffer;
1977 * portable code should never use this for more than 32 bytes.
1978 * Performance-sensitive or bulk transfer code should instead use
1979 * spi_{async,sync}() calls with dma-safe buffers.
1981 int spi_write_then_read(struct spi_device *spi,
1982 const void *txbuf, unsigned n_tx,
1983 void *rxbuf, unsigned n_rx)
1985 static DEFINE_MUTEX(lock);
1988 struct spi_message message;
1989 struct spi_transfer x[2];
1992 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1993 * copying here, (as a pure convenience thing), but we can
1994 * keep heap costs out of the hot path unless someone else is
1995 * using the pre-allocated buffer or the transfer is too large.
1997 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
1998 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
1999 GFP_KERNEL | GFP_DMA);
2006 spi_message_init(&message);
2007 memset(x, 0, sizeof(x));
2010 spi_message_add_tail(&x[0], &message);
2014 spi_message_add_tail(&x[1], &message);
2017 memcpy(local_buf, txbuf, n_tx);
2018 x[0].tx_buf = local_buf;
2019 x[1].rx_buf = local_buf + n_tx;
2022 status = spi_sync(spi, &message);
2024 memcpy(rxbuf, x[1].rx_buf, n_rx);
2026 if (x[0].tx_buf == buf)
2027 mutex_unlock(&lock);
2033 EXPORT_SYMBOL_GPL(spi_write_then_read);
2035 /*-------------------------------------------------------------------------*/
2037 static int __init spi_init(void)
2041 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2047 status = bus_register(&spi_bus_type);
2051 status = class_register(&spi_master_class);
2057 bus_unregister(&spi_bus_type);
2065 /* board_info is normally registered in arch_initcall(),
2066 * but even essential drivers wait till later
2068 * REVISIT only boardinfo really needs static linking. the rest (device and
2069 * driver registration) _could_ be dynamically linked (modular) ... costs
2070 * include needing to have boardinfo data structures be much more public.
2072 postcore_initcall(spi_init);