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);
361 * spi_add_device - Add spi_device allocated with spi_alloc_device
362 * @spi: spi_device to register
364 * Companion function to spi_alloc_device. Devices allocated with
365 * spi_alloc_device can be added onto the spi bus with this function.
367 * Returns 0 on success; negative errno on failure
369 int spi_add_device(struct spi_device *spi)
371 static DEFINE_MUTEX(spi_add_lock);
372 struct spi_master *master = spi->master;
373 struct device *dev = master->dev.parent;
377 /* Chipselects are numbered 0..max; validate. */
378 if (spi->chip_select >= master->num_chipselect) {
379 dev_err(dev, "cs%d >= max %d\n",
381 master->num_chipselect);
385 /* Set the bus ID string */
386 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
390 /* We need to make sure there's no other device with this
391 * chipselect **BEFORE** we call setup(), else we'll trash
392 * its configuration. Lock against concurrent add() calls.
394 mutex_lock(&spi_add_lock);
396 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
398 dev_err(dev, "chipselect %d already in use\n",
405 if (master->cs_gpios)
406 spi->cs_gpio = master->cs_gpios[spi->chip_select];
408 /* Drivers may modify this initial i/o setup, but will
409 * normally rely on the device being setup. Devices
410 * using SPI_CS_HIGH can't coexist well otherwise...
412 status = spi_setup(spi);
414 dev_err(dev, "can't setup %s, status %d\n",
415 dev_name(&spi->dev), status);
419 /* Device may be bound to an active driver when this returns */
420 status = device_add(&spi->dev);
422 dev_err(dev, "can't add %s, status %d\n",
423 dev_name(&spi->dev), status);
425 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
428 mutex_unlock(&spi_add_lock);
431 EXPORT_SYMBOL_GPL(spi_add_device);
434 * spi_new_device - instantiate one new SPI device
435 * @master: Controller to which device is connected
436 * @chip: Describes the SPI device
439 * On typical mainboards, this is purely internal; and it's not needed
440 * after board init creates the hard-wired devices. Some development
441 * platforms may not be able to use spi_register_board_info though, and
442 * this is exported so that for example a USB or parport based adapter
443 * driver could add devices (which it would learn about out-of-band).
445 * Returns the new device, or NULL.
447 struct spi_device *spi_new_device(struct spi_master *master,
448 struct spi_board_info *chip)
450 struct spi_device *proxy;
453 /* NOTE: caller did any chip->bus_num checks necessary.
455 * Also, unless we change the return value convention to use
456 * error-or-pointer (not NULL-or-pointer), troubleshootability
457 * suggests syslogged diagnostics are best here (ugh).
460 proxy = spi_alloc_device(master);
464 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
466 proxy->chip_select = chip->chip_select;
467 proxy->max_speed_hz = chip->max_speed_hz;
468 proxy->mode = chip->mode;
469 proxy->irq = chip->irq;
470 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
471 proxy->dev.platform_data = (void *) chip->platform_data;
472 proxy->controller_data = chip->controller_data;
473 proxy->controller_state = NULL;
475 status = spi_add_device(proxy);
483 EXPORT_SYMBOL_GPL(spi_new_device);
485 static void spi_match_master_to_boardinfo(struct spi_master *master,
486 struct spi_board_info *bi)
488 struct spi_device *dev;
490 if (master->bus_num != bi->bus_num)
493 dev = spi_new_device(master, bi);
495 dev_err(master->dev.parent, "can't create new device for %s\n",
500 * spi_register_board_info - register SPI devices for a given board
501 * @info: array of chip descriptors
502 * @n: how many descriptors are provided
505 * Board-specific early init code calls this (probably during arch_initcall)
506 * with segments of the SPI device table. Any device nodes are created later,
507 * after the relevant parent SPI controller (bus_num) is defined. We keep
508 * this table of devices forever, so that reloading a controller driver will
509 * not make Linux forget about these hard-wired devices.
511 * Other code can also call this, e.g. a particular add-on board might provide
512 * SPI devices through its expansion connector, so code initializing that board
513 * would naturally declare its SPI devices.
515 * The board info passed can safely be __initdata ... but be careful of
516 * any embedded pointers (platform_data, etc), they're copied as-is.
518 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
520 struct boardinfo *bi;
523 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
527 for (i = 0; i < n; i++, bi++, info++) {
528 struct spi_master *master;
530 memcpy(&bi->board_info, info, sizeof(*info));
531 mutex_lock(&board_lock);
532 list_add_tail(&bi->list, &board_list);
533 list_for_each_entry(master, &spi_master_list, list)
534 spi_match_master_to_boardinfo(master, &bi->board_info);
535 mutex_unlock(&board_lock);
541 /*-------------------------------------------------------------------------*/
543 static void spi_set_cs(struct spi_device *spi, bool enable)
545 if (spi->mode & SPI_CS_HIGH)
548 if (spi->cs_gpio >= 0)
549 gpio_set_value(spi->cs_gpio, !enable);
550 else if (spi->master->set_cs)
551 spi->master->set_cs(spi, !enable);
555 * spi_transfer_one_message - Default implementation of transfer_one_message()
557 * This is a standard implementation of transfer_one_message() for
558 * drivers which impelment a transfer_one() operation. It provides
559 * standard handling of delays and chip select management.
561 static int spi_transfer_one_message(struct spi_master *master,
562 struct spi_message *msg)
564 struct spi_transfer *xfer;
566 bool keep_cs = false;
569 spi_set_cs(msg->spi, true);
571 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
572 trace_spi_transfer_start(msg, xfer);
574 reinit_completion(&master->xfer_completion);
576 ret = master->transfer_one(master, msg->spi, xfer);
578 dev_err(&msg->spi->dev,
579 "SPI transfer failed: %d\n", ret);
584 wait_for_completion(&master->xfer_completion);
586 trace_spi_transfer_stop(msg, xfer);
588 if (msg->status != -EINPROGRESS)
591 if (xfer->delay_usecs)
592 udelay(xfer->delay_usecs);
594 if (xfer->cs_change) {
595 if (list_is_last(&xfer->transfer_list,
600 spi_set_cs(msg->spi, cur_cs);
604 msg->actual_length += xfer->len;
608 if (ret != 0 || !keep_cs)
609 spi_set_cs(msg->spi, false);
611 if (msg->status == -EINPROGRESS)
614 spi_finalize_current_message(master);
620 * spi_finalize_current_transfer - report completion of a transfer
622 * Called by SPI drivers using the core transfer_one_message()
623 * implementation to notify it that the current interrupt driven
624 * transfer has finised and the next one may be scheduled.
626 void spi_finalize_current_transfer(struct spi_master *master)
628 complete(&master->xfer_completion);
630 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
633 * spi_pump_messages - kthread work function which processes spi message queue
634 * @work: pointer to kthread work struct contained in the master struct
636 * This function checks if there is any spi message in the queue that
637 * needs processing and if so call out to the driver to initialize hardware
638 * and transfer each message.
641 static void spi_pump_messages(struct kthread_work *work)
643 struct spi_master *master =
644 container_of(work, struct spi_master, pump_messages);
646 bool was_busy = false;
649 /* Lock queue and check for queue work */
650 spin_lock_irqsave(&master->queue_lock, flags);
651 if (list_empty(&master->queue) || !master->running) {
653 spin_unlock_irqrestore(&master->queue_lock, flags);
656 master->busy = false;
657 spin_unlock_irqrestore(&master->queue_lock, flags);
658 if (master->unprepare_transfer_hardware &&
659 master->unprepare_transfer_hardware(master))
660 dev_err(&master->dev,
661 "failed to unprepare transfer hardware\n");
662 if (master->auto_runtime_pm) {
663 pm_runtime_mark_last_busy(master->dev.parent);
664 pm_runtime_put_autosuspend(master->dev.parent);
666 trace_spi_master_idle(master);
670 /* Make sure we are not already running a message */
671 if (master->cur_msg) {
672 spin_unlock_irqrestore(&master->queue_lock, flags);
675 /* Extract head of queue */
677 list_entry(master->queue.next, struct spi_message, queue);
679 list_del_init(&master->cur_msg->queue);
684 spin_unlock_irqrestore(&master->queue_lock, flags);
686 if (!was_busy && master->auto_runtime_pm) {
687 ret = pm_runtime_get_sync(master->dev.parent);
689 dev_err(&master->dev, "Failed to power device: %d\n",
696 trace_spi_master_busy(master);
698 if (!was_busy && master->prepare_transfer_hardware) {
699 ret = master->prepare_transfer_hardware(master);
701 dev_err(&master->dev,
702 "failed to prepare transfer hardware\n");
704 if (master->auto_runtime_pm)
705 pm_runtime_put(master->dev.parent);
710 trace_spi_message_start(master->cur_msg);
712 if (master->prepare_message) {
713 ret = master->prepare_message(master, master->cur_msg);
715 dev_err(&master->dev,
716 "failed to prepare message: %d\n", ret);
717 master->cur_msg->status = ret;
718 spi_finalize_current_message(master);
721 master->cur_msg_prepared = true;
724 ret = master->transfer_one_message(master, master->cur_msg);
726 dev_err(&master->dev,
727 "failed to transfer one message from queue\n");
732 static int spi_init_queue(struct spi_master *master)
734 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
736 INIT_LIST_HEAD(&master->queue);
737 spin_lock_init(&master->queue_lock);
739 master->running = false;
740 master->busy = false;
742 init_kthread_worker(&master->kworker);
743 master->kworker_task = kthread_run(kthread_worker_fn,
744 &master->kworker, "%s",
745 dev_name(&master->dev));
746 if (IS_ERR(master->kworker_task)) {
747 dev_err(&master->dev, "failed to create message pump task\n");
750 init_kthread_work(&master->pump_messages, spi_pump_messages);
753 * Master config will indicate if this controller should run the
754 * message pump with high (realtime) priority to reduce the transfer
755 * latency on the bus by minimising the delay between a transfer
756 * request and the scheduling of the message pump thread. Without this
757 * setting the message pump thread will remain at default priority.
760 dev_info(&master->dev,
761 "will run message pump with realtime priority\n");
762 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
769 * spi_get_next_queued_message() - called by driver to check for queued
771 * @master: the master to check for queued messages
773 * If there are more messages in the queue, the next message is returned from
776 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
778 struct spi_message *next;
781 /* get a pointer to the next message, if any */
782 spin_lock_irqsave(&master->queue_lock, flags);
783 if (list_empty(&master->queue))
786 next = list_entry(master->queue.next,
787 struct spi_message, queue);
788 spin_unlock_irqrestore(&master->queue_lock, flags);
792 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
795 * spi_finalize_current_message() - the current message is complete
796 * @master: the master to return the message to
798 * Called by the driver to notify the core that the message in the front of the
799 * queue is complete and can be removed from the queue.
801 void spi_finalize_current_message(struct spi_master *master)
803 struct spi_message *mesg;
807 spin_lock_irqsave(&master->queue_lock, flags);
808 mesg = master->cur_msg;
809 master->cur_msg = NULL;
811 queue_kthread_work(&master->kworker, &master->pump_messages);
812 spin_unlock_irqrestore(&master->queue_lock, flags);
814 if (master->cur_msg_prepared && master->unprepare_message) {
815 ret = master->unprepare_message(master, mesg);
817 dev_err(&master->dev,
818 "failed to unprepare message: %d\n", ret);
821 master->cur_msg_prepared = false;
825 mesg->complete(mesg->context);
827 trace_spi_message_done(mesg);
829 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
831 static int spi_start_queue(struct spi_master *master)
835 spin_lock_irqsave(&master->queue_lock, flags);
837 if (master->running || master->busy) {
838 spin_unlock_irqrestore(&master->queue_lock, flags);
842 master->running = true;
843 master->cur_msg = NULL;
844 spin_unlock_irqrestore(&master->queue_lock, flags);
846 queue_kthread_work(&master->kworker, &master->pump_messages);
851 static int spi_stop_queue(struct spi_master *master)
854 unsigned limit = 500;
857 spin_lock_irqsave(&master->queue_lock, flags);
860 * This is a bit lame, but is optimized for the common execution path.
861 * A wait_queue on the master->busy could be used, but then the common
862 * execution path (pump_messages) would be required to call wake_up or
863 * friends on every SPI message. Do this instead.
865 while ((!list_empty(&master->queue) || master->busy) && limit--) {
866 spin_unlock_irqrestore(&master->queue_lock, flags);
868 spin_lock_irqsave(&master->queue_lock, flags);
871 if (!list_empty(&master->queue) || master->busy)
874 master->running = false;
876 spin_unlock_irqrestore(&master->queue_lock, flags);
879 dev_warn(&master->dev,
880 "could not stop message queue\n");
886 static int spi_destroy_queue(struct spi_master *master)
890 ret = spi_stop_queue(master);
893 * flush_kthread_worker will block until all work is done.
894 * If the reason that stop_queue timed out is that the work will never
895 * finish, then it does no good to call flush/stop thread, so
899 dev_err(&master->dev, "problem destroying queue\n");
903 flush_kthread_worker(&master->kworker);
904 kthread_stop(master->kworker_task);
910 * spi_queued_transfer - transfer function for queued transfers
911 * @spi: spi device which is requesting transfer
912 * @msg: spi message which is to handled is queued to driver queue
914 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
916 struct spi_master *master = spi->master;
919 spin_lock_irqsave(&master->queue_lock, flags);
921 if (!master->running) {
922 spin_unlock_irqrestore(&master->queue_lock, flags);
925 msg->actual_length = 0;
926 msg->status = -EINPROGRESS;
928 list_add_tail(&msg->queue, &master->queue);
930 queue_kthread_work(&master->kworker, &master->pump_messages);
932 spin_unlock_irqrestore(&master->queue_lock, flags);
936 static int spi_master_initialize_queue(struct spi_master *master)
940 master->queued = true;
941 master->transfer = spi_queued_transfer;
942 if (!master->transfer_one_message)
943 master->transfer_one_message = spi_transfer_one_message;
945 /* Initialize and start queue */
946 ret = spi_init_queue(master);
948 dev_err(&master->dev, "problem initializing queue\n");
951 ret = spi_start_queue(master);
953 dev_err(&master->dev, "problem starting queue\n");
954 goto err_start_queue;
961 spi_destroy_queue(master);
965 /*-------------------------------------------------------------------------*/
967 #if defined(CONFIG_OF)
969 * of_register_spi_devices() - Register child devices onto the SPI bus
970 * @master: Pointer to spi_master device
972 * Registers an spi_device for each child node of master node which has a 'reg'
975 static void of_register_spi_devices(struct spi_master *master)
977 struct spi_device *spi;
978 struct device_node *nc;
982 if (!master->dev.of_node)
985 for_each_available_child_of_node(master->dev.of_node, nc) {
986 /* Alloc an spi_device */
987 spi = spi_alloc_device(master);
989 dev_err(&master->dev, "spi_device alloc error for %s\n",
995 /* Select device driver */
996 if (of_modalias_node(nc, spi->modalias,
997 sizeof(spi->modalias)) < 0) {
998 dev_err(&master->dev, "cannot find modalias for %s\n",
1004 /* Device address */
1005 rc = of_property_read_u32(nc, "reg", &value);
1007 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1012 spi->chip_select = value;
1014 /* Mode (clock phase/polarity/etc.) */
1015 if (of_find_property(nc, "spi-cpha", NULL))
1016 spi->mode |= SPI_CPHA;
1017 if (of_find_property(nc, "spi-cpol", NULL))
1018 spi->mode |= SPI_CPOL;
1019 if (of_find_property(nc, "spi-cs-high", NULL))
1020 spi->mode |= SPI_CS_HIGH;
1021 if (of_find_property(nc, "spi-3wire", NULL))
1022 spi->mode |= SPI_3WIRE;
1024 /* Device DUAL/QUAD mode */
1025 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1030 spi->mode |= SPI_TX_DUAL;
1033 spi->mode |= SPI_TX_QUAD;
1036 dev_err(&master->dev,
1037 "spi-tx-bus-width %d not supported\n",
1044 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1049 spi->mode |= SPI_RX_DUAL;
1052 spi->mode |= SPI_RX_QUAD;
1055 dev_err(&master->dev,
1056 "spi-rx-bus-width %d not supported\n",
1064 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1066 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1071 spi->max_speed_hz = value;
1074 spi->irq = irq_of_parse_and_map(nc, 0);
1076 /* Store a pointer to the node in the device structure */
1078 spi->dev.of_node = nc;
1080 /* Register the new device */
1081 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1082 rc = spi_add_device(spi);
1084 dev_err(&master->dev, "spi_device register error %s\n",
1092 static void of_register_spi_devices(struct spi_master *master) { }
1096 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1098 struct spi_device *spi = data;
1100 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1101 struct acpi_resource_spi_serialbus *sb;
1103 sb = &ares->data.spi_serial_bus;
1104 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1105 spi->chip_select = sb->device_selection;
1106 spi->max_speed_hz = sb->connection_speed;
1108 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1109 spi->mode |= SPI_CPHA;
1110 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1111 spi->mode |= SPI_CPOL;
1112 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1113 spi->mode |= SPI_CS_HIGH;
1115 } else if (spi->irq < 0) {
1118 if (acpi_dev_resource_interrupt(ares, 0, &r))
1122 /* Always tell the ACPI core to skip this resource */
1126 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1127 void *data, void **return_value)
1129 struct spi_master *master = data;
1130 struct list_head resource_list;
1131 struct acpi_device *adev;
1132 struct spi_device *spi;
1135 if (acpi_bus_get_device(handle, &adev))
1137 if (acpi_bus_get_status(adev) || !adev->status.present)
1140 spi = spi_alloc_device(master);
1142 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1143 dev_name(&adev->dev));
1144 return AE_NO_MEMORY;
1147 ACPI_HANDLE_SET(&spi->dev, handle);
1150 INIT_LIST_HEAD(&resource_list);
1151 ret = acpi_dev_get_resources(adev, &resource_list,
1152 acpi_spi_add_resource, spi);
1153 acpi_dev_free_resource_list(&resource_list);
1155 if (ret < 0 || !spi->max_speed_hz) {
1160 adev->power.flags.ignore_parent = true;
1161 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1162 if (spi_add_device(spi)) {
1163 adev->power.flags.ignore_parent = false;
1164 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1165 dev_name(&adev->dev));
1172 static void acpi_register_spi_devices(struct spi_master *master)
1177 handle = ACPI_HANDLE(master->dev.parent);
1181 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1182 acpi_spi_add_device, NULL,
1184 if (ACPI_FAILURE(status))
1185 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1188 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1189 #endif /* CONFIG_ACPI */
1191 static void spi_master_release(struct device *dev)
1193 struct spi_master *master;
1195 master = container_of(dev, struct spi_master, dev);
1199 static struct class spi_master_class = {
1200 .name = "spi_master",
1201 .owner = THIS_MODULE,
1202 .dev_release = spi_master_release,
1208 * spi_alloc_master - allocate SPI master controller
1209 * @dev: the controller, possibly using the platform_bus
1210 * @size: how much zeroed driver-private data to allocate; the pointer to this
1211 * memory is in the driver_data field of the returned device,
1212 * accessible with spi_master_get_devdata().
1213 * Context: can sleep
1215 * This call is used only by SPI master controller drivers, which are the
1216 * only ones directly touching chip registers. It's how they allocate
1217 * an spi_master structure, prior to calling spi_register_master().
1219 * This must be called from context that can sleep. It returns the SPI
1220 * master structure on success, else NULL.
1222 * The caller is responsible for assigning the bus number and initializing
1223 * the master's methods before calling spi_register_master(); and (after errors
1224 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1227 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1229 struct spi_master *master;
1234 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1238 device_initialize(&master->dev);
1239 master->bus_num = -1;
1240 master->num_chipselect = 1;
1241 master->dev.class = &spi_master_class;
1242 master->dev.parent = get_device(dev);
1243 spi_master_set_devdata(master, &master[1]);
1247 EXPORT_SYMBOL_GPL(spi_alloc_master);
1250 static int of_spi_register_master(struct spi_master *master)
1253 struct device_node *np = master->dev.of_node;
1258 nb = of_gpio_named_count(np, "cs-gpios");
1259 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1261 /* Return error only for an incorrectly formed cs-gpios property */
1262 if (nb == 0 || nb == -ENOENT)
1267 cs = devm_kzalloc(&master->dev,
1268 sizeof(int) * master->num_chipselect,
1270 master->cs_gpios = cs;
1272 if (!master->cs_gpios)
1275 for (i = 0; i < master->num_chipselect; i++)
1278 for (i = 0; i < nb; i++)
1279 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1284 static int of_spi_register_master(struct spi_master *master)
1291 * spi_register_master - register SPI master controller
1292 * @master: initialized master, originally from spi_alloc_master()
1293 * Context: can sleep
1295 * SPI master controllers connect to their drivers using some non-SPI bus,
1296 * such as the platform bus. The final stage of probe() in that code
1297 * includes calling spi_register_master() to hook up to this SPI bus glue.
1299 * SPI controllers use board specific (often SOC specific) bus numbers,
1300 * and board-specific addressing for SPI devices combines those numbers
1301 * with chip select numbers. Since SPI does not directly support dynamic
1302 * device identification, boards need configuration tables telling which
1303 * chip is at which address.
1305 * This must be called from context that can sleep. It returns zero on
1306 * success, else a negative error code (dropping the master's refcount).
1307 * After a successful return, the caller is responsible for calling
1308 * spi_unregister_master().
1310 int spi_register_master(struct spi_master *master)
1312 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1313 struct device *dev = master->dev.parent;
1314 struct boardinfo *bi;
1315 int status = -ENODEV;
1321 status = of_spi_register_master(master);
1325 /* even if it's just one always-selected device, there must
1326 * be at least one chipselect
1328 if (master->num_chipselect == 0)
1331 if ((master->bus_num < 0) && master->dev.of_node)
1332 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1334 /* convention: dynamically assigned bus IDs count down from the max */
1335 if (master->bus_num < 0) {
1336 /* FIXME switch to an IDR based scheme, something like
1337 * I2C now uses, so we can't run out of "dynamic" IDs
1339 master->bus_num = atomic_dec_return(&dyn_bus_id);
1343 spin_lock_init(&master->bus_lock_spinlock);
1344 mutex_init(&master->bus_lock_mutex);
1345 master->bus_lock_flag = 0;
1346 init_completion(&master->xfer_completion);
1348 /* register the device, then userspace will see it.
1349 * registration fails if the bus ID is in use.
1351 dev_set_name(&master->dev, "spi%u", master->bus_num);
1352 status = device_add(&master->dev);
1355 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1356 dynamic ? " (dynamic)" : "");
1358 /* If we're using a queued driver, start the queue */
1359 if (master->transfer)
1360 dev_info(dev, "master is unqueued, this is deprecated\n");
1362 status = spi_master_initialize_queue(master);
1364 device_del(&master->dev);
1369 mutex_lock(&board_lock);
1370 list_add_tail(&master->list, &spi_master_list);
1371 list_for_each_entry(bi, &board_list, list)
1372 spi_match_master_to_boardinfo(master, &bi->board_info);
1373 mutex_unlock(&board_lock);
1375 /* Register devices from the device tree and ACPI */
1376 of_register_spi_devices(master);
1377 acpi_register_spi_devices(master);
1381 EXPORT_SYMBOL_GPL(spi_register_master);
1383 static void devm_spi_unregister(struct device *dev, void *res)
1385 spi_unregister_master(*(struct spi_master **)res);
1389 * dev_spi_register_master - register managed SPI master controller
1390 * @dev: device managing SPI master
1391 * @master: initialized master, originally from spi_alloc_master()
1392 * Context: can sleep
1394 * Register a SPI device as with spi_register_master() which will
1395 * automatically be unregister
1397 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1399 struct spi_master **ptr;
1402 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1406 ret = spi_register_master(master);
1409 devres_add(dev, ptr);
1416 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1418 static int __unregister(struct device *dev, void *null)
1420 spi_unregister_device(to_spi_device(dev));
1425 * spi_unregister_master - unregister SPI master controller
1426 * @master: the master being unregistered
1427 * Context: can sleep
1429 * This call is used only by SPI master controller drivers, which are the
1430 * only ones directly touching chip registers.
1432 * This must be called from context that can sleep.
1434 void spi_unregister_master(struct spi_master *master)
1438 if (master->queued) {
1439 if (spi_destroy_queue(master))
1440 dev_err(&master->dev, "queue remove failed\n");
1443 mutex_lock(&board_lock);
1444 list_del(&master->list);
1445 mutex_unlock(&board_lock);
1447 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1448 device_unregister(&master->dev);
1450 EXPORT_SYMBOL_GPL(spi_unregister_master);
1452 int spi_master_suspend(struct spi_master *master)
1456 /* Basically no-ops for non-queued masters */
1457 if (!master->queued)
1460 ret = spi_stop_queue(master);
1462 dev_err(&master->dev, "queue stop failed\n");
1466 EXPORT_SYMBOL_GPL(spi_master_suspend);
1468 int spi_master_resume(struct spi_master *master)
1472 if (!master->queued)
1475 ret = spi_start_queue(master);
1477 dev_err(&master->dev, "queue restart failed\n");
1481 EXPORT_SYMBOL_GPL(spi_master_resume);
1483 static int __spi_master_match(struct device *dev, const void *data)
1485 struct spi_master *m;
1486 const u16 *bus_num = data;
1488 m = container_of(dev, struct spi_master, dev);
1489 return m->bus_num == *bus_num;
1493 * spi_busnum_to_master - look up master associated with bus_num
1494 * @bus_num: the master's bus number
1495 * Context: can sleep
1497 * This call may be used with devices that are registered after
1498 * arch init time. It returns a refcounted pointer to the relevant
1499 * spi_master (which the caller must release), or NULL if there is
1500 * no such master registered.
1502 struct spi_master *spi_busnum_to_master(u16 bus_num)
1505 struct spi_master *master = NULL;
1507 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1508 __spi_master_match);
1510 master = container_of(dev, struct spi_master, dev);
1511 /* reference got in class_find_device */
1514 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1517 /*-------------------------------------------------------------------------*/
1519 /* Core methods for SPI master protocol drivers. Some of the
1520 * other core methods are currently defined as inline functions.
1524 * spi_setup - setup SPI mode and clock rate
1525 * @spi: the device whose settings are being modified
1526 * Context: can sleep, and no requests are queued to the device
1528 * SPI protocol drivers may need to update the transfer mode if the
1529 * device doesn't work with its default. They may likewise need
1530 * to update clock rates or word sizes from initial values. This function
1531 * changes those settings, and must be called from a context that can sleep.
1532 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1533 * effect the next time the device is selected and data is transferred to
1534 * or from it. When this function returns, the spi device is deselected.
1536 * Note that this call will fail if the protocol driver specifies an option
1537 * that the underlying controller or its driver does not support. For
1538 * example, not all hardware supports wire transfers using nine bit words,
1539 * LSB-first wire encoding, or active-high chipselects.
1541 int spi_setup(struct spi_device *spi)
1546 /* check mode to prevent that DUAL and QUAD set at the same time
1548 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1549 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1551 "setup: can not select dual and quad at the same time\n");
1554 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1556 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1557 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1559 /* help drivers fail *cleanly* when they need options
1560 * that aren't supported with their current master
1562 bad_bits = spi->mode & ~spi->master->mode_bits;
1564 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1569 if (!spi->bits_per_word)
1570 spi->bits_per_word = 8;
1572 if (spi->master->setup)
1573 status = spi->master->setup(spi);
1575 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1576 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1577 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1578 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1579 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1580 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1581 spi->bits_per_word, spi->max_speed_hz,
1586 EXPORT_SYMBOL_GPL(spi_setup);
1588 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1590 struct spi_master *master = spi->master;
1591 struct spi_transfer *xfer;
1595 trace_spi_message_submit(message);
1597 if (list_empty(&message->transfers))
1599 if (!message->complete)
1602 /* Half-duplex links include original MicroWire, and ones with
1603 * only one data pin like SPI_3WIRE (switches direction) or where
1604 * either MOSI or MISO is missing. They can also be caused by
1605 * software limitations.
1607 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1608 || (spi->mode & SPI_3WIRE)) {
1609 unsigned flags = master->flags;
1611 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1612 if (xfer->rx_buf && xfer->tx_buf)
1614 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1616 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1622 * Set transfer bits_per_word and max speed as spi device default if
1623 * it is not set for this transfer.
1624 * Set transfer tx_nbits and rx_nbits as single transfer default
1625 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1627 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1628 message->frame_length += xfer->len;
1629 if (!xfer->bits_per_word)
1630 xfer->bits_per_word = spi->bits_per_word;
1631 if (!xfer->speed_hz) {
1632 xfer->speed_hz = spi->max_speed_hz;
1633 if (master->max_speed_hz &&
1634 xfer->speed_hz > master->max_speed_hz)
1635 xfer->speed_hz = master->max_speed_hz;
1638 if (master->bits_per_word_mask) {
1639 /* Only 32 bits fit in the mask */
1640 if (xfer->bits_per_word > 32)
1642 if (!(master->bits_per_word_mask &
1643 BIT(xfer->bits_per_word - 1)))
1647 if (xfer->speed_hz && master->min_speed_hz &&
1648 xfer->speed_hz < master->min_speed_hz)
1650 if (xfer->speed_hz && master->max_speed_hz &&
1651 xfer->speed_hz > master->max_speed_hz)
1654 if (xfer->tx_buf && !xfer->tx_nbits)
1655 xfer->tx_nbits = SPI_NBITS_SINGLE;
1656 if (xfer->rx_buf && !xfer->rx_nbits)
1657 xfer->rx_nbits = SPI_NBITS_SINGLE;
1658 /* check transfer tx/rx_nbits:
1659 * 1. keep the value is not out of single, dual and quad
1660 * 2. keep tx/rx_nbits is contained by mode in spi_device
1661 * 3. if SPI_3WIRE, tx/rx_nbits should be in single
1664 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1665 xfer->tx_nbits != SPI_NBITS_DUAL &&
1666 xfer->tx_nbits != SPI_NBITS_QUAD)
1668 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1669 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1671 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1672 !(spi->mode & SPI_TX_QUAD))
1674 if ((spi->mode & SPI_3WIRE) &&
1675 (xfer->tx_nbits != SPI_NBITS_SINGLE))
1678 /* check transfer rx_nbits */
1680 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1681 xfer->rx_nbits != SPI_NBITS_DUAL &&
1682 xfer->rx_nbits != SPI_NBITS_QUAD)
1684 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1685 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1687 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1688 !(spi->mode & SPI_RX_QUAD))
1690 if ((spi->mode & SPI_3WIRE) &&
1691 (xfer->rx_nbits != SPI_NBITS_SINGLE))
1696 message->status = -EINPROGRESS;
1697 return master->transfer(spi, message);
1701 * spi_async - asynchronous SPI transfer
1702 * @spi: device with which data will be exchanged
1703 * @message: describes the data transfers, including completion callback
1704 * Context: any (irqs may be blocked, etc)
1706 * This call may be used in_irq and other contexts which can't sleep,
1707 * as well as from task contexts which can sleep.
1709 * The completion callback is invoked in a context which can't sleep.
1710 * Before that invocation, the value of message->status is undefined.
1711 * When the callback is issued, message->status holds either zero (to
1712 * indicate complete success) or a negative error code. After that
1713 * callback returns, the driver which issued the transfer request may
1714 * deallocate the associated memory; it's no longer in use by any SPI
1715 * core or controller driver code.
1717 * Note that although all messages to a spi_device are handled in
1718 * FIFO order, messages may go to different devices in other orders.
1719 * Some device might be higher priority, or have various "hard" access
1720 * time requirements, for example.
1722 * On detection of any fault during the transfer, processing of
1723 * the entire message is aborted, and the device is deselected.
1724 * Until returning from the associated message completion callback,
1725 * no other spi_message queued to that device will be processed.
1726 * (This rule applies equally to all the synchronous transfer calls,
1727 * which are wrappers around this core asynchronous primitive.)
1729 int spi_async(struct spi_device *spi, struct spi_message *message)
1731 struct spi_master *master = spi->master;
1733 unsigned long flags;
1735 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1737 if (master->bus_lock_flag)
1740 ret = __spi_async(spi, message);
1742 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1746 EXPORT_SYMBOL_GPL(spi_async);
1749 * spi_async_locked - version of spi_async with exclusive bus usage
1750 * @spi: device with which data will be exchanged
1751 * @message: describes the data transfers, including completion callback
1752 * Context: any (irqs may be blocked, etc)
1754 * This call may be used in_irq and other contexts which can't sleep,
1755 * as well as from task contexts which can sleep.
1757 * The completion callback is invoked in a context which can't sleep.
1758 * Before that invocation, the value of message->status is undefined.
1759 * When the callback is issued, message->status holds either zero (to
1760 * indicate complete success) or a negative error code. After that
1761 * callback returns, the driver which issued the transfer request may
1762 * deallocate the associated memory; it's no longer in use by any SPI
1763 * core or controller driver code.
1765 * Note that although all messages to a spi_device are handled in
1766 * FIFO order, messages may go to different devices in other orders.
1767 * Some device might be higher priority, or have various "hard" access
1768 * time requirements, for example.
1770 * On detection of any fault during the transfer, processing of
1771 * the entire message is aborted, and the device is deselected.
1772 * Until returning from the associated message completion callback,
1773 * no other spi_message queued to that device will be processed.
1774 * (This rule applies equally to all the synchronous transfer calls,
1775 * which are wrappers around this core asynchronous primitive.)
1777 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1779 struct spi_master *master = spi->master;
1781 unsigned long flags;
1783 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1785 ret = __spi_async(spi, message);
1787 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1792 EXPORT_SYMBOL_GPL(spi_async_locked);
1795 /*-------------------------------------------------------------------------*/
1797 /* Utility methods for SPI master protocol drivers, layered on
1798 * top of the core. Some other utility methods are defined as
1802 static void spi_complete(void *arg)
1807 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1810 DECLARE_COMPLETION_ONSTACK(done);
1812 struct spi_master *master = spi->master;
1814 message->complete = spi_complete;
1815 message->context = &done;
1818 mutex_lock(&master->bus_lock_mutex);
1820 status = spi_async_locked(spi, message);
1823 mutex_unlock(&master->bus_lock_mutex);
1826 wait_for_completion(&done);
1827 status = message->status;
1829 message->context = NULL;
1834 * spi_sync - blocking/synchronous SPI data transfers
1835 * @spi: device with which data will be exchanged
1836 * @message: describes the data transfers
1837 * Context: can sleep
1839 * This call may only be used from a context that may sleep. The sleep
1840 * is non-interruptible, and has no timeout. Low-overhead controller
1841 * drivers may DMA directly into and out of the message buffers.
1843 * Note that the SPI device's chip select is active during the message,
1844 * and then is normally disabled between messages. Drivers for some
1845 * frequently-used devices may want to minimize costs of selecting a chip,
1846 * by leaving it selected in anticipation that the next message will go
1847 * to the same chip. (That may increase power usage.)
1849 * Also, the caller is guaranteeing that the memory associated with the
1850 * message will not be freed before this call returns.
1852 * It returns zero on success, else a negative error code.
1854 int spi_sync(struct spi_device *spi, struct spi_message *message)
1856 return __spi_sync(spi, message, 0);
1858 EXPORT_SYMBOL_GPL(spi_sync);
1861 * spi_sync_locked - version of spi_sync with exclusive bus usage
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 * This call should be used by drivers that require exclusive access to the
1871 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1872 * be released by a spi_bus_unlock call when the exclusive access is over.
1874 * It returns zero on success, else a negative error code.
1876 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1878 return __spi_sync(spi, message, 1);
1880 EXPORT_SYMBOL_GPL(spi_sync_locked);
1883 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1884 * @master: SPI bus master that should be locked for exclusive bus access
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.
1890 * This call should be used by drivers that require exclusive access to the
1891 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1892 * exclusive access is over. Data transfer must be done by spi_sync_locked
1893 * and spi_async_locked calls when the SPI bus lock is held.
1895 * It returns zero on success, else a negative error code.
1897 int spi_bus_lock(struct spi_master *master)
1899 unsigned long flags;
1901 mutex_lock(&master->bus_lock_mutex);
1903 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1904 master->bus_lock_flag = 1;
1905 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1907 /* mutex remains locked until spi_bus_unlock is called */
1911 EXPORT_SYMBOL_GPL(spi_bus_lock);
1914 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1915 * @master: SPI bus master that was locked for exclusive bus access
1916 * Context: can sleep
1918 * This call may only be used from a context that may sleep. The sleep
1919 * is non-interruptible, and has no timeout.
1921 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1924 * It returns zero on success, else a negative error code.
1926 int spi_bus_unlock(struct spi_master *master)
1928 master->bus_lock_flag = 0;
1930 mutex_unlock(&master->bus_lock_mutex);
1934 EXPORT_SYMBOL_GPL(spi_bus_unlock);
1936 /* portable code must never pass more than 32 bytes */
1937 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
1942 * spi_write_then_read - SPI synchronous write followed by read
1943 * @spi: device with which data will be exchanged
1944 * @txbuf: data to be written (need not be dma-safe)
1945 * @n_tx: size of txbuf, in bytes
1946 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1947 * @n_rx: size of rxbuf, in bytes
1948 * Context: can sleep
1950 * This performs a half duplex MicroWire style transaction with the
1951 * device, sending txbuf and then reading rxbuf. The return value
1952 * is zero for success, else a negative errno status code.
1953 * This call may only be used from a context that may sleep.
1955 * Parameters to this routine are always copied using a small buffer;
1956 * portable code should never use this for more than 32 bytes.
1957 * Performance-sensitive or bulk transfer code should instead use
1958 * spi_{async,sync}() calls with dma-safe buffers.
1960 int spi_write_then_read(struct spi_device *spi,
1961 const void *txbuf, unsigned n_tx,
1962 void *rxbuf, unsigned n_rx)
1964 static DEFINE_MUTEX(lock);
1967 struct spi_message message;
1968 struct spi_transfer x[2];
1971 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1972 * copying here, (as a pure convenience thing), but we can
1973 * keep heap costs out of the hot path unless someone else is
1974 * using the pre-allocated buffer or the transfer is too large.
1976 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
1977 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
1978 GFP_KERNEL | GFP_DMA);
1985 spi_message_init(&message);
1986 memset(x, 0, sizeof(x));
1989 spi_message_add_tail(&x[0], &message);
1993 spi_message_add_tail(&x[1], &message);
1996 memcpy(local_buf, txbuf, n_tx);
1997 x[0].tx_buf = local_buf;
1998 x[1].rx_buf = local_buf + n_tx;
2001 status = spi_sync(spi, &message);
2003 memcpy(rxbuf, x[1].rx_buf, n_rx);
2005 if (x[0].tx_buf == buf)
2006 mutex_unlock(&lock);
2012 EXPORT_SYMBOL_GPL(spi_write_then_read);
2014 /*-------------------------------------------------------------------------*/
2016 static int __init spi_init(void)
2020 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2026 status = bus_register(&spi_bus_type);
2030 status = class_register(&spi_master_class);
2036 bus_unregister(&spi_bus_type);
2044 /* board_info is normally registered in arch_initcall(),
2045 * but even essential drivers wait till later
2047 * REVISIT only boardinfo really needs static linking. the rest (device and
2048 * driver registration) _could_ be dynamically linked (modular) ... costs
2049 * include needing to have boardinfo data structures be much more public.
2051 postcore_initcall(spi_init);