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.h>
37 #include <linux/delay.h>
38 #include <linux/kthread.h>
40 static void spidev_release(struct device *dev)
42 struct spi_device *spi = to_spi_device(dev);
44 /* spi masters may cleanup for released devices */
45 if (spi->master->cleanup)
46 spi->master->cleanup(spi);
48 spi_master_put(spi->master);
53 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
55 const struct spi_device *spi = to_spi_device(dev);
57 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
60 static struct device_attribute spi_dev_attrs[] = {
65 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
66 * and the sysfs version makes coldplug work too.
69 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
70 const struct spi_device *sdev)
73 if (!strcmp(sdev->modalias, id->name))
80 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
82 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
84 return spi_match_id(sdrv->id_table, sdev);
86 EXPORT_SYMBOL_GPL(spi_get_device_id);
88 static int spi_match_device(struct device *dev, struct device_driver *drv)
90 const struct spi_device *spi = to_spi_device(dev);
91 const struct spi_driver *sdrv = to_spi_driver(drv);
93 /* Attempt an OF style match */
94 if (of_driver_match_device(dev, drv))
98 return !!spi_match_id(sdrv->id_table, spi);
100 return strcmp(spi->modalias, drv->name) == 0;
103 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
105 const struct spi_device *spi = to_spi_device(dev);
107 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
111 #ifdef CONFIG_PM_SLEEP
112 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
115 struct spi_driver *drv = to_spi_driver(dev->driver);
117 /* suspend will stop irqs and dma; no more i/o */
120 value = drv->suspend(to_spi_device(dev), message);
122 dev_dbg(dev, "... can't suspend\n");
127 static int spi_legacy_resume(struct device *dev)
130 struct spi_driver *drv = to_spi_driver(dev->driver);
132 /* resume may restart the i/o queue */
135 value = drv->resume(to_spi_device(dev));
137 dev_dbg(dev, "... can't resume\n");
142 static int spi_pm_suspend(struct device *dev)
144 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
147 return pm_generic_suspend(dev);
149 return spi_legacy_suspend(dev, PMSG_SUSPEND);
152 static int spi_pm_resume(struct device *dev)
154 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
157 return pm_generic_resume(dev);
159 return spi_legacy_resume(dev);
162 static int spi_pm_freeze(struct device *dev)
164 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
167 return pm_generic_freeze(dev);
169 return spi_legacy_suspend(dev, PMSG_FREEZE);
172 static int spi_pm_thaw(struct device *dev)
174 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
177 return pm_generic_thaw(dev);
179 return spi_legacy_resume(dev);
182 static int spi_pm_poweroff(struct device *dev)
184 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
187 return pm_generic_poweroff(dev);
189 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
192 static int spi_pm_restore(struct device *dev)
194 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
197 return pm_generic_restore(dev);
199 return spi_legacy_resume(dev);
202 #define spi_pm_suspend NULL
203 #define spi_pm_resume NULL
204 #define spi_pm_freeze NULL
205 #define spi_pm_thaw NULL
206 #define spi_pm_poweroff NULL
207 #define spi_pm_restore NULL
210 static const struct dev_pm_ops spi_pm = {
211 .suspend = spi_pm_suspend,
212 .resume = spi_pm_resume,
213 .freeze = spi_pm_freeze,
215 .poweroff = spi_pm_poweroff,
216 .restore = spi_pm_restore,
218 pm_generic_runtime_suspend,
219 pm_generic_runtime_resume,
220 pm_generic_runtime_idle
224 struct bus_type spi_bus_type = {
226 .dev_attrs = spi_dev_attrs,
227 .match = spi_match_device,
228 .uevent = spi_uevent,
231 EXPORT_SYMBOL_GPL(spi_bus_type);
234 static int spi_drv_probe(struct device *dev)
236 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
238 return sdrv->probe(to_spi_device(dev));
241 static int spi_drv_remove(struct device *dev)
243 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
245 return sdrv->remove(to_spi_device(dev));
248 static void spi_drv_shutdown(struct device *dev)
250 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
252 sdrv->shutdown(to_spi_device(dev));
256 * spi_register_driver - register a SPI driver
257 * @sdrv: the driver to register
260 int spi_register_driver(struct spi_driver *sdrv)
262 sdrv->driver.bus = &spi_bus_type;
264 sdrv->driver.probe = spi_drv_probe;
266 sdrv->driver.remove = spi_drv_remove;
268 sdrv->driver.shutdown = spi_drv_shutdown;
269 return driver_register(&sdrv->driver);
271 EXPORT_SYMBOL_GPL(spi_register_driver);
273 /*-------------------------------------------------------------------------*/
275 /* SPI devices should normally not be created by SPI device drivers; that
276 * would make them board-specific. Similarly with SPI master drivers.
277 * Device registration normally goes into like arch/.../mach.../board-YYY.c
278 * with other readonly (flashable) information about mainboard devices.
282 struct list_head list;
283 struct spi_board_info board_info;
286 static LIST_HEAD(board_list);
287 static LIST_HEAD(spi_master_list);
290 * Used to protect add/del opertion for board_info list and
291 * spi_master list, and their matching process
293 static DEFINE_MUTEX(board_lock);
296 * spi_alloc_device - Allocate a new SPI device
297 * @master: Controller to which device is connected
300 * Allows a driver to allocate and initialize a spi_device without
301 * registering it immediately. This allows a driver to directly
302 * fill the spi_device with device parameters before calling
303 * spi_add_device() on it.
305 * Caller is responsible to call spi_add_device() on the returned
306 * spi_device structure to add it to the SPI master. If the caller
307 * needs to discard the spi_device without adding it, then it should
308 * call spi_dev_put() on it.
310 * Returns a pointer to the new device, or NULL.
312 struct spi_device *spi_alloc_device(struct spi_master *master)
314 struct spi_device *spi;
315 struct device *dev = master->dev.parent;
317 if (!spi_master_get(master))
320 spi = kzalloc(sizeof *spi, GFP_KERNEL);
322 dev_err(dev, "cannot alloc spi_device\n");
323 spi_master_put(master);
327 spi->master = master;
328 spi->dev.parent = &master->dev;
329 spi->dev.bus = &spi_bus_type;
330 spi->dev.release = spidev_release;
331 spi->cs_gpio = -EINVAL;
332 device_initialize(&spi->dev);
335 EXPORT_SYMBOL_GPL(spi_alloc_device);
338 * spi_add_device - Add spi_device allocated with spi_alloc_device
339 * @spi: spi_device to register
341 * Companion function to spi_alloc_device. Devices allocated with
342 * spi_alloc_device can be added onto the spi bus with this function.
344 * Returns 0 on success; negative errno on failure
346 int spi_add_device(struct spi_device *spi)
348 static DEFINE_MUTEX(spi_add_lock);
349 struct spi_master *master = spi->master;
350 struct device *dev = master->dev.parent;
354 /* Chipselects are numbered 0..max; validate. */
355 if (spi->chip_select >= master->num_chipselect) {
356 dev_err(dev, "cs%d >= max %d\n",
358 master->num_chipselect);
362 /* Set the bus ID string */
363 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
367 /* We need to make sure there's no other device with this
368 * chipselect **BEFORE** we call setup(), else we'll trash
369 * its configuration. Lock against concurrent add() calls.
371 mutex_lock(&spi_add_lock);
373 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
375 dev_err(dev, "chipselect %d already in use\n",
382 if (master->cs_gpios)
383 spi->cs_gpio = master->cs_gpios[spi->chip_select];
385 /* Drivers may modify this initial i/o setup, but will
386 * normally rely on the device being setup. Devices
387 * using SPI_CS_HIGH can't coexist well otherwise...
389 status = spi_setup(spi);
391 dev_err(dev, "can't setup %s, status %d\n",
392 dev_name(&spi->dev), status);
396 /* Device may be bound to an active driver when this returns */
397 status = device_add(&spi->dev);
399 dev_err(dev, "can't add %s, status %d\n",
400 dev_name(&spi->dev), status);
402 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
405 mutex_unlock(&spi_add_lock);
408 EXPORT_SYMBOL_GPL(spi_add_device);
411 * spi_new_device - instantiate one new SPI device
412 * @master: Controller to which device is connected
413 * @chip: Describes the SPI device
416 * On typical mainboards, this is purely internal; and it's not needed
417 * after board init creates the hard-wired devices. Some development
418 * platforms may not be able to use spi_register_board_info though, and
419 * this is exported so that for example a USB or parport based adapter
420 * driver could add devices (which it would learn about out-of-band).
422 * Returns the new device, or NULL.
424 struct spi_device *spi_new_device(struct spi_master *master,
425 struct spi_board_info *chip)
427 struct spi_device *proxy;
430 /* NOTE: caller did any chip->bus_num checks necessary.
432 * Also, unless we change the return value convention to use
433 * error-or-pointer (not NULL-or-pointer), troubleshootability
434 * suggests syslogged diagnostics are best here (ugh).
437 proxy = spi_alloc_device(master);
441 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
443 proxy->chip_select = chip->chip_select;
444 proxy->max_speed_hz = chip->max_speed_hz;
445 proxy->mode = chip->mode;
446 proxy->irq = chip->irq;
447 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
448 proxy->dev.platform_data = (void *) chip->platform_data;
449 proxy->controller_data = chip->controller_data;
450 proxy->controller_state = NULL;
452 status = spi_add_device(proxy);
460 EXPORT_SYMBOL_GPL(spi_new_device);
462 static void spi_match_master_to_boardinfo(struct spi_master *master,
463 struct spi_board_info *bi)
465 struct spi_device *dev;
467 if (master->bus_num != bi->bus_num)
470 dev = spi_new_device(master, bi);
472 dev_err(master->dev.parent, "can't create new device for %s\n",
477 * spi_register_board_info - register SPI devices for a given board
478 * @info: array of chip descriptors
479 * @n: how many descriptors are provided
482 * Board-specific early init code calls this (probably during arch_initcall)
483 * with segments of the SPI device table. Any device nodes are created later,
484 * after the relevant parent SPI controller (bus_num) is defined. We keep
485 * this table of devices forever, so that reloading a controller driver will
486 * not make Linux forget about these hard-wired devices.
488 * Other code can also call this, e.g. a particular add-on board might provide
489 * SPI devices through its expansion connector, so code initializing that board
490 * would naturally declare its SPI devices.
492 * The board info passed can safely be __initdata ... but be careful of
493 * any embedded pointers (platform_data, etc), they're copied as-is.
495 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
497 struct boardinfo *bi;
500 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
504 for (i = 0; i < n; i++, bi++, info++) {
505 struct spi_master *master;
507 memcpy(&bi->board_info, info, sizeof(*info));
508 mutex_lock(&board_lock);
509 list_add_tail(&bi->list, &board_list);
510 list_for_each_entry(master, &spi_master_list, list)
511 spi_match_master_to_boardinfo(master, &bi->board_info);
512 mutex_unlock(&board_lock);
518 /*-------------------------------------------------------------------------*/
521 * spi_pump_messages - kthread work function which processes spi message queue
522 * @work: pointer to kthread work struct contained in the master struct
524 * This function checks if there is any spi message in the queue that
525 * needs processing and if so call out to the driver to initialize hardware
526 * and transfer each message.
529 static void spi_pump_messages(struct kthread_work *work)
531 struct spi_master *master =
532 container_of(work, struct spi_master, pump_messages);
534 bool was_busy = false;
537 /* Lock queue and check for queue work */
538 spin_lock_irqsave(&master->queue_lock, flags);
539 if (list_empty(&master->queue) || !master->running) {
540 if (master->busy && master->unprepare_transfer_hardware) {
541 ret = master->unprepare_transfer_hardware(master);
543 spin_unlock_irqrestore(&master->queue_lock, flags);
544 dev_err(&master->dev,
545 "failed to unprepare transfer hardware\n");
549 master->busy = false;
550 spin_unlock_irqrestore(&master->queue_lock, flags);
554 /* Make sure we are not already running a message */
555 if (master->cur_msg) {
556 spin_unlock_irqrestore(&master->queue_lock, flags);
559 /* Extract head of queue */
561 list_entry(master->queue.next, struct spi_message, queue);
563 list_del_init(&master->cur_msg->queue);
568 spin_unlock_irqrestore(&master->queue_lock, flags);
570 if (!was_busy && master->prepare_transfer_hardware) {
571 ret = master->prepare_transfer_hardware(master);
573 dev_err(&master->dev,
574 "failed to prepare transfer hardware\n");
579 ret = master->transfer_one_message(master, master->cur_msg);
581 dev_err(&master->dev,
582 "failed to transfer one message from queue\n");
587 static int spi_init_queue(struct spi_master *master)
589 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
591 INIT_LIST_HEAD(&master->queue);
592 spin_lock_init(&master->queue_lock);
594 master->running = false;
595 master->busy = false;
597 init_kthread_worker(&master->kworker);
598 master->kworker_task = kthread_run(kthread_worker_fn,
600 dev_name(&master->dev));
601 if (IS_ERR(master->kworker_task)) {
602 dev_err(&master->dev, "failed to create message pump task\n");
605 init_kthread_work(&master->pump_messages, spi_pump_messages);
608 * Master config will indicate if this controller should run the
609 * message pump with high (realtime) priority to reduce the transfer
610 * latency on the bus by minimising the delay between a transfer
611 * request and the scheduling of the message pump thread. Without this
612 * setting the message pump thread will remain at default priority.
615 dev_info(&master->dev,
616 "will run message pump with realtime priority\n");
617 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
624 * spi_get_next_queued_message() - called by driver to check for queued
626 * @master: the master to check for queued messages
628 * If there are more messages in the queue, the next message is returned from
631 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
633 struct spi_message *next;
636 /* get a pointer to the next message, if any */
637 spin_lock_irqsave(&master->queue_lock, flags);
638 if (list_empty(&master->queue))
641 next = list_entry(master->queue.next,
642 struct spi_message, queue);
643 spin_unlock_irqrestore(&master->queue_lock, flags);
647 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
650 * spi_finalize_current_message() - the current message is complete
651 * @master: the master to return the message to
653 * Called by the driver to notify the core that the message in the front of the
654 * queue is complete and can be removed from the queue.
656 void spi_finalize_current_message(struct spi_master *master)
658 struct spi_message *mesg;
661 spin_lock_irqsave(&master->queue_lock, flags);
662 mesg = master->cur_msg;
663 master->cur_msg = NULL;
665 queue_kthread_work(&master->kworker, &master->pump_messages);
666 spin_unlock_irqrestore(&master->queue_lock, flags);
670 mesg->complete(mesg->context);
672 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
674 static int spi_start_queue(struct spi_master *master)
678 spin_lock_irqsave(&master->queue_lock, flags);
680 if (master->running || master->busy) {
681 spin_unlock_irqrestore(&master->queue_lock, flags);
685 master->running = true;
686 master->cur_msg = NULL;
687 spin_unlock_irqrestore(&master->queue_lock, flags);
689 queue_kthread_work(&master->kworker, &master->pump_messages);
694 static int spi_stop_queue(struct spi_master *master)
697 unsigned limit = 500;
700 spin_lock_irqsave(&master->queue_lock, flags);
703 * This is a bit lame, but is optimized for the common execution path.
704 * A wait_queue on the master->busy could be used, but then the common
705 * execution path (pump_messages) would be required to call wake_up or
706 * friends on every SPI message. Do this instead.
708 while ((!list_empty(&master->queue) || master->busy) && limit--) {
709 spin_unlock_irqrestore(&master->queue_lock, flags);
711 spin_lock_irqsave(&master->queue_lock, flags);
714 if (!list_empty(&master->queue) || master->busy)
717 master->running = false;
719 spin_unlock_irqrestore(&master->queue_lock, flags);
722 dev_warn(&master->dev,
723 "could not stop message queue\n");
729 static int spi_destroy_queue(struct spi_master *master)
733 ret = spi_stop_queue(master);
736 * flush_kthread_worker will block until all work is done.
737 * If the reason that stop_queue timed out is that the work will never
738 * finish, then it does no good to call flush/stop thread, so
742 dev_err(&master->dev, "problem destroying queue\n");
746 flush_kthread_worker(&master->kworker);
747 kthread_stop(master->kworker_task);
753 * spi_queued_transfer - transfer function for queued transfers
754 * @spi: spi device which is requesting transfer
755 * @msg: spi message which is to handled is queued to driver queue
757 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
759 struct spi_master *master = spi->master;
762 spin_lock_irqsave(&master->queue_lock, flags);
764 if (!master->running) {
765 spin_unlock_irqrestore(&master->queue_lock, flags);
768 msg->actual_length = 0;
769 msg->status = -EINPROGRESS;
771 list_add_tail(&msg->queue, &master->queue);
772 if (master->running && !master->busy)
773 queue_kthread_work(&master->kworker, &master->pump_messages);
775 spin_unlock_irqrestore(&master->queue_lock, flags);
779 static int spi_master_initialize_queue(struct spi_master *master)
783 master->queued = true;
784 master->transfer = spi_queued_transfer;
786 /* Initialize and start queue */
787 ret = spi_init_queue(master);
789 dev_err(&master->dev, "problem initializing queue\n");
792 ret = spi_start_queue(master);
794 dev_err(&master->dev, "problem starting queue\n");
795 goto err_start_queue;
802 spi_destroy_queue(master);
806 /*-------------------------------------------------------------------------*/
808 #if defined(CONFIG_OF) && !defined(CONFIG_SPARC)
810 * of_register_spi_devices() - Register child devices onto the SPI bus
811 * @master: Pointer to spi_master device
813 * Registers an spi_device for each child node of master node which has a 'reg'
816 static void of_register_spi_devices(struct spi_master *master)
818 struct spi_device *spi;
819 struct device_node *nc;
824 if (!master->dev.of_node)
827 for_each_child_of_node(master->dev.of_node, nc) {
828 /* Alloc an spi_device */
829 spi = spi_alloc_device(master);
831 dev_err(&master->dev, "spi_device alloc error for %s\n",
837 /* Select device driver */
838 if (of_modalias_node(nc, spi->modalias,
839 sizeof(spi->modalias)) < 0) {
840 dev_err(&master->dev, "cannot find modalias for %s\n",
847 prop = of_get_property(nc, "reg", &len);
848 if (!prop || len < sizeof(*prop)) {
849 dev_err(&master->dev, "%s has no 'reg' property\n",
854 spi->chip_select = be32_to_cpup(prop);
856 /* Mode (clock phase/polarity/etc.) */
857 if (of_find_property(nc, "spi-cpha", NULL))
858 spi->mode |= SPI_CPHA;
859 if (of_find_property(nc, "spi-cpol", NULL))
860 spi->mode |= SPI_CPOL;
861 if (of_find_property(nc, "spi-cs-high", NULL))
862 spi->mode |= SPI_CS_HIGH;
863 if (of_find_property(nc, "spi-3wire", NULL))
864 spi->mode |= SPI_3WIRE;
867 prop = of_get_property(nc, "spi-max-frequency", &len);
868 if (!prop || len < sizeof(*prop)) {
869 dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
874 spi->max_speed_hz = be32_to_cpup(prop);
877 spi->irq = irq_of_parse_and_map(nc, 0);
879 /* Store a pointer to the node in the device structure */
881 spi->dev.of_node = nc;
883 /* Register the new device */
884 request_module(spi->modalias);
885 rc = spi_add_device(spi);
887 dev_err(&master->dev, "spi_device register error %s\n",
895 static void of_register_spi_devices(struct spi_master *master) { }
898 static void spi_master_release(struct device *dev)
900 struct spi_master *master;
902 master = container_of(dev, struct spi_master, dev);
906 static struct class spi_master_class = {
907 .name = "spi_master",
908 .owner = THIS_MODULE,
909 .dev_release = spi_master_release,
915 * spi_alloc_master - allocate SPI master controller
916 * @dev: the controller, possibly using the platform_bus
917 * @size: how much zeroed driver-private data to allocate; the pointer to this
918 * memory is in the driver_data field of the returned device,
919 * accessible with spi_master_get_devdata().
922 * This call is used only by SPI master controller drivers, which are the
923 * only ones directly touching chip registers. It's how they allocate
924 * an spi_master structure, prior to calling spi_register_master().
926 * This must be called from context that can sleep. It returns the SPI
927 * master structure on success, else NULL.
929 * The caller is responsible for assigning the bus number and initializing
930 * the master's methods before calling spi_register_master(); and (after errors
931 * adding the device) calling spi_master_put() and kfree() to prevent a memory
934 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
936 struct spi_master *master;
941 master = kzalloc(size + sizeof *master, GFP_KERNEL);
945 device_initialize(&master->dev);
946 master->bus_num = -1;
947 master->num_chipselect = 1;
948 master->dev.class = &spi_master_class;
949 master->dev.parent = get_device(dev);
950 spi_master_set_devdata(master, &master[1]);
954 EXPORT_SYMBOL_GPL(spi_alloc_master);
957 static int of_spi_register_master(struct spi_master *master)
961 struct device_node *np = master->dev.of_node;
966 nb = of_gpio_named_count(np, "cs-gpios");
967 master->num_chipselect = max(nb, master->num_chipselect);
972 cs = devm_kzalloc(&master->dev,
973 sizeof(int) * master->num_chipselect,
975 master->cs_gpios = cs;
977 if (!master->cs_gpios)
980 memset(cs, -EINVAL, master->num_chipselect);
982 for (i = 0; i < nb; i++)
983 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
988 static int of_spi_register_master(struct spi_master *master)
995 * spi_register_master - register SPI master controller
996 * @master: initialized master, originally from spi_alloc_master()
999 * SPI master controllers connect to their drivers using some non-SPI bus,
1000 * such as the platform bus. The final stage of probe() in that code
1001 * includes calling spi_register_master() to hook up to this SPI bus glue.
1003 * SPI controllers use board specific (often SOC specific) bus numbers,
1004 * and board-specific addressing for SPI devices combines those numbers
1005 * with chip select numbers. Since SPI does not directly support dynamic
1006 * device identification, boards need configuration tables telling which
1007 * chip is at which address.
1009 * This must be called from context that can sleep. It returns zero on
1010 * success, else a negative error code (dropping the master's refcount).
1011 * After a successful return, the caller is responsible for calling
1012 * spi_unregister_master().
1014 int spi_register_master(struct spi_master *master)
1016 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1017 struct device *dev = master->dev.parent;
1018 struct boardinfo *bi;
1019 int status = -ENODEV;
1025 status = of_spi_register_master(master);
1029 /* even if it's just one always-selected device, there must
1030 * be at least one chipselect
1032 if (master->num_chipselect == 0)
1035 /* convention: dynamically assigned bus IDs count down from the max */
1036 if (master->bus_num < 0) {
1037 /* FIXME switch to an IDR based scheme, something like
1038 * I2C now uses, so we can't run out of "dynamic" IDs
1040 master->bus_num = atomic_dec_return(&dyn_bus_id);
1044 spin_lock_init(&master->bus_lock_spinlock);
1045 mutex_init(&master->bus_lock_mutex);
1046 master->bus_lock_flag = 0;
1048 /* register the device, then userspace will see it.
1049 * registration fails if the bus ID is in use.
1051 dev_set_name(&master->dev, "spi%u", master->bus_num);
1052 status = device_add(&master->dev);
1055 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1056 dynamic ? " (dynamic)" : "");
1058 /* If we're using a queued driver, start the queue */
1059 if (master->transfer)
1060 dev_info(dev, "master is unqueued, this is deprecated\n");
1062 status = spi_master_initialize_queue(master);
1064 device_unregister(&master->dev);
1069 mutex_lock(&board_lock);
1070 list_add_tail(&master->list, &spi_master_list);
1071 list_for_each_entry(bi, &board_list, list)
1072 spi_match_master_to_boardinfo(master, &bi->board_info);
1073 mutex_unlock(&board_lock);
1075 /* Register devices from the device tree */
1076 of_register_spi_devices(master);
1080 EXPORT_SYMBOL_GPL(spi_register_master);
1082 static int __unregister(struct device *dev, void *null)
1084 spi_unregister_device(to_spi_device(dev));
1089 * spi_unregister_master - unregister SPI master controller
1090 * @master: the master being unregistered
1091 * Context: can sleep
1093 * This call is used only by SPI master controller drivers, which are the
1094 * only ones directly touching chip registers.
1096 * This must be called from context that can sleep.
1098 void spi_unregister_master(struct spi_master *master)
1102 if (master->queued) {
1103 if (spi_destroy_queue(master))
1104 dev_err(&master->dev, "queue remove failed\n");
1107 mutex_lock(&board_lock);
1108 list_del(&master->list);
1109 mutex_unlock(&board_lock);
1111 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1112 device_unregister(&master->dev);
1114 EXPORT_SYMBOL_GPL(spi_unregister_master);
1116 int spi_master_suspend(struct spi_master *master)
1120 /* Basically no-ops for non-queued masters */
1121 if (!master->queued)
1124 ret = spi_stop_queue(master);
1126 dev_err(&master->dev, "queue stop failed\n");
1130 EXPORT_SYMBOL_GPL(spi_master_suspend);
1132 int spi_master_resume(struct spi_master *master)
1136 if (!master->queued)
1139 ret = spi_start_queue(master);
1141 dev_err(&master->dev, "queue restart failed\n");
1145 EXPORT_SYMBOL_GPL(spi_master_resume);
1147 static int __spi_master_match(struct device *dev, void *data)
1149 struct spi_master *m;
1150 u16 *bus_num = data;
1152 m = container_of(dev, struct spi_master, dev);
1153 return m->bus_num == *bus_num;
1157 * spi_busnum_to_master - look up master associated with bus_num
1158 * @bus_num: the master's bus number
1159 * Context: can sleep
1161 * This call may be used with devices that are registered after
1162 * arch init time. It returns a refcounted pointer to the relevant
1163 * spi_master (which the caller must release), or NULL if there is
1164 * no such master registered.
1166 struct spi_master *spi_busnum_to_master(u16 bus_num)
1169 struct spi_master *master = NULL;
1171 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1172 __spi_master_match);
1174 master = container_of(dev, struct spi_master, dev);
1175 /* reference got in class_find_device */
1178 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1181 /*-------------------------------------------------------------------------*/
1183 /* Core methods for SPI master protocol drivers. Some of the
1184 * other core methods are currently defined as inline functions.
1188 * spi_setup - setup SPI mode and clock rate
1189 * @spi: the device whose settings are being modified
1190 * Context: can sleep, and no requests are queued to the device
1192 * SPI protocol drivers may need to update the transfer mode if the
1193 * device doesn't work with its default. They may likewise need
1194 * to update clock rates or word sizes from initial values. This function
1195 * changes those settings, and must be called from a context that can sleep.
1196 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1197 * effect the next time the device is selected and data is transferred to
1198 * or from it. When this function returns, the spi device is deselected.
1200 * Note that this call will fail if the protocol driver specifies an option
1201 * that the underlying controller or its driver does not support. For
1202 * example, not all hardware supports wire transfers using nine bit words,
1203 * LSB-first wire encoding, or active-high chipselects.
1205 int spi_setup(struct spi_device *spi)
1210 /* help drivers fail *cleanly* when they need options
1211 * that aren't supported with their current master
1213 bad_bits = spi->mode & ~spi->master->mode_bits;
1215 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1220 if (!spi->bits_per_word)
1221 spi->bits_per_word = 8;
1223 if (spi->master->setup)
1224 status = spi->master->setup(spi);
1226 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
1227 "%u bits/w, %u Hz max --> %d\n",
1228 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1229 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1230 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1231 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1232 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1233 spi->bits_per_word, spi->max_speed_hz,
1238 EXPORT_SYMBOL_GPL(spi_setup);
1240 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1242 struct spi_master *master = spi->master;
1243 struct spi_transfer *xfer;
1245 /* Half-duplex links include original MicroWire, and ones with
1246 * only one data pin like SPI_3WIRE (switches direction) or where
1247 * either MOSI or MISO is missing. They can also be caused by
1248 * software limitations.
1250 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1251 || (spi->mode & SPI_3WIRE)) {
1252 unsigned flags = master->flags;
1254 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1255 if (xfer->rx_buf && xfer->tx_buf)
1257 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1259 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1265 * Set transfer bits_per_word as spi device default if it is not
1266 * set for this transfer.
1268 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1269 if (!xfer->bits_per_word)
1270 xfer->bits_per_word = spi->bits_per_word;
1274 message->status = -EINPROGRESS;
1275 return master->transfer(spi, message);
1279 * spi_async - asynchronous SPI transfer
1280 * @spi: device with which data will be exchanged
1281 * @message: describes the data transfers, including completion callback
1282 * Context: any (irqs may be blocked, etc)
1284 * This call may be used in_irq and other contexts which can't sleep,
1285 * as well as from task contexts which can sleep.
1287 * The completion callback is invoked in a context which can't sleep.
1288 * Before that invocation, the value of message->status is undefined.
1289 * When the callback is issued, message->status holds either zero (to
1290 * indicate complete success) or a negative error code. After that
1291 * callback returns, the driver which issued the transfer request may
1292 * deallocate the associated memory; it's no longer in use by any SPI
1293 * core or controller driver code.
1295 * Note that although all messages to a spi_device are handled in
1296 * FIFO order, messages may go to different devices in other orders.
1297 * Some device might be higher priority, or have various "hard" access
1298 * time requirements, for example.
1300 * On detection of any fault during the transfer, processing of
1301 * the entire message is aborted, and the device is deselected.
1302 * Until returning from the associated message completion callback,
1303 * no other spi_message queued to that device will be processed.
1304 * (This rule applies equally to all the synchronous transfer calls,
1305 * which are wrappers around this core asynchronous primitive.)
1307 int spi_async(struct spi_device *spi, struct spi_message *message)
1309 struct spi_master *master = spi->master;
1311 unsigned long flags;
1313 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1315 if (master->bus_lock_flag)
1318 ret = __spi_async(spi, message);
1320 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1324 EXPORT_SYMBOL_GPL(spi_async);
1327 * spi_async_locked - version of spi_async with exclusive bus usage
1328 * @spi: device with which data will be exchanged
1329 * @message: describes the data transfers, including completion callback
1330 * Context: any (irqs may be blocked, etc)
1332 * This call may be used in_irq and other contexts which can't sleep,
1333 * as well as from task contexts which can sleep.
1335 * The completion callback is invoked in a context which can't sleep.
1336 * Before that invocation, the value of message->status is undefined.
1337 * When the callback is issued, message->status holds either zero (to
1338 * indicate complete success) or a negative error code. After that
1339 * callback returns, the driver which issued the transfer request may
1340 * deallocate the associated memory; it's no longer in use by any SPI
1341 * core or controller driver code.
1343 * Note that although all messages to a spi_device are handled in
1344 * FIFO order, messages may go to different devices in other orders.
1345 * Some device might be higher priority, or have various "hard" access
1346 * time requirements, for example.
1348 * On detection of any fault during the transfer, processing of
1349 * the entire message is aborted, and the device is deselected.
1350 * Until returning from the associated message completion callback,
1351 * no other spi_message queued to that device will be processed.
1352 * (This rule applies equally to all the synchronous transfer calls,
1353 * which are wrappers around this core asynchronous primitive.)
1355 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1357 struct spi_master *master = spi->master;
1359 unsigned long flags;
1361 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1363 ret = __spi_async(spi, message);
1365 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1370 EXPORT_SYMBOL_GPL(spi_async_locked);
1373 /*-------------------------------------------------------------------------*/
1375 /* Utility methods for SPI master protocol drivers, layered on
1376 * top of the core. Some other utility methods are defined as
1380 static void spi_complete(void *arg)
1385 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1388 DECLARE_COMPLETION_ONSTACK(done);
1390 struct spi_master *master = spi->master;
1392 message->complete = spi_complete;
1393 message->context = &done;
1396 mutex_lock(&master->bus_lock_mutex);
1398 status = spi_async_locked(spi, message);
1401 mutex_unlock(&master->bus_lock_mutex);
1404 wait_for_completion(&done);
1405 status = message->status;
1407 message->context = NULL;
1412 * spi_sync - blocking/synchronous SPI data transfers
1413 * @spi: device with which data will be exchanged
1414 * @message: describes the data transfers
1415 * Context: can sleep
1417 * This call may only be used from a context that may sleep. The sleep
1418 * is non-interruptible, and has no timeout. Low-overhead controller
1419 * drivers may DMA directly into and out of the message buffers.
1421 * Note that the SPI device's chip select is active during the message,
1422 * and then is normally disabled between messages. Drivers for some
1423 * frequently-used devices may want to minimize costs of selecting a chip,
1424 * by leaving it selected in anticipation that the next message will go
1425 * to the same chip. (That may increase power usage.)
1427 * Also, the caller is guaranteeing that the memory associated with the
1428 * message will not be freed before this call returns.
1430 * It returns zero on success, else a negative error code.
1432 int spi_sync(struct spi_device *spi, struct spi_message *message)
1434 return __spi_sync(spi, message, 0);
1436 EXPORT_SYMBOL_GPL(spi_sync);
1439 * spi_sync_locked - version of spi_sync with exclusive bus usage
1440 * @spi: device with which data will be exchanged
1441 * @message: describes the data transfers
1442 * Context: can sleep
1444 * This call may only be used from a context that may sleep. The sleep
1445 * is non-interruptible, and has no timeout. Low-overhead controller
1446 * drivers may DMA directly into and out of the message buffers.
1448 * This call should be used by drivers that require exclusive access to the
1449 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1450 * be released by a spi_bus_unlock call when the exclusive access is over.
1452 * It returns zero on success, else a negative error code.
1454 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1456 return __spi_sync(spi, message, 1);
1458 EXPORT_SYMBOL_GPL(spi_sync_locked);
1461 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1462 * @master: SPI bus master that should be locked for exclusive bus access
1463 * Context: can sleep
1465 * This call may only be used from a context that may sleep. The sleep
1466 * is non-interruptible, and has no timeout.
1468 * This call should be used by drivers that require exclusive access to the
1469 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1470 * exclusive access is over. Data transfer must be done by spi_sync_locked
1471 * and spi_async_locked calls when the SPI bus lock is held.
1473 * It returns zero on success, else a negative error code.
1475 int spi_bus_lock(struct spi_master *master)
1477 unsigned long flags;
1479 mutex_lock(&master->bus_lock_mutex);
1481 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1482 master->bus_lock_flag = 1;
1483 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1485 /* mutex remains locked until spi_bus_unlock is called */
1489 EXPORT_SYMBOL_GPL(spi_bus_lock);
1492 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1493 * @master: SPI bus master that was locked for exclusive bus access
1494 * Context: can sleep
1496 * This call may only be used from a context that may sleep. The sleep
1497 * is non-interruptible, and has no timeout.
1499 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1502 * It returns zero on success, else a negative error code.
1504 int spi_bus_unlock(struct spi_master *master)
1506 master->bus_lock_flag = 0;
1508 mutex_unlock(&master->bus_lock_mutex);
1512 EXPORT_SYMBOL_GPL(spi_bus_unlock);
1514 /* portable code must never pass more than 32 bytes */
1515 #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1520 * spi_write_then_read - SPI synchronous write followed by read
1521 * @spi: device with which data will be exchanged
1522 * @txbuf: data to be written (need not be dma-safe)
1523 * @n_tx: size of txbuf, in bytes
1524 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1525 * @n_rx: size of rxbuf, in bytes
1526 * Context: can sleep
1528 * This performs a half duplex MicroWire style transaction with the
1529 * device, sending txbuf and then reading rxbuf. The return value
1530 * is zero for success, else a negative errno status code.
1531 * This call may only be used from a context that may sleep.
1533 * Parameters to this routine are always copied using a small buffer;
1534 * portable code should never use this for more than 32 bytes.
1535 * Performance-sensitive or bulk transfer code should instead use
1536 * spi_{async,sync}() calls with dma-safe buffers.
1538 int spi_write_then_read(struct spi_device *spi,
1539 const void *txbuf, unsigned n_tx,
1540 void *rxbuf, unsigned n_rx)
1542 static DEFINE_MUTEX(lock);
1545 struct spi_message message;
1546 struct spi_transfer x[2];
1549 /* Use preallocated DMA-safe buffer if we can. We can't avoid
1550 * copying here, (as a pure convenience thing), but we can
1551 * keep heap costs out of the hot path unless someone else is
1552 * using the pre-allocated buffer or the transfer is too large.
1554 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
1555 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx), GFP_KERNEL);
1562 spi_message_init(&message);
1563 memset(x, 0, sizeof x);
1566 spi_message_add_tail(&x[0], &message);
1570 spi_message_add_tail(&x[1], &message);
1573 memcpy(local_buf, txbuf, n_tx);
1574 x[0].tx_buf = local_buf;
1575 x[1].rx_buf = local_buf + n_tx;
1578 status = spi_sync(spi, &message);
1580 memcpy(rxbuf, x[1].rx_buf, n_rx);
1582 if (x[0].tx_buf == buf)
1583 mutex_unlock(&lock);
1589 EXPORT_SYMBOL_GPL(spi_write_then_read);
1591 /*-------------------------------------------------------------------------*/
1593 static int __init spi_init(void)
1597 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1603 status = bus_register(&spi_bus_type);
1607 status = class_register(&spi_master_class);
1613 bus_unregister(&spi_bus_type);
1621 /* board_info is normally registered in arch_initcall(),
1622 * but even essential drivers wait till later
1624 * REVISIT only boardinfo really needs static linking. the rest (device and
1625 * driver registration) _could_ be dynamically linked (modular) ... costs
1626 * include needing to have boardinfo data structures be much more public.
1628 postcore_initcall(spi_init);