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/pm_runtime.h>
34 #include <linux/export.h>
35 #include <linux/sched.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 static void spidev_release(struct device *dev)
43 struct spi_device *spi = to_spi_device(dev);
45 /* spi masters may cleanup for released devices */
46 if (spi->master->cleanup)
47 spi->master->cleanup(spi);
49 spi_master_put(spi->master);
54 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
56 const struct spi_device *spi = to_spi_device(dev);
58 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
61 static struct device_attribute spi_dev_attrs[] = {
66 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
67 * and the sysfs version makes coldplug work too.
70 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
71 const struct spi_device *sdev)
74 if (!strcmp(sdev->modalias, id->name))
81 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
83 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
85 return spi_match_id(sdrv->id_table, sdev);
87 EXPORT_SYMBOL_GPL(spi_get_device_id);
89 static int spi_match_device(struct device *dev, struct device_driver *drv)
91 const struct spi_device *spi = to_spi_device(dev);
92 const struct spi_driver *sdrv = to_spi_driver(drv);
94 /* Attempt an OF style match */
95 if (of_driver_match_device(dev, drv))
99 if (acpi_driver_match_device(dev, drv))
103 return !!spi_match_id(sdrv->id_table, spi);
105 return strcmp(spi->modalias, drv->name) == 0;
108 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
110 const struct spi_device *spi = to_spi_device(dev);
112 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
116 #ifdef CONFIG_PM_SLEEP
117 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
120 struct spi_driver *drv = to_spi_driver(dev->driver);
122 /* suspend will stop irqs and dma; no more i/o */
125 value = drv->suspend(to_spi_device(dev), message);
127 dev_dbg(dev, "... can't suspend\n");
132 static int spi_legacy_resume(struct device *dev)
135 struct spi_driver *drv = to_spi_driver(dev->driver);
137 /* resume may restart the i/o queue */
140 value = drv->resume(to_spi_device(dev));
142 dev_dbg(dev, "... can't resume\n");
147 static int spi_pm_suspend(struct device *dev)
149 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
152 return pm_generic_suspend(dev);
154 return spi_legacy_suspend(dev, PMSG_SUSPEND);
157 static int spi_pm_resume(struct device *dev)
159 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
162 return pm_generic_resume(dev);
164 return spi_legacy_resume(dev);
167 static int spi_pm_freeze(struct device *dev)
169 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
172 return pm_generic_freeze(dev);
174 return spi_legacy_suspend(dev, PMSG_FREEZE);
177 static int spi_pm_thaw(struct device *dev)
179 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
182 return pm_generic_thaw(dev);
184 return spi_legacy_resume(dev);
187 static int spi_pm_poweroff(struct device *dev)
189 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
192 return pm_generic_poweroff(dev);
194 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
197 static int spi_pm_restore(struct device *dev)
199 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
202 return pm_generic_restore(dev);
204 return spi_legacy_resume(dev);
207 #define spi_pm_suspend NULL
208 #define spi_pm_resume NULL
209 #define spi_pm_freeze NULL
210 #define spi_pm_thaw NULL
211 #define spi_pm_poweroff NULL
212 #define spi_pm_restore NULL
215 static const struct dev_pm_ops spi_pm = {
216 .suspend = spi_pm_suspend,
217 .resume = spi_pm_resume,
218 .freeze = spi_pm_freeze,
220 .poweroff = spi_pm_poweroff,
221 .restore = spi_pm_restore,
223 pm_generic_runtime_suspend,
224 pm_generic_runtime_resume,
225 pm_generic_runtime_idle
229 struct bus_type spi_bus_type = {
231 .dev_attrs = spi_dev_attrs,
232 .match = spi_match_device,
233 .uevent = spi_uevent,
236 EXPORT_SYMBOL_GPL(spi_bus_type);
239 static int spi_drv_probe(struct device *dev)
241 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
243 return sdrv->probe(to_spi_device(dev));
246 static int spi_drv_remove(struct device *dev)
248 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
250 return sdrv->remove(to_spi_device(dev));
253 static void spi_drv_shutdown(struct device *dev)
255 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
257 sdrv->shutdown(to_spi_device(dev));
261 * spi_register_driver - register a SPI driver
262 * @sdrv: the driver to register
265 int spi_register_driver(struct spi_driver *sdrv)
267 sdrv->driver.bus = &spi_bus_type;
269 sdrv->driver.probe = spi_drv_probe;
271 sdrv->driver.remove = spi_drv_remove;
273 sdrv->driver.shutdown = spi_drv_shutdown;
274 return driver_register(&sdrv->driver);
276 EXPORT_SYMBOL_GPL(spi_register_driver);
278 /*-------------------------------------------------------------------------*/
280 /* SPI devices should normally not be created by SPI device drivers; that
281 * would make them board-specific. Similarly with SPI master drivers.
282 * Device registration normally goes into like arch/.../mach.../board-YYY.c
283 * with other readonly (flashable) information about mainboard devices.
287 struct list_head list;
288 struct spi_board_info board_info;
291 static LIST_HEAD(board_list);
292 static LIST_HEAD(spi_master_list);
295 * Used to protect add/del opertion for board_info list and
296 * spi_master list, and their matching process
298 static DEFINE_MUTEX(board_lock);
301 * spi_alloc_device - Allocate a new SPI device
302 * @master: Controller to which device is connected
305 * Allows a driver to allocate and initialize a spi_device without
306 * registering it immediately. This allows a driver to directly
307 * fill the spi_device with device parameters before calling
308 * spi_add_device() on it.
310 * Caller is responsible to call spi_add_device() on the returned
311 * spi_device structure to add it to the SPI master. If the caller
312 * needs to discard the spi_device without adding it, then it should
313 * call spi_dev_put() on it.
315 * Returns a pointer to the new device, or NULL.
317 struct spi_device *spi_alloc_device(struct spi_master *master)
319 struct spi_device *spi;
320 struct device *dev = master->dev.parent;
322 if (!spi_master_get(master))
325 spi = kzalloc(sizeof *spi, GFP_KERNEL);
327 dev_err(dev, "cannot alloc spi_device\n");
328 spi_master_put(master);
332 spi->master = master;
333 spi->dev.parent = &master->dev;
334 spi->dev.bus = &spi_bus_type;
335 spi->dev.release = spidev_release;
336 device_initialize(&spi->dev);
339 EXPORT_SYMBOL_GPL(spi_alloc_device);
342 * spi_add_device - Add spi_device allocated with spi_alloc_device
343 * @spi: spi_device to register
345 * Companion function to spi_alloc_device. Devices allocated with
346 * spi_alloc_device can be added onto the spi bus with this function.
348 * Returns 0 on success; negative errno on failure
350 int spi_add_device(struct spi_device *spi)
352 static DEFINE_MUTEX(spi_add_lock);
353 struct device *dev = spi->master->dev.parent;
357 /* Chipselects are numbered 0..max; validate. */
358 if (spi->chip_select >= spi->master->num_chipselect) {
359 dev_err(dev, "cs%d >= max %d\n",
361 spi->master->num_chipselect);
365 /* Set the bus ID string */
366 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
370 /* We need to make sure there's no other device with this
371 * chipselect **BEFORE** we call setup(), else we'll trash
372 * its configuration. Lock against concurrent add() calls.
374 mutex_lock(&spi_add_lock);
376 d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
378 dev_err(dev, "chipselect %d already in use\n",
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.
496 spi_register_board_info(struct spi_board_info const *info, unsigned n)
498 struct boardinfo *bi;
501 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
505 for (i = 0; i < n; i++, bi++, info++) {
506 struct spi_master *master;
508 memcpy(&bi->board_info, info, sizeof(*info));
509 mutex_lock(&board_lock);
510 list_add_tail(&bi->list, &board_list);
511 list_for_each_entry(master, &spi_master_list, list)
512 spi_match_master_to_boardinfo(master, &bi->board_info);
513 mutex_unlock(&board_lock);
519 /*-------------------------------------------------------------------------*/
522 * spi_pump_messages - kthread work function which processes spi message queue
523 * @work: pointer to kthread work struct contained in the master struct
525 * This function checks if there is any spi message in the queue that
526 * needs processing and if so call out to the driver to initialize hardware
527 * and transfer each message.
530 static void spi_pump_messages(struct kthread_work *work)
532 struct spi_master *master =
533 container_of(work, struct spi_master, pump_messages);
535 bool was_busy = false;
538 /* Lock queue and check for queue work */
539 spin_lock_irqsave(&master->queue_lock, flags);
540 if (list_empty(&master->queue) || !master->running) {
541 if (master->busy && master->unprepare_transfer_hardware) {
542 ret = master->unprepare_transfer_hardware(master);
544 spin_unlock_irqrestore(&master->queue_lock, flags);
545 dev_err(&master->dev,
546 "failed to unprepare transfer hardware\n");
550 master->busy = false;
551 spin_unlock_irqrestore(&master->queue_lock, flags);
555 /* Make sure we are not already running a message */
556 if (master->cur_msg) {
557 spin_unlock_irqrestore(&master->queue_lock, flags);
560 /* Extract head of queue */
562 list_entry(master->queue.next, struct spi_message, queue);
564 list_del_init(&master->cur_msg->queue);
569 spin_unlock_irqrestore(&master->queue_lock, flags);
571 if (!was_busy && master->prepare_transfer_hardware) {
572 ret = master->prepare_transfer_hardware(master);
574 dev_err(&master->dev,
575 "failed to prepare transfer hardware\n");
580 ret = master->transfer_one_message(master, master->cur_msg);
582 dev_err(&master->dev,
583 "failed to transfer one message from queue\n");
588 static int spi_init_queue(struct spi_master *master)
590 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
592 INIT_LIST_HEAD(&master->queue);
593 spin_lock_init(&master->queue_lock);
595 master->running = false;
596 master->busy = false;
598 init_kthread_worker(&master->kworker);
599 master->kworker_task = kthread_run(kthread_worker_fn,
601 dev_name(&master->dev));
602 if (IS_ERR(master->kworker_task)) {
603 dev_err(&master->dev, "failed to create message pump task\n");
606 init_kthread_work(&master->pump_messages, spi_pump_messages);
609 * Master config will indicate if this controller should run the
610 * message pump with high (realtime) priority to reduce the transfer
611 * latency on the bus by minimising the delay between a transfer
612 * request and the scheduling of the message pump thread. Without this
613 * setting the message pump thread will remain at default priority.
616 dev_info(&master->dev,
617 "will run message pump with realtime priority\n");
618 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
625 * spi_get_next_queued_message() - called by driver to check for queued
627 * @master: the master to check for queued messages
629 * If there are more messages in the queue, the next message is returned from
632 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
634 struct spi_message *next;
637 /* get a pointer to the next message, if any */
638 spin_lock_irqsave(&master->queue_lock, flags);
639 if (list_empty(&master->queue))
642 next = list_entry(master->queue.next,
643 struct spi_message, queue);
644 spin_unlock_irqrestore(&master->queue_lock, flags);
648 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
651 * spi_finalize_current_message() - the current message is complete
652 * @master: the master to return the message to
654 * Called by the driver to notify the core that the message in the front of the
655 * queue is complete and can be removed from the queue.
657 void spi_finalize_current_message(struct spi_master *master)
659 struct spi_message *mesg;
662 spin_lock_irqsave(&master->queue_lock, flags);
663 mesg = master->cur_msg;
664 master->cur_msg = NULL;
666 queue_kthread_work(&master->kworker, &master->pump_messages);
667 spin_unlock_irqrestore(&master->queue_lock, flags);
671 mesg->complete(mesg->context);
673 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
675 static int spi_start_queue(struct spi_master *master)
679 spin_lock_irqsave(&master->queue_lock, flags);
681 if (master->running || master->busy) {
682 spin_unlock_irqrestore(&master->queue_lock, flags);
686 master->running = true;
687 master->cur_msg = NULL;
688 spin_unlock_irqrestore(&master->queue_lock, flags);
690 queue_kthread_work(&master->kworker, &master->pump_messages);
695 static int spi_stop_queue(struct spi_master *master)
698 unsigned limit = 500;
701 spin_lock_irqsave(&master->queue_lock, flags);
704 * This is a bit lame, but is optimized for the common execution path.
705 * A wait_queue on the master->busy could be used, but then the common
706 * execution path (pump_messages) would be required to call wake_up or
707 * friends on every SPI message. Do this instead.
709 while ((!list_empty(&master->queue) || master->busy) && limit--) {
710 spin_unlock_irqrestore(&master->queue_lock, flags);
712 spin_lock_irqsave(&master->queue_lock, flags);
715 if (!list_empty(&master->queue) || master->busy)
718 master->running = false;
720 spin_unlock_irqrestore(&master->queue_lock, flags);
723 dev_warn(&master->dev,
724 "could not stop message queue\n");
730 static int spi_destroy_queue(struct spi_master *master)
734 ret = spi_stop_queue(master);
737 * flush_kthread_worker will block until all work is done.
738 * If the reason that stop_queue timed out is that the work will never
739 * finish, then it does no good to call flush/stop thread, so
743 dev_err(&master->dev, "problem destroying queue\n");
747 flush_kthread_worker(&master->kworker);
748 kthread_stop(master->kworker_task);
754 * spi_queued_transfer - transfer function for queued transfers
755 * @spi: spi device which is requesting transfer
756 * @msg: spi message which is to handled is queued to driver queue
758 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
760 struct spi_master *master = spi->master;
763 spin_lock_irqsave(&master->queue_lock, flags);
765 if (!master->running) {
766 spin_unlock_irqrestore(&master->queue_lock, flags);
769 msg->actual_length = 0;
770 msg->status = -EINPROGRESS;
772 list_add_tail(&msg->queue, &master->queue);
773 if (master->running && !master->busy)
774 queue_kthread_work(&master->kworker, &master->pump_messages);
776 spin_unlock_irqrestore(&master->queue_lock, flags);
780 static int spi_master_initialize_queue(struct spi_master *master)
784 master->queued = true;
785 master->transfer = spi_queued_transfer;
787 /* Initialize and start queue */
788 ret = spi_init_queue(master);
790 dev_err(&master->dev, "problem initializing queue\n");
793 ret = spi_start_queue(master);
795 dev_err(&master->dev, "problem starting queue\n");
796 goto err_start_queue;
803 spi_destroy_queue(master);
807 /*-------------------------------------------------------------------------*/
809 #if defined(CONFIG_OF) && !defined(CONFIG_SPARC)
811 * of_register_spi_devices() - Register child devices onto the SPI bus
812 * @master: Pointer to spi_master device
814 * Registers an spi_device for each child node of master node which has a 'reg'
817 static void of_register_spi_devices(struct spi_master *master)
819 struct spi_device *spi;
820 struct device_node *nc;
825 if (!master->dev.of_node)
828 for_each_available_child_of_node(master->dev.of_node, nc) {
829 /* Alloc an spi_device */
830 spi = spi_alloc_device(master);
832 dev_err(&master->dev, "spi_device alloc error for %s\n",
838 /* Select device driver */
839 if (of_modalias_node(nc, spi->modalias,
840 sizeof(spi->modalias)) < 0) {
841 dev_err(&master->dev, "cannot find modalias for %s\n",
848 prop = of_get_property(nc, "reg", &len);
849 if (!prop || len < sizeof(*prop)) {
850 dev_err(&master->dev, "%s has no 'reg' property\n",
855 spi->chip_select = be32_to_cpup(prop);
857 /* Mode (clock phase/polarity/etc.) */
858 if (of_find_property(nc, "spi-cpha", NULL))
859 spi->mode |= SPI_CPHA;
860 if (of_find_property(nc, "spi-cpol", NULL))
861 spi->mode |= SPI_CPOL;
862 if (of_find_property(nc, "spi-cs-high", NULL))
863 spi->mode |= SPI_CS_HIGH;
866 prop = of_get_property(nc, "spi-max-frequency", &len);
867 if (!prop || len < sizeof(*prop)) {
868 dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
873 spi->max_speed_hz = be32_to_cpup(prop);
876 spi->irq = irq_of_parse_and_map(nc, 0);
878 /* Store a pointer to the node in the device structure */
880 spi->dev.of_node = nc;
882 /* Register the new device */
883 request_module(spi->modalias);
884 rc = spi_add_device(spi);
886 dev_err(&master->dev, "spi_device register error %s\n",
894 static void of_register_spi_devices(struct spi_master *master) { }
898 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
900 struct spi_device *spi = data;
902 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
903 struct acpi_resource_spi_serialbus *sb;
905 sb = &ares->data.spi_serial_bus;
906 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
907 spi->chip_select = sb->device_selection;
908 spi->max_speed_hz = sb->connection_speed;
910 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
911 spi->mode |= SPI_CPHA;
912 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
913 spi->mode |= SPI_CPOL;
914 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
915 spi->mode |= SPI_CS_HIGH;
917 } else if (spi->irq < 0) {
920 if (acpi_dev_resource_interrupt(ares, 0, &r))
924 /* Always tell the ACPI core to skip this resource */
928 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
929 void *data, void **return_value)
931 struct spi_master *master = data;
932 struct list_head resource_list;
933 struct acpi_device *adev;
934 struct spi_device *spi;
937 if (acpi_bus_get_device(handle, &adev))
939 if (acpi_bus_get_status(adev) || !adev->status.present)
942 spi = spi_alloc_device(master);
944 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
945 dev_name(&adev->dev));
949 ACPI_HANDLE_SET(&spi->dev, handle);
952 INIT_LIST_HEAD(&resource_list);
953 ret = acpi_dev_get_resources(adev, &resource_list,
954 acpi_spi_add_resource, spi);
955 acpi_dev_free_resource_list(&resource_list);
957 if (ret < 0 || !spi->max_speed_hz) {
962 strlcpy(spi->modalias, dev_name(&adev->dev), sizeof(spi->modalias));
963 if (spi_add_device(spi)) {
964 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
965 dev_name(&adev->dev));
972 static void acpi_register_spi_devices(struct spi_master *master)
977 handle = ACPI_HANDLE(&master->dev);
981 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
982 acpi_spi_add_device, NULL,
984 if (ACPI_FAILURE(status))
985 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
988 static inline void acpi_register_spi_devices(struct spi_master *master) {}
989 #endif /* CONFIG_ACPI */
991 static void spi_master_release(struct device *dev)
993 struct spi_master *master;
995 master = container_of(dev, struct spi_master, dev);
999 static struct class spi_master_class = {
1000 .name = "spi_master",
1001 .owner = THIS_MODULE,
1002 .dev_release = spi_master_release,
1008 * spi_alloc_master - allocate SPI master controller
1009 * @dev: the controller, possibly using the platform_bus
1010 * @size: how much zeroed driver-private data to allocate; the pointer to this
1011 * memory is in the driver_data field of the returned device,
1012 * accessible with spi_master_get_devdata().
1013 * Context: can sleep
1015 * This call is used only by SPI master controller drivers, which are the
1016 * only ones directly touching chip registers. It's how they allocate
1017 * an spi_master structure, prior to calling spi_register_master().
1019 * This must be called from context that can sleep. It returns the SPI
1020 * master structure on success, else NULL.
1022 * The caller is responsible for assigning the bus number and initializing
1023 * the master's methods before calling spi_register_master(); and (after errors
1024 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1027 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1029 struct spi_master *master;
1034 master = kzalloc(size + sizeof *master, GFP_KERNEL);
1038 device_initialize(&master->dev);
1039 master->bus_num = -1;
1040 master->num_chipselect = 1;
1041 master->dev.class = &spi_master_class;
1042 master->dev.parent = get_device(dev);
1043 spi_master_set_devdata(master, &master[1]);
1047 EXPORT_SYMBOL_GPL(spi_alloc_master);
1050 * spi_register_master - register SPI master controller
1051 * @master: initialized master, originally from spi_alloc_master()
1052 * Context: can sleep
1054 * SPI master controllers connect to their drivers using some non-SPI bus,
1055 * such as the platform bus. The final stage of probe() in that code
1056 * includes calling spi_register_master() to hook up to this SPI bus glue.
1058 * SPI controllers use board specific (often SOC specific) bus numbers,
1059 * and board-specific addressing for SPI devices combines those numbers
1060 * with chip select numbers. Since SPI does not directly support dynamic
1061 * device identification, boards need configuration tables telling which
1062 * chip is at which address.
1064 * This must be called from context that can sleep. It returns zero on
1065 * success, else a negative error code (dropping the master's refcount).
1066 * After a successful return, the caller is responsible for calling
1067 * spi_unregister_master().
1069 int spi_register_master(struct spi_master *master)
1071 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1072 struct device *dev = master->dev.parent;
1073 struct boardinfo *bi;
1074 int status = -ENODEV;
1080 /* even if it's just one always-selected device, there must
1081 * be at least one chipselect
1083 if (master->num_chipselect == 0)
1086 /* convention: dynamically assigned bus IDs count down from the max */
1087 if (master->bus_num < 0) {
1088 /* FIXME switch to an IDR based scheme, something like
1089 * I2C now uses, so we can't run out of "dynamic" IDs
1091 master->bus_num = atomic_dec_return(&dyn_bus_id);
1095 spin_lock_init(&master->bus_lock_spinlock);
1096 mutex_init(&master->bus_lock_mutex);
1097 master->bus_lock_flag = 0;
1099 /* register the device, then userspace will see it.
1100 * registration fails if the bus ID is in use.
1102 dev_set_name(&master->dev, "spi%u", master->bus_num);
1103 status = device_add(&master->dev);
1106 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1107 dynamic ? " (dynamic)" : "");
1109 /* If we're using a queued driver, start the queue */
1110 if (master->transfer)
1111 dev_info(dev, "master is unqueued, this is deprecated\n");
1113 status = spi_master_initialize_queue(master);
1115 device_unregister(&master->dev);
1120 mutex_lock(&board_lock);
1121 list_add_tail(&master->list, &spi_master_list);
1122 list_for_each_entry(bi, &board_list, list)
1123 spi_match_master_to_boardinfo(master, &bi->board_info);
1124 mutex_unlock(&board_lock);
1126 /* Register devices from the device tree and ACPI */
1127 of_register_spi_devices(master);
1128 acpi_register_spi_devices(master);
1132 EXPORT_SYMBOL_GPL(spi_register_master);
1134 static int __unregister(struct device *dev, void *null)
1136 spi_unregister_device(to_spi_device(dev));
1141 * spi_unregister_master - unregister SPI master controller
1142 * @master: the master being unregistered
1143 * Context: can sleep
1145 * This call is used only by SPI master controller drivers, which are the
1146 * only ones directly touching chip registers.
1148 * This must be called from context that can sleep.
1150 void spi_unregister_master(struct spi_master *master)
1154 if (master->queued) {
1155 if (spi_destroy_queue(master))
1156 dev_err(&master->dev, "queue remove failed\n");
1159 mutex_lock(&board_lock);
1160 list_del(&master->list);
1161 mutex_unlock(&board_lock);
1163 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1164 device_unregister(&master->dev);
1166 EXPORT_SYMBOL_GPL(spi_unregister_master);
1168 int spi_master_suspend(struct spi_master *master)
1172 /* Basically no-ops for non-queued masters */
1173 if (!master->queued)
1176 ret = spi_stop_queue(master);
1178 dev_err(&master->dev, "queue stop failed\n");
1182 EXPORT_SYMBOL_GPL(spi_master_suspend);
1184 int spi_master_resume(struct spi_master *master)
1188 if (!master->queued)
1191 ret = spi_start_queue(master);
1193 dev_err(&master->dev, "queue restart failed\n");
1197 EXPORT_SYMBOL_GPL(spi_master_resume);
1199 static int __spi_master_match(struct device *dev, void *data)
1201 struct spi_master *m;
1202 u16 *bus_num = data;
1204 m = container_of(dev, struct spi_master, dev);
1205 return m->bus_num == *bus_num;
1209 * spi_busnum_to_master - look up master associated with bus_num
1210 * @bus_num: the master's bus number
1211 * Context: can sleep
1213 * This call may be used with devices that are registered after
1214 * arch init time. It returns a refcounted pointer to the relevant
1215 * spi_master (which the caller must release), or NULL if there is
1216 * no such master registered.
1218 struct spi_master *spi_busnum_to_master(u16 bus_num)
1221 struct spi_master *master = NULL;
1223 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1224 __spi_master_match);
1226 master = container_of(dev, struct spi_master, dev);
1227 /* reference got in class_find_device */
1230 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1233 /*-------------------------------------------------------------------------*/
1235 /* Core methods for SPI master protocol drivers. Some of the
1236 * other core methods are currently defined as inline functions.
1240 * spi_setup - setup SPI mode and clock rate
1241 * @spi: the device whose settings are being modified
1242 * Context: can sleep, and no requests are queued to the device
1244 * SPI protocol drivers may need to update the transfer mode if the
1245 * device doesn't work with its default. They may likewise need
1246 * to update clock rates or word sizes from initial values. This function
1247 * changes those settings, and must be called from a context that can sleep.
1248 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1249 * effect the next time the device is selected and data is transferred to
1250 * or from it. When this function returns, the spi device is deselected.
1252 * Note that this call will fail if the protocol driver specifies an option
1253 * that the underlying controller or its driver does not support. For
1254 * example, not all hardware supports wire transfers using nine bit words,
1255 * LSB-first wire encoding, or active-high chipselects.
1257 int spi_setup(struct spi_device *spi)
1262 /* help drivers fail *cleanly* when they need options
1263 * that aren't supported with their current master
1265 bad_bits = spi->mode & ~spi->master->mode_bits;
1267 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1272 if (!spi->bits_per_word)
1273 spi->bits_per_word = 8;
1275 status = spi->master->setup(spi);
1277 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
1278 "%u bits/w, %u Hz max --> %d\n",
1279 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1280 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1281 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1282 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1283 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1284 spi->bits_per_word, spi->max_speed_hz,
1289 EXPORT_SYMBOL_GPL(spi_setup);
1291 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1293 struct spi_master *master = spi->master;
1295 /* Half-duplex links include original MicroWire, and ones with
1296 * only one data pin like SPI_3WIRE (switches direction) or where
1297 * either MOSI or MISO is missing. They can also be caused by
1298 * software limitations.
1300 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1301 || (spi->mode & SPI_3WIRE)) {
1302 struct spi_transfer *xfer;
1303 unsigned flags = master->flags;
1305 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1306 if (xfer->rx_buf && xfer->tx_buf)
1308 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1310 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1316 message->status = -EINPROGRESS;
1317 return master->transfer(spi, message);
1321 * spi_async - asynchronous SPI transfer
1322 * @spi: device with which data will be exchanged
1323 * @message: describes the data transfers, including completion callback
1324 * Context: any (irqs may be blocked, etc)
1326 * This call may be used in_irq and other contexts which can't sleep,
1327 * as well as from task contexts which can sleep.
1329 * The completion callback is invoked in a context which can't sleep.
1330 * Before that invocation, the value of message->status is undefined.
1331 * When the callback is issued, message->status holds either zero (to
1332 * indicate complete success) or a negative error code. After that
1333 * callback returns, the driver which issued the transfer request may
1334 * deallocate the associated memory; it's no longer in use by any SPI
1335 * core or controller driver code.
1337 * Note that although all messages to a spi_device are handled in
1338 * FIFO order, messages may go to different devices in other orders.
1339 * Some device might be higher priority, or have various "hard" access
1340 * time requirements, for example.
1342 * On detection of any fault during the transfer, processing of
1343 * the entire message is aborted, and the device is deselected.
1344 * Until returning from the associated message completion callback,
1345 * no other spi_message queued to that device will be processed.
1346 * (This rule applies equally to all the synchronous transfer calls,
1347 * which are wrappers around this core asynchronous primitive.)
1349 int spi_async(struct spi_device *spi, struct spi_message *message)
1351 struct spi_master *master = spi->master;
1353 unsigned long flags;
1355 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1357 if (master->bus_lock_flag)
1360 ret = __spi_async(spi, message);
1362 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1366 EXPORT_SYMBOL_GPL(spi_async);
1369 * spi_async_locked - version of spi_async with exclusive bus usage
1370 * @spi: device with which data will be exchanged
1371 * @message: describes the data transfers, including completion callback
1372 * Context: any (irqs may be blocked, etc)
1374 * This call may be used in_irq and other contexts which can't sleep,
1375 * as well as from task contexts which can sleep.
1377 * The completion callback is invoked in a context which can't sleep.
1378 * Before that invocation, the value of message->status is undefined.
1379 * When the callback is issued, message->status holds either zero (to
1380 * indicate complete success) or a negative error code. After that
1381 * callback returns, the driver which issued the transfer request may
1382 * deallocate the associated memory; it's no longer in use by any SPI
1383 * core or controller driver code.
1385 * Note that although all messages to a spi_device are handled in
1386 * FIFO order, messages may go to different devices in other orders.
1387 * Some device might be higher priority, or have various "hard" access
1388 * time requirements, for example.
1390 * On detection of any fault during the transfer, processing of
1391 * the entire message is aborted, and the device is deselected.
1392 * Until returning from the associated message completion callback,
1393 * no other spi_message queued to that device will be processed.
1394 * (This rule applies equally to all the synchronous transfer calls,
1395 * which are wrappers around this core asynchronous primitive.)
1397 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1399 struct spi_master *master = spi->master;
1401 unsigned long flags;
1403 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1405 ret = __spi_async(spi, message);
1407 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1412 EXPORT_SYMBOL_GPL(spi_async_locked);
1415 /*-------------------------------------------------------------------------*/
1417 /* Utility methods for SPI master protocol drivers, layered on
1418 * top of the core. Some other utility methods are defined as
1422 static void spi_complete(void *arg)
1427 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
1430 DECLARE_COMPLETION_ONSTACK(done);
1432 struct spi_master *master = spi->master;
1434 message->complete = spi_complete;
1435 message->context = &done;
1438 mutex_lock(&master->bus_lock_mutex);
1440 status = spi_async_locked(spi, message);
1443 mutex_unlock(&master->bus_lock_mutex);
1446 wait_for_completion(&done);
1447 status = message->status;
1449 message->context = NULL;
1454 * spi_sync - blocking/synchronous SPI data transfers
1455 * @spi: device with which data will be exchanged
1456 * @message: describes the data transfers
1457 * Context: can sleep
1459 * This call may only be used from a context that may sleep. The sleep
1460 * is non-interruptible, and has no timeout. Low-overhead controller
1461 * drivers may DMA directly into and out of the message buffers.
1463 * Note that the SPI device's chip select is active during the message,
1464 * and then is normally disabled between messages. Drivers for some
1465 * frequently-used devices may want to minimize costs of selecting a chip,
1466 * by leaving it selected in anticipation that the next message will go
1467 * to the same chip. (That may increase power usage.)
1469 * Also, the caller is guaranteeing that the memory associated with the
1470 * message will not be freed before this call returns.
1472 * It returns zero on success, else a negative error code.
1474 int spi_sync(struct spi_device *spi, struct spi_message *message)
1476 return __spi_sync(spi, message, 0);
1478 EXPORT_SYMBOL_GPL(spi_sync);
1481 * spi_sync_locked - version of spi_sync with exclusive bus usage
1482 * @spi: device with which data will be exchanged
1483 * @message: describes the data transfers
1484 * Context: can sleep
1486 * This call may only be used from a context that may sleep. The sleep
1487 * is non-interruptible, and has no timeout. Low-overhead controller
1488 * drivers may DMA directly into and out of the message buffers.
1490 * This call should be used by drivers that require exclusive access to the
1491 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
1492 * be released by a spi_bus_unlock call when the exclusive access is over.
1494 * It returns zero on success, else a negative error code.
1496 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
1498 return __spi_sync(spi, message, 1);
1500 EXPORT_SYMBOL_GPL(spi_sync_locked);
1503 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
1504 * @master: SPI bus master that should be locked for exclusive bus access
1505 * Context: can sleep
1507 * This call may only be used from a context that may sleep. The sleep
1508 * is non-interruptible, and has no timeout.
1510 * This call should be used by drivers that require exclusive access to the
1511 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
1512 * exclusive access is over. Data transfer must be done by spi_sync_locked
1513 * and spi_async_locked calls when the SPI bus lock is held.
1515 * It returns zero on success, else a negative error code.
1517 int spi_bus_lock(struct spi_master *master)
1519 unsigned long flags;
1521 mutex_lock(&master->bus_lock_mutex);
1523 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1524 master->bus_lock_flag = 1;
1525 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1527 /* mutex remains locked until spi_bus_unlock is called */
1531 EXPORT_SYMBOL_GPL(spi_bus_lock);
1534 * spi_bus_unlock - release the lock for exclusive SPI bus usage
1535 * @master: SPI bus master that was locked for exclusive bus access
1536 * Context: can sleep
1538 * This call may only be used from a context that may sleep. The sleep
1539 * is non-interruptible, and has no timeout.
1541 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
1544 * It returns zero on success, else a negative error code.
1546 int spi_bus_unlock(struct spi_master *master)
1548 master->bus_lock_flag = 0;
1550 mutex_unlock(&master->bus_lock_mutex);
1554 EXPORT_SYMBOL_GPL(spi_bus_unlock);
1556 /* portable code must never pass more than 32 bytes */
1557 #define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
1562 * spi_write_then_read - SPI synchronous write followed by read
1563 * @spi: device with which data will be exchanged
1564 * @txbuf: data to be written (need not be dma-safe)
1565 * @n_tx: size of txbuf, in bytes
1566 * @rxbuf: buffer into which data will be read (need not be dma-safe)
1567 * @n_rx: size of rxbuf, in bytes
1568 * Context: can sleep
1570 * This performs a half duplex MicroWire style transaction with the
1571 * device, sending txbuf and then reading rxbuf. The return value
1572 * is zero for success, else a negative errno status code.
1573 * This call may only be used from a context that may sleep.
1575 * Parameters to this routine are always copied using a small buffer;
1576 * portable code should never use this for more than 32 bytes.
1577 * Performance-sensitive or bulk transfer code should instead use
1578 * spi_{async,sync}() calls with dma-safe buffers.
1580 int spi_write_then_read(struct spi_device *spi,
1581 const void *txbuf, unsigned n_tx,
1582 void *rxbuf, unsigned n_rx)
1584 static DEFINE_MUTEX(lock);
1587 struct spi_message message;
1588 struct spi_transfer x[2];
1591 /* Use preallocated DMA-safe buffer. We can't avoid copying here,
1592 * (as a pure convenience thing), but we can keep heap costs
1593 * out of the hot path ...
1595 if ((n_tx + n_rx) > SPI_BUFSIZ)
1598 spi_message_init(&message);
1599 memset(x, 0, sizeof x);
1602 spi_message_add_tail(&x[0], &message);
1606 spi_message_add_tail(&x[1], &message);
1609 /* ... unless someone else is using the pre-allocated buffer */
1610 if (!mutex_trylock(&lock)) {
1611 local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1617 memcpy(local_buf, txbuf, n_tx);
1618 x[0].tx_buf = local_buf;
1619 x[1].rx_buf = local_buf + n_tx;
1622 status = spi_sync(spi, &message);
1624 memcpy(rxbuf, x[1].rx_buf, n_rx);
1626 if (x[0].tx_buf == buf)
1627 mutex_unlock(&lock);
1633 EXPORT_SYMBOL_GPL(spi_write_then_read);
1635 /*-------------------------------------------------------------------------*/
1637 static int __init spi_init(void)
1641 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
1647 status = bus_register(&spi_bus_type);
1651 status = class_register(&spi_master_class);
1657 bus_unregister(&spi_bus_type);
1665 /* board_info is normally registered in arch_initcall(),
1666 * but even essential drivers wait till later
1668 * REVISIT only boardinfo really needs static linking. the rest (device and
1669 * driver registration) _could_ be dynamically linked (modular) ... costs
1670 * include needing to have boardinfo data structures be much more public.
1672 postcore_initcall(spi_init);