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/dma-mapping.h>
28 #include <linux/dmaengine.h>
29 #include <linux/mutex.h>
30 #include <linux/of_device.h>
31 #include <linux/of_irq.h>
32 #include <linux/slab.h>
33 #include <linux/mod_devicetable.h>
34 #include <linux/spi/spi.h>
35 #include <linux/of_gpio.h>
36 #include <linux/pm_runtime.h>
37 #include <linux/export.h>
38 #include <linux/sched/rt.h>
39 #include <linux/delay.h>
40 #include <linux/kthread.h>
41 #include <linux/ioport.h>
42 #include <linux/acpi.h>
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/spi.h>
47 static void spidev_release(struct device *dev)
49 struct spi_device *spi = to_spi_device(dev);
51 /* spi masters may cleanup for released devices */
52 if (spi->master->cleanup)
53 spi->master->cleanup(spi);
55 spi_master_put(spi->master);
60 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
62 const struct spi_device *spi = to_spi_device(dev);
65 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
69 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
71 static DEVICE_ATTR_RO(modalias);
73 static struct attribute *spi_dev_attrs[] = {
74 &dev_attr_modalias.attr,
77 ATTRIBUTE_GROUPS(spi_dev);
79 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
80 * and the sysfs version makes coldplug work too.
83 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
84 const struct spi_device *sdev)
87 if (!strcmp(sdev->modalias, id->name))
94 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
96 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
98 return spi_match_id(sdrv->id_table, sdev);
100 EXPORT_SYMBOL_GPL(spi_get_device_id);
102 static int spi_match_device(struct device *dev, struct device_driver *drv)
104 const struct spi_device *spi = to_spi_device(dev);
105 const struct spi_driver *sdrv = to_spi_driver(drv);
107 /* Attempt an OF style match */
108 if (of_driver_match_device(dev, drv))
112 if (acpi_driver_match_device(dev, drv))
116 return !!spi_match_id(sdrv->id_table, spi);
118 return strcmp(spi->modalias, drv->name) == 0;
121 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
123 const struct spi_device *spi = to_spi_device(dev);
126 rc = acpi_device_uevent_modalias(dev, env);
130 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
134 #ifdef CONFIG_PM_SLEEP
135 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
138 struct spi_driver *drv = to_spi_driver(dev->driver);
140 /* suspend will stop irqs and dma; no more i/o */
143 value = drv->suspend(to_spi_device(dev), message);
145 dev_dbg(dev, "... can't suspend\n");
150 static int spi_legacy_resume(struct device *dev)
153 struct spi_driver *drv = to_spi_driver(dev->driver);
155 /* resume may restart the i/o queue */
158 value = drv->resume(to_spi_device(dev));
160 dev_dbg(dev, "... can't resume\n");
165 static int spi_pm_suspend(struct device *dev)
167 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
170 return pm_generic_suspend(dev);
172 return spi_legacy_suspend(dev, PMSG_SUSPEND);
175 static int spi_pm_resume(struct device *dev)
177 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
180 return pm_generic_resume(dev);
182 return spi_legacy_resume(dev);
185 static int spi_pm_freeze(struct device *dev)
187 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
190 return pm_generic_freeze(dev);
192 return spi_legacy_suspend(dev, PMSG_FREEZE);
195 static int spi_pm_thaw(struct device *dev)
197 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
200 return pm_generic_thaw(dev);
202 return spi_legacy_resume(dev);
205 static int spi_pm_poweroff(struct device *dev)
207 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
210 return pm_generic_poweroff(dev);
212 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
215 static int spi_pm_restore(struct device *dev)
217 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
220 return pm_generic_restore(dev);
222 return spi_legacy_resume(dev);
225 #define spi_pm_suspend NULL
226 #define spi_pm_resume NULL
227 #define spi_pm_freeze NULL
228 #define spi_pm_thaw NULL
229 #define spi_pm_poweroff NULL
230 #define spi_pm_restore NULL
233 static const struct dev_pm_ops spi_pm = {
234 .suspend = spi_pm_suspend,
235 .resume = spi_pm_resume,
236 .freeze = spi_pm_freeze,
238 .poweroff = spi_pm_poweroff,
239 .restore = spi_pm_restore,
241 pm_generic_runtime_suspend,
242 pm_generic_runtime_resume,
247 struct bus_type spi_bus_type = {
249 .dev_groups = spi_dev_groups,
250 .match = spi_match_device,
251 .uevent = spi_uevent,
254 EXPORT_SYMBOL_GPL(spi_bus_type);
257 static int spi_drv_probe(struct device *dev)
259 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
260 struct spi_device *spi = to_spi_device(dev);
263 acpi_dev_pm_attach(&spi->dev, true);
264 ret = sdrv->probe(spi);
266 acpi_dev_pm_detach(&spi->dev, true);
271 static int spi_drv_remove(struct device *dev)
273 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
274 struct spi_device *spi = to_spi_device(dev);
277 ret = sdrv->remove(spi);
278 acpi_dev_pm_detach(&spi->dev, true);
283 static void spi_drv_shutdown(struct device *dev)
285 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
287 sdrv->shutdown(to_spi_device(dev));
291 * spi_register_driver - register a SPI driver
292 * @sdrv: the driver to register
295 int spi_register_driver(struct spi_driver *sdrv)
297 sdrv->driver.bus = &spi_bus_type;
299 sdrv->driver.probe = spi_drv_probe;
301 sdrv->driver.remove = spi_drv_remove;
303 sdrv->driver.shutdown = spi_drv_shutdown;
304 return driver_register(&sdrv->driver);
306 EXPORT_SYMBOL_GPL(spi_register_driver);
308 /*-------------------------------------------------------------------------*/
310 /* SPI devices should normally not be created by SPI device drivers; that
311 * would make them board-specific. Similarly with SPI master drivers.
312 * Device registration normally goes into like arch/.../mach.../board-YYY.c
313 * with other readonly (flashable) information about mainboard devices.
317 struct list_head list;
318 struct spi_board_info board_info;
321 static LIST_HEAD(board_list);
322 static LIST_HEAD(spi_master_list);
325 * Used to protect add/del opertion for board_info list and
326 * spi_master list, and their matching process
328 static DEFINE_MUTEX(board_lock);
331 * spi_alloc_device - Allocate a new SPI device
332 * @master: Controller to which device is connected
335 * Allows a driver to allocate and initialize a spi_device without
336 * registering it immediately. This allows a driver to directly
337 * fill the spi_device with device parameters before calling
338 * spi_add_device() on it.
340 * Caller is responsible to call spi_add_device() on the returned
341 * spi_device structure to add it to the SPI master. If the caller
342 * needs to discard the spi_device without adding it, then it should
343 * call spi_dev_put() on it.
345 * Returns a pointer to the new device, or NULL.
347 struct spi_device *spi_alloc_device(struct spi_master *master)
349 struct spi_device *spi;
350 struct device *dev = master->dev.parent;
352 if (!spi_master_get(master))
355 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
357 dev_err(dev, "cannot alloc spi_device\n");
358 spi_master_put(master);
362 spi->master = master;
363 spi->dev.parent = &master->dev;
364 spi->dev.bus = &spi_bus_type;
365 spi->dev.release = spidev_release;
366 spi->cs_gpio = -ENOENT;
367 device_initialize(&spi->dev);
370 EXPORT_SYMBOL_GPL(spi_alloc_device);
372 static void spi_dev_set_name(struct spi_device *spi)
374 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
377 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
381 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
385 static int spi_dev_check(struct device *dev, void *data)
387 struct spi_device *spi = to_spi_device(dev);
388 struct spi_device *new_spi = data;
390 if (spi->master == new_spi->master &&
391 spi->chip_select == new_spi->chip_select)
397 * spi_add_device - Add spi_device allocated with spi_alloc_device
398 * @spi: spi_device to register
400 * Companion function to spi_alloc_device. Devices allocated with
401 * spi_alloc_device can be added onto the spi bus with this function.
403 * Returns 0 on success; negative errno on failure
405 int spi_add_device(struct spi_device *spi)
407 static DEFINE_MUTEX(spi_add_lock);
408 struct spi_master *master = spi->master;
409 struct device *dev = master->dev.parent;
412 /* Chipselects are numbered 0..max; validate. */
413 if (spi->chip_select >= master->num_chipselect) {
414 dev_err(dev, "cs%d >= max %d\n",
416 master->num_chipselect);
420 /* Set the bus ID string */
421 spi_dev_set_name(spi);
423 /* We need to make sure there's no other device with this
424 * chipselect **BEFORE** we call setup(), else we'll trash
425 * its configuration. Lock against concurrent add() calls.
427 mutex_lock(&spi_add_lock);
429 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
431 dev_err(dev, "chipselect %d already in use\n",
436 if (master->cs_gpios)
437 spi->cs_gpio = master->cs_gpios[spi->chip_select];
439 /* Drivers may modify this initial i/o setup, but will
440 * normally rely on the device being setup. Devices
441 * using SPI_CS_HIGH can't coexist well otherwise...
443 status = spi_setup(spi);
445 dev_err(dev, "can't setup %s, status %d\n",
446 dev_name(&spi->dev), status);
450 /* Device may be bound to an active driver when this returns */
451 status = device_add(&spi->dev);
453 dev_err(dev, "can't add %s, status %d\n",
454 dev_name(&spi->dev), status);
456 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
459 mutex_unlock(&spi_add_lock);
462 EXPORT_SYMBOL_GPL(spi_add_device);
465 * spi_new_device - instantiate one new SPI device
466 * @master: Controller to which device is connected
467 * @chip: Describes the SPI device
470 * On typical mainboards, this is purely internal; and it's not needed
471 * after board init creates the hard-wired devices. Some development
472 * platforms may not be able to use spi_register_board_info though, and
473 * this is exported so that for example a USB or parport based adapter
474 * driver could add devices (which it would learn about out-of-band).
476 * Returns the new device, or NULL.
478 struct spi_device *spi_new_device(struct spi_master *master,
479 struct spi_board_info *chip)
481 struct spi_device *proxy;
484 /* NOTE: caller did any chip->bus_num checks necessary.
486 * Also, unless we change the return value convention to use
487 * error-or-pointer (not NULL-or-pointer), troubleshootability
488 * suggests syslogged diagnostics are best here (ugh).
491 proxy = spi_alloc_device(master);
495 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
497 proxy->chip_select = chip->chip_select;
498 proxy->max_speed_hz = chip->max_speed_hz;
499 proxy->mode = chip->mode;
500 proxy->irq = chip->irq;
501 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
502 proxy->dev.platform_data = (void *) chip->platform_data;
503 proxy->controller_data = chip->controller_data;
504 proxy->controller_state = NULL;
506 status = spi_add_device(proxy);
514 EXPORT_SYMBOL_GPL(spi_new_device);
516 static void spi_match_master_to_boardinfo(struct spi_master *master,
517 struct spi_board_info *bi)
519 struct spi_device *dev;
521 if (master->bus_num != bi->bus_num)
524 dev = spi_new_device(master, bi);
526 dev_err(master->dev.parent, "can't create new device for %s\n",
531 * spi_register_board_info - register SPI devices for a given board
532 * @info: array of chip descriptors
533 * @n: how many descriptors are provided
536 * Board-specific early init code calls this (probably during arch_initcall)
537 * with segments of the SPI device table. Any device nodes are created later,
538 * after the relevant parent SPI controller (bus_num) is defined. We keep
539 * this table of devices forever, so that reloading a controller driver will
540 * not make Linux forget about these hard-wired devices.
542 * Other code can also call this, e.g. a particular add-on board might provide
543 * SPI devices through its expansion connector, so code initializing that board
544 * would naturally declare its SPI devices.
546 * The board info passed can safely be __initdata ... but be careful of
547 * any embedded pointers (platform_data, etc), they're copied as-is.
549 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
551 struct boardinfo *bi;
554 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
558 for (i = 0; i < n; i++, bi++, info++) {
559 struct spi_master *master;
561 memcpy(&bi->board_info, info, sizeof(*info));
562 mutex_lock(&board_lock);
563 list_add_tail(&bi->list, &board_list);
564 list_for_each_entry(master, &spi_master_list, list)
565 spi_match_master_to_boardinfo(master, &bi->board_info);
566 mutex_unlock(&board_lock);
572 /*-------------------------------------------------------------------------*/
574 static void spi_set_cs(struct spi_device *spi, bool enable)
576 if (spi->mode & SPI_CS_HIGH)
579 if (spi->cs_gpio >= 0)
580 gpio_set_value(spi->cs_gpio, !enable);
581 else if (spi->master->set_cs)
582 spi->master->set_cs(spi, !enable);
585 static int spi_map_buf(struct spi_master *master, struct device *dev,
586 struct sg_table *sgt, void *buf, size_t len,
587 enum dma_data_direction dir)
589 const bool vmalloced_buf = is_vmalloc_addr(buf);
590 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
591 const int sgs = DIV_ROUND_UP(len, desc_len);
592 struct page *vm_page;
597 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
601 for (i = 0; i < sgs; i++) {
602 min = min_t(size_t, len, desc_len);
605 vm_page = vmalloc_to_page(buf);
610 sg_buf = page_address(vm_page) +
611 ((size_t)buf & ~PAGE_MASK);
616 sg_set_buf(&sgt->sgl[i], sg_buf, min);
622 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
633 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
634 struct sg_table *sgt, enum dma_data_direction dir)
636 if (sgt->orig_nents) {
637 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
642 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
644 struct device *tx_dev, *rx_dev;
645 struct spi_transfer *xfer;
647 size_t max_tx, max_rx;
650 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
654 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
655 if ((master->flags & SPI_MASTER_MUST_TX) &&
657 max_tx = max(xfer->len, max_tx);
658 if ((master->flags & SPI_MASTER_MUST_RX) &&
660 max_rx = max(xfer->len, max_rx);
664 tmp = krealloc(master->dummy_tx, max_tx,
665 GFP_KERNEL | GFP_DMA);
668 master->dummy_tx = tmp;
669 memset(tmp, 0, max_tx);
673 tmp = krealloc(master->dummy_rx, max_rx,
674 GFP_KERNEL | GFP_DMA);
677 master->dummy_rx = tmp;
680 if (max_tx || max_rx) {
681 list_for_each_entry(xfer, &msg->transfers,
684 xfer->tx_buf = master->dummy_tx;
686 xfer->rx_buf = master->dummy_rx;
691 if (!master->can_dma)
694 tx_dev = &master->dma_tx->dev->device;
695 rx_dev = &master->dma_rx->dev->device;
697 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
698 if (!master->can_dma(master, msg->spi, xfer))
701 if (xfer->tx_buf != NULL) {
702 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
703 (void *)xfer->tx_buf, xfer->len,
709 if (xfer->rx_buf != NULL) {
710 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
711 xfer->rx_buf, xfer->len,
714 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
721 master->cur_msg_mapped = true;
726 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
728 struct spi_transfer *xfer;
729 struct device *tx_dev, *rx_dev;
731 if (!master->cur_msg_mapped || !master->can_dma)
734 tx_dev = &master->dma_tx->dev->device;
735 rx_dev = &master->dma_rx->dev->device;
737 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
738 if (!master->can_dma(master, msg->spi, xfer))
741 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
742 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
749 * spi_transfer_one_message - Default implementation of transfer_one_message()
751 * This is a standard implementation of transfer_one_message() for
752 * drivers which impelment a transfer_one() operation. It provides
753 * standard handling of delays and chip select management.
755 static int spi_transfer_one_message(struct spi_master *master,
756 struct spi_message *msg)
758 struct spi_transfer *xfer;
760 bool keep_cs = false;
763 spi_set_cs(msg->spi, true);
765 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
766 trace_spi_transfer_start(msg, xfer);
768 reinit_completion(&master->xfer_completion);
770 ret = master->transfer_one(master, msg->spi, xfer);
772 dev_err(&msg->spi->dev,
773 "SPI transfer failed: %d\n", ret);
779 wait_for_completion(&master->xfer_completion);
782 trace_spi_transfer_stop(msg, xfer);
784 if (msg->status != -EINPROGRESS)
787 if (xfer->delay_usecs)
788 udelay(xfer->delay_usecs);
790 if (xfer->cs_change) {
791 if (list_is_last(&xfer->transfer_list,
796 spi_set_cs(msg->spi, cur_cs);
800 msg->actual_length += xfer->len;
804 if (ret != 0 || !keep_cs)
805 spi_set_cs(msg->spi, false);
807 if (msg->status == -EINPROGRESS)
810 spi_finalize_current_message(master);
816 * spi_finalize_current_transfer - report completion of a transfer
818 * Called by SPI drivers using the core transfer_one_message()
819 * implementation to notify it that the current interrupt driven
820 * transfer has finished and the next one may be scheduled.
822 void spi_finalize_current_transfer(struct spi_master *master)
824 complete(&master->xfer_completion);
826 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
829 * spi_pump_messages - kthread work function which processes spi message queue
830 * @work: pointer to kthread work struct contained in the master struct
832 * This function checks if there is any spi message in the queue that
833 * needs processing and if so call out to the driver to initialize hardware
834 * and transfer each message.
837 static void spi_pump_messages(struct kthread_work *work)
839 struct spi_master *master =
840 container_of(work, struct spi_master, pump_messages);
842 bool was_busy = false;
845 /* Lock queue and check for queue work */
846 spin_lock_irqsave(&master->queue_lock, flags);
847 if (list_empty(&master->queue) || !master->running) {
849 spin_unlock_irqrestore(&master->queue_lock, flags);
852 master->busy = false;
853 spin_unlock_irqrestore(&master->queue_lock, flags);
854 kfree(master->dummy_rx);
855 master->dummy_rx = NULL;
856 kfree(master->dummy_tx);
857 master->dummy_tx = NULL;
858 if (master->unprepare_transfer_hardware &&
859 master->unprepare_transfer_hardware(master))
860 dev_err(&master->dev,
861 "failed to unprepare transfer hardware\n");
862 if (master->auto_runtime_pm) {
863 pm_runtime_mark_last_busy(master->dev.parent);
864 pm_runtime_put_autosuspend(master->dev.parent);
866 trace_spi_master_idle(master);
870 /* Make sure we are not already running a message */
871 if (master->cur_msg) {
872 spin_unlock_irqrestore(&master->queue_lock, flags);
875 /* Extract head of queue */
877 list_first_entry(&master->queue, struct spi_message, queue);
879 list_del_init(&master->cur_msg->queue);
884 spin_unlock_irqrestore(&master->queue_lock, flags);
886 if (!was_busy && master->auto_runtime_pm) {
887 ret = pm_runtime_get_sync(master->dev.parent);
889 dev_err(&master->dev, "Failed to power device: %d\n",
896 trace_spi_master_busy(master);
898 if (!was_busy && master->prepare_transfer_hardware) {
899 ret = master->prepare_transfer_hardware(master);
901 dev_err(&master->dev,
902 "failed to prepare transfer hardware\n");
904 if (master->auto_runtime_pm)
905 pm_runtime_put(master->dev.parent);
910 trace_spi_message_start(master->cur_msg);
912 if (master->prepare_message) {
913 ret = master->prepare_message(master, master->cur_msg);
915 dev_err(&master->dev,
916 "failed to prepare message: %d\n", ret);
917 master->cur_msg->status = ret;
918 spi_finalize_current_message(master);
921 master->cur_msg_prepared = true;
924 ret = spi_map_msg(master, master->cur_msg);
926 master->cur_msg->status = ret;
927 spi_finalize_current_message(master);
931 ret = master->transfer_one_message(master, master->cur_msg);
933 dev_err(&master->dev,
934 "failed to transfer one message from queue\n");
939 static int spi_init_queue(struct spi_master *master)
941 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
943 INIT_LIST_HEAD(&master->queue);
944 spin_lock_init(&master->queue_lock);
946 master->running = false;
947 master->busy = false;
949 init_kthread_worker(&master->kworker);
950 master->kworker_task = kthread_run(kthread_worker_fn,
951 &master->kworker, "%s",
952 dev_name(&master->dev));
953 if (IS_ERR(master->kworker_task)) {
954 dev_err(&master->dev, "failed to create message pump task\n");
957 init_kthread_work(&master->pump_messages, spi_pump_messages);
960 * Master config will indicate if this controller should run the
961 * message pump with high (realtime) priority to reduce the transfer
962 * latency on the bus by minimising the delay between a transfer
963 * request and the scheduling of the message pump thread. Without this
964 * setting the message pump thread will remain at default priority.
967 dev_info(&master->dev,
968 "will run message pump with realtime priority\n");
969 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
976 * spi_get_next_queued_message() - called by driver to check for queued
978 * @master: the master to check for queued messages
980 * If there are more messages in the queue, the next message is returned from
983 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
985 struct spi_message *next;
988 /* get a pointer to the next message, if any */
989 spin_lock_irqsave(&master->queue_lock, flags);
990 next = list_first_entry_or_null(&master->queue, struct spi_message,
992 spin_unlock_irqrestore(&master->queue_lock, flags);
996 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
999 * spi_finalize_current_message() - the current message is complete
1000 * @master: the master to return the message to
1002 * Called by the driver to notify the core that the message in the front of the
1003 * queue is complete and can be removed from the queue.
1005 void spi_finalize_current_message(struct spi_master *master)
1007 struct spi_message *mesg;
1008 unsigned long flags;
1011 spin_lock_irqsave(&master->queue_lock, flags);
1012 mesg = master->cur_msg;
1013 master->cur_msg = NULL;
1015 queue_kthread_work(&master->kworker, &master->pump_messages);
1016 spin_unlock_irqrestore(&master->queue_lock, flags);
1018 spi_unmap_msg(master, mesg);
1020 if (master->cur_msg_prepared && master->unprepare_message) {
1021 ret = master->unprepare_message(master, mesg);
1023 dev_err(&master->dev,
1024 "failed to unprepare message: %d\n", ret);
1027 master->cur_msg_prepared = false;
1031 mesg->complete(mesg->context);
1033 trace_spi_message_done(mesg);
1035 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1037 static int spi_start_queue(struct spi_master *master)
1039 unsigned long flags;
1041 spin_lock_irqsave(&master->queue_lock, flags);
1043 if (master->running || master->busy) {
1044 spin_unlock_irqrestore(&master->queue_lock, flags);
1048 master->running = true;
1049 master->cur_msg = NULL;
1050 spin_unlock_irqrestore(&master->queue_lock, flags);
1052 queue_kthread_work(&master->kworker, &master->pump_messages);
1057 static int spi_stop_queue(struct spi_master *master)
1059 unsigned long flags;
1060 unsigned limit = 500;
1063 spin_lock_irqsave(&master->queue_lock, flags);
1066 * This is a bit lame, but is optimized for the common execution path.
1067 * A wait_queue on the master->busy could be used, but then the common
1068 * execution path (pump_messages) would be required to call wake_up or
1069 * friends on every SPI message. Do this instead.
1071 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1072 spin_unlock_irqrestore(&master->queue_lock, flags);
1074 spin_lock_irqsave(&master->queue_lock, flags);
1077 if (!list_empty(&master->queue) || master->busy)
1080 master->running = false;
1082 spin_unlock_irqrestore(&master->queue_lock, flags);
1085 dev_warn(&master->dev,
1086 "could not stop message queue\n");
1092 static int spi_destroy_queue(struct spi_master *master)
1096 ret = spi_stop_queue(master);
1099 * flush_kthread_worker will block until all work is done.
1100 * If the reason that stop_queue timed out is that the work will never
1101 * finish, then it does no good to call flush/stop thread, so
1105 dev_err(&master->dev, "problem destroying queue\n");
1109 flush_kthread_worker(&master->kworker);
1110 kthread_stop(master->kworker_task);
1116 * spi_queued_transfer - transfer function for queued transfers
1117 * @spi: spi device which is requesting transfer
1118 * @msg: spi message which is to handled is queued to driver queue
1120 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1122 struct spi_master *master = spi->master;
1123 unsigned long flags;
1125 spin_lock_irqsave(&master->queue_lock, flags);
1127 if (!master->running) {
1128 spin_unlock_irqrestore(&master->queue_lock, flags);
1131 msg->actual_length = 0;
1132 msg->status = -EINPROGRESS;
1134 list_add_tail(&msg->queue, &master->queue);
1136 queue_kthread_work(&master->kworker, &master->pump_messages);
1138 spin_unlock_irqrestore(&master->queue_lock, flags);
1142 static int spi_master_initialize_queue(struct spi_master *master)
1146 master->queued = true;
1147 master->transfer = spi_queued_transfer;
1148 if (!master->transfer_one_message)
1149 master->transfer_one_message = spi_transfer_one_message;
1151 /* Initialize and start queue */
1152 ret = spi_init_queue(master);
1154 dev_err(&master->dev, "problem initializing queue\n");
1155 goto err_init_queue;
1157 ret = spi_start_queue(master);
1159 dev_err(&master->dev, "problem starting queue\n");
1160 goto err_start_queue;
1167 spi_destroy_queue(master);
1171 /*-------------------------------------------------------------------------*/
1173 #if defined(CONFIG_OF)
1175 * of_register_spi_devices() - Register child devices onto the SPI bus
1176 * @master: Pointer to spi_master device
1178 * Registers an spi_device for each child node of master node which has a 'reg'
1181 static void of_register_spi_devices(struct spi_master *master)
1183 struct spi_device *spi;
1184 struct device_node *nc;
1188 if (!master->dev.of_node)
1191 for_each_available_child_of_node(master->dev.of_node, nc) {
1192 /* Alloc an spi_device */
1193 spi = spi_alloc_device(master);
1195 dev_err(&master->dev, "spi_device alloc error for %s\n",
1201 /* Select device driver */
1202 if (of_modalias_node(nc, spi->modalias,
1203 sizeof(spi->modalias)) < 0) {
1204 dev_err(&master->dev, "cannot find modalias for %s\n",
1210 /* Device address */
1211 rc = of_property_read_u32(nc, "reg", &value);
1213 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1218 spi->chip_select = value;
1220 /* Mode (clock phase/polarity/etc.) */
1221 if (of_find_property(nc, "spi-cpha", NULL))
1222 spi->mode |= SPI_CPHA;
1223 if (of_find_property(nc, "spi-cpol", NULL))
1224 spi->mode |= SPI_CPOL;
1225 if (of_find_property(nc, "spi-cs-high", NULL))
1226 spi->mode |= SPI_CS_HIGH;
1227 if (of_find_property(nc, "spi-3wire", NULL))
1228 spi->mode |= SPI_3WIRE;
1230 /* Device DUAL/QUAD mode */
1231 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1236 spi->mode |= SPI_TX_DUAL;
1239 spi->mode |= SPI_TX_QUAD;
1242 dev_warn(&master->dev,
1243 "spi-tx-bus-width %d not supported\n",
1249 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1254 spi->mode |= SPI_RX_DUAL;
1257 spi->mode |= SPI_RX_QUAD;
1260 dev_warn(&master->dev,
1261 "spi-rx-bus-width %d not supported\n",
1268 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1270 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1275 spi->max_speed_hz = value;
1278 spi->irq = irq_of_parse_and_map(nc, 0);
1280 /* Store a pointer to the node in the device structure */
1282 spi->dev.of_node = nc;
1284 /* Register the new device */
1285 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1286 rc = spi_add_device(spi);
1288 dev_err(&master->dev, "spi_device register error %s\n",
1296 static void of_register_spi_devices(struct spi_master *master) { }
1300 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1302 struct spi_device *spi = data;
1304 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1305 struct acpi_resource_spi_serialbus *sb;
1307 sb = &ares->data.spi_serial_bus;
1308 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1309 spi->chip_select = sb->device_selection;
1310 spi->max_speed_hz = sb->connection_speed;
1312 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1313 spi->mode |= SPI_CPHA;
1314 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1315 spi->mode |= SPI_CPOL;
1316 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1317 spi->mode |= SPI_CS_HIGH;
1319 } else if (spi->irq < 0) {
1322 if (acpi_dev_resource_interrupt(ares, 0, &r))
1326 /* Always tell the ACPI core to skip this resource */
1330 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1331 void *data, void **return_value)
1333 struct spi_master *master = data;
1334 struct list_head resource_list;
1335 struct acpi_device *adev;
1336 struct spi_device *spi;
1339 if (acpi_bus_get_device(handle, &adev))
1341 if (acpi_bus_get_status(adev) || !adev->status.present)
1344 spi = spi_alloc_device(master);
1346 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1347 dev_name(&adev->dev));
1348 return AE_NO_MEMORY;
1351 ACPI_COMPANION_SET(&spi->dev, adev);
1354 INIT_LIST_HEAD(&resource_list);
1355 ret = acpi_dev_get_resources(adev, &resource_list,
1356 acpi_spi_add_resource, spi);
1357 acpi_dev_free_resource_list(&resource_list);
1359 if (ret < 0 || !spi->max_speed_hz) {
1364 adev->power.flags.ignore_parent = true;
1365 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1366 if (spi_add_device(spi)) {
1367 adev->power.flags.ignore_parent = false;
1368 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1369 dev_name(&adev->dev));
1376 static void acpi_register_spi_devices(struct spi_master *master)
1381 handle = ACPI_HANDLE(master->dev.parent);
1385 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1386 acpi_spi_add_device, NULL,
1388 if (ACPI_FAILURE(status))
1389 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1392 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1393 #endif /* CONFIG_ACPI */
1395 static void spi_master_release(struct device *dev)
1397 struct spi_master *master;
1399 master = container_of(dev, struct spi_master, dev);
1403 static struct class spi_master_class = {
1404 .name = "spi_master",
1405 .owner = THIS_MODULE,
1406 .dev_release = spi_master_release,
1412 * spi_alloc_master - allocate SPI master controller
1413 * @dev: the controller, possibly using the platform_bus
1414 * @size: how much zeroed driver-private data to allocate; the pointer to this
1415 * memory is in the driver_data field of the returned device,
1416 * accessible with spi_master_get_devdata().
1417 * Context: can sleep
1419 * This call is used only by SPI master controller drivers, which are the
1420 * only ones directly touching chip registers. It's how they allocate
1421 * an spi_master structure, prior to calling spi_register_master().
1423 * This must be called from context that can sleep. It returns the SPI
1424 * master structure on success, else NULL.
1426 * The caller is responsible for assigning the bus number and initializing
1427 * the master's methods before calling spi_register_master(); and (after errors
1428 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1431 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1433 struct spi_master *master;
1438 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1442 device_initialize(&master->dev);
1443 master->bus_num = -1;
1444 master->num_chipselect = 1;
1445 master->dev.class = &spi_master_class;
1446 master->dev.parent = get_device(dev);
1447 spi_master_set_devdata(master, &master[1]);
1451 EXPORT_SYMBOL_GPL(spi_alloc_master);
1454 static int of_spi_register_master(struct spi_master *master)
1457 struct device_node *np = master->dev.of_node;
1462 nb = of_gpio_named_count(np, "cs-gpios");
1463 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1465 /* Return error only for an incorrectly formed cs-gpios property */
1466 if (nb == 0 || nb == -ENOENT)
1471 cs = devm_kzalloc(&master->dev,
1472 sizeof(int) * master->num_chipselect,
1474 master->cs_gpios = cs;
1476 if (!master->cs_gpios)
1479 for (i = 0; i < master->num_chipselect; i++)
1482 for (i = 0; i < nb; i++)
1483 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1488 static int of_spi_register_master(struct spi_master *master)
1495 * spi_register_master - register SPI master controller
1496 * @master: initialized master, originally from spi_alloc_master()
1497 * Context: can sleep
1499 * SPI master controllers connect to their drivers using some non-SPI bus,
1500 * such as the platform bus. The final stage of probe() in that code
1501 * includes calling spi_register_master() to hook up to this SPI bus glue.
1503 * SPI controllers use board specific (often SOC specific) bus numbers,
1504 * and board-specific addressing for SPI devices combines those numbers
1505 * with chip select numbers. Since SPI does not directly support dynamic
1506 * device identification, boards need configuration tables telling which
1507 * chip is at which address.
1509 * This must be called from context that can sleep. It returns zero on
1510 * success, else a negative error code (dropping the master's refcount).
1511 * After a successful return, the caller is responsible for calling
1512 * spi_unregister_master().
1514 int spi_register_master(struct spi_master *master)
1516 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1517 struct device *dev = master->dev.parent;
1518 struct boardinfo *bi;
1519 int status = -ENODEV;
1525 status = of_spi_register_master(master);
1529 /* even if it's just one always-selected device, there must
1530 * be at least one chipselect
1532 if (master->num_chipselect == 0)
1535 if ((master->bus_num < 0) && master->dev.of_node)
1536 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1538 /* convention: dynamically assigned bus IDs count down from the max */
1539 if (master->bus_num < 0) {
1540 /* FIXME switch to an IDR based scheme, something like
1541 * I2C now uses, so we can't run out of "dynamic" IDs
1543 master->bus_num = atomic_dec_return(&dyn_bus_id);
1547 spin_lock_init(&master->bus_lock_spinlock);
1548 mutex_init(&master->bus_lock_mutex);
1549 master->bus_lock_flag = 0;
1550 init_completion(&master->xfer_completion);
1551 if (!master->max_dma_len)
1552 master->max_dma_len = INT_MAX;
1554 /* register the device, then userspace will see it.
1555 * registration fails if the bus ID is in use.
1557 dev_set_name(&master->dev, "spi%u", master->bus_num);
1558 status = device_add(&master->dev);
1561 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1562 dynamic ? " (dynamic)" : "");
1564 /* If we're using a queued driver, start the queue */
1565 if (master->transfer)
1566 dev_info(dev, "master is unqueued, this is deprecated\n");
1568 status = spi_master_initialize_queue(master);
1570 device_del(&master->dev);
1575 mutex_lock(&board_lock);
1576 list_add_tail(&master->list, &spi_master_list);
1577 list_for_each_entry(bi, &board_list, list)
1578 spi_match_master_to_boardinfo(master, &bi->board_info);
1579 mutex_unlock(&board_lock);
1581 /* Register devices from the device tree and ACPI */
1582 of_register_spi_devices(master);
1583 acpi_register_spi_devices(master);
1587 EXPORT_SYMBOL_GPL(spi_register_master);
1589 static void devm_spi_unregister(struct device *dev, void *res)
1591 spi_unregister_master(*(struct spi_master **)res);
1595 * dev_spi_register_master - register managed SPI master controller
1596 * @dev: device managing SPI master
1597 * @master: initialized master, originally from spi_alloc_master()
1598 * Context: can sleep
1600 * Register a SPI device as with spi_register_master() which will
1601 * automatically be unregister
1603 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1605 struct spi_master **ptr;
1608 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1612 ret = spi_register_master(master);
1615 devres_add(dev, ptr);
1622 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1624 static int __unregister(struct device *dev, void *null)
1626 spi_unregister_device(to_spi_device(dev));
1631 * spi_unregister_master - unregister SPI master controller
1632 * @master: the master being unregistered
1633 * Context: can sleep
1635 * This call is used only by SPI master controller drivers, which are the
1636 * only ones directly touching chip registers.
1638 * This must be called from context that can sleep.
1640 void spi_unregister_master(struct spi_master *master)
1644 if (master->queued) {
1645 if (spi_destroy_queue(master))
1646 dev_err(&master->dev, "queue remove failed\n");
1649 mutex_lock(&board_lock);
1650 list_del(&master->list);
1651 mutex_unlock(&board_lock);
1653 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1654 device_unregister(&master->dev);
1656 EXPORT_SYMBOL_GPL(spi_unregister_master);
1658 int spi_master_suspend(struct spi_master *master)
1662 /* Basically no-ops for non-queued masters */
1663 if (!master->queued)
1666 ret = spi_stop_queue(master);
1668 dev_err(&master->dev, "queue stop failed\n");
1672 EXPORT_SYMBOL_GPL(spi_master_suspend);
1674 int spi_master_resume(struct spi_master *master)
1678 if (!master->queued)
1681 ret = spi_start_queue(master);
1683 dev_err(&master->dev, "queue restart failed\n");
1687 EXPORT_SYMBOL_GPL(spi_master_resume);
1689 static int __spi_master_match(struct device *dev, const void *data)
1691 struct spi_master *m;
1692 const u16 *bus_num = data;
1694 m = container_of(dev, struct spi_master, dev);
1695 return m->bus_num == *bus_num;
1699 * spi_busnum_to_master - look up master associated with bus_num
1700 * @bus_num: the master's bus number
1701 * Context: can sleep
1703 * This call may be used with devices that are registered after
1704 * arch init time. It returns a refcounted pointer to the relevant
1705 * spi_master (which the caller must release), or NULL if there is
1706 * no such master registered.
1708 struct spi_master *spi_busnum_to_master(u16 bus_num)
1711 struct spi_master *master = NULL;
1713 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1714 __spi_master_match);
1716 master = container_of(dev, struct spi_master, dev);
1717 /* reference got in class_find_device */
1720 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1723 /*-------------------------------------------------------------------------*/
1725 /* Core methods for SPI master protocol drivers. Some of the
1726 * other core methods are currently defined as inline functions.
1730 * spi_setup - setup SPI mode and clock rate
1731 * @spi: the device whose settings are being modified
1732 * Context: can sleep, and no requests are queued to the device
1734 * SPI protocol drivers may need to update the transfer mode if the
1735 * device doesn't work with its default. They may likewise need
1736 * to update clock rates or word sizes from initial values. This function
1737 * changes those settings, and must be called from a context that can sleep.
1738 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1739 * effect the next time the device is selected and data is transferred to
1740 * or from it. When this function returns, the spi device is deselected.
1742 * Note that this call will fail if the protocol driver specifies an option
1743 * that the underlying controller or its driver does not support. For
1744 * example, not all hardware supports wire transfers using nine bit words,
1745 * LSB-first wire encoding, or active-high chipselects.
1747 int spi_setup(struct spi_device *spi)
1749 unsigned bad_bits, ugly_bits;
1752 /* check mode to prevent that DUAL and QUAD set at the same time
1754 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1755 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1757 "setup: can not select dual and quad at the same time\n");
1760 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1762 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1763 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1765 /* help drivers fail *cleanly* when they need options
1766 * that aren't supported with their current master
1768 bad_bits = spi->mode & ~spi->master->mode_bits;
1769 ugly_bits = bad_bits &
1770 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1773 "setup: ignoring unsupported mode bits %x\n",
1775 spi->mode &= ~ugly_bits;
1776 bad_bits &= ~ugly_bits;
1779 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1784 if (!spi->bits_per_word)
1785 spi->bits_per_word = 8;
1787 if (spi->master->setup)
1788 status = spi->master->setup(spi);
1790 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1791 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1792 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1793 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1794 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1795 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1796 spi->bits_per_word, spi->max_speed_hz,
1801 EXPORT_SYMBOL_GPL(spi_setup);
1803 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1805 struct spi_master *master = spi->master;
1806 struct spi_transfer *xfer;
1808 if (list_empty(&message->transfers))
1810 if (!message->complete)
1813 /* Half-duplex links include original MicroWire, and ones with
1814 * only one data pin like SPI_3WIRE (switches direction) or where
1815 * either MOSI or MISO is missing. They can also be caused by
1816 * software limitations.
1818 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1819 || (spi->mode & SPI_3WIRE)) {
1820 unsigned flags = master->flags;
1822 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1823 if (xfer->rx_buf && xfer->tx_buf)
1825 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1827 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1833 * Set transfer bits_per_word and max speed as spi device default if
1834 * it is not set for this transfer.
1835 * Set transfer tx_nbits and rx_nbits as single transfer default
1836 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1838 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1839 message->frame_length += xfer->len;
1840 if (!xfer->bits_per_word)
1841 xfer->bits_per_word = spi->bits_per_word;
1842 if (!xfer->speed_hz) {
1843 xfer->speed_hz = spi->max_speed_hz;
1844 if (master->max_speed_hz &&
1845 xfer->speed_hz > master->max_speed_hz)
1846 xfer->speed_hz = master->max_speed_hz;
1849 if (master->bits_per_word_mask) {
1850 /* Only 32 bits fit in the mask */
1851 if (xfer->bits_per_word > 32)
1853 if (!(master->bits_per_word_mask &
1854 BIT(xfer->bits_per_word - 1)))
1858 if (xfer->speed_hz && master->min_speed_hz &&
1859 xfer->speed_hz < master->min_speed_hz)
1861 if (xfer->speed_hz && master->max_speed_hz &&
1862 xfer->speed_hz > master->max_speed_hz)
1865 if (xfer->tx_buf && !xfer->tx_nbits)
1866 xfer->tx_nbits = SPI_NBITS_SINGLE;
1867 if (xfer->rx_buf && !xfer->rx_nbits)
1868 xfer->rx_nbits = SPI_NBITS_SINGLE;
1869 /* check transfer tx/rx_nbits:
1870 * 1. check the value matches one of single, dual and quad
1871 * 2. check tx/rx_nbits match the mode in spi_device
1874 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1875 xfer->tx_nbits != SPI_NBITS_DUAL &&
1876 xfer->tx_nbits != SPI_NBITS_QUAD)
1878 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1879 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1881 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1882 !(spi->mode & SPI_TX_QUAD))
1885 /* check transfer rx_nbits */
1887 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1888 xfer->rx_nbits != SPI_NBITS_DUAL &&
1889 xfer->rx_nbits != SPI_NBITS_QUAD)
1891 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1892 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1894 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1895 !(spi->mode & SPI_RX_QUAD))
1900 message->status = -EINPROGRESS;
1905 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1907 struct spi_master *master = spi->master;
1911 trace_spi_message_submit(message);
1913 return master->transfer(spi, message);
1917 * spi_async - asynchronous SPI transfer
1918 * @spi: device with which data will be exchanged
1919 * @message: describes the data transfers, including completion callback
1920 * Context: any (irqs may be blocked, etc)
1922 * This call may be used in_irq and other contexts which can't sleep,
1923 * as well as from task contexts which can sleep.
1925 * The completion callback is invoked in a context which can't sleep.
1926 * Before that invocation, the value of message->status is undefined.
1927 * When the callback is issued, message->status holds either zero (to
1928 * indicate complete success) or a negative error code. After that
1929 * callback returns, the driver which issued the transfer request may
1930 * deallocate the associated memory; it's no longer in use by any SPI
1931 * core or controller driver code.
1933 * Note that although all messages to a spi_device are handled in
1934 * FIFO order, messages may go to different devices in other orders.
1935 * Some device might be higher priority, or have various "hard" access
1936 * time requirements, for example.
1938 * On detection of any fault during the transfer, processing of
1939 * the entire message is aborted, and the device is deselected.
1940 * Until returning from the associated message completion callback,
1941 * no other spi_message queued to that device will be processed.
1942 * (This rule applies equally to all the synchronous transfer calls,
1943 * which are wrappers around this core asynchronous primitive.)
1945 int spi_async(struct spi_device *spi, struct spi_message *message)
1947 struct spi_master *master = spi->master;
1949 unsigned long flags;
1951 ret = __spi_validate(spi, message);
1955 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1957 if (master->bus_lock_flag)
1960 ret = __spi_async(spi, message);
1962 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1966 EXPORT_SYMBOL_GPL(spi_async);
1969 * spi_async_locked - version of spi_async with exclusive bus usage
1970 * @spi: device with which data will be exchanged
1971 * @message: describes the data transfers, including completion callback
1972 * Context: any (irqs may be blocked, etc)
1974 * This call may be used in_irq and other contexts which can't sleep,
1975 * as well as from task contexts which can sleep.
1977 * The completion callback is invoked in a context which can't sleep.
1978 * Before that invocation, the value of message->status is undefined.
1979 * When the callback is issued, message->status holds either zero (to
1980 * indicate complete success) or a negative error code. After that
1981 * callback returns, the driver which issued the transfer request may
1982 * deallocate the associated memory; it's no longer in use by any SPI
1983 * core or controller driver code.
1985 * Note that although all messages to a spi_device are handled in
1986 * FIFO order, messages may go to different devices in other orders.
1987 * Some device might be higher priority, or have various "hard" access
1988 * time requirements, for example.
1990 * On detection of any fault during the transfer, processing of
1991 * the entire message is aborted, and the device is deselected.
1992 * Until returning from the associated message completion callback,
1993 * no other spi_message queued to that device will be processed.
1994 * (This rule applies equally to all the synchronous transfer calls,
1995 * which are wrappers around this core asynchronous primitive.)
1997 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
1999 struct spi_master *master = spi->master;
2001 unsigned long flags;
2003 ret = __spi_validate(spi, message);
2007 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2009 ret = __spi_async(spi, message);
2011 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2016 EXPORT_SYMBOL_GPL(spi_async_locked);
2019 /*-------------------------------------------------------------------------*/
2021 /* Utility methods for SPI master protocol drivers, layered on
2022 * top of the core. Some other utility methods are defined as
2026 static void spi_complete(void *arg)
2031 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2034 DECLARE_COMPLETION_ONSTACK(done);
2036 struct spi_master *master = spi->master;
2038 message->complete = spi_complete;
2039 message->context = &done;
2042 mutex_lock(&master->bus_lock_mutex);
2044 status = spi_async_locked(spi, message);
2047 mutex_unlock(&master->bus_lock_mutex);
2050 wait_for_completion(&done);
2051 status = message->status;
2053 message->context = NULL;
2058 * spi_sync - blocking/synchronous SPI data transfers
2059 * @spi: device with which data will be exchanged
2060 * @message: describes the data transfers
2061 * Context: can sleep
2063 * This call may only be used from a context that may sleep. The sleep
2064 * is non-interruptible, and has no timeout. Low-overhead controller
2065 * drivers may DMA directly into and out of the message buffers.
2067 * Note that the SPI device's chip select is active during the message,
2068 * and then is normally disabled between messages. Drivers for some
2069 * frequently-used devices may want to minimize costs of selecting a chip,
2070 * by leaving it selected in anticipation that the next message will go
2071 * to the same chip. (That may increase power usage.)
2073 * Also, the caller is guaranteeing that the memory associated with the
2074 * message will not be freed before this call returns.
2076 * It returns zero on success, else a negative error code.
2078 int spi_sync(struct spi_device *spi, struct spi_message *message)
2080 return __spi_sync(spi, message, 0);
2082 EXPORT_SYMBOL_GPL(spi_sync);
2085 * spi_sync_locked - version of spi_sync with exclusive bus usage
2086 * @spi: device with which data will be exchanged
2087 * @message: describes the data transfers
2088 * Context: can sleep
2090 * This call may only be used from a context that may sleep. The sleep
2091 * is non-interruptible, and has no timeout. Low-overhead controller
2092 * drivers may DMA directly into and out of the message buffers.
2094 * This call should be used by drivers that require exclusive access to the
2095 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2096 * be released by a spi_bus_unlock call when the exclusive access is over.
2098 * It returns zero on success, else a negative error code.
2100 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2102 return __spi_sync(spi, message, 1);
2104 EXPORT_SYMBOL_GPL(spi_sync_locked);
2107 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2108 * @master: SPI bus master that should be locked for exclusive bus access
2109 * Context: can sleep
2111 * This call may only be used from a context that may sleep. The sleep
2112 * is non-interruptible, and has no timeout.
2114 * This call should be used by drivers that require exclusive access to the
2115 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2116 * exclusive access is over. Data transfer must be done by spi_sync_locked
2117 * and spi_async_locked calls when the SPI bus lock is held.
2119 * It returns zero on success, else a negative error code.
2121 int spi_bus_lock(struct spi_master *master)
2123 unsigned long flags;
2125 mutex_lock(&master->bus_lock_mutex);
2127 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2128 master->bus_lock_flag = 1;
2129 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2131 /* mutex remains locked until spi_bus_unlock is called */
2135 EXPORT_SYMBOL_GPL(spi_bus_lock);
2138 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2139 * @master: SPI bus master that was locked for exclusive bus access
2140 * Context: can sleep
2142 * This call may only be used from a context that may sleep. The sleep
2143 * is non-interruptible, and has no timeout.
2145 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2148 * It returns zero on success, else a negative error code.
2150 int spi_bus_unlock(struct spi_master *master)
2152 master->bus_lock_flag = 0;
2154 mutex_unlock(&master->bus_lock_mutex);
2158 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2160 /* portable code must never pass more than 32 bytes */
2161 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2166 * spi_write_then_read - SPI synchronous write followed by read
2167 * @spi: device with which data will be exchanged
2168 * @txbuf: data to be written (need not be dma-safe)
2169 * @n_tx: size of txbuf, in bytes
2170 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2171 * @n_rx: size of rxbuf, in bytes
2172 * Context: can sleep
2174 * This performs a half duplex MicroWire style transaction with the
2175 * device, sending txbuf and then reading rxbuf. The return value
2176 * is zero for success, else a negative errno status code.
2177 * This call may only be used from a context that may sleep.
2179 * Parameters to this routine are always copied using a small buffer;
2180 * portable code should never use this for more than 32 bytes.
2181 * Performance-sensitive or bulk transfer code should instead use
2182 * spi_{async,sync}() calls with dma-safe buffers.
2184 int spi_write_then_read(struct spi_device *spi,
2185 const void *txbuf, unsigned n_tx,
2186 void *rxbuf, unsigned n_rx)
2188 static DEFINE_MUTEX(lock);
2191 struct spi_message message;
2192 struct spi_transfer x[2];
2195 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2196 * copying here, (as a pure convenience thing), but we can
2197 * keep heap costs out of the hot path unless someone else is
2198 * using the pre-allocated buffer or the transfer is too large.
2200 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2201 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2202 GFP_KERNEL | GFP_DMA);
2209 spi_message_init(&message);
2210 memset(x, 0, sizeof(x));
2213 spi_message_add_tail(&x[0], &message);
2217 spi_message_add_tail(&x[1], &message);
2220 memcpy(local_buf, txbuf, n_tx);
2221 x[0].tx_buf = local_buf;
2222 x[1].rx_buf = local_buf + n_tx;
2225 status = spi_sync(spi, &message);
2227 memcpy(rxbuf, x[1].rx_buf, n_rx);
2229 if (x[0].tx_buf == buf)
2230 mutex_unlock(&lock);
2236 EXPORT_SYMBOL_GPL(spi_write_then_read);
2238 /*-------------------------------------------------------------------------*/
2240 static int __init spi_init(void)
2244 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2250 status = bus_register(&spi_bus_type);
2254 status = class_register(&spi_master_class);
2260 bus_unregister(&spi_bus_type);
2268 /* board_info is normally registered in arch_initcall(),
2269 * but even essential drivers wait till later
2271 * REVISIT only boardinfo really needs static linking. the rest (device and
2272 * driver registration) _could_ be dynamically linked (modular) ... costs
2273 * include needing to have boardinfo data structures be much more public.
2275 postcore_initcall(spi_init);