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);
262 acpi_dev_pm_attach(dev, true);
263 ret = sdrv->probe(to_spi_device(dev));
265 acpi_dev_pm_detach(dev, true);
270 static int spi_drv_remove(struct device *dev)
272 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
275 ret = sdrv->remove(to_spi_device(dev));
276 acpi_dev_pm_detach(dev, true);
281 static void spi_drv_shutdown(struct device *dev)
283 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
285 sdrv->shutdown(to_spi_device(dev));
289 * spi_register_driver - register a SPI driver
290 * @sdrv: the driver to register
293 int spi_register_driver(struct spi_driver *sdrv)
295 sdrv->driver.bus = &spi_bus_type;
297 sdrv->driver.probe = spi_drv_probe;
299 sdrv->driver.remove = spi_drv_remove;
301 sdrv->driver.shutdown = spi_drv_shutdown;
302 return driver_register(&sdrv->driver);
304 EXPORT_SYMBOL_GPL(spi_register_driver);
306 /*-------------------------------------------------------------------------*/
308 /* SPI devices should normally not be created by SPI device drivers; that
309 * would make them board-specific. Similarly with SPI master drivers.
310 * Device registration normally goes into like arch/.../mach.../board-YYY.c
311 * with other readonly (flashable) information about mainboard devices.
315 struct list_head list;
316 struct spi_board_info board_info;
319 static LIST_HEAD(board_list);
320 static LIST_HEAD(spi_master_list);
323 * Used to protect add/del opertion for board_info list and
324 * spi_master list, and their matching process
326 static DEFINE_MUTEX(board_lock);
329 * spi_alloc_device - Allocate a new SPI device
330 * @master: Controller to which device is connected
333 * Allows a driver to allocate and initialize a spi_device without
334 * registering it immediately. This allows a driver to directly
335 * fill the spi_device with device parameters before calling
336 * spi_add_device() on it.
338 * Caller is responsible to call spi_add_device() on the returned
339 * spi_device structure to add it to the SPI master. If the caller
340 * needs to discard the spi_device without adding it, then it should
341 * call spi_dev_put() on it.
343 * Returns a pointer to the new device, or NULL.
345 struct spi_device *spi_alloc_device(struct spi_master *master)
347 struct spi_device *spi;
348 struct device *dev = master->dev.parent;
350 if (!spi_master_get(master))
353 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
355 dev_err(dev, "cannot alloc spi_device\n");
356 spi_master_put(master);
360 spi->master = master;
361 spi->dev.parent = &master->dev;
362 spi->dev.bus = &spi_bus_type;
363 spi->dev.release = spidev_release;
364 spi->cs_gpio = -ENOENT;
365 device_initialize(&spi->dev);
368 EXPORT_SYMBOL_GPL(spi_alloc_device);
370 static void spi_dev_set_name(struct spi_device *spi)
372 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
375 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
379 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
383 static int spi_dev_check(struct device *dev, void *data)
385 struct spi_device *spi = to_spi_device(dev);
386 struct spi_device *new_spi = data;
388 if (spi->master == new_spi->master &&
389 spi->chip_select == new_spi->chip_select)
395 * spi_add_device - Add spi_device allocated with spi_alloc_device
396 * @spi: spi_device to register
398 * Companion function to spi_alloc_device. Devices allocated with
399 * spi_alloc_device can be added onto the spi bus with this function.
401 * Returns 0 on success; negative errno on failure
403 int spi_add_device(struct spi_device *spi)
405 static DEFINE_MUTEX(spi_add_lock);
406 struct spi_master *master = spi->master;
407 struct device *dev = master->dev.parent;
410 /* Chipselects are numbered 0..max; validate. */
411 if (spi->chip_select >= master->num_chipselect) {
412 dev_err(dev, "cs%d >= max %d\n",
414 master->num_chipselect);
418 /* Set the bus ID string */
419 spi_dev_set_name(spi);
421 /* We need to make sure there's no other device with this
422 * chipselect **BEFORE** we call setup(), else we'll trash
423 * its configuration. Lock against concurrent add() calls.
425 mutex_lock(&spi_add_lock);
427 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
429 dev_err(dev, "chipselect %d already in use\n",
434 if (master->cs_gpios)
435 spi->cs_gpio = master->cs_gpios[spi->chip_select];
437 /* Drivers may modify this initial i/o setup, but will
438 * normally rely on the device being setup. Devices
439 * using SPI_CS_HIGH can't coexist well otherwise...
441 status = spi_setup(spi);
443 dev_err(dev, "can't setup %s, status %d\n",
444 dev_name(&spi->dev), status);
448 /* Device may be bound to an active driver when this returns */
449 status = device_add(&spi->dev);
451 dev_err(dev, "can't add %s, status %d\n",
452 dev_name(&spi->dev), status);
454 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
457 mutex_unlock(&spi_add_lock);
460 EXPORT_SYMBOL_GPL(spi_add_device);
463 * spi_new_device - instantiate one new SPI device
464 * @master: Controller to which device is connected
465 * @chip: Describes the SPI device
468 * On typical mainboards, this is purely internal; and it's not needed
469 * after board init creates the hard-wired devices. Some development
470 * platforms may not be able to use spi_register_board_info though, and
471 * this is exported so that for example a USB or parport based adapter
472 * driver could add devices (which it would learn about out-of-band).
474 * Returns the new device, or NULL.
476 struct spi_device *spi_new_device(struct spi_master *master,
477 struct spi_board_info *chip)
479 struct spi_device *proxy;
482 /* NOTE: caller did any chip->bus_num checks necessary.
484 * Also, unless we change the return value convention to use
485 * error-or-pointer (not NULL-or-pointer), troubleshootability
486 * suggests syslogged diagnostics are best here (ugh).
489 proxy = spi_alloc_device(master);
493 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
495 proxy->chip_select = chip->chip_select;
496 proxy->max_speed_hz = chip->max_speed_hz;
497 proxy->mode = chip->mode;
498 proxy->irq = chip->irq;
499 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
500 proxy->dev.platform_data = (void *) chip->platform_data;
501 proxy->controller_data = chip->controller_data;
502 proxy->controller_state = NULL;
504 status = spi_add_device(proxy);
512 EXPORT_SYMBOL_GPL(spi_new_device);
514 static void spi_match_master_to_boardinfo(struct spi_master *master,
515 struct spi_board_info *bi)
517 struct spi_device *dev;
519 if (master->bus_num != bi->bus_num)
522 dev = spi_new_device(master, bi);
524 dev_err(master->dev.parent, "can't create new device for %s\n",
529 * spi_register_board_info - register SPI devices for a given board
530 * @info: array of chip descriptors
531 * @n: how many descriptors are provided
534 * Board-specific early init code calls this (probably during arch_initcall)
535 * with segments of the SPI device table. Any device nodes are created later,
536 * after the relevant parent SPI controller (bus_num) is defined. We keep
537 * this table of devices forever, so that reloading a controller driver will
538 * not make Linux forget about these hard-wired devices.
540 * Other code can also call this, e.g. a particular add-on board might provide
541 * SPI devices through its expansion connector, so code initializing that board
542 * would naturally declare its SPI devices.
544 * The board info passed can safely be __initdata ... but be careful of
545 * any embedded pointers (platform_data, etc), they're copied as-is.
547 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
549 struct boardinfo *bi;
552 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
556 for (i = 0; i < n; i++, bi++, info++) {
557 struct spi_master *master;
559 memcpy(&bi->board_info, info, sizeof(*info));
560 mutex_lock(&board_lock);
561 list_add_tail(&bi->list, &board_list);
562 list_for_each_entry(master, &spi_master_list, list)
563 spi_match_master_to_boardinfo(master, &bi->board_info);
564 mutex_unlock(&board_lock);
570 /*-------------------------------------------------------------------------*/
572 static void spi_set_cs(struct spi_device *spi, bool enable)
574 if (spi->mode & SPI_CS_HIGH)
577 if (spi->cs_gpio >= 0)
578 gpio_set_value(spi->cs_gpio, !enable);
579 else if (spi->master->set_cs)
580 spi->master->set_cs(spi, !enable);
583 static int spi_map_buf(struct spi_master *master, struct device *dev,
584 struct sg_table *sgt, void *buf, size_t len,
585 enum dma_data_direction dir)
587 const bool vmalloced_buf = is_vmalloc_addr(buf);
588 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
589 const int sgs = DIV_ROUND_UP(len, desc_len);
590 struct page *vm_page;
595 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
599 for (i = 0; i < sgs; i++) {
600 min = min_t(size_t, len, desc_len);
603 vm_page = vmalloc_to_page(buf);
608 sg_buf = page_address(vm_page) +
609 ((size_t)buf & ~PAGE_MASK);
614 sg_set_buf(&sgt->sgl[i], sg_buf, min);
620 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
631 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
632 struct sg_table *sgt, enum dma_data_direction dir)
634 if (sgt->orig_nents) {
635 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
640 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
642 struct device *tx_dev, *rx_dev;
643 struct spi_transfer *xfer;
645 unsigned int max_tx, max_rx;
648 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
652 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
653 if ((master->flags & SPI_MASTER_MUST_TX) &&
655 max_tx = max(xfer->len, max_tx);
656 if ((master->flags & SPI_MASTER_MUST_RX) &&
658 max_rx = max(xfer->len, max_rx);
662 tmp = krealloc(master->dummy_tx, max_tx,
663 GFP_KERNEL | GFP_DMA);
666 master->dummy_tx = tmp;
667 memset(tmp, 0, max_tx);
671 tmp = krealloc(master->dummy_rx, max_rx,
672 GFP_KERNEL | GFP_DMA);
675 master->dummy_rx = tmp;
678 if (max_tx || max_rx) {
679 list_for_each_entry(xfer, &msg->transfers,
682 xfer->tx_buf = master->dummy_tx;
684 xfer->rx_buf = master->dummy_rx;
689 if (!master->can_dma)
692 tx_dev = &master->dma_tx->dev->device;
693 rx_dev = &master->dma_rx->dev->device;
695 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
696 if (!master->can_dma(master, msg->spi, xfer))
699 if (xfer->tx_buf != NULL) {
700 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
701 (void *)xfer->tx_buf, xfer->len,
707 if (xfer->rx_buf != NULL) {
708 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
709 xfer->rx_buf, xfer->len,
712 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
719 master->cur_msg_mapped = true;
724 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
726 struct spi_transfer *xfer;
727 struct device *tx_dev, *rx_dev;
729 if (!master->cur_msg_mapped || !master->can_dma)
732 tx_dev = &master->dma_tx->dev->device;
733 rx_dev = &master->dma_rx->dev->device;
735 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
736 if (!master->can_dma(master, msg->spi, xfer))
739 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
740 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
747 * spi_transfer_one_message - Default implementation of transfer_one_message()
749 * This is a standard implementation of transfer_one_message() for
750 * drivers which impelment a transfer_one() operation. It provides
751 * standard handling of delays and chip select management.
753 static int spi_transfer_one_message(struct spi_master *master,
754 struct spi_message *msg)
756 struct spi_transfer *xfer;
757 bool keep_cs = false;
760 spi_set_cs(msg->spi, true);
762 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
763 trace_spi_transfer_start(msg, xfer);
765 reinit_completion(&master->xfer_completion);
767 ret = master->transfer_one(master, msg->spi, xfer);
769 dev_err(&msg->spi->dev,
770 "SPI transfer failed: %d\n", ret);
776 wait_for_completion(&master->xfer_completion);
779 trace_spi_transfer_stop(msg, xfer);
781 if (msg->status != -EINPROGRESS)
784 if (xfer->delay_usecs)
785 udelay(xfer->delay_usecs);
787 if (xfer->cs_change) {
788 if (list_is_last(&xfer->transfer_list,
792 spi_set_cs(msg->spi, false);
794 spi_set_cs(msg->spi, true);
798 msg->actual_length += xfer->len;
802 if (ret != 0 || !keep_cs)
803 spi_set_cs(msg->spi, false);
805 if (msg->status == -EINPROGRESS)
808 spi_finalize_current_message(master);
814 * spi_finalize_current_transfer - report completion of a transfer
816 * Called by SPI drivers using the core transfer_one_message()
817 * implementation to notify it that the current interrupt driven
818 * transfer has finished and the next one may be scheduled.
820 void spi_finalize_current_transfer(struct spi_master *master)
822 complete(&master->xfer_completion);
824 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
827 * spi_pump_messages - kthread work function which processes spi message queue
828 * @work: pointer to kthread work struct contained in the master struct
830 * This function checks if there is any spi message in the queue that
831 * needs processing and if so call out to the driver to initialize hardware
832 * and transfer each message.
835 static void spi_pump_messages(struct kthread_work *work)
837 struct spi_master *master =
838 container_of(work, struct spi_master, pump_messages);
840 bool was_busy = false;
843 /* Lock queue and check for queue work */
844 spin_lock_irqsave(&master->queue_lock, flags);
845 if (list_empty(&master->queue) || !master->running) {
847 spin_unlock_irqrestore(&master->queue_lock, flags);
850 master->busy = false;
851 spin_unlock_irqrestore(&master->queue_lock, flags);
852 kfree(master->dummy_rx);
853 master->dummy_rx = NULL;
854 kfree(master->dummy_tx);
855 master->dummy_tx = NULL;
856 if (master->unprepare_transfer_hardware &&
857 master->unprepare_transfer_hardware(master))
858 dev_err(&master->dev,
859 "failed to unprepare transfer hardware\n");
860 if (master->auto_runtime_pm) {
861 pm_runtime_mark_last_busy(master->dev.parent);
862 pm_runtime_put_autosuspend(master->dev.parent);
864 trace_spi_master_idle(master);
868 /* Make sure we are not already running a message */
869 if (master->cur_msg) {
870 spin_unlock_irqrestore(&master->queue_lock, flags);
873 /* Extract head of queue */
875 list_first_entry(&master->queue, struct spi_message, queue);
877 list_del_init(&master->cur_msg->queue);
882 spin_unlock_irqrestore(&master->queue_lock, flags);
884 if (!was_busy && master->auto_runtime_pm) {
885 ret = pm_runtime_get_sync(master->dev.parent);
887 dev_err(&master->dev, "Failed to power device: %d\n",
894 trace_spi_master_busy(master);
896 if (!was_busy && master->prepare_transfer_hardware) {
897 ret = master->prepare_transfer_hardware(master);
899 dev_err(&master->dev,
900 "failed to prepare transfer hardware\n");
902 if (master->auto_runtime_pm)
903 pm_runtime_put(master->dev.parent);
908 trace_spi_message_start(master->cur_msg);
910 if (master->prepare_message) {
911 ret = master->prepare_message(master, master->cur_msg);
913 dev_err(&master->dev,
914 "failed to prepare message: %d\n", ret);
915 master->cur_msg->status = ret;
916 spi_finalize_current_message(master);
919 master->cur_msg_prepared = true;
922 ret = spi_map_msg(master, master->cur_msg);
924 master->cur_msg->status = ret;
925 spi_finalize_current_message(master);
929 ret = master->transfer_one_message(master, master->cur_msg);
931 dev_err(&master->dev,
932 "failed to transfer one message from queue\n");
937 static int spi_init_queue(struct spi_master *master)
939 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
941 INIT_LIST_HEAD(&master->queue);
942 spin_lock_init(&master->queue_lock);
944 master->running = false;
945 master->busy = false;
947 init_kthread_worker(&master->kworker);
948 master->kworker_task = kthread_run(kthread_worker_fn,
949 &master->kworker, "%s",
950 dev_name(&master->dev));
951 if (IS_ERR(master->kworker_task)) {
952 dev_err(&master->dev, "failed to create message pump task\n");
955 init_kthread_work(&master->pump_messages, spi_pump_messages);
958 * Master config will indicate if this controller should run the
959 * message pump with high (realtime) priority to reduce the transfer
960 * latency on the bus by minimising the delay between a transfer
961 * request and the scheduling of the message pump thread. Without this
962 * setting the message pump thread will remain at default priority.
965 dev_info(&master->dev,
966 "will run message pump with realtime priority\n");
967 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
974 * spi_get_next_queued_message() - called by driver to check for queued
976 * @master: the master to check for queued messages
978 * If there are more messages in the queue, the next message is returned from
981 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
983 struct spi_message *next;
986 /* get a pointer to the next message, if any */
987 spin_lock_irqsave(&master->queue_lock, flags);
988 next = list_first_entry_or_null(&master->queue, struct spi_message,
990 spin_unlock_irqrestore(&master->queue_lock, flags);
994 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
997 * spi_finalize_current_message() - the current message is complete
998 * @master: the master to return the message to
1000 * Called by the driver to notify the core that the message in the front of the
1001 * queue is complete and can be removed from the queue.
1003 void spi_finalize_current_message(struct spi_master *master)
1005 struct spi_message *mesg;
1006 unsigned long flags;
1009 spin_lock_irqsave(&master->queue_lock, flags);
1010 mesg = master->cur_msg;
1011 master->cur_msg = NULL;
1013 queue_kthread_work(&master->kworker, &master->pump_messages);
1014 spin_unlock_irqrestore(&master->queue_lock, flags);
1016 spi_unmap_msg(master, mesg);
1018 if (master->cur_msg_prepared && master->unprepare_message) {
1019 ret = master->unprepare_message(master, mesg);
1021 dev_err(&master->dev,
1022 "failed to unprepare message: %d\n", ret);
1025 master->cur_msg_prepared = false;
1029 mesg->complete(mesg->context);
1031 trace_spi_message_done(mesg);
1033 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1035 static int spi_start_queue(struct spi_master *master)
1037 unsigned long flags;
1039 spin_lock_irqsave(&master->queue_lock, flags);
1041 if (master->running || master->busy) {
1042 spin_unlock_irqrestore(&master->queue_lock, flags);
1046 master->running = true;
1047 master->cur_msg = NULL;
1048 spin_unlock_irqrestore(&master->queue_lock, flags);
1050 queue_kthread_work(&master->kworker, &master->pump_messages);
1055 static int spi_stop_queue(struct spi_master *master)
1057 unsigned long flags;
1058 unsigned limit = 500;
1061 spin_lock_irqsave(&master->queue_lock, flags);
1064 * This is a bit lame, but is optimized for the common execution path.
1065 * A wait_queue on the master->busy could be used, but then the common
1066 * execution path (pump_messages) would be required to call wake_up or
1067 * friends on every SPI message. Do this instead.
1069 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1070 spin_unlock_irqrestore(&master->queue_lock, flags);
1071 usleep_range(10000, 11000);
1072 spin_lock_irqsave(&master->queue_lock, flags);
1075 if (!list_empty(&master->queue) || master->busy)
1078 master->running = false;
1080 spin_unlock_irqrestore(&master->queue_lock, flags);
1083 dev_warn(&master->dev,
1084 "could not stop message queue\n");
1090 static int spi_destroy_queue(struct spi_master *master)
1094 ret = spi_stop_queue(master);
1097 * flush_kthread_worker will block until all work is done.
1098 * If the reason that stop_queue timed out is that the work will never
1099 * finish, then it does no good to call flush/stop thread, so
1103 dev_err(&master->dev, "problem destroying queue\n");
1107 flush_kthread_worker(&master->kworker);
1108 kthread_stop(master->kworker_task);
1114 * spi_queued_transfer - transfer function for queued transfers
1115 * @spi: spi device which is requesting transfer
1116 * @msg: spi message which is to handled is queued to driver queue
1118 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1120 struct spi_master *master = spi->master;
1121 unsigned long flags;
1123 spin_lock_irqsave(&master->queue_lock, flags);
1125 if (!master->running) {
1126 spin_unlock_irqrestore(&master->queue_lock, flags);
1129 msg->actual_length = 0;
1130 msg->status = -EINPROGRESS;
1132 list_add_tail(&msg->queue, &master->queue);
1134 queue_kthread_work(&master->kworker, &master->pump_messages);
1136 spin_unlock_irqrestore(&master->queue_lock, flags);
1140 static int spi_master_initialize_queue(struct spi_master *master)
1144 master->queued = true;
1145 master->transfer = spi_queued_transfer;
1146 if (!master->transfer_one_message)
1147 master->transfer_one_message = spi_transfer_one_message;
1149 /* Initialize and start queue */
1150 ret = spi_init_queue(master);
1152 dev_err(&master->dev, "problem initializing queue\n");
1153 goto err_init_queue;
1155 ret = spi_start_queue(master);
1157 dev_err(&master->dev, "problem starting queue\n");
1158 goto err_start_queue;
1165 spi_destroy_queue(master);
1169 /*-------------------------------------------------------------------------*/
1171 #if defined(CONFIG_OF)
1173 * of_register_spi_devices() - Register child devices onto the SPI bus
1174 * @master: Pointer to spi_master device
1176 * Registers an spi_device for each child node of master node which has a 'reg'
1179 static void of_register_spi_devices(struct spi_master *master)
1181 struct spi_device *spi;
1182 struct device_node *nc;
1186 if (!master->dev.of_node)
1189 for_each_available_child_of_node(master->dev.of_node, nc) {
1190 /* Alloc an spi_device */
1191 spi = spi_alloc_device(master);
1193 dev_err(&master->dev, "spi_device alloc error for %s\n",
1199 /* Select device driver */
1200 if (of_modalias_node(nc, spi->modalias,
1201 sizeof(spi->modalias)) < 0) {
1202 dev_err(&master->dev, "cannot find modalias for %s\n",
1208 /* Device address */
1209 rc = of_property_read_u32(nc, "reg", &value);
1211 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1216 spi->chip_select = value;
1218 /* Mode (clock phase/polarity/etc.) */
1219 if (of_find_property(nc, "spi-cpha", NULL))
1220 spi->mode |= SPI_CPHA;
1221 if (of_find_property(nc, "spi-cpol", NULL))
1222 spi->mode |= SPI_CPOL;
1223 if (of_find_property(nc, "spi-cs-high", NULL))
1224 spi->mode |= SPI_CS_HIGH;
1225 if (of_find_property(nc, "spi-3wire", NULL))
1226 spi->mode |= SPI_3WIRE;
1228 /* Device DUAL/QUAD mode */
1229 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1234 spi->mode |= SPI_TX_DUAL;
1237 spi->mode |= SPI_TX_QUAD;
1240 dev_err(&master->dev,
1241 "spi-tx-bus-width %d not supported\n",
1248 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1253 spi->mode |= SPI_RX_DUAL;
1256 spi->mode |= SPI_RX_QUAD;
1259 dev_err(&master->dev,
1260 "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)
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;
1770 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1775 if (!spi->bits_per_word)
1776 spi->bits_per_word = 8;
1778 if (!spi->max_speed_hz)
1779 spi->max_speed_hz = spi->master->max_speed_hz;
1781 if (spi->master->setup)
1782 status = spi->master->setup(spi);
1784 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1785 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1786 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1787 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1788 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1789 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1790 spi->bits_per_word, spi->max_speed_hz,
1795 EXPORT_SYMBOL_GPL(spi_setup);
1797 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1799 struct spi_master *master = spi->master;
1800 struct spi_transfer *xfer;
1803 if (list_empty(&message->transfers))
1806 /* Half-duplex links include original MicroWire, and ones with
1807 * only one data pin like SPI_3WIRE (switches direction) or where
1808 * either MOSI or MISO is missing. They can also be caused by
1809 * software limitations.
1811 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1812 || (spi->mode & SPI_3WIRE)) {
1813 unsigned flags = master->flags;
1815 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1816 if (xfer->rx_buf && xfer->tx_buf)
1818 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1820 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1826 * Set transfer bits_per_word and max speed as spi device default if
1827 * it is not set for this transfer.
1828 * Set transfer tx_nbits and rx_nbits as single transfer default
1829 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1831 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1832 message->frame_length += xfer->len;
1833 if (!xfer->bits_per_word)
1834 xfer->bits_per_word = spi->bits_per_word;
1836 if (!xfer->speed_hz)
1837 xfer->speed_hz = spi->max_speed_hz;
1839 if (master->max_speed_hz &&
1840 xfer->speed_hz > master->max_speed_hz)
1841 xfer->speed_hz = master->max_speed_hz;
1843 if (master->bits_per_word_mask) {
1844 /* Only 32 bits fit in the mask */
1845 if (xfer->bits_per_word > 32)
1847 if (!(master->bits_per_word_mask &
1848 BIT(xfer->bits_per_word - 1)))
1853 * SPI transfer length should be multiple of SPI word size
1854 * where SPI word size should be power-of-two multiple
1856 if (xfer->bits_per_word <= 8)
1858 else if (xfer->bits_per_word <= 16)
1863 /* No partial transfers accepted */
1864 if (xfer->len % w_size)
1867 if (xfer->speed_hz && master->min_speed_hz &&
1868 xfer->speed_hz < master->min_speed_hz)
1871 if (xfer->tx_buf && !xfer->tx_nbits)
1872 xfer->tx_nbits = SPI_NBITS_SINGLE;
1873 if (xfer->rx_buf && !xfer->rx_nbits)
1874 xfer->rx_nbits = SPI_NBITS_SINGLE;
1875 /* check transfer tx/rx_nbits:
1876 * 1. check the value matches one of single, dual and quad
1877 * 2. check tx/rx_nbits match the mode in spi_device
1880 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1881 xfer->tx_nbits != SPI_NBITS_DUAL &&
1882 xfer->tx_nbits != SPI_NBITS_QUAD)
1884 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1885 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1887 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1888 !(spi->mode & SPI_TX_QUAD))
1891 /* check transfer rx_nbits */
1893 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1894 xfer->rx_nbits != SPI_NBITS_DUAL &&
1895 xfer->rx_nbits != SPI_NBITS_QUAD)
1897 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1898 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1900 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1901 !(spi->mode & SPI_RX_QUAD))
1906 message->status = -EINPROGRESS;
1911 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1913 struct spi_master *master = spi->master;
1917 trace_spi_message_submit(message);
1919 return master->transfer(spi, message);
1923 * spi_async - asynchronous SPI transfer
1924 * @spi: device with which data will be exchanged
1925 * @message: describes the data transfers, including completion callback
1926 * Context: any (irqs may be blocked, etc)
1928 * This call may be used in_irq and other contexts which can't sleep,
1929 * as well as from task contexts which can sleep.
1931 * The completion callback is invoked in a context which can't sleep.
1932 * Before that invocation, the value of message->status is undefined.
1933 * When the callback is issued, message->status holds either zero (to
1934 * indicate complete success) or a negative error code. After that
1935 * callback returns, the driver which issued the transfer request may
1936 * deallocate the associated memory; it's no longer in use by any SPI
1937 * core or controller driver code.
1939 * Note that although all messages to a spi_device are handled in
1940 * FIFO order, messages may go to different devices in other orders.
1941 * Some device might be higher priority, or have various "hard" access
1942 * time requirements, for example.
1944 * On detection of any fault during the transfer, processing of
1945 * the entire message is aborted, and the device is deselected.
1946 * Until returning from the associated message completion callback,
1947 * no other spi_message queued to that device will be processed.
1948 * (This rule applies equally to all the synchronous transfer calls,
1949 * which are wrappers around this core asynchronous primitive.)
1951 int spi_async(struct spi_device *spi, struct spi_message *message)
1953 struct spi_master *master = spi->master;
1955 unsigned long flags;
1957 ret = __spi_validate(spi, message);
1961 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
1963 if (master->bus_lock_flag)
1966 ret = __spi_async(spi, message);
1968 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
1972 EXPORT_SYMBOL_GPL(spi_async);
1975 * spi_async_locked - version of spi_async with exclusive bus usage
1976 * @spi: device with which data will be exchanged
1977 * @message: describes the data transfers, including completion callback
1978 * Context: any (irqs may be blocked, etc)
1980 * This call may be used in_irq and other contexts which can't sleep,
1981 * as well as from task contexts which can sleep.
1983 * The completion callback is invoked in a context which can't sleep.
1984 * Before that invocation, the value of message->status is undefined.
1985 * When the callback is issued, message->status holds either zero (to
1986 * indicate complete success) or a negative error code. After that
1987 * callback returns, the driver which issued the transfer request may
1988 * deallocate the associated memory; it's no longer in use by any SPI
1989 * core or controller driver code.
1991 * Note that although all messages to a spi_device are handled in
1992 * FIFO order, messages may go to different devices in other orders.
1993 * Some device might be higher priority, or have various "hard" access
1994 * time requirements, for example.
1996 * On detection of any fault during the transfer, processing of
1997 * the entire message is aborted, and the device is deselected.
1998 * Until returning from the associated message completion callback,
1999 * no other spi_message queued to that device will be processed.
2000 * (This rule applies equally to all the synchronous transfer calls,
2001 * which are wrappers around this core asynchronous primitive.)
2003 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2005 struct spi_master *master = spi->master;
2007 unsigned long flags;
2009 ret = __spi_validate(spi, message);
2013 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2015 ret = __spi_async(spi, message);
2017 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2022 EXPORT_SYMBOL_GPL(spi_async_locked);
2025 /*-------------------------------------------------------------------------*/
2027 /* Utility methods for SPI master protocol drivers, layered on
2028 * top of the core. Some other utility methods are defined as
2032 static void spi_complete(void *arg)
2037 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2040 DECLARE_COMPLETION_ONSTACK(done);
2042 struct spi_master *master = spi->master;
2044 message->complete = spi_complete;
2045 message->context = &done;
2048 mutex_lock(&master->bus_lock_mutex);
2050 status = spi_async_locked(spi, message);
2053 mutex_unlock(&master->bus_lock_mutex);
2056 wait_for_completion(&done);
2057 status = message->status;
2059 message->context = NULL;
2064 * spi_sync - blocking/synchronous SPI data transfers
2065 * @spi: device with which data will be exchanged
2066 * @message: describes the data transfers
2067 * Context: can sleep
2069 * This call may only be used from a context that may sleep. The sleep
2070 * is non-interruptible, and has no timeout. Low-overhead controller
2071 * drivers may DMA directly into and out of the message buffers.
2073 * Note that the SPI device's chip select is active during the message,
2074 * and then is normally disabled between messages. Drivers for some
2075 * frequently-used devices may want to minimize costs of selecting a chip,
2076 * by leaving it selected in anticipation that the next message will go
2077 * to the same chip. (That may increase power usage.)
2079 * Also, the caller is guaranteeing that the memory associated with the
2080 * message will not be freed before this call returns.
2082 * It returns zero on success, else a negative error code.
2084 int spi_sync(struct spi_device *spi, struct spi_message *message)
2086 return __spi_sync(spi, message, 0);
2088 EXPORT_SYMBOL_GPL(spi_sync);
2091 * spi_sync_locked - version of spi_sync with exclusive bus usage
2092 * @spi: device with which data will be exchanged
2093 * @message: describes the data transfers
2094 * Context: can sleep
2096 * This call may only be used from a context that may sleep. The sleep
2097 * is non-interruptible, and has no timeout. Low-overhead controller
2098 * drivers may DMA directly into and out of the message buffers.
2100 * This call should be used by drivers that require exclusive access to the
2101 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2102 * be released by a spi_bus_unlock call when the exclusive access is over.
2104 * It returns zero on success, else a negative error code.
2106 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2108 return __spi_sync(spi, message, 1);
2110 EXPORT_SYMBOL_GPL(spi_sync_locked);
2113 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2114 * @master: SPI bus master that should be locked for exclusive bus access
2115 * Context: can sleep
2117 * This call may only be used from a context that may sleep. The sleep
2118 * is non-interruptible, and has no timeout.
2120 * This call should be used by drivers that require exclusive access to the
2121 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2122 * exclusive access is over. Data transfer must be done by spi_sync_locked
2123 * and spi_async_locked calls when the SPI bus lock is held.
2125 * It returns zero on success, else a negative error code.
2127 int spi_bus_lock(struct spi_master *master)
2129 unsigned long flags;
2131 mutex_lock(&master->bus_lock_mutex);
2133 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2134 master->bus_lock_flag = 1;
2135 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2137 /* mutex remains locked until spi_bus_unlock is called */
2141 EXPORT_SYMBOL_GPL(spi_bus_lock);
2144 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2145 * @master: SPI bus master that was locked for exclusive bus access
2146 * Context: can sleep
2148 * This call may only be used from a context that may sleep. The sleep
2149 * is non-interruptible, and has no timeout.
2151 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2154 * It returns zero on success, else a negative error code.
2156 int spi_bus_unlock(struct spi_master *master)
2158 master->bus_lock_flag = 0;
2160 mutex_unlock(&master->bus_lock_mutex);
2164 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2166 /* portable code must never pass more than 32 bytes */
2167 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2172 * spi_write_then_read - SPI synchronous write followed by read
2173 * @spi: device with which data will be exchanged
2174 * @txbuf: data to be written (need not be dma-safe)
2175 * @n_tx: size of txbuf, in bytes
2176 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2177 * @n_rx: size of rxbuf, in bytes
2178 * Context: can sleep
2180 * This performs a half duplex MicroWire style transaction with the
2181 * device, sending txbuf and then reading rxbuf. The return value
2182 * is zero for success, else a negative errno status code.
2183 * This call may only be used from a context that may sleep.
2185 * Parameters to this routine are always copied using a small buffer;
2186 * portable code should never use this for more than 32 bytes.
2187 * Performance-sensitive or bulk transfer code should instead use
2188 * spi_{async,sync}() calls with dma-safe buffers.
2190 int spi_write_then_read(struct spi_device *spi,
2191 const void *txbuf, unsigned n_tx,
2192 void *rxbuf, unsigned n_rx)
2194 static DEFINE_MUTEX(lock);
2197 struct spi_message message;
2198 struct spi_transfer x[2];
2201 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2202 * copying here, (as a pure convenience thing), but we can
2203 * keep heap costs out of the hot path unless someone else is
2204 * using the pre-allocated buffer or the transfer is too large.
2206 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2207 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2208 GFP_KERNEL | GFP_DMA);
2215 spi_message_init(&message);
2216 memset(x, 0, sizeof(x));
2219 spi_message_add_tail(&x[0], &message);
2223 spi_message_add_tail(&x[1], &message);
2226 memcpy(local_buf, txbuf, n_tx);
2227 x[0].tx_buf = local_buf;
2228 x[1].rx_buf = local_buf + n_tx;
2231 status = spi_sync(spi, &message);
2233 memcpy(rxbuf, x[1].rx_buf, n_rx);
2235 if (x[0].tx_buf == buf)
2236 mutex_unlock(&lock);
2242 EXPORT_SYMBOL_GPL(spi_write_then_read);
2244 /*-------------------------------------------------------------------------*/
2246 static int __init spi_init(void)
2250 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2256 status = bus_register(&spi_bus_type);
2260 status = class_register(&spi_master_class);
2266 bus_unregister(&spi_bus_type);
2274 /* board_info is normally registered in arch_initcall(),
2275 * but even essential drivers wait till later
2277 * REVISIT only boardinfo really needs static linking. the rest (device and
2278 * driver registration) _could_ be dynamically linked (modular) ... costs
2279 * include needing to have boardinfo data structures be much more public.
2281 postcore_initcall(spi_init);