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 #ifdef CONFIG_HAS_DMA
584 static int spi_map_buf(struct spi_master *master, struct device *dev,
585 struct sg_table *sgt, void *buf, size_t len,
586 enum dma_data_direction dir)
588 const bool vmalloced_buf = is_vmalloc_addr(buf);
589 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
590 const int sgs = DIV_ROUND_UP(len, desc_len);
591 struct page *vm_page;
596 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
600 for (i = 0; i < sgs; i++) {
601 min = min_t(size_t, len, desc_len);
604 vm_page = vmalloc_to_page(buf);
609 sg_buf = page_address(vm_page) +
610 ((size_t)buf & ~PAGE_MASK);
615 sg_set_buf(&sgt->sgl[i], sg_buf, min);
621 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
632 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
633 struct sg_table *sgt, enum dma_data_direction dir)
635 if (sgt->orig_nents) {
636 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
641 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
643 struct device *tx_dev, *rx_dev;
644 struct spi_transfer *xfer;
647 if (!master->can_dma)
650 tx_dev = &master->dma_tx->dev->device;
651 rx_dev = &master->dma_rx->dev->device;
653 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
654 if (!master->can_dma(master, msg->spi, xfer))
657 if (xfer->tx_buf != NULL) {
658 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
659 (void *)xfer->tx_buf, xfer->len,
665 if (xfer->rx_buf != NULL) {
666 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
667 xfer->rx_buf, xfer->len,
670 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
677 master->cur_msg_mapped = true;
682 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
684 struct spi_transfer *xfer;
685 struct device *tx_dev, *rx_dev;
687 if (!master->cur_msg_mapped || !master->can_dma)
690 tx_dev = &master->dma_tx->dev->device;
691 rx_dev = &master->dma_rx->dev->device;
693 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
694 if (!master->can_dma(master, msg->spi, xfer))
697 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
698 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
703 #else /* !CONFIG_HAS_DMA */
704 static inline int __spi_map_msg(struct spi_master *master,
705 struct spi_message *msg)
710 static inline int spi_unmap_msg(struct spi_master *master,
711 struct spi_message *msg)
715 #endif /* !CONFIG_HAS_DMA */
717 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
719 struct spi_transfer *xfer;
721 unsigned int max_tx, max_rx;
723 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
727 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
728 if ((master->flags & SPI_MASTER_MUST_TX) &&
730 max_tx = max(xfer->len, max_tx);
731 if ((master->flags & SPI_MASTER_MUST_RX) &&
733 max_rx = max(xfer->len, max_rx);
737 tmp = krealloc(master->dummy_tx, max_tx,
738 GFP_KERNEL | GFP_DMA);
741 master->dummy_tx = tmp;
742 memset(tmp, 0, max_tx);
746 tmp = krealloc(master->dummy_rx, max_rx,
747 GFP_KERNEL | GFP_DMA);
750 master->dummy_rx = tmp;
753 if (max_tx || max_rx) {
754 list_for_each_entry(xfer, &msg->transfers,
757 xfer->tx_buf = master->dummy_tx;
759 xfer->rx_buf = master->dummy_rx;
764 return __spi_map_msg(master, msg);
768 * spi_transfer_one_message - Default implementation of transfer_one_message()
770 * This is a standard implementation of transfer_one_message() for
771 * drivers which impelment a transfer_one() operation. It provides
772 * standard handling of delays and chip select management.
774 static int spi_transfer_one_message(struct spi_master *master,
775 struct spi_message *msg)
777 struct spi_transfer *xfer;
778 bool keep_cs = false;
782 spi_set_cs(msg->spi, true);
784 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
785 trace_spi_transfer_start(msg, xfer);
787 reinit_completion(&master->xfer_completion);
789 ret = master->transfer_one(master, msg->spi, xfer);
791 dev_err(&msg->spi->dev,
792 "SPI transfer failed: %d\n", ret);
798 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
799 ms += ms + 100; /* some tolerance */
801 ms = wait_for_completion_timeout(&master->xfer_completion,
802 msecs_to_jiffies(ms));
806 dev_err(&msg->spi->dev, "SPI transfer timed out\n");
807 msg->status = -ETIMEDOUT;
810 trace_spi_transfer_stop(msg, xfer);
812 if (msg->status != -EINPROGRESS)
815 if (xfer->delay_usecs)
816 udelay(xfer->delay_usecs);
818 if (xfer->cs_change) {
819 if (list_is_last(&xfer->transfer_list,
823 spi_set_cs(msg->spi, false);
825 spi_set_cs(msg->spi, true);
829 msg->actual_length += xfer->len;
833 if (ret != 0 || !keep_cs)
834 spi_set_cs(msg->spi, false);
836 if (msg->status == -EINPROGRESS)
839 spi_finalize_current_message(master);
845 * spi_finalize_current_transfer - report completion of a transfer
847 * Called by SPI drivers using the core transfer_one_message()
848 * implementation to notify it that the current interrupt driven
849 * transfer has finished and the next one may be scheduled.
851 void spi_finalize_current_transfer(struct spi_master *master)
853 complete(&master->xfer_completion);
855 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
858 * spi_pump_messages - kthread work function which processes spi message queue
859 * @work: pointer to kthread work struct contained in the master struct
861 * This function checks if there is any spi message in the queue that
862 * needs processing and if so call out to the driver to initialize hardware
863 * and transfer each message.
866 static void spi_pump_messages(struct kthread_work *work)
868 struct spi_master *master =
869 container_of(work, struct spi_master, pump_messages);
871 bool was_busy = false;
874 /* Lock queue and check for queue work */
875 spin_lock_irqsave(&master->queue_lock, flags);
876 if (list_empty(&master->queue) || !master->running) {
878 spin_unlock_irqrestore(&master->queue_lock, flags);
881 master->busy = false;
882 spin_unlock_irqrestore(&master->queue_lock, flags);
883 kfree(master->dummy_rx);
884 master->dummy_rx = NULL;
885 kfree(master->dummy_tx);
886 master->dummy_tx = NULL;
887 if (master->unprepare_transfer_hardware &&
888 master->unprepare_transfer_hardware(master))
889 dev_err(&master->dev,
890 "failed to unprepare transfer hardware\n");
891 if (master->auto_runtime_pm) {
892 pm_runtime_mark_last_busy(master->dev.parent);
893 pm_runtime_put_autosuspend(master->dev.parent);
895 trace_spi_master_idle(master);
899 /* Make sure we are not already running a message */
900 if (master->cur_msg) {
901 spin_unlock_irqrestore(&master->queue_lock, flags);
904 /* Extract head of queue */
906 list_first_entry(&master->queue, struct spi_message, queue);
908 list_del_init(&master->cur_msg->queue);
913 spin_unlock_irqrestore(&master->queue_lock, flags);
915 if (!was_busy && master->auto_runtime_pm) {
916 ret = pm_runtime_get_sync(master->dev.parent);
918 dev_err(&master->dev, "Failed to power device: %d\n",
925 trace_spi_master_busy(master);
927 if (!was_busy && master->prepare_transfer_hardware) {
928 ret = master->prepare_transfer_hardware(master);
930 dev_err(&master->dev,
931 "failed to prepare transfer hardware\n");
933 if (master->auto_runtime_pm)
934 pm_runtime_put(master->dev.parent);
939 trace_spi_message_start(master->cur_msg);
941 if (master->prepare_message) {
942 ret = master->prepare_message(master, master->cur_msg);
944 dev_err(&master->dev,
945 "failed to prepare message: %d\n", ret);
946 master->cur_msg->status = ret;
947 spi_finalize_current_message(master);
950 master->cur_msg_prepared = true;
953 ret = spi_map_msg(master, master->cur_msg);
955 master->cur_msg->status = ret;
956 spi_finalize_current_message(master);
960 ret = master->transfer_one_message(master, master->cur_msg);
962 dev_err(&master->dev,
963 "failed to transfer one message from queue\n");
968 static int spi_init_queue(struct spi_master *master)
970 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
972 INIT_LIST_HEAD(&master->queue);
973 spin_lock_init(&master->queue_lock);
975 master->running = false;
976 master->busy = false;
978 init_kthread_worker(&master->kworker);
979 master->kworker_task = kthread_run(kthread_worker_fn,
980 &master->kworker, "%s",
981 dev_name(&master->dev));
982 if (IS_ERR(master->kworker_task)) {
983 dev_err(&master->dev, "failed to create message pump task\n");
986 init_kthread_work(&master->pump_messages, spi_pump_messages);
989 * Master config will indicate if this controller should run the
990 * message pump with high (realtime) priority to reduce the transfer
991 * latency on the bus by minimising the delay between a transfer
992 * request and the scheduling of the message pump thread. Without this
993 * setting the message pump thread will remain at default priority.
996 dev_info(&master->dev,
997 "will run message pump with realtime priority\n");
998 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1005 * spi_get_next_queued_message() - called by driver to check for queued
1007 * @master: the master to check for queued messages
1009 * If there are more messages in the queue, the next message is returned from
1012 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1014 struct spi_message *next;
1015 unsigned long flags;
1017 /* get a pointer to the next message, if any */
1018 spin_lock_irqsave(&master->queue_lock, flags);
1019 next = list_first_entry_or_null(&master->queue, struct spi_message,
1021 spin_unlock_irqrestore(&master->queue_lock, flags);
1025 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1028 * spi_finalize_current_message() - the current message is complete
1029 * @master: the master to return the message to
1031 * Called by the driver to notify the core that the message in the front of the
1032 * queue is complete and can be removed from the queue.
1034 void spi_finalize_current_message(struct spi_master *master)
1036 struct spi_message *mesg;
1037 unsigned long flags;
1040 spin_lock_irqsave(&master->queue_lock, flags);
1041 mesg = master->cur_msg;
1042 master->cur_msg = NULL;
1044 queue_kthread_work(&master->kworker, &master->pump_messages);
1045 spin_unlock_irqrestore(&master->queue_lock, flags);
1047 spi_unmap_msg(master, mesg);
1049 if (master->cur_msg_prepared && master->unprepare_message) {
1050 ret = master->unprepare_message(master, mesg);
1052 dev_err(&master->dev,
1053 "failed to unprepare message: %d\n", ret);
1056 master->cur_msg_prepared = false;
1060 mesg->complete(mesg->context);
1062 trace_spi_message_done(mesg);
1064 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1066 static int spi_start_queue(struct spi_master *master)
1068 unsigned long flags;
1070 spin_lock_irqsave(&master->queue_lock, flags);
1072 if (master->running || master->busy) {
1073 spin_unlock_irqrestore(&master->queue_lock, flags);
1077 master->running = true;
1078 master->cur_msg = NULL;
1079 spin_unlock_irqrestore(&master->queue_lock, flags);
1081 queue_kthread_work(&master->kworker, &master->pump_messages);
1086 static int spi_stop_queue(struct spi_master *master)
1088 unsigned long flags;
1089 unsigned limit = 500;
1092 spin_lock_irqsave(&master->queue_lock, flags);
1095 * This is a bit lame, but is optimized for the common execution path.
1096 * A wait_queue on the master->busy could be used, but then the common
1097 * execution path (pump_messages) would be required to call wake_up or
1098 * friends on every SPI message. Do this instead.
1100 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1101 spin_unlock_irqrestore(&master->queue_lock, flags);
1102 usleep_range(10000, 11000);
1103 spin_lock_irqsave(&master->queue_lock, flags);
1106 if (!list_empty(&master->queue) || master->busy)
1109 master->running = false;
1111 spin_unlock_irqrestore(&master->queue_lock, flags);
1114 dev_warn(&master->dev,
1115 "could not stop message queue\n");
1121 static int spi_destroy_queue(struct spi_master *master)
1125 ret = spi_stop_queue(master);
1128 * flush_kthread_worker will block until all work is done.
1129 * If the reason that stop_queue timed out is that the work will never
1130 * finish, then it does no good to call flush/stop thread, so
1134 dev_err(&master->dev, "problem destroying queue\n");
1138 flush_kthread_worker(&master->kworker);
1139 kthread_stop(master->kworker_task);
1145 * spi_queued_transfer - transfer function for queued transfers
1146 * @spi: spi device which is requesting transfer
1147 * @msg: spi message which is to handled is queued to driver queue
1149 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1151 struct spi_master *master = spi->master;
1152 unsigned long flags;
1154 spin_lock_irqsave(&master->queue_lock, flags);
1156 if (!master->running) {
1157 spin_unlock_irqrestore(&master->queue_lock, flags);
1160 msg->actual_length = 0;
1161 msg->status = -EINPROGRESS;
1163 list_add_tail(&msg->queue, &master->queue);
1165 queue_kthread_work(&master->kworker, &master->pump_messages);
1167 spin_unlock_irqrestore(&master->queue_lock, flags);
1171 static int spi_master_initialize_queue(struct spi_master *master)
1175 master->transfer = spi_queued_transfer;
1176 if (!master->transfer_one_message)
1177 master->transfer_one_message = spi_transfer_one_message;
1179 /* Initialize and start queue */
1180 ret = spi_init_queue(master);
1182 dev_err(&master->dev, "problem initializing queue\n");
1183 goto err_init_queue;
1185 master->queued = true;
1186 ret = spi_start_queue(master);
1188 dev_err(&master->dev, "problem starting queue\n");
1189 goto err_start_queue;
1195 spi_destroy_queue(master);
1200 /*-------------------------------------------------------------------------*/
1202 #if defined(CONFIG_OF)
1204 * of_register_spi_devices() - Register child devices onto the SPI bus
1205 * @master: Pointer to spi_master device
1207 * Registers an spi_device for each child node of master node which has a 'reg'
1210 static void of_register_spi_devices(struct spi_master *master)
1212 struct spi_device *spi;
1213 struct device_node *nc;
1217 if (!master->dev.of_node)
1220 for_each_available_child_of_node(master->dev.of_node, nc) {
1221 /* Alloc an spi_device */
1222 spi = spi_alloc_device(master);
1224 dev_err(&master->dev, "spi_device alloc error for %s\n",
1230 /* Select device driver */
1231 if (of_modalias_node(nc, spi->modalias,
1232 sizeof(spi->modalias)) < 0) {
1233 dev_err(&master->dev, "cannot find modalias for %s\n",
1239 /* Device address */
1240 rc = of_property_read_u32(nc, "reg", &value);
1242 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1247 spi->chip_select = value;
1249 /* Mode (clock phase/polarity/etc.) */
1250 if (of_find_property(nc, "spi-cpha", NULL))
1251 spi->mode |= SPI_CPHA;
1252 if (of_find_property(nc, "spi-cpol", NULL))
1253 spi->mode |= SPI_CPOL;
1254 if (of_find_property(nc, "spi-cs-high", NULL))
1255 spi->mode |= SPI_CS_HIGH;
1256 if (of_find_property(nc, "spi-3wire", NULL))
1257 spi->mode |= SPI_3WIRE;
1258 if (of_find_property(nc, "spi-lsb-first", NULL))
1259 spi->mode |= SPI_LSB_FIRST;
1261 /* Device DUAL/QUAD mode */
1262 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1267 spi->mode |= SPI_TX_DUAL;
1270 spi->mode |= SPI_TX_QUAD;
1273 dev_warn(&master->dev,
1274 "spi-tx-bus-width %d not supported\n",
1280 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1285 spi->mode |= SPI_RX_DUAL;
1288 spi->mode |= SPI_RX_QUAD;
1291 dev_warn(&master->dev,
1292 "spi-rx-bus-width %d not supported\n",
1299 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1301 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1306 spi->max_speed_hz = value;
1309 spi->irq = irq_of_parse_and_map(nc, 0);
1311 /* Store a pointer to the node in the device structure */
1313 spi->dev.of_node = nc;
1315 /* Register the new device */
1316 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1317 rc = spi_add_device(spi);
1319 dev_err(&master->dev, "spi_device register error %s\n",
1327 static void of_register_spi_devices(struct spi_master *master) { }
1331 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1333 struct spi_device *spi = data;
1335 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1336 struct acpi_resource_spi_serialbus *sb;
1338 sb = &ares->data.spi_serial_bus;
1339 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1340 spi->chip_select = sb->device_selection;
1341 spi->max_speed_hz = sb->connection_speed;
1343 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1344 spi->mode |= SPI_CPHA;
1345 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1346 spi->mode |= SPI_CPOL;
1347 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1348 spi->mode |= SPI_CS_HIGH;
1350 } else if (spi->irq < 0) {
1353 if (acpi_dev_resource_interrupt(ares, 0, &r))
1357 /* Always tell the ACPI core to skip this resource */
1361 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1362 void *data, void **return_value)
1364 struct spi_master *master = data;
1365 struct list_head resource_list;
1366 struct acpi_device *adev;
1367 struct spi_device *spi;
1370 if (acpi_bus_get_device(handle, &adev))
1372 if (acpi_bus_get_status(adev) || !adev->status.present)
1375 spi = spi_alloc_device(master);
1377 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1378 dev_name(&adev->dev));
1379 return AE_NO_MEMORY;
1382 ACPI_COMPANION_SET(&spi->dev, adev);
1385 INIT_LIST_HEAD(&resource_list);
1386 ret = acpi_dev_get_resources(adev, &resource_list,
1387 acpi_spi_add_resource, spi);
1388 acpi_dev_free_resource_list(&resource_list);
1390 if (ret < 0 || !spi->max_speed_hz) {
1395 adev->power.flags.ignore_parent = true;
1396 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1397 if (spi_add_device(spi)) {
1398 adev->power.flags.ignore_parent = false;
1399 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1400 dev_name(&adev->dev));
1407 static void acpi_register_spi_devices(struct spi_master *master)
1412 handle = ACPI_HANDLE(master->dev.parent);
1416 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1417 acpi_spi_add_device, NULL,
1419 if (ACPI_FAILURE(status))
1420 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1423 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1424 #endif /* CONFIG_ACPI */
1426 static void spi_master_release(struct device *dev)
1428 struct spi_master *master;
1430 master = container_of(dev, struct spi_master, dev);
1434 static struct class spi_master_class = {
1435 .name = "spi_master",
1436 .owner = THIS_MODULE,
1437 .dev_release = spi_master_release,
1443 * spi_alloc_master - allocate SPI master controller
1444 * @dev: the controller, possibly using the platform_bus
1445 * @size: how much zeroed driver-private data to allocate; the pointer to this
1446 * memory is in the driver_data field of the returned device,
1447 * accessible with spi_master_get_devdata().
1448 * Context: can sleep
1450 * This call is used only by SPI master controller drivers, which are the
1451 * only ones directly touching chip registers. It's how they allocate
1452 * an spi_master structure, prior to calling spi_register_master().
1454 * This must be called from context that can sleep. It returns the SPI
1455 * master structure on success, else NULL.
1457 * The caller is responsible for assigning the bus number and initializing
1458 * the master's methods before calling spi_register_master(); and (after errors
1459 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1462 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1464 struct spi_master *master;
1469 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1473 device_initialize(&master->dev);
1474 master->bus_num = -1;
1475 master->num_chipselect = 1;
1476 master->dev.class = &spi_master_class;
1477 master->dev.parent = get_device(dev);
1478 spi_master_set_devdata(master, &master[1]);
1482 EXPORT_SYMBOL_GPL(spi_alloc_master);
1485 static int of_spi_register_master(struct spi_master *master)
1488 struct device_node *np = master->dev.of_node;
1493 nb = of_gpio_named_count(np, "cs-gpios");
1494 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1496 /* Return error only for an incorrectly formed cs-gpios property */
1497 if (nb == 0 || nb == -ENOENT)
1502 cs = devm_kzalloc(&master->dev,
1503 sizeof(int) * master->num_chipselect,
1505 master->cs_gpios = cs;
1507 if (!master->cs_gpios)
1510 for (i = 0; i < master->num_chipselect; i++)
1513 for (i = 0; i < nb; i++)
1514 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1519 static int of_spi_register_master(struct spi_master *master)
1526 * spi_register_master - register SPI master controller
1527 * @master: initialized master, originally from spi_alloc_master()
1528 * Context: can sleep
1530 * SPI master controllers connect to their drivers using some non-SPI bus,
1531 * such as the platform bus. The final stage of probe() in that code
1532 * includes calling spi_register_master() to hook up to this SPI bus glue.
1534 * SPI controllers use board specific (often SOC specific) bus numbers,
1535 * and board-specific addressing for SPI devices combines those numbers
1536 * with chip select numbers. Since SPI does not directly support dynamic
1537 * device identification, boards need configuration tables telling which
1538 * chip is at which address.
1540 * This must be called from context that can sleep. It returns zero on
1541 * success, else a negative error code (dropping the master's refcount).
1542 * After a successful return, the caller is responsible for calling
1543 * spi_unregister_master().
1545 int spi_register_master(struct spi_master *master)
1547 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1548 struct device *dev = master->dev.parent;
1549 struct boardinfo *bi;
1550 int status = -ENODEV;
1556 status = of_spi_register_master(master);
1560 /* even if it's just one always-selected device, there must
1561 * be at least one chipselect
1563 if (master->num_chipselect == 0)
1566 if ((master->bus_num < 0) && master->dev.of_node)
1567 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1569 /* convention: dynamically assigned bus IDs count down from the max */
1570 if (master->bus_num < 0) {
1571 /* FIXME switch to an IDR based scheme, something like
1572 * I2C now uses, so we can't run out of "dynamic" IDs
1574 master->bus_num = atomic_dec_return(&dyn_bus_id);
1578 spin_lock_init(&master->bus_lock_spinlock);
1579 mutex_init(&master->bus_lock_mutex);
1580 master->bus_lock_flag = 0;
1581 init_completion(&master->xfer_completion);
1582 if (!master->max_dma_len)
1583 master->max_dma_len = INT_MAX;
1585 /* register the device, then userspace will see it.
1586 * registration fails if the bus ID is in use.
1588 dev_set_name(&master->dev, "spi%u", master->bus_num);
1589 status = device_add(&master->dev);
1592 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1593 dynamic ? " (dynamic)" : "");
1595 /* If we're using a queued driver, start the queue */
1596 if (master->transfer)
1597 dev_info(dev, "master is unqueued, this is deprecated\n");
1599 status = spi_master_initialize_queue(master);
1601 device_del(&master->dev);
1606 mutex_lock(&board_lock);
1607 list_add_tail(&master->list, &spi_master_list);
1608 list_for_each_entry(bi, &board_list, list)
1609 spi_match_master_to_boardinfo(master, &bi->board_info);
1610 mutex_unlock(&board_lock);
1612 /* Register devices from the device tree and ACPI */
1613 of_register_spi_devices(master);
1614 acpi_register_spi_devices(master);
1618 EXPORT_SYMBOL_GPL(spi_register_master);
1620 static void devm_spi_unregister(struct device *dev, void *res)
1622 spi_unregister_master(*(struct spi_master **)res);
1626 * dev_spi_register_master - register managed SPI master controller
1627 * @dev: device managing SPI master
1628 * @master: initialized master, originally from spi_alloc_master()
1629 * Context: can sleep
1631 * Register a SPI device as with spi_register_master() which will
1632 * automatically be unregister
1634 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1636 struct spi_master **ptr;
1639 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1643 ret = spi_register_master(master);
1646 devres_add(dev, ptr);
1653 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1655 static int __unregister(struct device *dev, void *null)
1657 spi_unregister_device(to_spi_device(dev));
1662 * spi_unregister_master - unregister SPI master controller
1663 * @master: the master being unregistered
1664 * Context: can sleep
1666 * This call is used only by SPI master controller drivers, which are the
1667 * only ones directly touching chip registers.
1669 * This must be called from context that can sleep.
1671 void spi_unregister_master(struct spi_master *master)
1675 if (master->queued) {
1676 if (spi_destroy_queue(master))
1677 dev_err(&master->dev, "queue remove failed\n");
1680 mutex_lock(&board_lock);
1681 list_del(&master->list);
1682 mutex_unlock(&board_lock);
1684 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1685 device_unregister(&master->dev);
1687 EXPORT_SYMBOL_GPL(spi_unregister_master);
1689 int spi_master_suspend(struct spi_master *master)
1693 /* Basically no-ops for non-queued masters */
1694 if (!master->queued)
1697 ret = spi_stop_queue(master);
1699 dev_err(&master->dev, "queue stop failed\n");
1703 EXPORT_SYMBOL_GPL(spi_master_suspend);
1705 int spi_master_resume(struct spi_master *master)
1709 if (!master->queued)
1712 ret = spi_start_queue(master);
1714 dev_err(&master->dev, "queue restart failed\n");
1718 EXPORT_SYMBOL_GPL(spi_master_resume);
1720 static int __spi_master_match(struct device *dev, const void *data)
1722 struct spi_master *m;
1723 const u16 *bus_num = data;
1725 m = container_of(dev, struct spi_master, dev);
1726 return m->bus_num == *bus_num;
1730 * spi_busnum_to_master - look up master associated with bus_num
1731 * @bus_num: the master's bus number
1732 * Context: can sleep
1734 * This call may be used with devices that are registered after
1735 * arch init time. It returns a refcounted pointer to the relevant
1736 * spi_master (which the caller must release), or NULL if there is
1737 * no such master registered.
1739 struct spi_master *spi_busnum_to_master(u16 bus_num)
1742 struct spi_master *master = NULL;
1744 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1745 __spi_master_match);
1747 master = container_of(dev, struct spi_master, dev);
1748 /* reference got in class_find_device */
1751 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1754 /*-------------------------------------------------------------------------*/
1756 /* Core methods for SPI master protocol drivers. Some of the
1757 * other core methods are currently defined as inline functions.
1761 * spi_setup - setup SPI mode and clock rate
1762 * @spi: the device whose settings are being modified
1763 * Context: can sleep, and no requests are queued to the device
1765 * SPI protocol drivers may need to update the transfer mode if the
1766 * device doesn't work with its default. They may likewise need
1767 * to update clock rates or word sizes from initial values. This function
1768 * changes those settings, and must be called from a context that can sleep.
1769 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1770 * effect the next time the device is selected and data is transferred to
1771 * or from it. When this function returns, the spi device is deselected.
1773 * Note that this call will fail if the protocol driver specifies an option
1774 * that the underlying controller or its driver does not support. For
1775 * example, not all hardware supports wire transfers using nine bit words,
1776 * LSB-first wire encoding, or active-high chipselects.
1778 int spi_setup(struct spi_device *spi)
1780 unsigned bad_bits, ugly_bits;
1783 /* check mode to prevent that DUAL and QUAD set at the same time
1785 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1786 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1788 "setup: can not select dual and quad at the same time\n");
1791 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1793 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1794 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1796 /* help drivers fail *cleanly* when they need options
1797 * that aren't supported with their current master
1799 bad_bits = spi->mode & ~spi->master->mode_bits;
1800 ugly_bits = bad_bits &
1801 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1804 "setup: ignoring unsupported mode bits %x\n",
1806 spi->mode &= ~ugly_bits;
1807 bad_bits &= ~ugly_bits;
1810 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1815 if (!spi->bits_per_word)
1816 spi->bits_per_word = 8;
1818 if (!spi->max_speed_hz)
1819 spi->max_speed_hz = spi->master->max_speed_hz;
1821 if (spi->master->setup)
1822 status = spi->master->setup(spi);
1824 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1825 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1826 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1827 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1828 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1829 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1830 spi->bits_per_word, spi->max_speed_hz,
1835 EXPORT_SYMBOL_GPL(spi_setup);
1837 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1839 struct spi_master *master = spi->master;
1840 struct spi_transfer *xfer;
1843 if (list_empty(&message->transfers))
1846 /* Half-duplex links include original MicroWire, and ones with
1847 * only one data pin like SPI_3WIRE (switches direction) or where
1848 * either MOSI or MISO is missing. They can also be caused by
1849 * software limitations.
1851 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1852 || (spi->mode & SPI_3WIRE)) {
1853 unsigned flags = master->flags;
1855 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1856 if (xfer->rx_buf && xfer->tx_buf)
1858 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1860 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1866 * Set transfer bits_per_word and max speed as spi device default if
1867 * it is not set for this transfer.
1868 * Set transfer tx_nbits and rx_nbits as single transfer default
1869 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1871 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1872 message->frame_length += xfer->len;
1873 if (!xfer->bits_per_word)
1874 xfer->bits_per_word = spi->bits_per_word;
1876 if (!xfer->speed_hz)
1877 xfer->speed_hz = spi->max_speed_hz;
1879 if (master->max_speed_hz &&
1880 xfer->speed_hz > master->max_speed_hz)
1881 xfer->speed_hz = master->max_speed_hz;
1883 if (master->bits_per_word_mask) {
1884 /* Only 32 bits fit in the mask */
1885 if (xfer->bits_per_word > 32)
1887 if (!(master->bits_per_word_mask &
1888 BIT(xfer->bits_per_word - 1)))
1893 * SPI transfer length should be multiple of SPI word size
1894 * where SPI word size should be power-of-two multiple
1896 if (xfer->bits_per_word <= 8)
1898 else if (xfer->bits_per_word <= 16)
1903 /* No partial transfers accepted */
1904 if (xfer->len % w_size)
1907 if (xfer->speed_hz && master->min_speed_hz &&
1908 xfer->speed_hz < master->min_speed_hz)
1911 if (xfer->tx_buf && !xfer->tx_nbits)
1912 xfer->tx_nbits = SPI_NBITS_SINGLE;
1913 if (xfer->rx_buf && !xfer->rx_nbits)
1914 xfer->rx_nbits = SPI_NBITS_SINGLE;
1915 /* check transfer tx/rx_nbits:
1916 * 1. check the value matches one of single, dual and quad
1917 * 2. check tx/rx_nbits match the mode in spi_device
1920 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1921 xfer->tx_nbits != SPI_NBITS_DUAL &&
1922 xfer->tx_nbits != SPI_NBITS_QUAD)
1924 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1925 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1927 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1928 !(spi->mode & SPI_TX_QUAD))
1931 /* check transfer rx_nbits */
1933 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1934 xfer->rx_nbits != SPI_NBITS_DUAL &&
1935 xfer->rx_nbits != SPI_NBITS_QUAD)
1937 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1938 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1940 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1941 !(spi->mode & SPI_RX_QUAD))
1946 message->status = -EINPROGRESS;
1951 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1953 struct spi_master *master = spi->master;
1957 trace_spi_message_submit(message);
1959 return master->transfer(spi, message);
1963 * spi_async - asynchronous SPI transfer
1964 * @spi: device with which data will be exchanged
1965 * @message: describes the data transfers, including completion callback
1966 * Context: any (irqs may be blocked, etc)
1968 * This call may be used in_irq and other contexts which can't sleep,
1969 * as well as from task contexts which can sleep.
1971 * The completion callback is invoked in a context which can't sleep.
1972 * Before that invocation, the value of message->status is undefined.
1973 * When the callback is issued, message->status holds either zero (to
1974 * indicate complete success) or a negative error code. After that
1975 * callback returns, the driver which issued the transfer request may
1976 * deallocate the associated memory; it's no longer in use by any SPI
1977 * core or controller driver code.
1979 * Note that although all messages to a spi_device are handled in
1980 * FIFO order, messages may go to different devices in other orders.
1981 * Some device might be higher priority, or have various "hard" access
1982 * time requirements, for example.
1984 * On detection of any fault during the transfer, processing of
1985 * the entire message is aborted, and the device is deselected.
1986 * Until returning from the associated message completion callback,
1987 * no other spi_message queued to that device will be processed.
1988 * (This rule applies equally to all the synchronous transfer calls,
1989 * which are wrappers around this core asynchronous primitive.)
1991 int spi_async(struct spi_device *spi, struct spi_message *message)
1993 struct spi_master *master = spi->master;
1995 unsigned long flags;
1997 ret = __spi_validate(spi, message);
2001 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2003 if (master->bus_lock_flag)
2006 ret = __spi_async(spi, message);
2008 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2012 EXPORT_SYMBOL_GPL(spi_async);
2015 * spi_async_locked - version of spi_async with exclusive bus usage
2016 * @spi: device with which data will be exchanged
2017 * @message: describes the data transfers, including completion callback
2018 * Context: any (irqs may be blocked, etc)
2020 * This call may be used in_irq and other contexts which can't sleep,
2021 * as well as from task contexts which can sleep.
2023 * The completion callback is invoked in a context which can't sleep.
2024 * Before that invocation, the value of message->status is undefined.
2025 * When the callback is issued, message->status holds either zero (to
2026 * indicate complete success) or a negative error code. After that
2027 * callback returns, the driver which issued the transfer request may
2028 * deallocate the associated memory; it's no longer in use by any SPI
2029 * core or controller driver code.
2031 * Note that although all messages to a spi_device are handled in
2032 * FIFO order, messages may go to different devices in other orders.
2033 * Some device might be higher priority, or have various "hard" access
2034 * time requirements, for example.
2036 * On detection of any fault during the transfer, processing of
2037 * the entire message is aborted, and the device is deselected.
2038 * Until returning from the associated message completion callback,
2039 * no other spi_message queued to that device will be processed.
2040 * (This rule applies equally to all the synchronous transfer calls,
2041 * which are wrappers around this core asynchronous primitive.)
2043 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2045 struct spi_master *master = spi->master;
2047 unsigned long flags;
2049 ret = __spi_validate(spi, message);
2053 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2055 ret = __spi_async(spi, message);
2057 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2062 EXPORT_SYMBOL_GPL(spi_async_locked);
2065 /*-------------------------------------------------------------------------*/
2067 /* Utility methods for SPI master protocol drivers, layered on
2068 * top of the core. Some other utility methods are defined as
2072 static void spi_complete(void *arg)
2077 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2080 DECLARE_COMPLETION_ONSTACK(done);
2082 struct spi_master *master = spi->master;
2084 message->complete = spi_complete;
2085 message->context = &done;
2088 mutex_lock(&master->bus_lock_mutex);
2090 status = spi_async_locked(spi, message);
2093 mutex_unlock(&master->bus_lock_mutex);
2096 wait_for_completion(&done);
2097 status = message->status;
2099 message->context = NULL;
2104 * spi_sync - blocking/synchronous SPI data transfers
2105 * @spi: device with which data will be exchanged
2106 * @message: describes the data transfers
2107 * Context: can sleep
2109 * This call may only be used from a context that may sleep. The sleep
2110 * is non-interruptible, and has no timeout. Low-overhead controller
2111 * drivers may DMA directly into and out of the message buffers.
2113 * Note that the SPI device's chip select is active during the message,
2114 * and then is normally disabled between messages. Drivers for some
2115 * frequently-used devices may want to minimize costs of selecting a chip,
2116 * by leaving it selected in anticipation that the next message will go
2117 * to the same chip. (That may increase power usage.)
2119 * Also, the caller is guaranteeing that the memory associated with the
2120 * message will not be freed before this call returns.
2122 * It returns zero on success, else a negative error code.
2124 int spi_sync(struct spi_device *spi, struct spi_message *message)
2126 return __spi_sync(spi, message, 0);
2128 EXPORT_SYMBOL_GPL(spi_sync);
2131 * spi_sync_locked - version of spi_sync with exclusive bus usage
2132 * @spi: device with which data will be exchanged
2133 * @message: describes the data transfers
2134 * Context: can sleep
2136 * This call may only be used from a context that may sleep. The sleep
2137 * is non-interruptible, and has no timeout. Low-overhead controller
2138 * drivers may DMA directly into and out of the message buffers.
2140 * This call should be used by drivers that require exclusive access to the
2141 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2142 * be released by a spi_bus_unlock call when the exclusive access is over.
2144 * It returns zero on success, else a negative error code.
2146 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2148 return __spi_sync(spi, message, 1);
2150 EXPORT_SYMBOL_GPL(spi_sync_locked);
2153 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2154 * @master: SPI bus master that should be locked for exclusive bus access
2155 * Context: can sleep
2157 * This call may only be used from a context that may sleep. The sleep
2158 * is non-interruptible, and has no timeout.
2160 * This call should be used by drivers that require exclusive access to the
2161 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2162 * exclusive access is over. Data transfer must be done by spi_sync_locked
2163 * and spi_async_locked calls when the SPI bus lock is held.
2165 * It returns zero on success, else a negative error code.
2167 int spi_bus_lock(struct spi_master *master)
2169 unsigned long flags;
2171 mutex_lock(&master->bus_lock_mutex);
2173 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2174 master->bus_lock_flag = 1;
2175 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2177 /* mutex remains locked until spi_bus_unlock is called */
2181 EXPORT_SYMBOL_GPL(spi_bus_lock);
2184 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2185 * @master: SPI bus master that was locked for exclusive bus access
2186 * Context: can sleep
2188 * This call may only be used from a context that may sleep. The sleep
2189 * is non-interruptible, and has no timeout.
2191 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2194 * It returns zero on success, else a negative error code.
2196 int spi_bus_unlock(struct spi_master *master)
2198 master->bus_lock_flag = 0;
2200 mutex_unlock(&master->bus_lock_mutex);
2204 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2206 /* portable code must never pass more than 32 bytes */
2207 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2212 * spi_write_then_read - SPI synchronous write followed by read
2213 * @spi: device with which data will be exchanged
2214 * @txbuf: data to be written (need not be dma-safe)
2215 * @n_tx: size of txbuf, in bytes
2216 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2217 * @n_rx: size of rxbuf, in bytes
2218 * Context: can sleep
2220 * This performs a half duplex MicroWire style transaction with the
2221 * device, sending txbuf and then reading rxbuf. The return value
2222 * is zero for success, else a negative errno status code.
2223 * This call may only be used from a context that may sleep.
2225 * Parameters to this routine are always copied using a small buffer;
2226 * portable code should never use this for more than 32 bytes.
2227 * Performance-sensitive or bulk transfer code should instead use
2228 * spi_{async,sync}() calls with dma-safe buffers.
2230 int spi_write_then_read(struct spi_device *spi,
2231 const void *txbuf, unsigned n_tx,
2232 void *rxbuf, unsigned n_rx)
2234 static DEFINE_MUTEX(lock);
2237 struct spi_message message;
2238 struct spi_transfer x[2];
2241 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2242 * copying here, (as a pure convenience thing), but we can
2243 * keep heap costs out of the hot path unless someone else is
2244 * using the pre-allocated buffer or the transfer is too large.
2246 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2247 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2248 GFP_KERNEL | GFP_DMA);
2255 spi_message_init(&message);
2256 memset(x, 0, sizeof(x));
2259 spi_message_add_tail(&x[0], &message);
2263 spi_message_add_tail(&x[1], &message);
2266 memcpy(local_buf, txbuf, n_tx);
2267 x[0].tx_buf = local_buf;
2268 x[1].rx_buf = local_buf + n_tx;
2271 status = spi_sync(spi, &message);
2273 memcpy(rxbuf, x[1].rx_buf, n_rx);
2275 if (x[0].tx_buf == buf)
2276 mutex_unlock(&lock);
2282 EXPORT_SYMBOL_GPL(spi_write_then_read);
2284 /*-------------------------------------------------------------------------*/
2286 static int __init spi_init(void)
2290 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2296 status = bus_register(&spi_bus_type);
2300 status = class_register(&spi_master_class);
2306 bus_unregister(&spi_bus_type);
2314 /* board_info is normally registered in arch_initcall(),
2315 * but even essential drivers wait till later
2317 * REVISIT only boardinfo really needs static linking. the rest (device and
2318 * driver registration) _could_ be dynamically linked (modular) ... costs
2319 * include needing to have boardinfo data structures be much more public.
2321 postcore_initcall(spi_init);