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/clk/clk-conf.h>
33 #include <linux/slab.h>
34 #include <linux/mod_devicetable.h>
35 #include <linux/spi/spi.h>
36 #include <linux/of_gpio.h>
37 #include <linux/pm_runtime.h>
38 #include <linux/pm_domain.h>
39 #include <linux/export.h>
40 #include <linux/sched/rt.h>
41 #include <linux/delay.h>
42 #include <linux/kthread.h>
43 #include <linux/ioport.h>
44 #include <linux/acpi.h>
46 #define CREATE_TRACE_POINTS
47 #include <trace/events/spi.h>
49 static void spidev_release(struct device *dev)
51 struct spi_device *spi = to_spi_device(dev);
53 /* spi masters may cleanup for released devices */
54 if (spi->master->cleanup)
55 spi->master->cleanup(spi);
57 spi_master_put(spi->master);
62 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
64 const struct spi_device *spi = to_spi_device(dev);
67 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
71 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
73 static DEVICE_ATTR_RO(modalias);
75 static struct attribute *spi_dev_attrs[] = {
76 &dev_attr_modalias.attr,
79 ATTRIBUTE_GROUPS(spi_dev);
81 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
82 * and the sysfs version makes coldplug work too.
85 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
86 const struct spi_device *sdev)
89 if (!strcmp(sdev->modalias, id->name))
96 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
98 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
100 return spi_match_id(sdrv->id_table, sdev);
102 EXPORT_SYMBOL_GPL(spi_get_device_id);
104 static int spi_match_device(struct device *dev, struct device_driver *drv)
106 const struct spi_device *spi = to_spi_device(dev);
107 const struct spi_driver *sdrv = to_spi_driver(drv);
109 /* Attempt an OF style match */
110 if (of_driver_match_device(dev, drv))
114 if (acpi_driver_match_device(dev, drv))
118 return !!spi_match_id(sdrv->id_table, spi);
120 return strcmp(spi->modalias, drv->name) == 0;
123 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
125 const struct spi_device *spi = to_spi_device(dev);
128 rc = acpi_device_uevent_modalias(dev, env);
132 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
136 #ifdef CONFIG_PM_SLEEP
137 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
140 struct spi_driver *drv = to_spi_driver(dev->driver);
142 /* suspend will stop irqs and dma; no more i/o */
145 value = drv->suspend(to_spi_device(dev), message);
147 dev_dbg(dev, "... can't suspend\n");
152 static int spi_legacy_resume(struct device *dev)
155 struct spi_driver *drv = to_spi_driver(dev->driver);
157 /* resume may restart the i/o queue */
160 value = drv->resume(to_spi_device(dev));
162 dev_dbg(dev, "... can't resume\n");
167 static int spi_pm_suspend(struct device *dev)
169 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
172 return pm_generic_suspend(dev);
174 return spi_legacy_suspend(dev, PMSG_SUSPEND);
177 static int spi_pm_resume(struct device *dev)
179 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
182 return pm_generic_resume(dev);
184 return spi_legacy_resume(dev);
187 static int spi_pm_freeze(struct device *dev)
189 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
192 return pm_generic_freeze(dev);
194 return spi_legacy_suspend(dev, PMSG_FREEZE);
197 static int spi_pm_thaw(struct device *dev)
199 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
202 return pm_generic_thaw(dev);
204 return spi_legacy_resume(dev);
207 static int spi_pm_poweroff(struct device *dev)
209 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
212 return pm_generic_poweroff(dev);
214 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
217 static int spi_pm_restore(struct device *dev)
219 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
222 return pm_generic_restore(dev);
224 return spi_legacy_resume(dev);
227 #define spi_pm_suspend NULL
228 #define spi_pm_resume NULL
229 #define spi_pm_freeze NULL
230 #define spi_pm_thaw NULL
231 #define spi_pm_poweroff NULL
232 #define spi_pm_restore NULL
235 static const struct dev_pm_ops spi_pm = {
236 .suspend = spi_pm_suspend,
237 .resume = spi_pm_resume,
238 .freeze = spi_pm_freeze,
240 .poweroff = spi_pm_poweroff,
241 .restore = spi_pm_restore,
243 pm_generic_runtime_suspend,
244 pm_generic_runtime_resume,
249 struct bus_type spi_bus_type = {
251 .dev_groups = spi_dev_groups,
252 .match = spi_match_device,
253 .uevent = spi_uevent,
256 EXPORT_SYMBOL_GPL(spi_bus_type);
259 static int spi_drv_probe(struct device *dev)
261 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
264 ret = of_clk_set_defaults(dev->of_node, false);
268 ret = dev_pm_domain_attach(dev, true);
269 if (ret != -EPROBE_DEFER) {
270 ret = sdrv->probe(to_spi_device(dev));
272 dev_pm_domain_detach(dev, true);
278 static int spi_drv_remove(struct device *dev)
280 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
283 ret = sdrv->remove(to_spi_device(dev));
284 dev_pm_domain_detach(dev, true);
289 static void spi_drv_shutdown(struct device *dev)
291 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
293 sdrv->shutdown(to_spi_device(dev));
297 * spi_register_driver - register a SPI driver
298 * @sdrv: the driver to register
301 int spi_register_driver(struct spi_driver *sdrv)
303 sdrv->driver.bus = &spi_bus_type;
305 sdrv->driver.probe = spi_drv_probe;
307 sdrv->driver.remove = spi_drv_remove;
309 sdrv->driver.shutdown = spi_drv_shutdown;
310 return driver_register(&sdrv->driver);
312 EXPORT_SYMBOL_GPL(spi_register_driver);
314 /*-------------------------------------------------------------------------*/
316 /* SPI devices should normally not be created by SPI device drivers; that
317 * would make them board-specific. Similarly with SPI master drivers.
318 * Device registration normally goes into like arch/.../mach.../board-YYY.c
319 * with other readonly (flashable) information about mainboard devices.
323 struct list_head list;
324 struct spi_board_info board_info;
327 static LIST_HEAD(board_list);
328 static LIST_HEAD(spi_master_list);
331 * Used to protect add/del opertion for board_info list and
332 * spi_master list, and their matching process
334 static DEFINE_MUTEX(board_lock);
337 * spi_alloc_device - Allocate a new SPI device
338 * @master: Controller to which device is connected
341 * Allows a driver to allocate and initialize a spi_device without
342 * registering it immediately. This allows a driver to directly
343 * fill the spi_device with device parameters before calling
344 * spi_add_device() on it.
346 * Caller is responsible to call spi_add_device() on the returned
347 * spi_device structure to add it to the SPI master. If the caller
348 * needs to discard the spi_device without adding it, then it should
349 * call spi_dev_put() on it.
351 * Returns a pointer to the new device, or NULL.
353 struct spi_device *spi_alloc_device(struct spi_master *master)
355 struct spi_device *spi;
357 if (!spi_master_get(master))
360 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
362 spi_master_put(master);
366 spi->master = master;
367 spi->dev.parent = &master->dev;
368 spi->dev.bus = &spi_bus_type;
369 spi->dev.release = spidev_release;
370 spi->cs_gpio = -ENOENT;
371 device_initialize(&spi->dev);
374 EXPORT_SYMBOL_GPL(spi_alloc_device);
376 static void spi_dev_set_name(struct spi_device *spi)
378 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
381 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
385 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
389 static int spi_dev_check(struct device *dev, void *data)
391 struct spi_device *spi = to_spi_device(dev);
392 struct spi_device *new_spi = data;
394 if (spi->master == new_spi->master &&
395 spi->chip_select == new_spi->chip_select)
401 * spi_add_device - Add spi_device allocated with spi_alloc_device
402 * @spi: spi_device to register
404 * Companion function to spi_alloc_device. Devices allocated with
405 * spi_alloc_device can be added onto the spi bus with this function.
407 * Returns 0 on success; negative errno on failure
409 int spi_add_device(struct spi_device *spi)
411 static DEFINE_MUTEX(spi_add_lock);
412 struct spi_master *master = spi->master;
413 struct device *dev = master->dev.parent;
416 /* Chipselects are numbered 0..max; validate. */
417 if (spi->chip_select >= master->num_chipselect) {
418 dev_err(dev, "cs%d >= max %d\n",
420 master->num_chipselect);
424 /* Set the bus ID string */
425 spi_dev_set_name(spi);
427 /* We need to make sure there's no other device with this
428 * chipselect **BEFORE** we call setup(), else we'll trash
429 * its configuration. Lock against concurrent add() calls.
431 mutex_lock(&spi_add_lock);
433 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
435 dev_err(dev, "chipselect %d already in use\n",
440 if (master->cs_gpios)
441 spi->cs_gpio = master->cs_gpios[spi->chip_select];
443 /* Drivers may modify this initial i/o setup, but will
444 * normally rely on the device being setup. Devices
445 * using SPI_CS_HIGH can't coexist well otherwise...
447 status = spi_setup(spi);
449 dev_err(dev, "can't setup %s, status %d\n",
450 dev_name(&spi->dev), status);
454 /* Device may be bound to an active driver when this returns */
455 status = device_add(&spi->dev);
457 dev_err(dev, "can't add %s, status %d\n",
458 dev_name(&spi->dev), status);
460 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
463 mutex_unlock(&spi_add_lock);
466 EXPORT_SYMBOL_GPL(spi_add_device);
469 * spi_new_device - instantiate one new SPI device
470 * @master: Controller to which device is connected
471 * @chip: Describes the SPI device
474 * On typical mainboards, this is purely internal; and it's not needed
475 * after board init creates the hard-wired devices. Some development
476 * platforms may not be able to use spi_register_board_info though, and
477 * this is exported so that for example a USB or parport based adapter
478 * driver could add devices (which it would learn about out-of-band).
480 * Returns the new device, or NULL.
482 struct spi_device *spi_new_device(struct spi_master *master,
483 struct spi_board_info *chip)
485 struct spi_device *proxy;
488 /* NOTE: caller did any chip->bus_num checks necessary.
490 * Also, unless we change the return value convention to use
491 * error-or-pointer (not NULL-or-pointer), troubleshootability
492 * suggests syslogged diagnostics are best here (ugh).
495 proxy = spi_alloc_device(master);
499 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
501 proxy->chip_select = chip->chip_select;
502 proxy->max_speed_hz = chip->max_speed_hz;
503 proxy->mode = chip->mode;
504 proxy->irq = chip->irq;
505 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
506 proxy->dev.platform_data = (void *) chip->platform_data;
507 proxy->controller_data = chip->controller_data;
508 proxy->controller_state = NULL;
510 status = spi_add_device(proxy);
518 EXPORT_SYMBOL_GPL(spi_new_device);
520 static void spi_match_master_to_boardinfo(struct spi_master *master,
521 struct spi_board_info *bi)
523 struct spi_device *dev;
525 if (master->bus_num != bi->bus_num)
528 dev = spi_new_device(master, bi);
530 dev_err(master->dev.parent, "can't create new device for %s\n",
535 * spi_register_board_info - register SPI devices for a given board
536 * @info: array of chip descriptors
537 * @n: how many descriptors are provided
540 * Board-specific early init code calls this (probably during arch_initcall)
541 * with segments of the SPI device table. Any device nodes are created later,
542 * after the relevant parent SPI controller (bus_num) is defined. We keep
543 * this table of devices forever, so that reloading a controller driver will
544 * not make Linux forget about these hard-wired devices.
546 * Other code can also call this, e.g. a particular add-on board might provide
547 * SPI devices through its expansion connector, so code initializing that board
548 * would naturally declare its SPI devices.
550 * The board info passed can safely be __initdata ... but be careful of
551 * any embedded pointers (platform_data, etc), they're copied as-is.
553 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
555 struct boardinfo *bi;
561 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
565 for (i = 0; i < n; i++, bi++, info++) {
566 struct spi_master *master;
568 memcpy(&bi->board_info, info, sizeof(*info));
569 mutex_lock(&board_lock);
570 list_add_tail(&bi->list, &board_list);
571 list_for_each_entry(master, &spi_master_list, list)
572 spi_match_master_to_boardinfo(master, &bi->board_info);
573 mutex_unlock(&board_lock);
579 /*-------------------------------------------------------------------------*/
581 static void spi_set_cs(struct spi_device *spi, bool enable)
583 if (spi->mode & SPI_CS_HIGH)
586 if (spi->cs_gpio >= 0)
587 gpio_set_value(spi->cs_gpio, !enable);
588 else if (spi->master->set_cs)
589 spi->master->set_cs(spi, !enable);
592 #ifdef CONFIG_HAS_DMA
593 static int spi_map_buf(struct spi_master *master, struct device *dev,
594 struct sg_table *sgt, void *buf, size_t len,
595 enum dma_data_direction dir)
597 const bool vmalloced_buf = is_vmalloc_addr(buf);
598 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
599 const int sgs = DIV_ROUND_UP(len, desc_len);
600 struct page *vm_page;
605 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
609 for (i = 0; i < sgs; i++) {
610 min = min_t(size_t, len, desc_len);
613 vm_page = vmalloc_to_page(buf);
618 sg_set_page(&sgt->sgl[i], vm_page,
619 min, offset_in_page(buf));
622 sg_set_buf(&sgt->sgl[i], sg_buf, min);
630 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
643 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
644 struct sg_table *sgt, enum dma_data_direction dir)
646 if (sgt->orig_nents) {
647 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
652 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
654 struct device *tx_dev, *rx_dev;
655 struct spi_transfer *xfer;
658 if (!master->can_dma)
661 tx_dev = master->dma_tx->device->dev;
662 rx_dev = master->dma_rx->device->dev;
664 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
665 if (!master->can_dma(master, msg->spi, xfer))
668 if (xfer->tx_buf != NULL) {
669 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
670 (void *)xfer->tx_buf, xfer->len,
676 if (xfer->rx_buf != NULL) {
677 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
678 xfer->rx_buf, xfer->len,
681 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
688 master->cur_msg_mapped = true;
693 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
695 struct spi_transfer *xfer;
696 struct device *tx_dev, *rx_dev;
698 if (!master->cur_msg_mapped || !master->can_dma)
701 tx_dev = master->dma_tx->device->dev;
702 rx_dev = master->dma_rx->device->dev;
704 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
705 if (!master->can_dma(master, msg->spi, xfer))
708 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
709 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
714 #else /* !CONFIG_HAS_DMA */
715 static inline int __spi_map_msg(struct spi_master *master,
716 struct spi_message *msg)
721 static inline int spi_unmap_msg(struct spi_master *master,
722 struct spi_message *msg)
726 #endif /* !CONFIG_HAS_DMA */
728 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
730 struct spi_transfer *xfer;
732 unsigned int max_tx, max_rx;
734 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
738 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
739 if ((master->flags & SPI_MASTER_MUST_TX) &&
741 max_tx = max(xfer->len, max_tx);
742 if ((master->flags & SPI_MASTER_MUST_RX) &&
744 max_rx = max(xfer->len, max_rx);
748 tmp = krealloc(master->dummy_tx, max_tx,
749 GFP_KERNEL | GFP_DMA);
752 master->dummy_tx = tmp;
753 memset(tmp, 0, max_tx);
757 tmp = krealloc(master->dummy_rx, max_rx,
758 GFP_KERNEL | GFP_DMA);
761 master->dummy_rx = tmp;
764 if (max_tx || max_rx) {
765 list_for_each_entry(xfer, &msg->transfers,
768 xfer->tx_buf = master->dummy_tx;
770 xfer->rx_buf = master->dummy_rx;
775 return __spi_map_msg(master, msg);
779 * spi_transfer_one_message - Default implementation of transfer_one_message()
781 * This is a standard implementation of transfer_one_message() for
782 * drivers which impelment a transfer_one() operation. It provides
783 * standard handling of delays and chip select management.
785 static int spi_transfer_one_message(struct spi_master *master,
786 struct spi_message *msg)
788 struct spi_transfer *xfer;
789 bool keep_cs = false;
793 spi_set_cs(msg->spi, true);
795 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
796 trace_spi_transfer_start(msg, xfer);
798 if (xfer->tx_buf || xfer->rx_buf) {
799 reinit_completion(&master->xfer_completion);
801 ret = master->transfer_one(master, msg->spi, xfer);
803 dev_err(&msg->spi->dev,
804 "SPI transfer failed: %d\n", ret);
810 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
811 ms += ms + 100; /* some tolerance */
813 ms = wait_for_completion_timeout(&master->xfer_completion,
814 msecs_to_jiffies(ms));
818 dev_err(&msg->spi->dev,
819 "SPI transfer timed out\n");
820 msg->status = -ETIMEDOUT;
824 dev_err(&msg->spi->dev,
825 "Bufferless transfer has length %u\n",
829 trace_spi_transfer_stop(msg, xfer);
831 if (msg->status != -EINPROGRESS)
834 if (xfer->delay_usecs)
835 udelay(xfer->delay_usecs);
837 if (xfer->cs_change) {
838 if (list_is_last(&xfer->transfer_list,
842 spi_set_cs(msg->spi, false);
844 spi_set_cs(msg->spi, true);
848 msg->actual_length += xfer->len;
852 if (ret != 0 || !keep_cs)
853 spi_set_cs(msg->spi, false);
855 if (msg->status == -EINPROGRESS)
858 spi_finalize_current_message(master);
864 * spi_finalize_current_transfer - report completion of a transfer
865 * @master: the master reporting completion
867 * Called by SPI drivers using the core transfer_one_message()
868 * implementation to notify it that the current interrupt driven
869 * transfer has finished and the next one may be scheduled.
871 void spi_finalize_current_transfer(struct spi_master *master)
873 complete(&master->xfer_completion);
875 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
878 * spi_pump_messages - kthread work function which processes spi message queue
879 * @work: pointer to kthread work struct contained in the master struct
881 * This function checks if there is any spi message in the queue that
882 * needs processing and if so call out to the driver to initialize hardware
883 * and transfer each message.
886 static void spi_pump_messages(struct kthread_work *work)
888 struct spi_master *master =
889 container_of(work, struct spi_master, pump_messages);
891 bool was_busy = false;
894 /* Lock queue and check for queue work */
895 spin_lock_irqsave(&master->queue_lock, flags);
896 if (list_empty(&master->queue) || !master->running) {
898 spin_unlock_irqrestore(&master->queue_lock, flags);
901 master->busy = false;
902 spin_unlock_irqrestore(&master->queue_lock, flags);
903 kfree(master->dummy_rx);
904 master->dummy_rx = NULL;
905 kfree(master->dummy_tx);
906 master->dummy_tx = NULL;
907 if (master->unprepare_transfer_hardware &&
908 master->unprepare_transfer_hardware(master))
909 dev_err(&master->dev,
910 "failed to unprepare transfer hardware\n");
911 if (master->auto_runtime_pm) {
912 pm_runtime_mark_last_busy(master->dev.parent);
913 pm_runtime_put_autosuspend(master->dev.parent);
915 trace_spi_master_idle(master);
919 /* Make sure we are not already running a message */
920 if (master->cur_msg) {
921 spin_unlock_irqrestore(&master->queue_lock, flags);
924 /* Extract head of queue */
926 list_first_entry(&master->queue, struct spi_message, queue);
928 list_del_init(&master->cur_msg->queue);
933 spin_unlock_irqrestore(&master->queue_lock, flags);
935 if (!was_busy && master->auto_runtime_pm) {
936 ret = pm_runtime_get_sync(master->dev.parent);
938 dev_err(&master->dev, "Failed to power device: %d\n",
945 trace_spi_master_busy(master);
947 if (!was_busy && master->prepare_transfer_hardware) {
948 ret = master->prepare_transfer_hardware(master);
950 dev_err(&master->dev,
951 "failed to prepare transfer hardware\n");
953 if (master->auto_runtime_pm)
954 pm_runtime_put(master->dev.parent);
959 trace_spi_message_start(master->cur_msg);
961 if (master->prepare_message) {
962 ret = master->prepare_message(master, master->cur_msg);
964 dev_err(&master->dev,
965 "failed to prepare message: %d\n", ret);
966 master->cur_msg->status = ret;
967 spi_finalize_current_message(master);
970 master->cur_msg_prepared = true;
973 ret = spi_map_msg(master, master->cur_msg);
975 master->cur_msg->status = ret;
976 spi_finalize_current_message(master);
980 ret = master->transfer_one_message(master, master->cur_msg);
982 dev_err(&master->dev,
983 "failed to transfer one message from queue\n");
988 static int spi_init_queue(struct spi_master *master)
990 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
992 INIT_LIST_HEAD(&master->queue);
993 spin_lock_init(&master->queue_lock);
995 master->running = false;
996 master->busy = false;
998 init_kthread_worker(&master->kworker);
999 master->kworker_task = kthread_run(kthread_worker_fn,
1000 &master->kworker, "%s",
1001 dev_name(&master->dev));
1002 if (IS_ERR(master->kworker_task)) {
1003 dev_err(&master->dev, "failed to create message pump task\n");
1006 init_kthread_work(&master->pump_messages, spi_pump_messages);
1009 * Master config will indicate if this controller should run the
1010 * message pump with high (realtime) priority to reduce the transfer
1011 * latency on the bus by minimising the delay between a transfer
1012 * request and the scheduling of the message pump thread. Without this
1013 * setting the message pump thread will remain at default priority.
1016 dev_info(&master->dev,
1017 "will run message pump with realtime priority\n");
1018 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1025 * spi_get_next_queued_message() - called by driver to check for queued
1027 * @master: the master to check for queued messages
1029 * If there are more messages in the queue, the next message is returned from
1032 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1034 struct spi_message *next;
1035 unsigned long flags;
1037 /* get a pointer to the next message, if any */
1038 spin_lock_irqsave(&master->queue_lock, flags);
1039 next = list_first_entry_or_null(&master->queue, struct spi_message,
1041 spin_unlock_irqrestore(&master->queue_lock, flags);
1045 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1048 * spi_finalize_current_message() - the current message is complete
1049 * @master: the master to return the message to
1051 * Called by the driver to notify the core that the message in the front of the
1052 * queue is complete and can be removed from the queue.
1054 void spi_finalize_current_message(struct spi_master *master)
1056 struct spi_message *mesg;
1057 unsigned long flags;
1060 spin_lock_irqsave(&master->queue_lock, flags);
1061 mesg = master->cur_msg;
1062 spin_unlock_irqrestore(&master->queue_lock, flags);
1064 spi_unmap_msg(master, mesg);
1066 if (master->cur_msg_prepared && master->unprepare_message) {
1067 ret = master->unprepare_message(master, mesg);
1069 dev_err(&master->dev,
1070 "failed to unprepare message: %d\n", ret);
1074 spin_lock_irqsave(&master->queue_lock, flags);
1075 master->cur_msg = NULL;
1076 master->cur_msg_prepared = false;
1077 queue_kthread_work(&master->kworker, &master->pump_messages);
1078 spin_unlock_irqrestore(&master->queue_lock, flags);
1080 trace_spi_message_done(mesg);
1084 mesg->complete(mesg->context);
1086 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1088 static int spi_start_queue(struct spi_master *master)
1090 unsigned long flags;
1092 spin_lock_irqsave(&master->queue_lock, flags);
1094 if (master->running || master->busy) {
1095 spin_unlock_irqrestore(&master->queue_lock, flags);
1099 master->running = true;
1100 master->cur_msg = NULL;
1101 spin_unlock_irqrestore(&master->queue_lock, flags);
1103 queue_kthread_work(&master->kworker, &master->pump_messages);
1108 static int spi_stop_queue(struct spi_master *master)
1110 unsigned long flags;
1111 unsigned limit = 500;
1114 spin_lock_irqsave(&master->queue_lock, flags);
1117 * This is a bit lame, but is optimized for the common execution path.
1118 * A wait_queue on the master->busy could be used, but then the common
1119 * execution path (pump_messages) would be required to call wake_up or
1120 * friends on every SPI message. Do this instead.
1122 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1123 spin_unlock_irqrestore(&master->queue_lock, flags);
1124 usleep_range(10000, 11000);
1125 spin_lock_irqsave(&master->queue_lock, flags);
1128 if (!list_empty(&master->queue) || master->busy)
1131 master->running = false;
1133 spin_unlock_irqrestore(&master->queue_lock, flags);
1136 dev_warn(&master->dev,
1137 "could not stop message queue\n");
1143 static int spi_destroy_queue(struct spi_master *master)
1147 ret = spi_stop_queue(master);
1150 * flush_kthread_worker will block until all work is done.
1151 * If the reason that stop_queue timed out is that the work will never
1152 * finish, then it does no good to call flush/stop thread, so
1156 dev_err(&master->dev, "problem destroying queue\n");
1160 flush_kthread_worker(&master->kworker);
1161 kthread_stop(master->kworker_task);
1167 * spi_queued_transfer - transfer function for queued transfers
1168 * @spi: spi device which is requesting transfer
1169 * @msg: spi message which is to handled is queued to driver queue
1171 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1173 struct spi_master *master = spi->master;
1174 unsigned long flags;
1176 spin_lock_irqsave(&master->queue_lock, flags);
1178 if (!master->running) {
1179 spin_unlock_irqrestore(&master->queue_lock, flags);
1182 msg->actual_length = 0;
1183 msg->status = -EINPROGRESS;
1185 list_add_tail(&msg->queue, &master->queue);
1187 queue_kthread_work(&master->kworker, &master->pump_messages);
1189 spin_unlock_irqrestore(&master->queue_lock, flags);
1193 static int spi_master_initialize_queue(struct spi_master *master)
1197 master->transfer = spi_queued_transfer;
1198 if (!master->transfer_one_message)
1199 master->transfer_one_message = spi_transfer_one_message;
1201 /* Initialize and start queue */
1202 ret = spi_init_queue(master);
1204 dev_err(&master->dev, "problem initializing queue\n");
1205 goto err_init_queue;
1207 master->queued = true;
1208 ret = spi_start_queue(master);
1210 dev_err(&master->dev, "problem starting queue\n");
1211 goto err_start_queue;
1217 spi_destroy_queue(master);
1222 /*-------------------------------------------------------------------------*/
1224 #if defined(CONFIG_OF)
1226 * of_register_spi_devices() - Register child devices onto the SPI bus
1227 * @master: Pointer to spi_master device
1229 * Registers an spi_device for each child node of master node which has a 'reg'
1232 static void of_register_spi_devices(struct spi_master *master)
1234 struct spi_device *spi;
1235 struct device_node *nc;
1239 if (!master->dev.of_node)
1242 for_each_available_child_of_node(master->dev.of_node, nc) {
1243 /* Alloc an spi_device */
1244 spi = spi_alloc_device(master);
1246 dev_err(&master->dev, "spi_device alloc error for %s\n",
1252 /* Select device driver */
1253 if (of_modalias_node(nc, spi->modalias,
1254 sizeof(spi->modalias)) < 0) {
1255 dev_err(&master->dev, "cannot find modalias for %s\n",
1261 /* Device address */
1262 rc = of_property_read_u32(nc, "reg", &value);
1264 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1269 spi->chip_select = value;
1271 /* Mode (clock phase/polarity/etc.) */
1272 if (of_find_property(nc, "spi-cpha", NULL))
1273 spi->mode |= SPI_CPHA;
1274 if (of_find_property(nc, "spi-cpol", NULL))
1275 spi->mode |= SPI_CPOL;
1276 if (of_find_property(nc, "spi-cs-high", NULL))
1277 spi->mode |= SPI_CS_HIGH;
1278 if (of_find_property(nc, "spi-3wire", NULL))
1279 spi->mode |= SPI_3WIRE;
1280 if (of_find_property(nc, "spi-lsb-first", NULL))
1281 spi->mode |= SPI_LSB_FIRST;
1283 /* Device DUAL/QUAD mode */
1284 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1289 spi->mode |= SPI_TX_DUAL;
1292 spi->mode |= SPI_TX_QUAD;
1295 dev_warn(&master->dev,
1296 "spi-tx-bus-width %d not supported\n",
1302 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1307 spi->mode |= SPI_RX_DUAL;
1310 spi->mode |= SPI_RX_QUAD;
1313 dev_warn(&master->dev,
1314 "spi-rx-bus-width %d not supported\n",
1321 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1323 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1328 spi->max_speed_hz = value;
1331 spi->irq = irq_of_parse_and_map(nc, 0);
1333 /* Store a pointer to the node in the device structure */
1335 spi->dev.of_node = nc;
1337 /* Register the new device */
1338 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1339 rc = spi_add_device(spi);
1341 dev_err(&master->dev, "spi_device register error %s\n",
1349 static void of_register_spi_devices(struct spi_master *master) { }
1353 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1355 struct spi_device *spi = data;
1357 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1358 struct acpi_resource_spi_serialbus *sb;
1360 sb = &ares->data.spi_serial_bus;
1361 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1362 spi->chip_select = sb->device_selection;
1363 spi->max_speed_hz = sb->connection_speed;
1365 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1366 spi->mode |= SPI_CPHA;
1367 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1368 spi->mode |= SPI_CPOL;
1369 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1370 spi->mode |= SPI_CS_HIGH;
1372 } else if (spi->irq < 0) {
1375 if (acpi_dev_resource_interrupt(ares, 0, &r))
1379 /* Always tell the ACPI core to skip this resource */
1383 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1384 void *data, void **return_value)
1386 struct spi_master *master = data;
1387 struct list_head resource_list;
1388 struct acpi_device *adev;
1389 struct spi_device *spi;
1392 if (acpi_bus_get_device(handle, &adev))
1394 if (acpi_bus_get_status(adev) || !adev->status.present)
1397 spi = spi_alloc_device(master);
1399 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1400 dev_name(&adev->dev));
1401 return AE_NO_MEMORY;
1404 ACPI_COMPANION_SET(&spi->dev, adev);
1407 INIT_LIST_HEAD(&resource_list);
1408 ret = acpi_dev_get_resources(adev, &resource_list,
1409 acpi_spi_add_resource, spi);
1410 acpi_dev_free_resource_list(&resource_list);
1412 if (ret < 0 || !spi->max_speed_hz) {
1417 adev->power.flags.ignore_parent = true;
1418 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1419 if (spi_add_device(spi)) {
1420 adev->power.flags.ignore_parent = false;
1421 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1422 dev_name(&adev->dev));
1429 static void acpi_register_spi_devices(struct spi_master *master)
1434 handle = ACPI_HANDLE(master->dev.parent);
1438 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1439 acpi_spi_add_device, NULL,
1441 if (ACPI_FAILURE(status))
1442 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1445 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1446 #endif /* CONFIG_ACPI */
1448 static void spi_master_release(struct device *dev)
1450 struct spi_master *master;
1452 master = container_of(dev, struct spi_master, dev);
1456 static struct class spi_master_class = {
1457 .name = "spi_master",
1458 .owner = THIS_MODULE,
1459 .dev_release = spi_master_release,
1465 * spi_alloc_master - allocate SPI master controller
1466 * @dev: the controller, possibly using the platform_bus
1467 * @size: how much zeroed driver-private data to allocate; the pointer to this
1468 * memory is in the driver_data field of the returned device,
1469 * accessible with spi_master_get_devdata().
1470 * Context: can sleep
1472 * This call is used only by SPI master controller drivers, which are the
1473 * only ones directly touching chip registers. It's how they allocate
1474 * an spi_master structure, prior to calling spi_register_master().
1476 * This must be called from context that can sleep. It returns the SPI
1477 * master structure on success, else NULL.
1479 * The caller is responsible for assigning the bus number and initializing
1480 * the master's methods before calling spi_register_master(); and (after errors
1481 * adding the device) calling spi_master_put() to prevent a memory leak.
1483 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1485 struct spi_master *master;
1490 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1494 device_initialize(&master->dev);
1495 master->bus_num = -1;
1496 master->num_chipselect = 1;
1497 master->dev.class = &spi_master_class;
1498 master->dev.parent = get_device(dev);
1499 spi_master_set_devdata(master, &master[1]);
1503 EXPORT_SYMBOL_GPL(spi_alloc_master);
1506 static int of_spi_register_master(struct spi_master *master)
1509 struct device_node *np = master->dev.of_node;
1514 nb = of_gpio_named_count(np, "cs-gpios");
1515 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1517 /* Return error only for an incorrectly formed cs-gpios property */
1518 if (nb == 0 || nb == -ENOENT)
1523 cs = devm_kzalloc(&master->dev,
1524 sizeof(int) * master->num_chipselect,
1526 master->cs_gpios = cs;
1528 if (!master->cs_gpios)
1531 for (i = 0; i < master->num_chipselect; i++)
1534 for (i = 0; i < nb; i++)
1535 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1540 static int of_spi_register_master(struct spi_master *master)
1547 * spi_register_master - register SPI master controller
1548 * @master: initialized master, originally from spi_alloc_master()
1549 * Context: can sleep
1551 * SPI master controllers connect to their drivers using some non-SPI bus,
1552 * such as the platform bus. The final stage of probe() in that code
1553 * includes calling spi_register_master() to hook up to this SPI bus glue.
1555 * SPI controllers use board specific (often SOC specific) bus numbers,
1556 * and board-specific addressing for SPI devices combines those numbers
1557 * with chip select numbers. Since SPI does not directly support dynamic
1558 * device identification, boards need configuration tables telling which
1559 * chip is at which address.
1561 * This must be called from context that can sleep. It returns zero on
1562 * success, else a negative error code (dropping the master's refcount).
1563 * After a successful return, the caller is responsible for calling
1564 * spi_unregister_master().
1566 int spi_register_master(struct spi_master *master)
1568 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1569 struct device *dev = master->dev.parent;
1570 struct boardinfo *bi;
1571 int status = -ENODEV;
1577 status = of_spi_register_master(master);
1581 /* even if it's just one always-selected device, there must
1582 * be at least one chipselect
1584 if (master->num_chipselect == 0)
1587 if ((master->bus_num < 0) && master->dev.of_node)
1588 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1590 /* convention: dynamically assigned bus IDs count down from the max */
1591 if (master->bus_num < 0) {
1592 /* FIXME switch to an IDR based scheme, something like
1593 * I2C now uses, so we can't run out of "dynamic" IDs
1595 master->bus_num = atomic_dec_return(&dyn_bus_id);
1599 spin_lock_init(&master->bus_lock_spinlock);
1600 mutex_init(&master->bus_lock_mutex);
1601 master->bus_lock_flag = 0;
1602 init_completion(&master->xfer_completion);
1603 if (!master->max_dma_len)
1604 master->max_dma_len = INT_MAX;
1606 /* register the device, then userspace will see it.
1607 * registration fails if the bus ID is in use.
1609 dev_set_name(&master->dev, "spi%u", master->bus_num);
1610 status = device_add(&master->dev);
1613 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1614 dynamic ? " (dynamic)" : "");
1616 /* If we're using a queued driver, start the queue */
1617 if (master->transfer)
1618 dev_info(dev, "master is unqueued, this is deprecated\n");
1620 status = spi_master_initialize_queue(master);
1622 device_del(&master->dev);
1627 mutex_lock(&board_lock);
1628 list_add_tail(&master->list, &spi_master_list);
1629 list_for_each_entry(bi, &board_list, list)
1630 spi_match_master_to_boardinfo(master, &bi->board_info);
1631 mutex_unlock(&board_lock);
1633 /* Register devices from the device tree and ACPI */
1634 of_register_spi_devices(master);
1635 acpi_register_spi_devices(master);
1639 EXPORT_SYMBOL_GPL(spi_register_master);
1641 static void devm_spi_unregister(struct device *dev, void *res)
1643 spi_unregister_master(*(struct spi_master **)res);
1647 * dev_spi_register_master - register managed SPI master controller
1648 * @dev: device managing SPI master
1649 * @master: initialized master, originally from spi_alloc_master()
1650 * Context: can sleep
1652 * Register a SPI device as with spi_register_master() which will
1653 * automatically be unregister
1655 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1657 struct spi_master **ptr;
1660 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1664 ret = spi_register_master(master);
1667 devres_add(dev, ptr);
1674 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1676 static int __unregister(struct device *dev, void *null)
1678 spi_unregister_device(to_spi_device(dev));
1683 * spi_unregister_master - unregister SPI master controller
1684 * @master: the master being unregistered
1685 * Context: can sleep
1687 * This call is used only by SPI master controller drivers, which are the
1688 * only ones directly touching chip registers.
1690 * This must be called from context that can sleep.
1692 void spi_unregister_master(struct spi_master *master)
1696 if (master->queued) {
1697 if (spi_destroy_queue(master))
1698 dev_err(&master->dev, "queue remove failed\n");
1701 mutex_lock(&board_lock);
1702 list_del(&master->list);
1703 mutex_unlock(&board_lock);
1705 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1706 device_unregister(&master->dev);
1708 EXPORT_SYMBOL_GPL(spi_unregister_master);
1710 int spi_master_suspend(struct spi_master *master)
1714 /* Basically no-ops for non-queued masters */
1715 if (!master->queued)
1718 ret = spi_stop_queue(master);
1720 dev_err(&master->dev, "queue stop failed\n");
1724 EXPORT_SYMBOL_GPL(spi_master_suspend);
1726 int spi_master_resume(struct spi_master *master)
1730 if (!master->queued)
1733 ret = spi_start_queue(master);
1735 dev_err(&master->dev, "queue restart failed\n");
1739 EXPORT_SYMBOL_GPL(spi_master_resume);
1741 static int __spi_master_match(struct device *dev, const void *data)
1743 struct spi_master *m;
1744 const u16 *bus_num = data;
1746 m = container_of(dev, struct spi_master, dev);
1747 return m->bus_num == *bus_num;
1751 * spi_busnum_to_master - look up master associated with bus_num
1752 * @bus_num: the master's bus number
1753 * Context: can sleep
1755 * This call may be used with devices that are registered after
1756 * arch init time. It returns a refcounted pointer to the relevant
1757 * spi_master (which the caller must release), or NULL if there is
1758 * no such master registered.
1760 struct spi_master *spi_busnum_to_master(u16 bus_num)
1763 struct spi_master *master = NULL;
1765 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1766 __spi_master_match);
1768 master = container_of(dev, struct spi_master, dev);
1769 /* reference got in class_find_device */
1772 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1775 /*-------------------------------------------------------------------------*/
1777 /* Core methods for SPI master protocol drivers. Some of the
1778 * other core methods are currently defined as inline functions.
1782 * spi_setup - setup SPI mode and clock rate
1783 * @spi: the device whose settings are being modified
1784 * Context: can sleep, and no requests are queued to the device
1786 * SPI protocol drivers may need to update the transfer mode if the
1787 * device doesn't work with its default. They may likewise need
1788 * to update clock rates or word sizes from initial values. This function
1789 * changes those settings, and must be called from a context that can sleep.
1790 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1791 * effect the next time the device is selected and data is transferred to
1792 * or from it. When this function returns, the spi device is deselected.
1794 * Note that this call will fail if the protocol driver specifies an option
1795 * that the underlying controller or its driver does not support. For
1796 * example, not all hardware supports wire transfers using nine bit words,
1797 * LSB-first wire encoding, or active-high chipselects.
1799 int spi_setup(struct spi_device *spi)
1801 unsigned bad_bits, ugly_bits;
1804 /* check mode to prevent that DUAL and QUAD set at the same time
1806 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1807 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1809 "setup: can not select dual and quad at the same time\n");
1812 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1814 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1815 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1817 /* help drivers fail *cleanly* when they need options
1818 * that aren't supported with their current master
1820 bad_bits = spi->mode & ~spi->master->mode_bits;
1821 ugly_bits = bad_bits &
1822 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1825 "setup: ignoring unsupported mode bits %x\n",
1827 spi->mode &= ~ugly_bits;
1828 bad_bits &= ~ugly_bits;
1831 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1836 if (!spi->bits_per_word)
1837 spi->bits_per_word = 8;
1839 if (!spi->max_speed_hz)
1840 spi->max_speed_hz = spi->master->max_speed_hz;
1842 if (spi->master->setup)
1843 status = spi->master->setup(spi);
1845 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1846 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1847 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1848 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1849 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1850 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1851 spi->bits_per_word, spi->max_speed_hz,
1856 EXPORT_SYMBOL_GPL(spi_setup);
1858 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1860 struct spi_master *master = spi->master;
1861 struct spi_transfer *xfer;
1864 if (list_empty(&message->transfers))
1867 /* Half-duplex links include original MicroWire, and ones with
1868 * only one data pin like SPI_3WIRE (switches direction) or where
1869 * either MOSI or MISO is missing. They can also be caused by
1870 * software limitations.
1872 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1873 || (spi->mode & SPI_3WIRE)) {
1874 unsigned flags = master->flags;
1876 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1877 if (xfer->rx_buf && xfer->tx_buf)
1879 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1881 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1887 * Set transfer bits_per_word and max speed as spi device default if
1888 * it is not set for this transfer.
1889 * Set transfer tx_nbits and rx_nbits as single transfer default
1890 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1892 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1893 message->frame_length += xfer->len;
1894 if (!xfer->bits_per_word)
1895 xfer->bits_per_word = spi->bits_per_word;
1897 if (!xfer->speed_hz)
1898 xfer->speed_hz = spi->max_speed_hz;
1900 if (master->max_speed_hz &&
1901 xfer->speed_hz > master->max_speed_hz)
1902 xfer->speed_hz = master->max_speed_hz;
1904 if (master->bits_per_word_mask) {
1905 /* Only 32 bits fit in the mask */
1906 if (xfer->bits_per_word > 32)
1908 if (!(master->bits_per_word_mask &
1909 BIT(xfer->bits_per_word - 1)))
1914 * SPI transfer length should be multiple of SPI word size
1915 * where SPI word size should be power-of-two multiple
1917 if (xfer->bits_per_word <= 8)
1919 else if (xfer->bits_per_word <= 16)
1924 /* No partial transfers accepted */
1925 if (xfer->len % w_size)
1928 if (xfer->speed_hz && master->min_speed_hz &&
1929 xfer->speed_hz < master->min_speed_hz)
1932 if (xfer->tx_buf && !xfer->tx_nbits)
1933 xfer->tx_nbits = SPI_NBITS_SINGLE;
1934 if (xfer->rx_buf && !xfer->rx_nbits)
1935 xfer->rx_nbits = SPI_NBITS_SINGLE;
1936 /* check transfer tx/rx_nbits:
1937 * 1. check the value matches one of single, dual and quad
1938 * 2. check tx/rx_nbits match the mode in spi_device
1941 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1942 xfer->tx_nbits != SPI_NBITS_DUAL &&
1943 xfer->tx_nbits != SPI_NBITS_QUAD)
1945 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1946 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1948 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1949 !(spi->mode & SPI_TX_QUAD))
1952 /* check transfer rx_nbits */
1954 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1955 xfer->rx_nbits != SPI_NBITS_DUAL &&
1956 xfer->rx_nbits != SPI_NBITS_QUAD)
1958 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1959 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1961 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1962 !(spi->mode & SPI_RX_QUAD))
1967 message->status = -EINPROGRESS;
1972 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1974 struct spi_master *master = spi->master;
1978 trace_spi_message_submit(message);
1980 return master->transfer(spi, message);
1984 * spi_async - asynchronous SPI transfer
1985 * @spi: device with which data will be exchanged
1986 * @message: describes the data transfers, including completion callback
1987 * Context: any (irqs may be blocked, etc)
1989 * This call may be used in_irq and other contexts which can't sleep,
1990 * as well as from task contexts which can sleep.
1992 * The completion callback is invoked in a context which can't sleep.
1993 * Before that invocation, the value of message->status is undefined.
1994 * When the callback is issued, message->status holds either zero (to
1995 * indicate complete success) or a negative error code. After that
1996 * callback returns, the driver which issued the transfer request may
1997 * deallocate the associated memory; it's no longer in use by any SPI
1998 * core or controller driver code.
2000 * Note that although all messages to a spi_device are handled in
2001 * FIFO order, messages may go to different devices in other orders.
2002 * Some device might be higher priority, or have various "hard" access
2003 * time requirements, for example.
2005 * On detection of any fault during the transfer, processing of
2006 * the entire message is aborted, and the device is deselected.
2007 * Until returning from the associated message completion callback,
2008 * no other spi_message queued to that device will be processed.
2009 * (This rule applies equally to all the synchronous transfer calls,
2010 * which are wrappers around this core asynchronous primitive.)
2012 int spi_async(struct spi_device *spi, struct spi_message *message)
2014 struct spi_master *master = spi->master;
2016 unsigned long flags;
2018 ret = __spi_validate(spi, message);
2022 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2024 if (master->bus_lock_flag)
2027 ret = __spi_async(spi, message);
2029 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2033 EXPORT_SYMBOL_GPL(spi_async);
2036 * spi_async_locked - version of spi_async with exclusive bus usage
2037 * @spi: device with which data will be exchanged
2038 * @message: describes the data transfers, including completion callback
2039 * Context: any (irqs may be blocked, etc)
2041 * This call may be used in_irq and other contexts which can't sleep,
2042 * as well as from task contexts which can sleep.
2044 * The completion callback is invoked in a context which can't sleep.
2045 * Before that invocation, the value of message->status is undefined.
2046 * When the callback is issued, message->status holds either zero (to
2047 * indicate complete success) or a negative error code. After that
2048 * callback returns, the driver which issued the transfer request may
2049 * deallocate the associated memory; it's no longer in use by any SPI
2050 * core or controller driver code.
2052 * Note that although all messages to a spi_device are handled in
2053 * FIFO order, messages may go to different devices in other orders.
2054 * Some device might be higher priority, or have various "hard" access
2055 * time requirements, for example.
2057 * On detection of any fault during the transfer, processing of
2058 * the entire message is aborted, and the device is deselected.
2059 * Until returning from the associated message completion callback,
2060 * no other spi_message queued to that device will be processed.
2061 * (This rule applies equally to all the synchronous transfer calls,
2062 * which are wrappers around this core asynchronous primitive.)
2064 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2066 struct spi_master *master = spi->master;
2068 unsigned long flags;
2070 ret = __spi_validate(spi, message);
2074 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2076 ret = __spi_async(spi, message);
2078 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2083 EXPORT_SYMBOL_GPL(spi_async_locked);
2086 /*-------------------------------------------------------------------------*/
2088 /* Utility methods for SPI master protocol drivers, layered on
2089 * top of the core. Some other utility methods are defined as
2093 static void spi_complete(void *arg)
2098 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2101 DECLARE_COMPLETION_ONSTACK(done);
2103 struct spi_master *master = spi->master;
2105 message->complete = spi_complete;
2106 message->context = &done;
2109 mutex_lock(&master->bus_lock_mutex);
2111 status = spi_async_locked(spi, message);
2114 mutex_unlock(&master->bus_lock_mutex);
2117 wait_for_completion(&done);
2118 status = message->status;
2120 message->context = NULL;
2125 * spi_sync - blocking/synchronous SPI data transfers
2126 * @spi: device with which data will be exchanged
2127 * @message: describes the data transfers
2128 * Context: can sleep
2130 * This call may only be used from a context that may sleep. The sleep
2131 * is non-interruptible, and has no timeout. Low-overhead controller
2132 * drivers may DMA directly into and out of the message buffers.
2134 * Note that the SPI device's chip select is active during the message,
2135 * and then is normally disabled between messages. Drivers for some
2136 * frequently-used devices may want to minimize costs of selecting a chip,
2137 * by leaving it selected in anticipation that the next message will go
2138 * to the same chip. (That may increase power usage.)
2140 * Also, the caller is guaranteeing that the memory associated with the
2141 * message will not be freed before this call returns.
2143 * It returns zero on success, else a negative error code.
2145 int spi_sync(struct spi_device *spi, struct spi_message *message)
2147 return __spi_sync(spi, message, 0);
2149 EXPORT_SYMBOL_GPL(spi_sync);
2152 * spi_sync_locked - version of spi_sync with exclusive bus usage
2153 * @spi: device with which data will be exchanged
2154 * @message: describes the data transfers
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. Low-overhead controller
2159 * drivers may DMA directly into and out of the message buffers.
2161 * This call should be used by drivers that require exclusive access to the
2162 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2163 * be released by a spi_bus_unlock call when the exclusive access is over.
2165 * It returns zero on success, else a negative error code.
2167 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2169 return __spi_sync(spi, message, 1);
2171 EXPORT_SYMBOL_GPL(spi_sync_locked);
2174 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2175 * @master: SPI bus master that should be locked for exclusive bus access
2176 * Context: can sleep
2178 * This call may only be used from a context that may sleep. The sleep
2179 * is non-interruptible, and has no timeout.
2181 * This call should be used by drivers that require exclusive access to the
2182 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2183 * exclusive access is over. Data transfer must be done by spi_sync_locked
2184 * and spi_async_locked calls when the SPI bus lock is held.
2186 * It returns zero on success, else a negative error code.
2188 int spi_bus_lock(struct spi_master *master)
2190 unsigned long flags;
2192 mutex_lock(&master->bus_lock_mutex);
2194 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2195 master->bus_lock_flag = 1;
2196 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2198 /* mutex remains locked until spi_bus_unlock is called */
2202 EXPORT_SYMBOL_GPL(spi_bus_lock);
2205 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2206 * @master: SPI bus master that was locked for exclusive bus access
2207 * Context: can sleep
2209 * This call may only be used from a context that may sleep. The sleep
2210 * is non-interruptible, and has no timeout.
2212 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2215 * It returns zero on success, else a negative error code.
2217 int spi_bus_unlock(struct spi_master *master)
2219 master->bus_lock_flag = 0;
2221 mutex_unlock(&master->bus_lock_mutex);
2225 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2227 /* portable code must never pass more than 32 bytes */
2228 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2233 * spi_write_then_read - SPI synchronous write followed by read
2234 * @spi: device with which data will be exchanged
2235 * @txbuf: data to be written (need not be dma-safe)
2236 * @n_tx: size of txbuf, in bytes
2237 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2238 * @n_rx: size of rxbuf, in bytes
2239 * Context: can sleep
2241 * This performs a half duplex MicroWire style transaction with the
2242 * device, sending txbuf and then reading rxbuf. The return value
2243 * is zero for success, else a negative errno status code.
2244 * This call may only be used from a context that may sleep.
2246 * Parameters to this routine are always copied using a small buffer;
2247 * portable code should never use this for more than 32 bytes.
2248 * Performance-sensitive or bulk transfer code should instead use
2249 * spi_{async,sync}() calls with dma-safe buffers.
2251 int spi_write_then_read(struct spi_device *spi,
2252 const void *txbuf, unsigned n_tx,
2253 void *rxbuf, unsigned n_rx)
2255 static DEFINE_MUTEX(lock);
2258 struct spi_message message;
2259 struct spi_transfer x[2];
2262 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2263 * copying here, (as a pure convenience thing), but we can
2264 * keep heap costs out of the hot path unless someone else is
2265 * using the pre-allocated buffer or the transfer is too large.
2267 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2268 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2269 GFP_KERNEL | GFP_DMA);
2276 spi_message_init(&message);
2277 memset(x, 0, sizeof(x));
2280 spi_message_add_tail(&x[0], &message);
2284 spi_message_add_tail(&x[1], &message);
2287 memcpy(local_buf, txbuf, n_tx);
2288 x[0].tx_buf = local_buf;
2289 x[1].rx_buf = local_buf + n_tx;
2292 status = spi_sync(spi, &message);
2294 memcpy(rxbuf, x[1].rx_buf, n_rx);
2296 if (x[0].tx_buf == buf)
2297 mutex_unlock(&lock);
2303 EXPORT_SYMBOL_GPL(spi_write_then_read);
2305 /*-------------------------------------------------------------------------*/
2307 static int __init spi_init(void)
2311 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2317 status = bus_register(&spi_bus_type);
2321 status = class_register(&spi_master_class);
2327 bus_unregister(&spi_bus_type);
2335 /* board_info is normally registered in arch_initcall(),
2336 * but even essential drivers wait till later
2338 * REVISIT only boardinfo really needs static linking. the rest (device and
2339 * driver registration) _could_ be dynamically linked (modular) ... costs
2340 * include needing to have boardinfo data structures be much more public.
2342 postcore_initcall(spi_init);