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/export.h>
39 #include <linux/sched/rt.h>
40 #include <linux/delay.h>
41 #include <linux/kthread.h>
42 #include <linux/ioport.h>
43 #include <linux/acpi.h>
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/spi.h>
48 static void spidev_release(struct device *dev)
50 struct spi_device *spi = to_spi_device(dev);
52 /* spi masters may cleanup for released devices */
53 if (spi->master->cleanup)
54 spi->master->cleanup(spi);
56 spi_master_put(spi->master);
61 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
63 const struct spi_device *spi = to_spi_device(dev);
66 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
70 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
72 static DEVICE_ATTR_RO(modalias);
74 static struct attribute *spi_dev_attrs[] = {
75 &dev_attr_modalias.attr,
78 ATTRIBUTE_GROUPS(spi_dev);
80 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
81 * and the sysfs version makes coldplug work too.
84 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
85 const struct spi_device *sdev)
88 if (!strcmp(sdev->modalias, id->name))
95 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
97 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
99 return spi_match_id(sdrv->id_table, sdev);
101 EXPORT_SYMBOL_GPL(spi_get_device_id);
103 static int spi_match_device(struct device *dev, struct device_driver *drv)
105 const struct spi_device *spi = to_spi_device(dev);
106 const struct spi_driver *sdrv = to_spi_driver(drv);
108 /* Attempt an OF style match */
109 if (of_driver_match_device(dev, drv))
113 if (acpi_driver_match_device(dev, drv))
117 return !!spi_match_id(sdrv->id_table, spi);
119 return strcmp(spi->modalias, drv->name) == 0;
122 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
124 const struct spi_device *spi = to_spi_device(dev);
127 rc = acpi_device_uevent_modalias(dev, env);
131 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
135 #ifdef CONFIG_PM_SLEEP
136 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
139 struct spi_driver *drv = to_spi_driver(dev->driver);
141 /* suspend will stop irqs and dma; no more i/o */
144 value = drv->suspend(to_spi_device(dev), message);
146 dev_dbg(dev, "... can't suspend\n");
151 static int spi_legacy_resume(struct device *dev)
154 struct spi_driver *drv = to_spi_driver(dev->driver);
156 /* resume may restart the i/o queue */
159 value = drv->resume(to_spi_device(dev));
161 dev_dbg(dev, "... can't resume\n");
166 static int spi_pm_suspend(struct device *dev)
168 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
171 return pm_generic_suspend(dev);
173 return spi_legacy_suspend(dev, PMSG_SUSPEND);
176 static int spi_pm_resume(struct device *dev)
178 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
181 return pm_generic_resume(dev);
183 return spi_legacy_resume(dev);
186 static int spi_pm_freeze(struct device *dev)
188 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
191 return pm_generic_freeze(dev);
193 return spi_legacy_suspend(dev, PMSG_FREEZE);
196 static int spi_pm_thaw(struct device *dev)
198 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
201 return pm_generic_thaw(dev);
203 return spi_legacy_resume(dev);
206 static int spi_pm_poweroff(struct device *dev)
208 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
211 return pm_generic_poweroff(dev);
213 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
216 static int spi_pm_restore(struct device *dev)
218 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
221 return pm_generic_restore(dev);
223 return spi_legacy_resume(dev);
226 #define spi_pm_suspend NULL
227 #define spi_pm_resume NULL
228 #define spi_pm_freeze NULL
229 #define spi_pm_thaw NULL
230 #define spi_pm_poweroff NULL
231 #define spi_pm_restore NULL
234 static const struct dev_pm_ops spi_pm = {
235 .suspend = spi_pm_suspend,
236 .resume = spi_pm_resume,
237 .freeze = spi_pm_freeze,
239 .poweroff = spi_pm_poweroff,
240 .restore = spi_pm_restore,
242 pm_generic_runtime_suspend,
243 pm_generic_runtime_resume,
248 struct bus_type spi_bus_type = {
250 .dev_groups = spi_dev_groups,
251 .match = spi_match_device,
252 .uevent = spi_uevent,
255 EXPORT_SYMBOL_GPL(spi_bus_type);
258 static int spi_drv_probe(struct device *dev)
260 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
263 ret = of_clk_set_defaults(dev->of_node, false);
267 acpi_dev_pm_attach(dev, true);
268 ret = sdrv->probe(to_spi_device(dev));
270 acpi_dev_pm_detach(dev, true);
275 static int spi_drv_remove(struct device *dev)
277 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
280 ret = sdrv->remove(to_spi_device(dev));
281 acpi_dev_pm_detach(dev, true);
286 static void spi_drv_shutdown(struct device *dev)
288 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
290 sdrv->shutdown(to_spi_device(dev));
294 * spi_register_driver - register a SPI driver
295 * @sdrv: the driver to register
298 int spi_register_driver(struct spi_driver *sdrv)
300 sdrv->driver.bus = &spi_bus_type;
302 sdrv->driver.probe = spi_drv_probe;
304 sdrv->driver.remove = spi_drv_remove;
306 sdrv->driver.shutdown = spi_drv_shutdown;
307 return driver_register(&sdrv->driver);
309 EXPORT_SYMBOL_GPL(spi_register_driver);
311 /*-------------------------------------------------------------------------*/
313 /* SPI devices should normally not be created by SPI device drivers; that
314 * would make them board-specific. Similarly with SPI master drivers.
315 * Device registration normally goes into like arch/.../mach.../board-YYY.c
316 * with other readonly (flashable) information about mainboard devices.
320 struct list_head list;
321 struct spi_board_info board_info;
324 static LIST_HEAD(board_list);
325 static LIST_HEAD(spi_master_list);
328 * Used to protect add/del opertion for board_info list and
329 * spi_master list, and their matching process
331 static DEFINE_MUTEX(board_lock);
334 * spi_alloc_device - Allocate a new SPI device
335 * @master: Controller to which device is connected
338 * Allows a driver to allocate and initialize a spi_device without
339 * registering it immediately. This allows a driver to directly
340 * fill the spi_device with device parameters before calling
341 * spi_add_device() on it.
343 * Caller is responsible to call spi_add_device() on the returned
344 * spi_device structure to add it to the SPI master. If the caller
345 * needs to discard the spi_device without adding it, then it should
346 * call spi_dev_put() on it.
348 * Returns a pointer to the new device, or NULL.
350 struct spi_device *spi_alloc_device(struct spi_master *master)
352 struct spi_device *spi;
354 if (!spi_master_get(master))
357 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
359 spi_master_put(master);
363 spi->master = master;
364 spi->dev.parent = &master->dev;
365 spi->dev.bus = &spi_bus_type;
366 spi->dev.release = spidev_release;
367 spi->cs_gpio = -ENOENT;
368 device_initialize(&spi->dev);
371 EXPORT_SYMBOL_GPL(spi_alloc_device);
373 static void spi_dev_set_name(struct spi_device *spi)
375 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
378 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
382 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
386 static int spi_dev_check(struct device *dev, void *data)
388 struct spi_device *spi = to_spi_device(dev);
389 struct spi_device *new_spi = data;
391 if (spi->master == new_spi->master &&
392 spi->chip_select == new_spi->chip_select)
398 * spi_add_device - Add spi_device allocated with spi_alloc_device
399 * @spi: spi_device to register
401 * Companion function to spi_alloc_device. Devices allocated with
402 * spi_alloc_device can be added onto the spi bus with this function.
404 * Returns 0 on success; negative errno on failure
406 int spi_add_device(struct spi_device *spi)
408 static DEFINE_MUTEX(spi_add_lock);
409 struct spi_master *master = spi->master;
410 struct device *dev = master->dev.parent;
413 /* Chipselects are numbered 0..max; validate. */
414 if (spi->chip_select >= master->num_chipselect) {
415 dev_err(dev, "cs%d >= max %d\n",
417 master->num_chipselect);
421 /* Set the bus ID string */
422 spi_dev_set_name(spi);
424 /* We need to make sure there's no other device with this
425 * chipselect **BEFORE** we call setup(), else we'll trash
426 * its configuration. Lock against concurrent add() calls.
428 mutex_lock(&spi_add_lock);
430 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
432 dev_err(dev, "chipselect %d already in use\n",
437 if (master->cs_gpios)
438 spi->cs_gpio = master->cs_gpios[spi->chip_select];
440 /* Drivers may modify this initial i/o setup, but will
441 * normally rely on the device being setup. Devices
442 * using SPI_CS_HIGH can't coexist well otherwise...
444 status = spi_setup(spi);
446 dev_err(dev, "can't setup %s, status %d\n",
447 dev_name(&spi->dev), status);
451 /* Device may be bound to an active driver when this returns */
452 status = device_add(&spi->dev);
454 dev_err(dev, "can't add %s, status %d\n",
455 dev_name(&spi->dev), status);
457 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
460 mutex_unlock(&spi_add_lock);
463 EXPORT_SYMBOL_GPL(spi_add_device);
466 * spi_new_device - instantiate one new SPI device
467 * @master: Controller to which device is connected
468 * @chip: Describes the SPI device
471 * On typical mainboards, this is purely internal; and it's not needed
472 * after board init creates the hard-wired devices. Some development
473 * platforms may not be able to use spi_register_board_info though, and
474 * this is exported so that for example a USB or parport based adapter
475 * driver could add devices (which it would learn about out-of-band).
477 * Returns the new device, or NULL.
479 struct spi_device *spi_new_device(struct spi_master *master,
480 struct spi_board_info *chip)
482 struct spi_device *proxy;
485 /* NOTE: caller did any chip->bus_num checks necessary.
487 * Also, unless we change the return value convention to use
488 * error-or-pointer (not NULL-or-pointer), troubleshootability
489 * suggests syslogged diagnostics are best here (ugh).
492 proxy = spi_alloc_device(master);
496 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
498 proxy->chip_select = chip->chip_select;
499 proxy->max_speed_hz = chip->max_speed_hz;
500 proxy->mode = chip->mode;
501 proxy->irq = chip->irq;
502 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
503 proxy->dev.platform_data = (void *) chip->platform_data;
504 proxy->controller_data = chip->controller_data;
505 proxy->controller_state = NULL;
507 status = spi_add_device(proxy);
515 EXPORT_SYMBOL_GPL(spi_new_device);
517 static void spi_match_master_to_boardinfo(struct spi_master *master,
518 struct spi_board_info *bi)
520 struct spi_device *dev;
522 if (master->bus_num != bi->bus_num)
525 dev = spi_new_device(master, bi);
527 dev_err(master->dev.parent, "can't create new device for %s\n",
532 * spi_register_board_info - register SPI devices for a given board
533 * @info: array of chip descriptors
534 * @n: how many descriptors are provided
537 * Board-specific early init code calls this (probably during arch_initcall)
538 * with segments of the SPI device table. Any device nodes are created later,
539 * after the relevant parent SPI controller (bus_num) is defined. We keep
540 * this table of devices forever, so that reloading a controller driver will
541 * not make Linux forget about these hard-wired devices.
543 * Other code can also call this, e.g. a particular add-on board might provide
544 * SPI devices through its expansion connector, so code initializing that board
545 * would naturally declare its SPI devices.
547 * The board info passed can safely be __initdata ... but be careful of
548 * any embedded pointers (platform_data, etc), they're copied as-is.
550 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
552 struct boardinfo *bi;
555 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
559 for (i = 0; i < n; i++, bi++, info++) {
560 struct spi_master *master;
562 memcpy(&bi->board_info, info, sizeof(*info));
563 mutex_lock(&board_lock);
564 list_add_tail(&bi->list, &board_list);
565 list_for_each_entry(master, &spi_master_list, list)
566 spi_match_master_to_boardinfo(master, &bi->board_info);
567 mutex_unlock(&board_lock);
573 /*-------------------------------------------------------------------------*/
575 static void spi_set_cs(struct spi_device *spi, bool enable)
577 if (spi->mode & SPI_CS_HIGH)
580 if (spi->cs_gpio >= 0)
581 gpio_set_value(spi->cs_gpio, !enable);
582 else if (spi->master->set_cs)
583 spi->master->set_cs(spi, !enable);
586 #ifdef CONFIG_HAS_DMA
587 static int spi_map_buf(struct spi_master *master, struct device *dev,
588 struct sg_table *sgt, void *buf, size_t len,
589 enum dma_data_direction dir)
591 const bool vmalloced_buf = is_vmalloc_addr(buf);
592 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
593 const int sgs = DIV_ROUND_UP(len, desc_len);
594 struct page *vm_page;
599 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
603 for (i = 0; i < sgs; i++) {
604 min = min_t(size_t, len, desc_len);
607 vm_page = vmalloc_to_page(buf);
612 sg_buf = page_address(vm_page) +
613 ((size_t)buf & ~PAGE_MASK);
618 sg_set_buf(&sgt->sgl[i], sg_buf, min);
624 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
637 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
638 struct sg_table *sgt, enum dma_data_direction dir)
640 if (sgt->orig_nents) {
641 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
646 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
648 struct device *tx_dev, *rx_dev;
649 struct spi_transfer *xfer;
652 if (!master->can_dma)
655 tx_dev = master->dma_tx->device->dev;
656 rx_dev = master->dma_rx->device->dev;
658 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
659 if (!master->can_dma(master, msg->spi, xfer))
662 if (xfer->tx_buf != NULL) {
663 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
664 (void *)xfer->tx_buf, xfer->len,
670 if (xfer->rx_buf != NULL) {
671 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
672 xfer->rx_buf, xfer->len,
675 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
682 master->cur_msg_mapped = true;
687 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
689 struct spi_transfer *xfer;
690 struct device *tx_dev, *rx_dev;
692 if (!master->cur_msg_mapped || !master->can_dma)
695 tx_dev = master->dma_tx->device->dev;
696 rx_dev = master->dma_rx->device->dev;
698 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
699 if (!master->can_dma(master, msg->spi, xfer))
702 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
703 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
708 #else /* !CONFIG_HAS_DMA */
709 static inline int __spi_map_msg(struct spi_master *master,
710 struct spi_message *msg)
715 static inline int spi_unmap_msg(struct spi_master *master,
716 struct spi_message *msg)
720 #endif /* !CONFIG_HAS_DMA */
722 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
724 struct spi_transfer *xfer;
726 unsigned int max_tx, max_rx;
728 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
732 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
733 if ((master->flags & SPI_MASTER_MUST_TX) &&
735 max_tx = max(xfer->len, max_tx);
736 if ((master->flags & SPI_MASTER_MUST_RX) &&
738 max_rx = max(xfer->len, max_rx);
742 tmp = krealloc(master->dummy_tx, max_tx,
743 GFP_KERNEL | GFP_DMA);
746 master->dummy_tx = tmp;
747 memset(tmp, 0, max_tx);
751 tmp = krealloc(master->dummy_rx, max_rx,
752 GFP_KERNEL | GFP_DMA);
755 master->dummy_rx = tmp;
758 if (max_tx || max_rx) {
759 list_for_each_entry(xfer, &msg->transfers,
762 xfer->tx_buf = master->dummy_tx;
764 xfer->rx_buf = master->dummy_rx;
769 return __spi_map_msg(master, msg);
773 * spi_transfer_one_message - Default implementation of transfer_one_message()
775 * This is a standard implementation of transfer_one_message() for
776 * drivers which impelment a transfer_one() operation. It provides
777 * standard handling of delays and chip select management.
779 static int spi_transfer_one_message(struct spi_master *master,
780 struct spi_message *msg)
782 struct spi_transfer *xfer;
783 bool keep_cs = false;
787 spi_set_cs(msg->spi, true);
789 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
790 trace_spi_transfer_start(msg, xfer);
792 reinit_completion(&master->xfer_completion);
794 ret = master->transfer_one(master, msg->spi, xfer);
796 dev_err(&msg->spi->dev,
797 "SPI transfer failed: %d\n", ret);
803 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
804 ms += ms + 100; /* some tolerance */
806 ms = wait_for_completion_timeout(&master->xfer_completion,
807 msecs_to_jiffies(ms));
811 dev_err(&msg->spi->dev, "SPI transfer timed out\n");
812 msg->status = -ETIMEDOUT;
815 trace_spi_transfer_stop(msg, xfer);
817 if (msg->status != -EINPROGRESS)
820 if (xfer->delay_usecs)
821 udelay(xfer->delay_usecs);
823 if (xfer->cs_change) {
824 if (list_is_last(&xfer->transfer_list,
828 spi_set_cs(msg->spi, false);
830 spi_set_cs(msg->spi, true);
834 msg->actual_length += xfer->len;
838 if (ret != 0 || !keep_cs)
839 spi_set_cs(msg->spi, false);
841 if (msg->status == -EINPROGRESS)
844 spi_finalize_current_message(master);
850 * spi_finalize_current_transfer - report completion of a transfer
851 * @master: the master reporting completion
853 * Called by SPI drivers using the core transfer_one_message()
854 * implementation to notify it that the current interrupt driven
855 * transfer has finished and the next one may be scheduled.
857 void spi_finalize_current_transfer(struct spi_master *master)
859 complete(&master->xfer_completion);
861 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
864 * spi_pump_messages - kthread work function which processes spi message queue
865 * @work: pointer to kthread work struct contained in the master struct
867 * This function checks if there is any spi message in the queue that
868 * needs processing and if so call out to the driver to initialize hardware
869 * and transfer each message.
872 static void spi_pump_messages(struct kthread_work *work)
874 struct spi_master *master =
875 container_of(work, struct spi_master, pump_messages);
877 bool was_busy = false;
880 /* Lock queue and check for queue work */
881 spin_lock_irqsave(&master->queue_lock, flags);
882 if (list_empty(&master->queue) || !master->running) {
884 spin_unlock_irqrestore(&master->queue_lock, flags);
887 master->busy = false;
888 spin_unlock_irqrestore(&master->queue_lock, flags);
889 kfree(master->dummy_rx);
890 master->dummy_rx = NULL;
891 kfree(master->dummy_tx);
892 master->dummy_tx = NULL;
893 if (master->unprepare_transfer_hardware &&
894 master->unprepare_transfer_hardware(master))
895 dev_err(&master->dev,
896 "failed to unprepare transfer hardware\n");
897 if (master->auto_runtime_pm) {
898 pm_runtime_mark_last_busy(master->dev.parent);
899 pm_runtime_put_autosuspend(master->dev.parent);
901 trace_spi_master_idle(master);
905 /* Make sure we are not already running a message */
906 if (master->cur_msg) {
907 spin_unlock_irqrestore(&master->queue_lock, flags);
910 /* Extract head of queue */
912 list_first_entry(&master->queue, struct spi_message, queue);
914 list_del_init(&master->cur_msg->queue);
919 spin_unlock_irqrestore(&master->queue_lock, flags);
921 if (!was_busy && master->auto_runtime_pm) {
922 ret = pm_runtime_get_sync(master->dev.parent);
924 dev_err(&master->dev, "Failed to power device: %d\n",
931 trace_spi_master_busy(master);
933 if (!was_busy && master->prepare_transfer_hardware) {
934 ret = master->prepare_transfer_hardware(master);
936 dev_err(&master->dev,
937 "failed to prepare transfer hardware\n");
939 if (master->auto_runtime_pm)
940 pm_runtime_put(master->dev.parent);
945 trace_spi_message_start(master->cur_msg);
947 if (master->prepare_message) {
948 ret = master->prepare_message(master, master->cur_msg);
950 dev_err(&master->dev,
951 "failed to prepare message: %d\n", ret);
952 master->cur_msg->status = ret;
953 spi_finalize_current_message(master);
956 master->cur_msg_prepared = true;
959 ret = spi_map_msg(master, master->cur_msg);
961 master->cur_msg->status = ret;
962 spi_finalize_current_message(master);
966 ret = master->transfer_one_message(master, master->cur_msg);
968 dev_err(&master->dev,
969 "failed to transfer one message from queue\n");
974 static int spi_init_queue(struct spi_master *master)
976 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
978 INIT_LIST_HEAD(&master->queue);
979 spin_lock_init(&master->queue_lock);
981 master->running = false;
982 master->busy = false;
984 init_kthread_worker(&master->kworker);
985 master->kworker_task = kthread_run(kthread_worker_fn,
986 &master->kworker, "%s",
987 dev_name(&master->dev));
988 if (IS_ERR(master->kworker_task)) {
989 dev_err(&master->dev, "failed to create message pump task\n");
992 init_kthread_work(&master->pump_messages, spi_pump_messages);
995 * Master config will indicate if this controller should run the
996 * message pump with high (realtime) priority to reduce the transfer
997 * latency on the bus by minimising the delay between a transfer
998 * request and the scheduling of the message pump thread. Without this
999 * setting the message pump thread will remain at default priority.
1002 dev_info(&master->dev,
1003 "will run message pump with realtime priority\n");
1004 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1011 * spi_get_next_queued_message() - called by driver to check for queued
1013 * @master: the master to check for queued messages
1015 * If there are more messages in the queue, the next message is returned from
1018 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1020 struct spi_message *next;
1021 unsigned long flags;
1023 /* get a pointer to the next message, if any */
1024 spin_lock_irqsave(&master->queue_lock, flags);
1025 next = list_first_entry_or_null(&master->queue, struct spi_message,
1027 spin_unlock_irqrestore(&master->queue_lock, flags);
1031 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1034 * spi_finalize_current_message() - the current message is complete
1035 * @master: the master to return the message to
1037 * Called by the driver to notify the core that the message in the front of the
1038 * queue is complete and can be removed from the queue.
1040 void spi_finalize_current_message(struct spi_master *master)
1042 struct spi_message *mesg;
1043 unsigned long flags;
1046 spin_lock_irqsave(&master->queue_lock, flags);
1047 mesg = master->cur_msg;
1048 master->cur_msg = NULL;
1050 queue_kthread_work(&master->kworker, &master->pump_messages);
1051 spin_unlock_irqrestore(&master->queue_lock, flags);
1053 spi_unmap_msg(master, mesg);
1055 if (master->cur_msg_prepared && master->unprepare_message) {
1056 ret = master->unprepare_message(master, mesg);
1058 dev_err(&master->dev,
1059 "failed to unprepare message: %d\n", ret);
1062 master->cur_msg_prepared = false;
1066 mesg->complete(mesg->context);
1068 trace_spi_message_done(mesg);
1070 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1072 static int spi_start_queue(struct spi_master *master)
1074 unsigned long flags;
1076 spin_lock_irqsave(&master->queue_lock, flags);
1078 if (master->running || master->busy) {
1079 spin_unlock_irqrestore(&master->queue_lock, flags);
1083 master->running = true;
1084 master->cur_msg = NULL;
1085 spin_unlock_irqrestore(&master->queue_lock, flags);
1087 queue_kthread_work(&master->kworker, &master->pump_messages);
1092 static int spi_stop_queue(struct spi_master *master)
1094 unsigned long flags;
1095 unsigned limit = 500;
1098 spin_lock_irqsave(&master->queue_lock, flags);
1101 * This is a bit lame, but is optimized for the common execution path.
1102 * A wait_queue on the master->busy could be used, but then the common
1103 * execution path (pump_messages) would be required to call wake_up or
1104 * friends on every SPI message. Do this instead.
1106 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1107 spin_unlock_irqrestore(&master->queue_lock, flags);
1108 usleep_range(10000, 11000);
1109 spin_lock_irqsave(&master->queue_lock, flags);
1112 if (!list_empty(&master->queue) || master->busy)
1115 master->running = false;
1117 spin_unlock_irqrestore(&master->queue_lock, flags);
1120 dev_warn(&master->dev,
1121 "could not stop message queue\n");
1127 static int spi_destroy_queue(struct spi_master *master)
1131 ret = spi_stop_queue(master);
1134 * flush_kthread_worker will block until all work is done.
1135 * If the reason that stop_queue timed out is that the work will never
1136 * finish, then it does no good to call flush/stop thread, so
1140 dev_err(&master->dev, "problem destroying queue\n");
1144 flush_kthread_worker(&master->kworker);
1145 kthread_stop(master->kworker_task);
1151 * spi_queued_transfer - transfer function for queued transfers
1152 * @spi: spi device which is requesting transfer
1153 * @msg: spi message which is to handled is queued to driver queue
1155 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1157 struct spi_master *master = spi->master;
1158 unsigned long flags;
1160 spin_lock_irqsave(&master->queue_lock, flags);
1162 if (!master->running) {
1163 spin_unlock_irqrestore(&master->queue_lock, flags);
1166 msg->actual_length = 0;
1167 msg->status = -EINPROGRESS;
1169 list_add_tail(&msg->queue, &master->queue);
1171 queue_kthread_work(&master->kworker, &master->pump_messages);
1173 spin_unlock_irqrestore(&master->queue_lock, flags);
1177 static int spi_master_initialize_queue(struct spi_master *master)
1181 master->transfer = spi_queued_transfer;
1182 if (!master->transfer_one_message)
1183 master->transfer_one_message = spi_transfer_one_message;
1185 /* Initialize and start queue */
1186 ret = spi_init_queue(master);
1188 dev_err(&master->dev, "problem initializing queue\n");
1189 goto err_init_queue;
1191 master->queued = true;
1192 ret = spi_start_queue(master);
1194 dev_err(&master->dev, "problem starting queue\n");
1195 goto err_start_queue;
1201 spi_destroy_queue(master);
1206 /*-------------------------------------------------------------------------*/
1208 #if defined(CONFIG_OF)
1210 * of_register_spi_devices() - Register child devices onto the SPI bus
1211 * @master: Pointer to spi_master device
1213 * Registers an spi_device for each child node of master node which has a 'reg'
1216 static void of_register_spi_devices(struct spi_master *master)
1218 struct spi_device *spi;
1219 struct device_node *nc;
1223 if (!master->dev.of_node)
1226 for_each_available_child_of_node(master->dev.of_node, nc) {
1227 /* Alloc an spi_device */
1228 spi = spi_alloc_device(master);
1230 dev_err(&master->dev, "spi_device alloc error for %s\n",
1236 /* Select device driver */
1237 if (of_modalias_node(nc, spi->modalias,
1238 sizeof(spi->modalias)) < 0) {
1239 dev_err(&master->dev, "cannot find modalias for %s\n",
1245 /* Device address */
1246 rc = of_property_read_u32(nc, "reg", &value);
1248 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1253 spi->chip_select = value;
1255 /* Mode (clock phase/polarity/etc.) */
1256 if (of_find_property(nc, "spi-cpha", NULL))
1257 spi->mode |= SPI_CPHA;
1258 if (of_find_property(nc, "spi-cpol", NULL))
1259 spi->mode |= SPI_CPOL;
1260 if (of_find_property(nc, "spi-cs-high", NULL))
1261 spi->mode |= SPI_CS_HIGH;
1262 if (of_find_property(nc, "spi-3wire", NULL))
1263 spi->mode |= SPI_3WIRE;
1264 if (of_find_property(nc, "spi-lsb-first", NULL))
1265 spi->mode |= SPI_LSB_FIRST;
1267 /* Device DUAL/QUAD mode */
1268 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1273 spi->mode |= SPI_TX_DUAL;
1276 spi->mode |= SPI_TX_QUAD;
1279 dev_warn(&master->dev,
1280 "spi-tx-bus-width %d not supported\n",
1286 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1291 spi->mode |= SPI_RX_DUAL;
1294 spi->mode |= SPI_RX_QUAD;
1297 dev_warn(&master->dev,
1298 "spi-rx-bus-width %d not supported\n",
1305 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1307 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1312 spi->max_speed_hz = value;
1315 spi->irq = irq_of_parse_and_map(nc, 0);
1317 /* Store a pointer to the node in the device structure */
1319 spi->dev.of_node = nc;
1321 /* Register the new device */
1322 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1323 rc = spi_add_device(spi);
1325 dev_err(&master->dev, "spi_device register error %s\n",
1333 static void of_register_spi_devices(struct spi_master *master) { }
1337 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1339 struct spi_device *spi = data;
1341 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1342 struct acpi_resource_spi_serialbus *sb;
1344 sb = &ares->data.spi_serial_bus;
1345 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1346 spi->chip_select = sb->device_selection;
1347 spi->max_speed_hz = sb->connection_speed;
1349 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1350 spi->mode |= SPI_CPHA;
1351 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1352 spi->mode |= SPI_CPOL;
1353 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1354 spi->mode |= SPI_CS_HIGH;
1356 } else if (spi->irq < 0) {
1359 if (acpi_dev_resource_interrupt(ares, 0, &r))
1363 /* Always tell the ACPI core to skip this resource */
1367 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1368 void *data, void **return_value)
1370 struct spi_master *master = data;
1371 struct list_head resource_list;
1372 struct acpi_device *adev;
1373 struct spi_device *spi;
1376 if (acpi_bus_get_device(handle, &adev))
1378 if (acpi_bus_get_status(adev) || !adev->status.present)
1381 spi = spi_alloc_device(master);
1383 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1384 dev_name(&adev->dev));
1385 return AE_NO_MEMORY;
1388 ACPI_COMPANION_SET(&spi->dev, adev);
1391 INIT_LIST_HEAD(&resource_list);
1392 ret = acpi_dev_get_resources(adev, &resource_list,
1393 acpi_spi_add_resource, spi);
1394 acpi_dev_free_resource_list(&resource_list);
1396 if (ret < 0 || !spi->max_speed_hz) {
1401 adev->power.flags.ignore_parent = true;
1402 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1403 if (spi_add_device(spi)) {
1404 adev->power.flags.ignore_parent = false;
1405 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1406 dev_name(&adev->dev));
1413 static void acpi_register_spi_devices(struct spi_master *master)
1418 handle = ACPI_HANDLE(master->dev.parent);
1422 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1423 acpi_spi_add_device, NULL,
1425 if (ACPI_FAILURE(status))
1426 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1429 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1430 #endif /* CONFIG_ACPI */
1432 static void spi_master_release(struct device *dev)
1434 struct spi_master *master;
1436 master = container_of(dev, struct spi_master, dev);
1440 static struct class spi_master_class = {
1441 .name = "spi_master",
1442 .owner = THIS_MODULE,
1443 .dev_release = spi_master_release,
1449 * spi_alloc_master - allocate SPI master controller
1450 * @dev: the controller, possibly using the platform_bus
1451 * @size: how much zeroed driver-private data to allocate; the pointer to this
1452 * memory is in the driver_data field of the returned device,
1453 * accessible with spi_master_get_devdata().
1454 * Context: can sleep
1456 * This call is used only by SPI master controller drivers, which are the
1457 * only ones directly touching chip registers. It's how they allocate
1458 * an spi_master structure, prior to calling spi_register_master().
1460 * This must be called from context that can sleep. It returns the SPI
1461 * master structure on success, else NULL.
1463 * The caller is responsible for assigning the bus number and initializing
1464 * the master's methods before calling spi_register_master(); and (after errors
1465 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1468 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1470 struct spi_master *master;
1475 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1479 device_initialize(&master->dev);
1480 master->bus_num = -1;
1481 master->num_chipselect = 1;
1482 master->dev.class = &spi_master_class;
1483 master->dev.parent = get_device(dev);
1484 spi_master_set_devdata(master, &master[1]);
1488 EXPORT_SYMBOL_GPL(spi_alloc_master);
1491 static int of_spi_register_master(struct spi_master *master)
1494 struct device_node *np = master->dev.of_node;
1499 nb = of_gpio_named_count(np, "cs-gpios");
1500 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1502 /* Return error only for an incorrectly formed cs-gpios property */
1503 if (nb == 0 || nb == -ENOENT)
1508 cs = devm_kzalloc(&master->dev,
1509 sizeof(int) * master->num_chipselect,
1511 master->cs_gpios = cs;
1513 if (!master->cs_gpios)
1516 for (i = 0; i < master->num_chipselect; i++)
1519 for (i = 0; i < nb; i++)
1520 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1525 static int of_spi_register_master(struct spi_master *master)
1532 * spi_register_master - register SPI master controller
1533 * @master: initialized master, originally from spi_alloc_master()
1534 * Context: can sleep
1536 * SPI master controllers connect to their drivers using some non-SPI bus,
1537 * such as the platform bus. The final stage of probe() in that code
1538 * includes calling spi_register_master() to hook up to this SPI bus glue.
1540 * SPI controllers use board specific (often SOC specific) bus numbers,
1541 * and board-specific addressing for SPI devices combines those numbers
1542 * with chip select numbers. Since SPI does not directly support dynamic
1543 * device identification, boards need configuration tables telling which
1544 * chip is at which address.
1546 * This must be called from context that can sleep. It returns zero on
1547 * success, else a negative error code (dropping the master's refcount).
1548 * After a successful return, the caller is responsible for calling
1549 * spi_unregister_master().
1551 int spi_register_master(struct spi_master *master)
1553 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1554 struct device *dev = master->dev.parent;
1555 struct boardinfo *bi;
1556 int status = -ENODEV;
1562 status = of_spi_register_master(master);
1566 /* even if it's just one always-selected device, there must
1567 * be at least one chipselect
1569 if (master->num_chipselect == 0)
1572 if ((master->bus_num < 0) && master->dev.of_node)
1573 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1575 /* convention: dynamically assigned bus IDs count down from the max */
1576 if (master->bus_num < 0) {
1577 /* FIXME switch to an IDR based scheme, something like
1578 * I2C now uses, so we can't run out of "dynamic" IDs
1580 master->bus_num = atomic_dec_return(&dyn_bus_id);
1584 spin_lock_init(&master->bus_lock_spinlock);
1585 mutex_init(&master->bus_lock_mutex);
1586 master->bus_lock_flag = 0;
1587 init_completion(&master->xfer_completion);
1588 if (!master->max_dma_len)
1589 master->max_dma_len = INT_MAX;
1591 /* register the device, then userspace will see it.
1592 * registration fails if the bus ID is in use.
1594 dev_set_name(&master->dev, "spi%u", master->bus_num);
1595 status = device_add(&master->dev);
1598 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1599 dynamic ? " (dynamic)" : "");
1601 /* If we're using a queued driver, start the queue */
1602 if (master->transfer)
1603 dev_info(dev, "master is unqueued, this is deprecated\n");
1605 status = spi_master_initialize_queue(master);
1607 device_del(&master->dev);
1612 mutex_lock(&board_lock);
1613 list_add_tail(&master->list, &spi_master_list);
1614 list_for_each_entry(bi, &board_list, list)
1615 spi_match_master_to_boardinfo(master, &bi->board_info);
1616 mutex_unlock(&board_lock);
1618 /* Register devices from the device tree and ACPI */
1619 of_register_spi_devices(master);
1620 acpi_register_spi_devices(master);
1624 EXPORT_SYMBOL_GPL(spi_register_master);
1626 static void devm_spi_unregister(struct device *dev, void *res)
1628 spi_unregister_master(*(struct spi_master **)res);
1632 * dev_spi_register_master - register managed SPI master controller
1633 * @dev: device managing SPI master
1634 * @master: initialized master, originally from spi_alloc_master()
1635 * Context: can sleep
1637 * Register a SPI device as with spi_register_master() which will
1638 * automatically be unregister
1640 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1642 struct spi_master **ptr;
1645 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1649 ret = spi_register_master(master);
1652 devres_add(dev, ptr);
1659 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1661 static int __unregister(struct device *dev, void *null)
1663 spi_unregister_device(to_spi_device(dev));
1668 * spi_unregister_master - unregister SPI master controller
1669 * @master: the master being unregistered
1670 * Context: can sleep
1672 * This call is used only by SPI master controller drivers, which are the
1673 * only ones directly touching chip registers.
1675 * This must be called from context that can sleep.
1677 void spi_unregister_master(struct spi_master *master)
1681 if (master->queued) {
1682 if (spi_destroy_queue(master))
1683 dev_err(&master->dev, "queue remove failed\n");
1686 mutex_lock(&board_lock);
1687 list_del(&master->list);
1688 mutex_unlock(&board_lock);
1690 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1691 device_unregister(&master->dev);
1693 EXPORT_SYMBOL_GPL(spi_unregister_master);
1695 int spi_master_suspend(struct spi_master *master)
1699 /* Basically no-ops for non-queued masters */
1700 if (!master->queued)
1703 ret = spi_stop_queue(master);
1705 dev_err(&master->dev, "queue stop failed\n");
1709 EXPORT_SYMBOL_GPL(spi_master_suspend);
1711 int spi_master_resume(struct spi_master *master)
1715 if (!master->queued)
1718 ret = spi_start_queue(master);
1720 dev_err(&master->dev, "queue restart failed\n");
1724 EXPORT_SYMBOL_GPL(spi_master_resume);
1726 static int __spi_master_match(struct device *dev, const void *data)
1728 struct spi_master *m;
1729 const u16 *bus_num = data;
1731 m = container_of(dev, struct spi_master, dev);
1732 return m->bus_num == *bus_num;
1736 * spi_busnum_to_master - look up master associated with bus_num
1737 * @bus_num: the master's bus number
1738 * Context: can sleep
1740 * This call may be used with devices that are registered after
1741 * arch init time. It returns a refcounted pointer to the relevant
1742 * spi_master (which the caller must release), or NULL if there is
1743 * no such master registered.
1745 struct spi_master *spi_busnum_to_master(u16 bus_num)
1748 struct spi_master *master = NULL;
1750 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1751 __spi_master_match);
1753 master = container_of(dev, struct spi_master, dev);
1754 /* reference got in class_find_device */
1757 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1760 /*-------------------------------------------------------------------------*/
1762 /* Core methods for SPI master protocol drivers. Some of the
1763 * other core methods are currently defined as inline functions.
1767 * spi_setup - setup SPI mode and clock rate
1768 * @spi: the device whose settings are being modified
1769 * Context: can sleep, and no requests are queued to the device
1771 * SPI protocol drivers may need to update the transfer mode if the
1772 * device doesn't work with its default. They may likewise need
1773 * to update clock rates or word sizes from initial values. This function
1774 * changes those settings, and must be called from a context that can sleep.
1775 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1776 * effect the next time the device is selected and data is transferred to
1777 * or from it. When this function returns, the spi device is deselected.
1779 * Note that this call will fail if the protocol driver specifies an option
1780 * that the underlying controller or its driver does not support. For
1781 * example, not all hardware supports wire transfers using nine bit words,
1782 * LSB-first wire encoding, or active-high chipselects.
1784 int spi_setup(struct spi_device *spi)
1786 unsigned bad_bits, ugly_bits;
1789 /* check mode to prevent that DUAL and QUAD set at the same time
1791 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1792 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1794 "setup: can not select dual and quad at the same time\n");
1797 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1799 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1800 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1802 /* help drivers fail *cleanly* when they need options
1803 * that aren't supported with their current master
1805 bad_bits = spi->mode & ~spi->master->mode_bits;
1806 ugly_bits = bad_bits &
1807 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1810 "setup: ignoring unsupported mode bits %x\n",
1812 spi->mode &= ~ugly_bits;
1813 bad_bits &= ~ugly_bits;
1816 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1821 if (!spi->bits_per_word)
1822 spi->bits_per_word = 8;
1824 if (!spi->max_speed_hz)
1825 spi->max_speed_hz = spi->master->max_speed_hz;
1827 if (spi->master->setup)
1828 status = spi->master->setup(spi);
1830 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1831 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1832 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1833 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1834 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1835 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1836 spi->bits_per_word, spi->max_speed_hz,
1841 EXPORT_SYMBOL_GPL(spi_setup);
1843 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1845 struct spi_master *master = spi->master;
1846 struct spi_transfer *xfer;
1849 if (list_empty(&message->transfers))
1852 /* Half-duplex links include original MicroWire, and ones with
1853 * only one data pin like SPI_3WIRE (switches direction) or where
1854 * either MOSI or MISO is missing. They can also be caused by
1855 * software limitations.
1857 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1858 || (spi->mode & SPI_3WIRE)) {
1859 unsigned flags = master->flags;
1861 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1862 if (xfer->rx_buf && xfer->tx_buf)
1864 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1866 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1872 * Set transfer bits_per_word and max speed as spi device default if
1873 * it is not set for this transfer.
1874 * Set transfer tx_nbits and rx_nbits as single transfer default
1875 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1877 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1878 message->frame_length += xfer->len;
1879 if (!xfer->bits_per_word)
1880 xfer->bits_per_word = spi->bits_per_word;
1882 if (!xfer->speed_hz)
1883 xfer->speed_hz = spi->max_speed_hz;
1885 if (master->max_speed_hz &&
1886 xfer->speed_hz > master->max_speed_hz)
1887 xfer->speed_hz = master->max_speed_hz;
1889 if (master->bits_per_word_mask) {
1890 /* Only 32 bits fit in the mask */
1891 if (xfer->bits_per_word > 32)
1893 if (!(master->bits_per_word_mask &
1894 BIT(xfer->bits_per_word - 1)))
1899 * SPI transfer length should be multiple of SPI word size
1900 * where SPI word size should be power-of-two multiple
1902 if (xfer->bits_per_word <= 8)
1904 else if (xfer->bits_per_word <= 16)
1909 /* No partial transfers accepted */
1910 if (xfer->len % w_size)
1913 if (xfer->speed_hz && master->min_speed_hz &&
1914 xfer->speed_hz < master->min_speed_hz)
1917 if (xfer->tx_buf && !xfer->tx_nbits)
1918 xfer->tx_nbits = SPI_NBITS_SINGLE;
1919 if (xfer->rx_buf && !xfer->rx_nbits)
1920 xfer->rx_nbits = SPI_NBITS_SINGLE;
1921 /* check transfer tx/rx_nbits:
1922 * 1. check the value matches one of single, dual and quad
1923 * 2. check tx/rx_nbits match the mode in spi_device
1926 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1927 xfer->tx_nbits != SPI_NBITS_DUAL &&
1928 xfer->tx_nbits != SPI_NBITS_QUAD)
1930 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1931 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1933 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1934 !(spi->mode & SPI_TX_QUAD))
1937 /* check transfer rx_nbits */
1939 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1940 xfer->rx_nbits != SPI_NBITS_DUAL &&
1941 xfer->rx_nbits != SPI_NBITS_QUAD)
1943 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1944 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1946 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1947 !(spi->mode & SPI_RX_QUAD))
1952 message->status = -EINPROGRESS;
1957 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1959 struct spi_master *master = spi->master;
1963 trace_spi_message_submit(message);
1965 return master->transfer(spi, message);
1969 * spi_async - asynchronous SPI transfer
1970 * @spi: device with which data will be exchanged
1971 * @message: describes the data transfers, including completion callback
1972 * Context: any (irqs may be blocked, etc)
1974 * This call may be used in_irq and other contexts which can't sleep,
1975 * as well as from task contexts which can sleep.
1977 * The completion callback is invoked in a context which can't sleep.
1978 * Before that invocation, the value of message->status is undefined.
1979 * When the callback is issued, message->status holds either zero (to
1980 * indicate complete success) or a negative error code. After that
1981 * callback returns, the driver which issued the transfer request may
1982 * deallocate the associated memory; it's no longer in use by any SPI
1983 * core or controller driver code.
1985 * Note that although all messages to a spi_device are handled in
1986 * FIFO order, messages may go to different devices in other orders.
1987 * Some device might be higher priority, or have various "hard" access
1988 * time requirements, for example.
1990 * On detection of any fault during the transfer, processing of
1991 * the entire message is aborted, and the device is deselected.
1992 * Until returning from the associated message completion callback,
1993 * no other spi_message queued to that device will be processed.
1994 * (This rule applies equally to all the synchronous transfer calls,
1995 * which are wrappers around this core asynchronous primitive.)
1997 int spi_async(struct spi_device *spi, struct spi_message *message)
1999 struct spi_master *master = spi->master;
2001 unsigned long flags;
2003 ret = __spi_validate(spi, message);
2007 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2009 if (master->bus_lock_flag)
2012 ret = __spi_async(spi, message);
2014 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2018 EXPORT_SYMBOL_GPL(spi_async);
2021 * spi_async_locked - version of spi_async with exclusive bus usage
2022 * @spi: device with which data will be exchanged
2023 * @message: describes the data transfers, including completion callback
2024 * Context: any (irqs may be blocked, etc)
2026 * This call may be used in_irq and other contexts which can't sleep,
2027 * as well as from task contexts which can sleep.
2029 * The completion callback is invoked in a context which can't sleep.
2030 * Before that invocation, the value of message->status is undefined.
2031 * When the callback is issued, message->status holds either zero (to
2032 * indicate complete success) or a negative error code. After that
2033 * callback returns, the driver which issued the transfer request may
2034 * deallocate the associated memory; it's no longer in use by any SPI
2035 * core or controller driver code.
2037 * Note that although all messages to a spi_device are handled in
2038 * FIFO order, messages may go to different devices in other orders.
2039 * Some device might be higher priority, or have various "hard" access
2040 * time requirements, for example.
2042 * On detection of any fault during the transfer, processing of
2043 * the entire message is aborted, and the device is deselected.
2044 * Until returning from the associated message completion callback,
2045 * no other spi_message queued to that device will be processed.
2046 * (This rule applies equally to all the synchronous transfer calls,
2047 * which are wrappers around this core asynchronous primitive.)
2049 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2051 struct spi_master *master = spi->master;
2053 unsigned long flags;
2055 ret = __spi_validate(spi, message);
2059 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2061 ret = __spi_async(spi, message);
2063 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2068 EXPORT_SYMBOL_GPL(spi_async_locked);
2071 /*-------------------------------------------------------------------------*/
2073 /* Utility methods for SPI master protocol drivers, layered on
2074 * top of the core. Some other utility methods are defined as
2078 static void spi_complete(void *arg)
2083 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2086 DECLARE_COMPLETION_ONSTACK(done);
2088 struct spi_master *master = spi->master;
2090 message->complete = spi_complete;
2091 message->context = &done;
2094 mutex_lock(&master->bus_lock_mutex);
2096 status = spi_async_locked(spi, message);
2099 mutex_unlock(&master->bus_lock_mutex);
2102 wait_for_completion(&done);
2103 status = message->status;
2105 message->context = NULL;
2110 * spi_sync - blocking/synchronous SPI data transfers
2111 * @spi: device with which data will be exchanged
2112 * @message: describes the data transfers
2113 * Context: can sleep
2115 * This call may only be used from a context that may sleep. The sleep
2116 * is non-interruptible, and has no timeout. Low-overhead controller
2117 * drivers may DMA directly into and out of the message buffers.
2119 * Note that the SPI device's chip select is active during the message,
2120 * and then is normally disabled between messages. Drivers for some
2121 * frequently-used devices may want to minimize costs of selecting a chip,
2122 * by leaving it selected in anticipation that the next message will go
2123 * to the same chip. (That may increase power usage.)
2125 * Also, the caller is guaranteeing that the memory associated with the
2126 * message will not be freed before this call returns.
2128 * It returns zero on success, else a negative error code.
2130 int spi_sync(struct spi_device *spi, struct spi_message *message)
2132 return __spi_sync(spi, message, 0);
2134 EXPORT_SYMBOL_GPL(spi_sync);
2137 * spi_sync_locked - version of spi_sync with exclusive bus usage
2138 * @spi: device with which data will be exchanged
2139 * @message: describes the data transfers
2140 * Context: can sleep
2142 * This call may only be used from a context that may sleep. The sleep
2143 * is non-interruptible, and has no timeout. Low-overhead controller
2144 * drivers may DMA directly into and out of the message buffers.
2146 * This call should be used by drivers that require exclusive access to the
2147 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2148 * be released by a spi_bus_unlock call when the exclusive access is over.
2150 * It returns zero on success, else a negative error code.
2152 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2154 return __spi_sync(spi, message, 1);
2156 EXPORT_SYMBOL_GPL(spi_sync_locked);
2159 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2160 * @master: SPI bus master that should be locked for exclusive bus access
2161 * Context: can sleep
2163 * This call may only be used from a context that may sleep. The sleep
2164 * is non-interruptible, and has no timeout.
2166 * This call should be used by drivers that require exclusive access to the
2167 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2168 * exclusive access is over. Data transfer must be done by spi_sync_locked
2169 * and spi_async_locked calls when the SPI bus lock is held.
2171 * It returns zero on success, else a negative error code.
2173 int spi_bus_lock(struct spi_master *master)
2175 unsigned long flags;
2177 mutex_lock(&master->bus_lock_mutex);
2179 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2180 master->bus_lock_flag = 1;
2181 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2183 /* mutex remains locked until spi_bus_unlock is called */
2187 EXPORT_SYMBOL_GPL(spi_bus_lock);
2190 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2191 * @master: SPI bus master that was locked for exclusive bus access
2192 * Context: can sleep
2194 * This call may only be used from a context that may sleep. The sleep
2195 * is non-interruptible, and has no timeout.
2197 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2200 * It returns zero on success, else a negative error code.
2202 int spi_bus_unlock(struct spi_master *master)
2204 master->bus_lock_flag = 0;
2206 mutex_unlock(&master->bus_lock_mutex);
2210 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2212 /* portable code must never pass more than 32 bytes */
2213 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2218 * spi_write_then_read - SPI synchronous write followed by read
2219 * @spi: device with which data will be exchanged
2220 * @txbuf: data to be written (need not be dma-safe)
2221 * @n_tx: size of txbuf, in bytes
2222 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2223 * @n_rx: size of rxbuf, in bytes
2224 * Context: can sleep
2226 * This performs a half duplex MicroWire style transaction with the
2227 * device, sending txbuf and then reading rxbuf. The return value
2228 * is zero for success, else a negative errno status code.
2229 * This call may only be used from a context that may sleep.
2231 * Parameters to this routine are always copied using a small buffer;
2232 * portable code should never use this for more than 32 bytes.
2233 * Performance-sensitive or bulk transfer code should instead use
2234 * spi_{async,sync}() calls with dma-safe buffers.
2236 int spi_write_then_read(struct spi_device *spi,
2237 const void *txbuf, unsigned n_tx,
2238 void *rxbuf, unsigned n_rx)
2240 static DEFINE_MUTEX(lock);
2243 struct spi_message message;
2244 struct spi_transfer x[2];
2247 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2248 * copying here, (as a pure convenience thing), but we can
2249 * keep heap costs out of the hot path unless someone else is
2250 * using the pre-allocated buffer or the transfer is too large.
2252 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2253 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2254 GFP_KERNEL | GFP_DMA);
2261 spi_message_init(&message);
2262 memset(x, 0, sizeof(x));
2265 spi_message_add_tail(&x[0], &message);
2269 spi_message_add_tail(&x[1], &message);
2272 memcpy(local_buf, txbuf, n_tx);
2273 x[0].tx_buf = local_buf;
2274 x[1].rx_buf = local_buf + n_tx;
2277 status = spi_sync(spi, &message);
2279 memcpy(rxbuf, x[1].rx_buf, n_rx);
2281 if (x[0].tx_buf == buf)
2282 mutex_unlock(&lock);
2288 EXPORT_SYMBOL_GPL(spi_write_then_read);
2290 /*-------------------------------------------------------------------------*/
2292 static int __init spi_init(void)
2296 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2302 status = bus_register(&spi_bus_type);
2306 status = class_register(&spi_master_class);
2312 bus_unregister(&spi_bus_type);
2320 /* board_info is normally registered in arch_initcall(),
2321 * but even essential drivers wait till later
2323 * REVISIT only boardinfo really needs static linking. the rest (device and
2324 * driver registration) _could_ be dynamically linked (modular) ... costs
2325 * include needing to have boardinfo data structures be much more public.
2327 postcore_initcall(spi_init);