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.
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
44 static void spidev_release(struct device *dev)
46 struct spi_device *spi = to_spi_device(dev);
48 /* spi masters may cleanup for released devices */
49 if (spi->master->cleanup)
50 spi->master->cleanup(spi);
52 spi_master_put(spi->master);
57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 const struct spi_device *spi = to_spi_device(dev);
62 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 static DEVICE_ATTR_RO(modalias);
70 static struct attribute *spi_dev_attrs[] = {
71 &dev_attr_modalias.attr,
74 ATTRIBUTE_GROUPS(spi_dev);
76 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
77 * and the sysfs version makes coldplug work too.
80 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
81 const struct spi_device *sdev)
84 if (!strcmp(sdev->modalias, id->name))
91 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
93 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
95 return spi_match_id(sdrv->id_table, sdev);
97 EXPORT_SYMBOL_GPL(spi_get_device_id);
99 static int spi_match_device(struct device *dev, struct device_driver *drv)
101 const struct spi_device *spi = to_spi_device(dev);
102 const struct spi_driver *sdrv = to_spi_driver(drv);
104 /* Attempt an OF style match */
105 if (of_driver_match_device(dev, drv))
109 if (acpi_driver_match_device(dev, drv))
113 return !!spi_match_id(sdrv->id_table, spi);
115 return strcmp(spi->modalias, drv->name) == 0;
118 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
120 const struct spi_device *spi = to_spi_device(dev);
123 rc = acpi_device_uevent_modalias(dev, env);
127 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
131 #ifdef CONFIG_PM_SLEEP
132 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
135 struct spi_driver *drv = to_spi_driver(dev->driver);
137 /* suspend will stop irqs and dma; no more i/o */
140 value = drv->suspend(to_spi_device(dev), message);
142 dev_dbg(dev, "... can't suspend\n");
147 static int spi_legacy_resume(struct device *dev)
150 struct spi_driver *drv = to_spi_driver(dev->driver);
152 /* resume may restart the i/o queue */
155 value = drv->resume(to_spi_device(dev));
157 dev_dbg(dev, "... can't resume\n");
162 static int spi_pm_suspend(struct device *dev)
164 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
167 return pm_generic_suspend(dev);
169 return spi_legacy_suspend(dev, PMSG_SUSPEND);
172 static int spi_pm_resume(struct device *dev)
174 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
177 return pm_generic_resume(dev);
179 return spi_legacy_resume(dev);
182 static int spi_pm_freeze(struct device *dev)
184 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
187 return pm_generic_freeze(dev);
189 return spi_legacy_suspend(dev, PMSG_FREEZE);
192 static int spi_pm_thaw(struct device *dev)
194 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
197 return pm_generic_thaw(dev);
199 return spi_legacy_resume(dev);
202 static int spi_pm_poweroff(struct device *dev)
204 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
207 return pm_generic_poweroff(dev);
209 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
212 static int spi_pm_restore(struct device *dev)
214 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
217 return pm_generic_restore(dev);
219 return spi_legacy_resume(dev);
222 #define spi_pm_suspend NULL
223 #define spi_pm_resume NULL
224 #define spi_pm_freeze NULL
225 #define spi_pm_thaw NULL
226 #define spi_pm_poweroff NULL
227 #define spi_pm_restore NULL
230 static const struct dev_pm_ops spi_pm = {
231 .suspend = spi_pm_suspend,
232 .resume = spi_pm_resume,
233 .freeze = spi_pm_freeze,
235 .poweroff = spi_pm_poweroff,
236 .restore = spi_pm_restore,
238 pm_generic_runtime_suspend,
239 pm_generic_runtime_resume,
244 struct bus_type spi_bus_type = {
246 .dev_groups = spi_dev_groups,
247 .match = spi_match_device,
248 .uevent = spi_uevent,
251 EXPORT_SYMBOL_GPL(spi_bus_type);
254 static int spi_drv_probe(struct device *dev)
256 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
259 ret = of_clk_set_defaults(dev->of_node, false);
263 ret = dev_pm_domain_attach(dev, true);
264 if (ret != -EPROBE_DEFER) {
265 ret = sdrv->probe(to_spi_device(dev));
267 dev_pm_domain_detach(dev, true);
273 static int spi_drv_remove(struct device *dev)
275 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
278 ret = sdrv->remove(to_spi_device(dev));
279 dev_pm_domain_detach(dev, true);
284 static void spi_drv_shutdown(struct device *dev)
286 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
288 sdrv->shutdown(to_spi_device(dev));
292 * spi_register_driver - register a SPI driver
293 * @sdrv: the driver to register
296 int spi_register_driver(struct spi_driver *sdrv)
298 sdrv->driver.bus = &spi_bus_type;
300 sdrv->driver.probe = spi_drv_probe;
302 sdrv->driver.remove = spi_drv_remove;
304 sdrv->driver.shutdown = spi_drv_shutdown;
305 return driver_register(&sdrv->driver);
307 EXPORT_SYMBOL_GPL(spi_register_driver);
309 /*-------------------------------------------------------------------------*/
311 /* SPI devices should normally not be created by SPI device drivers; that
312 * would make them board-specific. Similarly with SPI master drivers.
313 * Device registration normally goes into like arch/.../mach.../board-YYY.c
314 * with other readonly (flashable) information about mainboard devices.
318 struct list_head list;
319 struct spi_board_info board_info;
322 static LIST_HEAD(board_list);
323 static LIST_HEAD(spi_master_list);
326 * Used to protect add/del opertion for board_info list and
327 * spi_master list, and their matching process
329 static DEFINE_MUTEX(board_lock);
332 * spi_alloc_device - Allocate a new SPI device
333 * @master: Controller to which device is connected
336 * Allows a driver to allocate and initialize a spi_device without
337 * registering it immediately. This allows a driver to directly
338 * fill the spi_device with device parameters before calling
339 * spi_add_device() on it.
341 * Caller is responsible to call spi_add_device() on the returned
342 * spi_device structure to add it to the SPI master. If the caller
343 * needs to discard the spi_device without adding it, then it should
344 * call spi_dev_put() on it.
346 * Returns a pointer to the new device, or NULL.
348 struct spi_device *spi_alloc_device(struct spi_master *master)
350 struct spi_device *spi;
352 if (!spi_master_get(master))
355 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
357 spi_master_put(master);
361 spi->master = master;
362 spi->dev.parent = &master->dev;
363 spi->dev.bus = &spi_bus_type;
364 spi->dev.release = spidev_release;
365 spi->cs_gpio = -ENOENT;
366 device_initialize(&spi->dev);
369 EXPORT_SYMBOL_GPL(spi_alloc_device);
371 static void spi_dev_set_name(struct spi_device *spi)
373 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
376 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
380 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
384 static int spi_dev_check(struct device *dev, void *data)
386 struct spi_device *spi = to_spi_device(dev);
387 struct spi_device *new_spi = data;
389 if (spi->master == new_spi->master &&
390 spi->chip_select == new_spi->chip_select)
396 * spi_add_device - Add spi_device allocated with spi_alloc_device
397 * @spi: spi_device to register
399 * Companion function to spi_alloc_device. Devices allocated with
400 * spi_alloc_device can be added onto the spi bus with this function.
402 * Returns 0 on success; negative errno on failure
404 int spi_add_device(struct spi_device *spi)
406 static DEFINE_MUTEX(spi_add_lock);
407 struct spi_master *master = spi->master;
408 struct device *dev = master->dev.parent;
411 /* Chipselects are numbered 0..max; validate. */
412 if (spi->chip_select >= master->num_chipselect) {
413 dev_err(dev, "cs%d >= max %d\n",
415 master->num_chipselect);
419 /* Set the bus ID string */
420 spi_dev_set_name(spi);
422 /* We need to make sure there's no other device with this
423 * chipselect **BEFORE** we call setup(), else we'll trash
424 * its configuration. Lock against concurrent add() calls.
426 mutex_lock(&spi_add_lock);
428 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
430 dev_err(dev, "chipselect %d already in use\n",
435 if (master->cs_gpios)
436 spi->cs_gpio = master->cs_gpios[spi->chip_select];
438 /* Drivers may modify this initial i/o setup, but will
439 * normally rely on the device being setup. Devices
440 * using SPI_CS_HIGH can't coexist well otherwise...
442 status = spi_setup(spi);
444 dev_err(dev, "can't setup %s, status %d\n",
445 dev_name(&spi->dev), status);
449 /* Device may be bound to an active driver when this returns */
450 status = device_add(&spi->dev);
452 dev_err(dev, "can't add %s, status %d\n",
453 dev_name(&spi->dev), status);
455 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
458 mutex_unlock(&spi_add_lock);
461 EXPORT_SYMBOL_GPL(spi_add_device);
464 * spi_new_device - instantiate one new SPI device
465 * @master: Controller to which device is connected
466 * @chip: Describes the SPI device
469 * On typical mainboards, this is purely internal; and it's not needed
470 * after board init creates the hard-wired devices. Some development
471 * platforms may not be able to use spi_register_board_info though, and
472 * this is exported so that for example a USB or parport based adapter
473 * driver could add devices (which it would learn about out-of-band).
475 * Returns the new device, or NULL.
477 struct spi_device *spi_new_device(struct spi_master *master,
478 struct spi_board_info *chip)
480 struct spi_device *proxy;
483 /* NOTE: caller did any chip->bus_num checks necessary.
485 * Also, unless we change the return value convention to use
486 * error-or-pointer (not NULL-or-pointer), troubleshootability
487 * suggests syslogged diagnostics are best here (ugh).
490 proxy = spi_alloc_device(master);
494 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
496 proxy->chip_select = chip->chip_select;
497 proxy->max_speed_hz = chip->max_speed_hz;
498 proxy->mode = chip->mode;
499 proxy->irq = chip->irq;
500 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
501 proxy->dev.platform_data = (void *) chip->platform_data;
502 proxy->controller_data = chip->controller_data;
503 proxy->controller_state = NULL;
505 status = spi_add_device(proxy);
513 EXPORT_SYMBOL_GPL(spi_new_device);
515 static void spi_match_master_to_boardinfo(struct spi_master *master,
516 struct spi_board_info *bi)
518 struct spi_device *dev;
520 if (master->bus_num != bi->bus_num)
523 dev = spi_new_device(master, bi);
525 dev_err(master->dev.parent, "can't create new device for %s\n",
530 * spi_register_board_info - register SPI devices for a given board
531 * @info: array of chip descriptors
532 * @n: how many descriptors are provided
535 * Board-specific early init code calls this (probably during arch_initcall)
536 * with segments of the SPI device table. Any device nodes are created later,
537 * after the relevant parent SPI controller (bus_num) is defined. We keep
538 * this table of devices forever, so that reloading a controller driver will
539 * not make Linux forget about these hard-wired devices.
541 * Other code can also call this, e.g. a particular add-on board might provide
542 * SPI devices through its expansion connector, so code initializing that board
543 * would naturally declare its SPI devices.
545 * The board info passed can safely be __initdata ... but be careful of
546 * any embedded pointers (platform_data, etc), they're copied as-is.
548 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
550 struct boardinfo *bi;
556 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
560 for (i = 0; i < n; i++, bi++, info++) {
561 struct spi_master *master;
563 memcpy(&bi->board_info, info, sizeof(*info));
564 mutex_lock(&board_lock);
565 list_add_tail(&bi->list, &board_list);
566 list_for_each_entry(master, &spi_master_list, list)
567 spi_match_master_to_boardinfo(master, &bi->board_info);
568 mutex_unlock(&board_lock);
574 /*-------------------------------------------------------------------------*/
576 static void spi_set_cs(struct spi_device *spi, bool enable)
578 if (spi->mode & SPI_CS_HIGH)
581 if (spi->cs_gpio >= 0)
582 gpio_set_value(spi->cs_gpio, !enable);
583 else if (spi->master->set_cs)
584 spi->master->set_cs(spi, !enable);
587 #ifdef CONFIG_HAS_DMA
588 static int spi_map_buf(struct spi_master *master, struct device *dev,
589 struct sg_table *sgt, void *buf, size_t len,
590 enum dma_data_direction dir)
592 const bool vmalloced_buf = is_vmalloc_addr(buf);
593 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
594 const int sgs = DIV_ROUND_UP(len, desc_len);
595 struct page *vm_page;
600 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
604 for (i = 0; i < sgs; i++) {
605 min = min_t(size_t, len, desc_len);
608 vm_page = vmalloc_to_page(buf);
613 sg_set_page(&sgt->sgl[i], vm_page,
614 min, offset_in_page(buf));
617 sg_set_buf(&sgt->sgl[i], sg_buf, min);
625 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
638 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
639 struct sg_table *sgt, enum dma_data_direction dir)
641 if (sgt->orig_nents) {
642 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
647 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
649 struct device *tx_dev, *rx_dev;
650 struct spi_transfer *xfer;
653 if (!master->can_dma)
656 tx_dev = master->dma_tx->device->dev;
657 rx_dev = master->dma_rx->device->dev;
659 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
660 if (!master->can_dma(master, msg->spi, xfer))
663 if (xfer->tx_buf != NULL) {
664 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
665 (void *)xfer->tx_buf, xfer->len,
671 if (xfer->rx_buf != NULL) {
672 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
673 xfer->rx_buf, xfer->len,
676 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
683 master->cur_msg_mapped = true;
688 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
690 struct spi_transfer *xfer;
691 struct device *tx_dev, *rx_dev;
693 if (!master->cur_msg_mapped || !master->can_dma)
696 tx_dev = master->dma_tx->device->dev;
697 rx_dev = master->dma_rx->device->dev;
699 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
700 if (!master->can_dma(master, msg->spi, xfer))
703 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
704 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
709 #else /* !CONFIG_HAS_DMA */
710 static inline int __spi_map_msg(struct spi_master *master,
711 struct spi_message *msg)
716 static inline int spi_unmap_msg(struct spi_master *master,
717 struct spi_message *msg)
721 #endif /* !CONFIG_HAS_DMA */
723 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
725 struct spi_transfer *xfer;
727 unsigned int max_tx, max_rx;
729 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
733 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
734 if ((master->flags & SPI_MASTER_MUST_TX) &&
736 max_tx = max(xfer->len, max_tx);
737 if ((master->flags & SPI_MASTER_MUST_RX) &&
739 max_rx = max(xfer->len, max_rx);
743 tmp = krealloc(master->dummy_tx, max_tx,
744 GFP_KERNEL | GFP_DMA);
747 master->dummy_tx = tmp;
748 memset(tmp, 0, max_tx);
752 tmp = krealloc(master->dummy_rx, max_rx,
753 GFP_KERNEL | GFP_DMA);
756 master->dummy_rx = tmp;
759 if (max_tx || max_rx) {
760 list_for_each_entry(xfer, &msg->transfers,
763 xfer->tx_buf = master->dummy_tx;
765 xfer->rx_buf = master->dummy_rx;
770 return __spi_map_msg(master, msg);
774 * spi_transfer_one_message - Default implementation of transfer_one_message()
776 * This is a standard implementation of transfer_one_message() for
777 * drivers which impelment a transfer_one() operation. It provides
778 * standard handling of delays and chip select management.
780 static int spi_transfer_one_message(struct spi_master *master,
781 struct spi_message *msg)
783 struct spi_transfer *xfer;
784 bool keep_cs = false;
786 unsigned long ms = 1;
788 spi_set_cs(msg->spi, true);
790 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
791 trace_spi_transfer_start(msg, xfer);
793 if (xfer->tx_buf || xfer->rx_buf) {
794 reinit_completion(&master->xfer_completion);
796 ret = master->transfer_one(master, msg->spi, xfer);
798 dev_err(&msg->spi->dev,
799 "SPI transfer failed: %d\n", ret);
805 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
806 ms += ms + 100; /* some tolerance */
808 ms = wait_for_completion_timeout(&master->xfer_completion,
809 msecs_to_jiffies(ms));
813 dev_err(&msg->spi->dev,
814 "SPI transfer timed out\n");
815 msg->status = -ETIMEDOUT;
819 dev_err(&msg->spi->dev,
820 "Bufferless transfer has length %u\n",
824 trace_spi_transfer_stop(msg, xfer);
826 if (msg->status != -EINPROGRESS)
829 if (xfer->delay_usecs)
830 udelay(xfer->delay_usecs);
832 if (xfer->cs_change) {
833 if (list_is_last(&xfer->transfer_list,
837 spi_set_cs(msg->spi, false);
839 spi_set_cs(msg->spi, true);
843 msg->actual_length += xfer->len;
847 if (ret != 0 || !keep_cs)
848 spi_set_cs(msg->spi, false);
850 if (msg->status == -EINPROGRESS)
853 spi_finalize_current_message(master);
859 * spi_finalize_current_transfer - report completion of a transfer
860 * @master: the master reporting completion
862 * Called by SPI drivers using the core transfer_one_message()
863 * implementation to notify it that the current interrupt driven
864 * transfer has finished and the next one may be scheduled.
866 void spi_finalize_current_transfer(struct spi_master *master)
868 complete(&master->xfer_completion);
870 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
873 * __spi_pump_messages - function which processes spi message queue
874 * @master: master to process queue for
875 * @in_kthread: true if we are in the context of the message pump thread
877 * This function checks if there is any spi message in the queue that
878 * needs processing and if so call out to the driver to initialize hardware
879 * and transfer each message.
881 * Note that it is called both from the kthread itself and also from
882 * inside spi_sync(); the queue extraction handling at the top of the
883 * function should deal with this safely.
885 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
888 bool was_busy = false;
892 spin_lock_irqsave(&master->queue_lock, flags);
894 /* Make sure we are not already running a message */
895 if (master->cur_msg) {
896 spin_unlock_irqrestore(&master->queue_lock, flags);
900 /* If another context is idling the device then defer */
901 if (master->idling) {
902 queue_kthread_work(&master->kworker, &master->pump_messages);
903 spin_unlock_irqrestore(&master->queue_lock, flags);
907 /* Check if the queue is idle */
908 if (list_empty(&master->queue) || !master->running) {
910 spin_unlock_irqrestore(&master->queue_lock, flags);
914 /* Only do teardown in the thread */
916 queue_kthread_work(&master->kworker,
917 &master->pump_messages);
918 spin_unlock_irqrestore(&master->queue_lock, flags);
922 master->busy = false;
923 master->idling = true;
924 spin_unlock_irqrestore(&master->queue_lock, flags);
926 kfree(master->dummy_rx);
927 master->dummy_rx = NULL;
928 kfree(master->dummy_tx);
929 master->dummy_tx = NULL;
930 if (master->unprepare_transfer_hardware &&
931 master->unprepare_transfer_hardware(master))
932 dev_err(&master->dev,
933 "failed to unprepare transfer hardware\n");
934 if (master->auto_runtime_pm) {
935 pm_runtime_mark_last_busy(master->dev.parent);
936 pm_runtime_put_autosuspend(master->dev.parent);
938 trace_spi_master_idle(master);
940 spin_lock_irqsave(&master->queue_lock, flags);
941 master->idling = false;
942 spin_unlock_irqrestore(&master->queue_lock, flags);
946 /* Extract head of queue */
948 list_first_entry(&master->queue, struct spi_message, queue);
950 list_del_init(&master->cur_msg->queue);
955 spin_unlock_irqrestore(&master->queue_lock, flags);
957 if (!was_busy && master->auto_runtime_pm) {
958 ret = pm_runtime_get_sync(master->dev.parent);
960 dev_err(&master->dev, "Failed to power device: %d\n",
967 trace_spi_master_busy(master);
969 if (!was_busy && master->prepare_transfer_hardware) {
970 ret = master->prepare_transfer_hardware(master);
972 dev_err(&master->dev,
973 "failed to prepare transfer hardware\n");
975 if (master->auto_runtime_pm)
976 pm_runtime_put(master->dev.parent);
981 trace_spi_message_start(master->cur_msg);
983 if (master->prepare_message) {
984 ret = master->prepare_message(master, master->cur_msg);
986 dev_err(&master->dev,
987 "failed to prepare message: %d\n", ret);
988 master->cur_msg->status = ret;
989 spi_finalize_current_message(master);
992 master->cur_msg_prepared = true;
995 ret = spi_map_msg(master, master->cur_msg);
997 master->cur_msg->status = ret;
998 spi_finalize_current_message(master);
1002 ret = master->transfer_one_message(master, master->cur_msg);
1004 dev_err(&master->dev,
1005 "failed to transfer one message from queue\n");
1011 * spi_pump_messages - kthread work function which processes spi message queue
1012 * @work: pointer to kthread work struct contained in the master struct
1014 static void spi_pump_messages(struct kthread_work *work)
1016 struct spi_master *master =
1017 container_of(work, struct spi_master, pump_messages);
1019 __spi_pump_messages(master, true);
1022 static int spi_init_queue(struct spi_master *master)
1024 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1026 master->running = false;
1027 master->busy = false;
1029 init_kthread_worker(&master->kworker);
1030 master->kworker_task = kthread_run(kthread_worker_fn,
1031 &master->kworker, "%s",
1032 dev_name(&master->dev));
1033 if (IS_ERR(master->kworker_task)) {
1034 dev_err(&master->dev, "failed to create message pump task\n");
1035 return PTR_ERR(master->kworker_task);
1037 init_kthread_work(&master->pump_messages, spi_pump_messages);
1040 * Master config will indicate if this controller should run the
1041 * message pump with high (realtime) priority to reduce the transfer
1042 * latency on the bus by minimising the delay between a transfer
1043 * request and the scheduling of the message pump thread. Without this
1044 * setting the message pump thread will remain at default priority.
1047 dev_info(&master->dev,
1048 "will run message pump with realtime priority\n");
1049 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1056 * spi_get_next_queued_message() - called by driver to check for queued
1058 * @master: the master to check for queued messages
1060 * If there are more messages in the queue, the next message is returned from
1063 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1065 struct spi_message *next;
1066 unsigned long flags;
1068 /* get a pointer to the next message, if any */
1069 spin_lock_irqsave(&master->queue_lock, flags);
1070 next = list_first_entry_or_null(&master->queue, struct spi_message,
1072 spin_unlock_irqrestore(&master->queue_lock, flags);
1076 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1079 * spi_finalize_current_message() - the current message is complete
1080 * @master: the master to return the message to
1082 * Called by the driver to notify the core that the message in the front of the
1083 * queue is complete and can be removed from the queue.
1085 void spi_finalize_current_message(struct spi_master *master)
1087 struct spi_message *mesg;
1088 unsigned long flags;
1091 spin_lock_irqsave(&master->queue_lock, flags);
1092 mesg = master->cur_msg;
1093 master->cur_msg = NULL;
1095 queue_kthread_work(&master->kworker, &master->pump_messages);
1096 spin_unlock_irqrestore(&master->queue_lock, flags);
1098 spi_unmap_msg(master, mesg);
1100 if (master->cur_msg_prepared && master->unprepare_message) {
1101 ret = master->unprepare_message(master, mesg);
1103 dev_err(&master->dev,
1104 "failed to unprepare message: %d\n", ret);
1108 trace_spi_message_done(mesg);
1110 master->cur_msg_prepared = false;
1114 mesg->complete(mesg->context);
1116 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1118 static int spi_start_queue(struct spi_master *master)
1120 unsigned long flags;
1122 spin_lock_irqsave(&master->queue_lock, flags);
1124 if (master->running || master->busy) {
1125 spin_unlock_irqrestore(&master->queue_lock, flags);
1129 master->running = true;
1130 master->cur_msg = NULL;
1131 spin_unlock_irqrestore(&master->queue_lock, flags);
1133 queue_kthread_work(&master->kworker, &master->pump_messages);
1138 static int spi_stop_queue(struct spi_master *master)
1140 unsigned long flags;
1141 unsigned limit = 500;
1144 spin_lock_irqsave(&master->queue_lock, flags);
1147 * This is a bit lame, but is optimized for the common execution path.
1148 * A wait_queue on the master->busy could be used, but then the common
1149 * execution path (pump_messages) would be required to call wake_up or
1150 * friends on every SPI message. Do this instead.
1152 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1153 spin_unlock_irqrestore(&master->queue_lock, flags);
1154 usleep_range(10000, 11000);
1155 spin_lock_irqsave(&master->queue_lock, flags);
1158 if (!list_empty(&master->queue) || master->busy)
1161 master->running = false;
1163 spin_unlock_irqrestore(&master->queue_lock, flags);
1166 dev_warn(&master->dev,
1167 "could not stop message queue\n");
1173 static int spi_destroy_queue(struct spi_master *master)
1177 ret = spi_stop_queue(master);
1180 * flush_kthread_worker will block until all work is done.
1181 * If the reason that stop_queue timed out is that the work will never
1182 * finish, then it does no good to call flush/stop thread, so
1186 dev_err(&master->dev, "problem destroying queue\n");
1190 flush_kthread_worker(&master->kworker);
1191 kthread_stop(master->kworker_task);
1196 static int __spi_queued_transfer(struct spi_device *spi,
1197 struct spi_message *msg,
1200 struct spi_master *master = spi->master;
1201 unsigned long flags;
1203 spin_lock_irqsave(&master->queue_lock, flags);
1205 if (!master->running) {
1206 spin_unlock_irqrestore(&master->queue_lock, flags);
1209 msg->actual_length = 0;
1210 msg->status = -EINPROGRESS;
1212 list_add_tail(&msg->queue, &master->queue);
1213 if (!master->busy && need_pump)
1214 queue_kthread_work(&master->kworker, &master->pump_messages);
1216 spin_unlock_irqrestore(&master->queue_lock, flags);
1221 * spi_queued_transfer - transfer function for queued transfers
1222 * @spi: spi device which is requesting transfer
1223 * @msg: spi message which is to handled is queued to driver queue
1225 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1227 return __spi_queued_transfer(spi, msg, true);
1230 static int spi_master_initialize_queue(struct spi_master *master)
1234 master->transfer = spi_queued_transfer;
1235 if (!master->transfer_one_message)
1236 master->transfer_one_message = spi_transfer_one_message;
1238 /* Initialize and start queue */
1239 ret = spi_init_queue(master);
1241 dev_err(&master->dev, "problem initializing queue\n");
1242 goto err_init_queue;
1244 master->queued = true;
1245 ret = spi_start_queue(master);
1247 dev_err(&master->dev, "problem starting queue\n");
1248 goto err_start_queue;
1254 spi_destroy_queue(master);
1259 /*-------------------------------------------------------------------------*/
1261 #if defined(CONFIG_OF)
1262 static struct spi_device *
1263 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1265 struct spi_device *spi;
1269 /* Alloc an spi_device */
1270 spi = spi_alloc_device(master);
1272 dev_err(&master->dev, "spi_device alloc error for %s\n",
1278 /* Select device driver */
1279 rc = of_modalias_node(nc, spi->modalias,
1280 sizeof(spi->modalias));
1282 dev_err(&master->dev, "cannot find modalias for %s\n",
1287 /* Device address */
1288 rc = of_property_read_u32(nc, "reg", &value);
1290 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1294 spi->chip_select = value;
1296 /* Mode (clock phase/polarity/etc.) */
1297 if (of_find_property(nc, "spi-cpha", NULL))
1298 spi->mode |= SPI_CPHA;
1299 if (of_find_property(nc, "spi-cpol", NULL))
1300 spi->mode |= SPI_CPOL;
1301 if (of_find_property(nc, "spi-cs-high", NULL))
1302 spi->mode |= SPI_CS_HIGH;
1303 if (of_find_property(nc, "spi-3wire", NULL))
1304 spi->mode |= SPI_3WIRE;
1305 if (of_find_property(nc, "spi-lsb-first", NULL))
1306 spi->mode |= SPI_LSB_FIRST;
1308 /* Device DUAL/QUAD mode */
1309 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1314 spi->mode |= SPI_TX_DUAL;
1317 spi->mode |= SPI_TX_QUAD;
1320 dev_warn(&master->dev,
1321 "spi-tx-bus-width %d not supported\n",
1327 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1332 spi->mode |= SPI_RX_DUAL;
1335 spi->mode |= SPI_RX_QUAD;
1338 dev_warn(&master->dev,
1339 "spi-rx-bus-width %d not supported\n",
1346 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1348 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1352 spi->max_speed_hz = value;
1355 spi->irq = irq_of_parse_and_map(nc, 0);
1357 /* Store a pointer to the node in the device structure */
1359 spi->dev.of_node = nc;
1361 /* Register the new device */
1362 rc = spi_add_device(spi);
1364 dev_err(&master->dev, "spi_device register error %s\n",
1377 * of_register_spi_devices() - Register child devices onto the SPI bus
1378 * @master: Pointer to spi_master device
1380 * Registers an spi_device for each child node of master node which has a 'reg'
1383 static void of_register_spi_devices(struct spi_master *master)
1385 struct spi_device *spi;
1386 struct device_node *nc;
1388 if (!master->dev.of_node)
1391 for_each_available_child_of_node(master->dev.of_node, nc) {
1392 spi = of_register_spi_device(master, nc);
1394 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1399 static void of_register_spi_devices(struct spi_master *master) { }
1403 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1405 struct spi_device *spi = data;
1407 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1408 struct acpi_resource_spi_serialbus *sb;
1410 sb = &ares->data.spi_serial_bus;
1411 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1412 spi->chip_select = sb->device_selection;
1413 spi->max_speed_hz = sb->connection_speed;
1415 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1416 spi->mode |= SPI_CPHA;
1417 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1418 spi->mode |= SPI_CPOL;
1419 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1420 spi->mode |= SPI_CS_HIGH;
1422 } else if (spi->irq < 0) {
1425 if (acpi_dev_resource_interrupt(ares, 0, &r))
1429 /* Always tell the ACPI core to skip this resource */
1433 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1434 void *data, void **return_value)
1436 struct spi_master *master = data;
1437 struct list_head resource_list;
1438 struct acpi_device *adev;
1439 struct spi_device *spi;
1442 if (acpi_bus_get_device(handle, &adev))
1444 if (acpi_bus_get_status(adev) || !adev->status.present)
1447 spi = spi_alloc_device(master);
1449 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1450 dev_name(&adev->dev));
1451 return AE_NO_MEMORY;
1454 ACPI_COMPANION_SET(&spi->dev, adev);
1457 INIT_LIST_HEAD(&resource_list);
1458 ret = acpi_dev_get_resources(adev, &resource_list,
1459 acpi_spi_add_resource, spi);
1460 acpi_dev_free_resource_list(&resource_list);
1462 if (ret < 0 || !spi->max_speed_hz) {
1467 adev->power.flags.ignore_parent = true;
1468 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1469 if (spi_add_device(spi)) {
1470 adev->power.flags.ignore_parent = false;
1471 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1472 dev_name(&adev->dev));
1479 static void acpi_register_spi_devices(struct spi_master *master)
1484 handle = ACPI_HANDLE(master->dev.parent);
1488 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1489 acpi_spi_add_device, NULL,
1491 if (ACPI_FAILURE(status))
1492 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1495 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1496 #endif /* CONFIG_ACPI */
1498 static void spi_master_release(struct device *dev)
1500 struct spi_master *master;
1502 master = container_of(dev, struct spi_master, dev);
1506 static struct class spi_master_class = {
1507 .name = "spi_master",
1508 .owner = THIS_MODULE,
1509 .dev_release = spi_master_release,
1515 * spi_alloc_master - allocate SPI master controller
1516 * @dev: the controller, possibly using the platform_bus
1517 * @size: how much zeroed driver-private data to allocate; the pointer to this
1518 * memory is in the driver_data field of the returned device,
1519 * accessible with spi_master_get_devdata().
1520 * Context: can sleep
1522 * This call is used only by SPI master controller drivers, which are the
1523 * only ones directly touching chip registers. It's how they allocate
1524 * an spi_master structure, prior to calling spi_register_master().
1526 * This must be called from context that can sleep. It returns the SPI
1527 * master structure on success, else NULL.
1529 * The caller is responsible for assigning the bus number and initializing
1530 * the master's methods before calling spi_register_master(); and (after errors
1531 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1534 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1536 struct spi_master *master;
1541 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1545 device_initialize(&master->dev);
1546 master->bus_num = -1;
1547 master->num_chipselect = 1;
1548 master->dev.class = &spi_master_class;
1549 master->dev.parent = get_device(dev);
1550 spi_master_set_devdata(master, &master[1]);
1554 EXPORT_SYMBOL_GPL(spi_alloc_master);
1557 static int of_spi_register_master(struct spi_master *master)
1560 struct device_node *np = master->dev.of_node;
1565 nb = of_gpio_named_count(np, "cs-gpios");
1566 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1568 /* Return error only for an incorrectly formed cs-gpios property */
1569 if (nb == 0 || nb == -ENOENT)
1574 cs = devm_kzalloc(&master->dev,
1575 sizeof(int) * master->num_chipselect,
1577 master->cs_gpios = cs;
1579 if (!master->cs_gpios)
1582 for (i = 0; i < master->num_chipselect; i++)
1585 for (i = 0; i < nb; i++)
1586 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1591 static int of_spi_register_master(struct spi_master *master)
1598 * spi_register_master - register SPI master controller
1599 * @master: initialized master, originally from spi_alloc_master()
1600 * Context: can sleep
1602 * SPI master controllers connect to their drivers using some non-SPI bus,
1603 * such as the platform bus. The final stage of probe() in that code
1604 * includes calling spi_register_master() to hook up to this SPI bus glue.
1606 * SPI controllers use board specific (often SOC specific) bus numbers,
1607 * and board-specific addressing for SPI devices combines those numbers
1608 * with chip select numbers. Since SPI does not directly support dynamic
1609 * device identification, boards need configuration tables telling which
1610 * chip is at which address.
1612 * This must be called from context that can sleep. It returns zero on
1613 * success, else a negative error code (dropping the master's refcount).
1614 * After a successful return, the caller is responsible for calling
1615 * spi_unregister_master().
1617 int spi_register_master(struct spi_master *master)
1619 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1620 struct device *dev = master->dev.parent;
1621 struct boardinfo *bi;
1622 int status = -ENODEV;
1628 status = of_spi_register_master(master);
1632 /* even if it's just one always-selected device, there must
1633 * be at least one chipselect
1635 if (master->num_chipselect == 0)
1638 if ((master->bus_num < 0) && master->dev.of_node)
1639 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1641 /* convention: dynamically assigned bus IDs count down from the max */
1642 if (master->bus_num < 0) {
1643 /* FIXME switch to an IDR based scheme, something like
1644 * I2C now uses, so we can't run out of "dynamic" IDs
1646 master->bus_num = atomic_dec_return(&dyn_bus_id);
1650 INIT_LIST_HEAD(&master->queue);
1651 spin_lock_init(&master->queue_lock);
1652 spin_lock_init(&master->bus_lock_spinlock);
1653 mutex_init(&master->bus_lock_mutex);
1654 master->bus_lock_flag = 0;
1655 init_completion(&master->xfer_completion);
1656 if (!master->max_dma_len)
1657 master->max_dma_len = INT_MAX;
1659 /* register the device, then userspace will see it.
1660 * registration fails if the bus ID is in use.
1662 dev_set_name(&master->dev, "spi%u", master->bus_num);
1663 status = device_add(&master->dev);
1666 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1667 dynamic ? " (dynamic)" : "");
1669 /* If we're using a queued driver, start the queue */
1670 if (master->transfer)
1671 dev_info(dev, "master is unqueued, this is deprecated\n");
1673 status = spi_master_initialize_queue(master);
1675 device_del(&master->dev);
1680 mutex_lock(&board_lock);
1681 list_add_tail(&master->list, &spi_master_list);
1682 list_for_each_entry(bi, &board_list, list)
1683 spi_match_master_to_boardinfo(master, &bi->board_info);
1684 mutex_unlock(&board_lock);
1686 /* Register devices from the device tree and ACPI */
1687 of_register_spi_devices(master);
1688 acpi_register_spi_devices(master);
1692 EXPORT_SYMBOL_GPL(spi_register_master);
1694 static void devm_spi_unregister(struct device *dev, void *res)
1696 spi_unregister_master(*(struct spi_master **)res);
1700 * dev_spi_register_master - register managed SPI master controller
1701 * @dev: device managing SPI master
1702 * @master: initialized master, originally from spi_alloc_master()
1703 * Context: can sleep
1705 * Register a SPI device as with spi_register_master() which will
1706 * automatically be unregister
1708 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1710 struct spi_master **ptr;
1713 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1717 ret = spi_register_master(master);
1720 devres_add(dev, ptr);
1727 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1729 static int __unregister(struct device *dev, void *null)
1731 spi_unregister_device(to_spi_device(dev));
1736 * spi_unregister_master - unregister SPI master controller
1737 * @master: the master being unregistered
1738 * Context: can sleep
1740 * This call is used only by SPI master controller drivers, which are the
1741 * only ones directly touching chip registers.
1743 * This must be called from context that can sleep.
1745 void spi_unregister_master(struct spi_master *master)
1749 if (master->queued) {
1750 if (spi_destroy_queue(master))
1751 dev_err(&master->dev, "queue remove failed\n");
1754 mutex_lock(&board_lock);
1755 list_del(&master->list);
1756 mutex_unlock(&board_lock);
1758 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1759 device_unregister(&master->dev);
1761 EXPORT_SYMBOL_GPL(spi_unregister_master);
1763 int spi_master_suspend(struct spi_master *master)
1767 /* Basically no-ops for non-queued masters */
1768 if (!master->queued)
1771 ret = spi_stop_queue(master);
1773 dev_err(&master->dev, "queue stop failed\n");
1777 EXPORT_SYMBOL_GPL(spi_master_suspend);
1779 int spi_master_resume(struct spi_master *master)
1783 if (!master->queued)
1786 ret = spi_start_queue(master);
1788 dev_err(&master->dev, "queue restart failed\n");
1792 EXPORT_SYMBOL_GPL(spi_master_resume);
1794 static int __spi_master_match(struct device *dev, const void *data)
1796 struct spi_master *m;
1797 const u16 *bus_num = data;
1799 m = container_of(dev, struct spi_master, dev);
1800 return m->bus_num == *bus_num;
1804 * spi_busnum_to_master - look up master associated with bus_num
1805 * @bus_num: the master's bus number
1806 * Context: can sleep
1808 * This call may be used with devices that are registered after
1809 * arch init time. It returns a refcounted pointer to the relevant
1810 * spi_master (which the caller must release), or NULL if there is
1811 * no such master registered.
1813 struct spi_master *spi_busnum_to_master(u16 bus_num)
1816 struct spi_master *master = NULL;
1818 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1819 __spi_master_match);
1821 master = container_of(dev, struct spi_master, dev);
1822 /* reference got in class_find_device */
1825 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1828 /*-------------------------------------------------------------------------*/
1830 /* Core methods for SPI master protocol drivers. Some of the
1831 * other core methods are currently defined as inline functions.
1835 * spi_setup - setup SPI mode and clock rate
1836 * @spi: the device whose settings are being modified
1837 * Context: can sleep, and no requests are queued to the device
1839 * SPI protocol drivers may need to update the transfer mode if the
1840 * device doesn't work with its default. They may likewise need
1841 * to update clock rates or word sizes from initial values. This function
1842 * changes those settings, and must be called from a context that can sleep.
1843 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1844 * effect the next time the device is selected and data is transferred to
1845 * or from it. When this function returns, the spi device is deselected.
1847 * Note that this call will fail if the protocol driver specifies an option
1848 * that the underlying controller or its driver does not support. For
1849 * example, not all hardware supports wire transfers using nine bit words,
1850 * LSB-first wire encoding, or active-high chipselects.
1852 int spi_setup(struct spi_device *spi)
1854 unsigned bad_bits, ugly_bits;
1857 /* check mode to prevent that DUAL and QUAD set at the same time
1859 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1860 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1862 "setup: can not select dual and quad at the same time\n");
1865 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1867 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1868 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1870 /* help drivers fail *cleanly* when they need options
1871 * that aren't supported with their current master
1873 bad_bits = spi->mode & ~spi->master->mode_bits;
1874 ugly_bits = bad_bits &
1875 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1878 "setup: ignoring unsupported mode bits %x\n",
1880 spi->mode &= ~ugly_bits;
1881 bad_bits &= ~ugly_bits;
1884 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1889 if (!spi->bits_per_word)
1890 spi->bits_per_word = 8;
1892 if (!spi->max_speed_hz)
1893 spi->max_speed_hz = spi->master->max_speed_hz;
1895 spi_set_cs(spi, false);
1897 if (spi->master->setup)
1898 status = spi->master->setup(spi);
1900 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1901 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1902 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1903 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1904 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1905 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1906 spi->bits_per_word, spi->max_speed_hz,
1911 EXPORT_SYMBOL_GPL(spi_setup);
1913 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1915 struct spi_master *master = spi->master;
1916 struct spi_transfer *xfer;
1919 if (list_empty(&message->transfers))
1922 /* Half-duplex links include original MicroWire, and ones with
1923 * only one data pin like SPI_3WIRE (switches direction) or where
1924 * either MOSI or MISO is missing. They can also be caused by
1925 * software limitations.
1927 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1928 || (spi->mode & SPI_3WIRE)) {
1929 unsigned flags = master->flags;
1931 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1932 if (xfer->rx_buf && xfer->tx_buf)
1934 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1936 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1942 * Set transfer bits_per_word and max speed as spi device default if
1943 * it is not set for this transfer.
1944 * Set transfer tx_nbits and rx_nbits as single transfer default
1945 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1947 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1948 message->frame_length += xfer->len;
1949 if (!xfer->bits_per_word)
1950 xfer->bits_per_word = spi->bits_per_word;
1952 if (!xfer->speed_hz)
1953 xfer->speed_hz = spi->max_speed_hz;
1955 if (master->max_speed_hz &&
1956 xfer->speed_hz > master->max_speed_hz)
1957 xfer->speed_hz = master->max_speed_hz;
1959 if (master->bits_per_word_mask) {
1960 /* Only 32 bits fit in the mask */
1961 if (xfer->bits_per_word > 32)
1963 if (!(master->bits_per_word_mask &
1964 BIT(xfer->bits_per_word - 1)))
1969 * SPI transfer length should be multiple of SPI word size
1970 * where SPI word size should be power-of-two multiple
1972 if (xfer->bits_per_word <= 8)
1974 else if (xfer->bits_per_word <= 16)
1979 /* No partial transfers accepted */
1980 if (xfer->len % w_size)
1983 if (xfer->speed_hz && master->min_speed_hz &&
1984 xfer->speed_hz < master->min_speed_hz)
1987 if (xfer->tx_buf && !xfer->tx_nbits)
1988 xfer->tx_nbits = SPI_NBITS_SINGLE;
1989 if (xfer->rx_buf && !xfer->rx_nbits)
1990 xfer->rx_nbits = SPI_NBITS_SINGLE;
1991 /* check transfer tx/rx_nbits:
1992 * 1. check the value matches one of single, dual and quad
1993 * 2. check tx/rx_nbits match the mode in spi_device
1996 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1997 xfer->tx_nbits != SPI_NBITS_DUAL &&
1998 xfer->tx_nbits != SPI_NBITS_QUAD)
2000 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2001 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2003 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2004 !(spi->mode & SPI_TX_QUAD))
2007 /* check transfer rx_nbits */
2009 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2010 xfer->rx_nbits != SPI_NBITS_DUAL &&
2011 xfer->rx_nbits != SPI_NBITS_QUAD)
2013 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2014 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2016 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2017 !(spi->mode & SPI_RX_QUAD))
2022 message->status = -EINPROGRESS;
2027 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2029 struct spi_master *master = spi->master;
2033 trace_spi_message_submit(message);
2035 return master->transfer(spi, message);
2039 * spi_async - asynchronous SPI transfer
2040 * @spi: device with which data will be exchanged
2041 * @message: describes the data transfers, including completion callback
2042 * Context: any (irqs may be blocked, etc)
2044 * This call may be used in_irq and other contexts which can't sleep,
2045 * as well as from task contexts which can sleep.
2047 * The completion callback is invoked in a context which can't sleep.
2048 * Before that invocation, the value of message->status is undefined.
2049 * When the callback is issued, message->status holds either zero (to
2050 * indicate complete success) or a negative error code. After that
2051 * callback returns, the driver which issued the transfer request may
2052 * deallocate the associated memory; it's no longer in use by any SPI
2053 * core or controller driver code.
2055 * Note that although all messages to a spi_device are handled in
2056 * FIFO order, messages may go to different devices in other orders.
2057 * Some device might be higher priority, or have various "hard" access
2058 * time requirements, for example.
2060 * On detection of any fault during the transfer, processing of
2061 * the entire message is aborted, and the device is deselected.
2062 * Until returning from the associated message completion callback,
2063 * no other spi_message queued to that device will be processed.
2064 * (This rule applies equally to all the synchronous transfer calls,
2065 * which are wrappers around this core asynchronous primitive.)
2067 int spi_async(struct spi_device *spi, struct spi_message *message)
2069 struct spi_master *master = spi->master;
2071 unsigned long flags;
2073 ret = __spi_validate(spi, message);
2077 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2079 if (master->bus_lock_flag)
2082 ret = __spi_async(spi, message);
2084 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2088 EXPORT_SYMBOL_GPL(spi_async);
2091 * spi_async_locked - version of spi_async with exclusive bus usage
2092 * @spi: device with which data will be exchanged
2093 * @message: describes the data transfers, including completion callback
2094 * Context: any (irqs may be blocked, etc)
2096 * This call may be used in_irq and other contexts which can't sleep,
2097 * as well as from task contexts which can sleep.
2099 * The completion callback is invoked in a context which can't sleep.
2100 * Before that invocation, the value of message->status is undefined.
2101 * When the callback is issued, message->status holds either zero (to
2102 * indicate complete success) or a negative error code. After that
2103 * callback returns, the driver which issued the transfer request may
2104 * deallocate the associated memory; it's no longer in use by any SPI
2105 * core or controller driver code.
2107 * Note that although all messages to a spi_device are handled in
2108 * FIFO order, messages may go to different devices in other orders.
2109 * Some device might be higher priority, or have various "hard" access
2110 * time requirements, for example.
2112 * On detection of any fault during the transfer, processing of
2113 * the entire message is aborted, and the device is deselected.
2114 * Until returning from the associated message completion callback,
2115 * no other spi_message queued to that device will be processed.
2116 * (This rule applies equally to all the synchronous transfer calls,
2117 * which are wrappers around this core asynchronous primitive.)
2119 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2121 struct spi_master *master = spi->master;
2123 unsigned long flags;
2125 ret = __spi_validate(spi, message);
2129 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2131 ret = __spi_async(spi, message);
2133 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2138 EXPORT_SYMBOL_GPL(spi_async_locked);
2141 /*-------------------------------------------------------------------------*/
2143 /* Utility methods for SPI master protocol drivers, layered on
2144 * top of the core. Some other utility methods are defined as
2148 static void spi_complete(void *arg)
2153 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2156 DECLARE_COMPLETION_ONSTACK(done);
2158 struct spi_master *master = spi->master;
2159 unsigned long flags;
2161 status = __spi_validate(spi, message);
2165 message->complete = spi_complete;
2166 message->context = &done;
2170 mutex_lock(&master->bus_lock_mutex);
2172 /* If we're not using the legacy transfer method then we will
2173 * try to transfer in the calling context so special case.
2174 * This code would be less tricky if we could remove the
2175 * support for driver implemented message queues.
2177 if (master->transfer == spi_queued_transfer) {
2178 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2180 trace_spi_message_submit(message);
2182 status = __spi_queued_transfer(spi, message, false);
2184 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2186 status = spi_async_locked(spi, message);
2190 mutex_unlock(&master->bus_lock_mutex);
2193 /* Push out the messages in the calling context if we
2196 if (master->transfer == spi_queued_transfer)
2197 __spi_pump_messages(master, false);
2199 wait_for_completion(&done);
2200 status = message->status;
2202 message->context = NULL;
2207 * spi_sync - blocking/synchronous SPI data transfers
2208 * @spi: device with which data will be exchanged
2209 * @message: describes the data transfers
2210 * Context: can sleep
2212 * This call may only be used from a context that may sleep. The sleep
2213 * is non-interruptible, and has no timeout. Low-overhead controller
2214 * drivers may DMA directly into and out of the message buffers.
2216 * Note that the SPI device's chip select is active during the message,
2217 * and then is normally disabled between messages. Drivers for some
2218 * frequently-used devices may want to minimize costs of selecting a chip,
2219 * by leaving it selected in anticipation that the next message will go
2220 * to the same chip. (That may increase power usage.)
2222 * Also, the caller is guaranteeing that the memory associated with the
2223 * message will not be freed before this call returns.
2225 * It returns zero on success, else a negative error code.
2227 int spi_sync(struct spi_device *spi, struct spi_message *message)
2229 return __spi_sync(spi, message, 0);
2231 EXPORT_SYMBOL_GPL(spi_sync);
2234 * spi_sync_locked - version of spi_sync with exclusive bus usage
2235 * @spi: device with which data will be exchanged
2236 * @message: describes the data transfers
2237 * Context: can sleep
2239 * This call may only be used from a context that may sleep. The sleep
2240 * is non-interruptible, and has no timeout. Low-overhead controller
2241 * drivers may DMA directly into and out of the message buffers.
2243 * This call should be used by drivers that require exclusive access to the
2244 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2245 * be released by a spi_bus_unlock call when the exclusive access is over.
2247 * It returns zero on success, else a negative error code.
2249 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2251 return __spi_sync(spi, message, 1);
2253 EXPORT_SYMBOL_GPL(spi_sync_locked);
2256 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2257 * @master: SPI bus master that should be locked for exclusive bus access
2258 * Context: can sleep
2260 * This call may only be used from a context that may sleep. The sleep
2261 * is non-interruptible, and has no timeout.
2263 * This call should be used by drivers that require exclusive access to the
2264 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2265 * exclusive access is over. Data transfer must be done by spi_sync_locked
2266 * and spi_async_locked calls when the SPI bus lock is held.
2268 * It returns zero on success, else a negative error code.
2270 int spi_bus_lock(struct spi_master *master)
2272 unsigned long flags;
2274 mutex_lock(&master->bus_lock_mutex);
2276 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2277 master->bus_lock_flag = 1;
2278 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2280 /* mutex remains locked until spi_bus_unlock is called */
2284 EXPORT_SYMBOL_GPL(spi_bus_lock);
2287 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2288 * @master: SPI bus master that was locked for exclusive bus access
2289 * Context: can sleep
2291 * This call may only be used from a context that may sleep. The sleep
2292 * is non-interruptible, and has no timeout.
2294 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2297 * It returns zero on success, else a negative error code.
2299 int spi_bus_unlock(struct spi_master *master)
2301 master->bus_lock_flag = 0;
2303 mutex_unlock(&master->bus_lock_mutex);
2307 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2309 /* portable code must never pass more than 32 bytes */
2310 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2315 * spi_write_then_read - SPI synchronous write followed by read
2316 * @spi: device with which data will be exchanged
2317 * @txbuf: data to be written (need not be dma-safe)
2318 * @n_tx: size of txbuf, in bytes
2319 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2320 * @n_rx: size of rxbuf, in bytes
2321 * Context: can sleep
2323 * This performs a half duplex MicroWire style transaction with the
2324 * device, sending txbuf and then reading rxbuf. The return value
2325 * is zero for success, else a negative errno status code.
2326 * This call may only be used from a context that may sleep.
2328 * Parameters to this routine are always copied using a small buffer;
2329 * portable code should never use this for more than 32 bytes.
2330 * Performance-sensitive or bulk transfer code should instead use
2331 * spi_{async,sync}() calls with dma-safe buffers.
2333 int spi_write_then_read(struct spi_device *spi,
2334 const void *txbuf, unsigned n_tx,
2335 void *rxbuf, unsigned n_rx)
2337 static DEFINE_MUTEX(lock);
2340 struct spi_message message;
2341 struct spi_transfer x[2];
2344 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2345 * copying here, (as a pure convenience thing), but we can
2346 * keep heap costs out of the hot path unless someone else is
2347 * using the pre-allocated buffer or the transfer is too large.
2349 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2350 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2351 GFP_KERNEL | GFP_DMA);
2358 spi_message_init(&message);
2359 memset(x, 0, sizeof(x));
2362 spi_message_add_tail(&x[0], &message);
2366 spi_message_add_tail(&x[1], &message);
2369 memcpy(local_buf, txbuf, n_tx);
2370 x[0].tx_buf = local_buf;
2371 x[1].rx_buf = local_buf + n_tx;
2374 status = spi_sync(spi, &message);
2376 memcpy(rxbuf, x[1].rx_buf, n_rx);
2378 if (x[0].tx_buf == buf)
2379 mutex_unlock(&lock);
2385 EXPORT_SYMBOL_GPL(spi_write_then_read);
2387 /*-------------------------------------------------------------------------*/
2389 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2390 static int __spi_of_device_match(struct device *dev, void *data)
2392 return dev->of_node == data;
2395 /* must call put_device() when done with returned spi_device device */
2396 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2398 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2399 __spi_of_device_match);
2400 return dev ? to_spi_device(dev) : NULL;
2403 static int __spi_of_master_match(struct device *dev, const void *data)
2405 return dev->of_node == data;
2408 /* the spi masters are not using spi_bus, so we find it with another way */
2409 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2413 dev = class_find_device(&spi_master_class, NULL, node,
2414 __spi_of_master_match);
2418 /* reference got in class_find_device */
2419 return container_of(dev, struct spi_master, dev);
2422 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2425 struct of_reconfig_data *rd = arg;
2426 struct spi_master *master;
2427 struct spi_device *spi;
2429 switch (of_reconfig_get_state_change(action, arg)) {
2430 case OF_RECONFIG_CHANGE_ADD:
2431 master = of_find_spi_master_by_node(rd->dn->parent);
2433 return NOTIFY_OK; /* not for us */
2435 spi = of_register_spi_device(master, rd->dn);
2436 put_device(&master->dev);
2439 pr_err("%s: failed to create for '%s'\n",
2440 __func__, rd->dn->full_name);
2441 return notifier_from_errno(PTR_ERR(spi));
2445 case OF_RECONFIG_CHANGE_REMOVE:
2446 /* find our device by node */
2447 spi = of_find_spi_device_by_node(rd->dn);
2449 return NOTIFY_OK; /* no? not meant for us */
2451 /* unregister takes one ref away */
2452 spi_unregister_device(spi);
2454 /* and put the reference of the find */
2455 put_device(&spi->dev);
2462 static struct notifier_block spi_of_notifier = {
2463 .notifier_call = of_spi_notify,
2465 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2466 extern struct notifier_block spi_of_notifier;
2467 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2469 static int __init spi_init(void)
2473 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2479 status = bus_register(&spi_bus_type);
2483 status = class_register(&spi_master_class);
2487 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2488 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2493 bus_unregister(&spi_bus_type);
2501 /* board_info is normally registered in arch_initcall(),
2502 * but even essential drivers wait till later
2504 * REVISIT only boardinfo really needs static linking. the rest (device and
2505 * driver registration) _could_ be dynamically linked (modular) ... costs
2506 * include needing to have boardinfo data structures be much more public.
2508 postcore_initcall(spi_init);