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 if (msg->status && master->handle_err)
854 master->handle_err(master, msg);
856 spi_finalize_current_message(master);
862 * spi_finalize_current_transfer - report completion of a transfer
863 * @master: the master reporting completion
865 * Called by SPI drivers using the core transfer_one_message()
866 * implementation to notify it that the current interrupt driven
867 * transfer has finished and the next one may be scheduled.
869 void spi_finalize_current_transfer(struct spi_master *master)
871 complete(&master->xfer_completion);
873 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
876 * __spi_pump_messages - function which processes spi message queue
877 * @master: master to process queue for
878 * @in_kthread: true if we are in the context of the message pump thread
880 * This function checks if there is any spi message in the queue that
881 * needs processing and if so call out to the driver to initialize hardware
882 * and transfer each message.
884 * Note that it is called both from the kthread itself and also from
885 * inside spi_sync(); the queue extraction handling at the top of the
886 * function should deal with this safely.
888 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
891 bool was_busy = false;
895 spin_lock_irqsave(&master->queue_lock, flags);
897 /* Make sure we are not already running a message */
898 if (master->cur_msg) {
899 spin_unlock_irqrestore(&master->queue_lock, flags);
903 /* If another context is idling the device then defer */
904 if (master->idling) {
905 queue_kthread_work(&master->kworker, &master->pump_messages);
906 spin_unlock_irqrestore(&master->queue_lock, flags);
910 /* Check if the queue is idle */
911 if (list_empty(&master->queue) || !master->running) {
913 spin_unlock_irqrestore(&master->queue_lock, flags);
917 /* Only do teardown in the thread */
919 queue_kthread_work(&master->kworker,
920 &master->pump_messages);
921 spin_unlock_irqrestore(&master->queue_lock, flags);
925 master->busy = false;
926 master->idling = true;
927 spin_unlock_irqrestore(&master->queue_lock, flags);
929 kfree(master->dummy_rx);
930 master->dummy_rx = NULL;
931 kfree(master->dummy_tx);
932 master->dummy_tx = NULL;
933 if (master->unprepare_transfer_hardware &&
934 master->unprepare_transfer_hardware(master))
935 dev_err(&master->dev,
936 "failed to unprepare transfer hardware\n");
937 if (master->auto_runtime_pm) {
938 pm_runtime_mark_last_busy(master->dev.parent);
939 pm_runtime_put_autosuspend(master->dev.parent);
941 trace_spi_master_idle(master);
943 spin_lock_irqsave(&master->queue_lock, flags);
944 master->idling = false;
945 spin_unlock_irqrestore(&master->queue_lock, flags);
949 /* Extract head of queue */
951 list_first_entry(&master->queue, struct spi_message, queue);
953 list_del_init(&master->cur_msg->queue);
958 spin_unlock_irqrestore(&master->queue_lock, flags);
960 if (!was_busy && master->auto_runtime_pm) {
961 ret = pm_runtime_get_sync(master->dev.parent);
963 dev_err(&master->dev, "Failed to power device: %d\n",
970 trace_spi_master_busy(master);
972 if (!was_busy && master->prepare_transfer_hardware) {
973 ret = master->prepare_transfer_hardware(master);
975 dev_err(&master->dev,
976 "failed to prepare transfer hardware\n");
978 if (master->auto_runtime_pm)
979 pm_runtime_put(master->dev.parent);
984 trace_spi_message_start(master->cur_msg);
986 if (master->prepare_message) {
987 ret = master->prepare_message(master, master->cur_msg);
989 dev_err(&master->dev,
990 "failed to prepare message: %d\n", ret);
991 master->cur_msg->status = ret;
992 spi_finalize_current_message(master);
995 master->cur_msg_prepared = true;
998 ret = spi_map_msg(master, master->cur_msg);
1000 master->cur_msg->status = ret;
1001 spi_finalize_current_message(master);
1005 ret = master->transfer_one_message(master, master->cur_msg);
1007 dev_err(&master->dev,
1008 "failed to transfer one message from queue\n");
1014 * spi_pump_messages - kthread work function which processes spi message queue
1015 * @work: pointer to kthread work struct contained in the master struct
1017 static void spi_pump_messages(struct kthread_work *work)
1019 struct spi_master *master =
1020 container_of(work, struct spi_master, pump_messages);
1022 __spi_pump_messages(master, true);
1025 static int spi_init_queue(struct spi_master *master)
1027 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1029 master->running = false;
1030 master->busy = false;
1032 init_kthread_worker(&master->kworker);
1033 master->kworker_task = kthread_run(kthread_worker_fn,
1034 &master->kworker, "%s",
1035 dev_name(&master->dev));
1036 if (IS_ERR(master->kworker_task)) {
1037 dev_err(&master->dev, "failed to create message pump task\n");
1038 return PTR_ERR(master->kworker_task);
1040 init_kthread_work(&master->pump_messages, spi_pump_messages);
1043 * Master config will indicate if this controller should run the
1044 * message pump with high (realtime) priority to reduce the transfer
1045 * latency on the bus by minimising the delay between a transfer
1046 * request and the scheduling of the message pump thread. Without this
1047 * setting the message pump thread will remain at default priority.
1050 dev_info(&master->dev,
1051 "will run message pump with realtime priority\n");
1052 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1059 * spi_get_next_queued_message() - called by driver to check for queued
1061 * @master: the master to check for queued messages
1063 * If there are more messages in the queue, the next message is returned from
1066 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1068 struct spi_message *next;
1069 unsigned long flags;
1071 /* get a pointer to the next message, if any */
1072 spin_lock_irqsave(&master->queue_lock, flags);
1073 next = list_first_entry_or_null(&master->queue, struct spi_message,
1075 spin_unlock_irqrestore(&master->queue_lock, flags);
1079 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1082 * spi_finalize_current_message() - the current message is complete
1083 * @master: the master to return the message to
1085 * Called by the driver to notify the core that the message in the front of the
1086 * queue is complete and can be removed from the queue.
1088 void spi_finalize_current_message(struct spi_master *master)
1090 struct spi_message *mesg;
1091 unsigned long flags;
1094 spin_lock_irqsave(&master->queue_lock, flags);
1095 mesg = master->cur_msg;
1096 master->cur_msg = NULL;
1098 queue_kthread_work(&master->kworker, &master->pump_messages);
1099 spin_unlock_irqrestore(&master->queue_lock, flags);
1101 spi_unmap_msg(master, mesg);
1103 if (master->cur_msg_prepared && master->unprepare_message) {
1104 ret = master->unprepare_message(master, mesg);
1106 dev_err(&master->dev,
1107 "failed to unprepare message: %d\n", ret);
1111 trace_spi_message_done(mesg);
1113 master->cur_msg_prepared = false;
1117 mesg->complete(mesg->context);
1119 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1121 static int spi_start_queue(struct spi_master *master)
1123 unsigned long flags;
1125 spin_lock_irqsave(&master->queue_lock, flags);
1127 if (master->running || master->busy) {
1128 spin_unlock_irqrestore(&master->queue_lock, flags);
1132 master->running = true;
1133 master->cur_msg = NULL;
1134 spin_unlock_irqrestore(&master->queue_lock, flags);
1136 queue_kthread_work(&master->kworker, &master->pump_messages);
1141 static int spi_stop_queue(struct spi_master *master)
1143 unsigned long flags;
1144 unsigned limit = 500;
1147 spin_lock_irqsave(&master->queue_lock, flags);
1150 * This is a bit lame, but is optimized for the common execution path.
1151 * A wait_queue on the master->busy could be used, but then the common
1152 * execution path (pump_messages) would be required to call wake_up or
1153 * friends on every SPI message. Do this instead.
1155 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1156 spin_unlock_irqrestore(&master->queue_lock, flags);
1157 usleep_range(10000, 11000);
1158 spin_lock_irqsave(&master->queue_lock, flags);
1161 if (!list_empty(&master->queue) || master->busy)
1164 master->running = false;
1166 spin_unlock_irqrestore(&master->queue_lock, flags);
1169 dev_warn(&master->dev,
1170 "could not stop message queue\n");
1176 static int spi_destroy_queue(struct spi_master *master)
1180 ret = spi_stop_queue(master);
1183 * flush_kthread_worker will block until all work is done.
1184 * If the reason that stop_queue timed out is that the work will never
1185 * finish, then it does no good to call flush/stop thread, so
1189 dev_err(&master->dev, "problem destroying queue\n");
1193 flush_kthread_worker(&master->kworker);
1194 kthread_stop(master->kworker_task);
1199 static int __spi_queued_transfer(struct spi_device *spi,
1200 struct spi_message *msg,
1203 struct spi_master *master = spi->master;
1204 unsigned long flags;
1206 spin_lock_irqsave(&master->queue_lock, flags);
1208 if (!master->running) {
1209 spin_unlock_irqrestore(&master->queue_lock, flags);
1212 msg->actual_length = 0;
1213 msg->status = -EINPROGRESS;
1215 list_add_tail(&msg->queue, &master->queue);
1216 if (!master->busy && need_pump)
1217 queue_kthread_work(&master->kworker, &master->pump_messages);
1219 spin_unlock_irqrestore(&master->queue_lock, flags);
1224 * spi_queued_transfer - transfer function for queued transfers
1225 * @spi: spi device which is requesting transfer
1226 * @msg: spi message which is to handled is queued to driver queue
1228 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1230 return __spi_queued_transfer(spi, msg, true);
1233 static int spi_master_initialize_queue(struct spi_master *master)
1237 master->transfer = spi_queued_transfer;
1238 if (!master->transfer_one_message)
1239 master->transfer_one_message = spi_transfer_one_message;
1241 /* Initialize and start queue */
1242 ret = spi_init_queue(master);
1244 dev_err(&master->dev, "problem initializing queue\n");
1245 goto err_init_queue;
1247 master->queued = true;
1248 ret = spi_start_queue(master);
1250 dev_err(&master->dev, "problem starting queue\n");
1251 goto err_start_queue;
1257 spi_destroy_queue(master);
1262 /*-------------------------------------------------------------------------*/
1264 #if defined(CONFIG_OF)
1265 static struct spi_device *
1266 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1268 struct spi_device *spi;
1272 /* Alloc an spi_device */
1273 spi = spi_alloc_device(master);
1275 dev_err(&master->dev, "spi_device alloc error for %s\n",
1281 /* Select device driver */
1282 rc = of_modalias_node(nc, spi->modalias,
1283 sizeof(spi->modalias));
1285 dev_err(&master->dev, "cannot find modalias for %s\n",
1290 /* Device address */
1291 rc = of_property_read_u32(nc, "reg", &value);
1293 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1297 spi->chip_select = value;
1299 /* Mode (clock phase/polarity/etc.) */
1300 if (of_find_property(nc, "spi-cpha", NULL))
1301 spi->mode |= SPI_CPHA;
1302 if (of_find_property(nc, "spi-cpol", NULL))
1303 spi->mode |= SPI_CPOL;
1304 if (of_find_property(nc, "spi-cs-high", NULL))
1305 spi->mode |= SPI_CS_HIGH;
1306 if (of_find_property(nc, "spi-3wire", NULL))
1307 spi->mode |= SPI_3WIRE;
1308 if (of_find_property(nc, "spi-lsb-first", NULL))
1309 spi->mode |= SPI_LSB_FIRST;
1311 /* Device DUAL/QUAD mode */
1312 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1317 spi->mode |= SPI_TX_DUAL;
1320 spi->mode |= SPI_TX_QUAD;
1323 dev_warn(&master->dev,
1324 "spi-tx-bus-width %d not supported\n",
1330 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1335 spi->mode |= SPI_RX_DUAL;
1338 spi->mode |= SPI_RX_QUAD;
1341 dev_warn(&master->dev,
1342 "spi-rx-bus-width %d not supported\n",
1349 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1351 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1355 spi->max_speed_hz = value;
1358 spi->irq = irq_of_parse_and_map(nc, 0);
1360 /* Store a pointer to the node in the device structure */
1362 spi->dev.of_node = nc;
1364 /* Register the new device */
1365 rc = spi_add_device(spi);
1367 dev_err(&master->dev, "spi_device register error %s\n",
1380 * of_register_spi_devices() - Register child devices onto the SPI bus
1381 * @master: Pointer to spi_master device
1383 * Registers an spi_device for each child node of master node which has a 'reg'
1386 static void of_register_spi_devices(struct spi_master *master)
1388 struct spi_device *spi;
1389 struct device_node *nc;
1391 if (!master->dev.of_node)
1394 for_each_available_child_of_node(master->dev.of_node, nc) {
1395 spi = of_register_spi_device(master, nc);
1397 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1402 static void of_register_spi_devices(struct spi_master *master) { }
1406 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1408 struct spi_device *spi = data;
1410 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1411 struct acpi_resource_spi_serialbus *sb;
1413 sb = &ares->data.spi_serial_bus;
1414 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1415 spi->chip_select = sb->device_selection;
1416 spi->max_speed_hz = sb->connection_speed;
1418 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1419 spi->mode |= SPI_CPHA;
1420 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1421 spi->mode |= SPI_CPOL;
1422 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1423 spi->mode |= SPI_CS_HIGH;
1425 } else if (spi->irq < 0) {
1428 if (acpi_dev_resource_interrupt(ares, 0, &r))
1432 /* Always tell the ACPI core to skip this resource */
1436 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1437 void *data, void **return_value)
1439 struct spi_master *master = data;
1440 struct list_head resource_list;
1441 struct acpi_device *adev;
1442 struct spi_device *spi;
1445 if (acpi_bus_get_device(handle, &adev))
1447 if (acpi_bus_get_status(adev) || !adev->status.present)
1450 spi = spi_alloc_device(master);
1452 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1453 dev_name(&adev->dev));
1454 return AE_NO_MEMORY;
1457 ACPI_COMPANION_SET(&spi->dev, adev);
1460 INIT_LIST_HEAD(&resource_list);
1461 ret = acpi_dev_get_resources(adev, &resource_list,
1462 acpi_spi_add_resource, spi);
1463 acpi_dev_free_resource_list(&resource_list);
1465 if (ret < 0 || !spi->max_speed_hz) {
1470 adev->power.flags.ignore_parent = true;
1471 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1472 if (spi_add_device(spi)) {
1473 adev->power.flags.ignore_parent = false;
1474 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1475 dev_name(&adev->dev));
1482 static void acpi_register_spi_devices(struct spi_master *master)
1487 handle = ACPI_HANDLE(master->dev.parent);
1491 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1492 acpi_spi_add_device, NULL,
1494 if (ACPI_FAILURE(status))
1495 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1498 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1499 #endif /* CONFIG_ACPI */
1501 static void spi_master_release(struct device *dev)
1503 struct spi_master *master;
1505 master = container_of(dev, struct spi_master, dev);
1509 static struct class spi_master_class = {
1510 .name = "spi_master",
1511 .owner = THIS_MODULE,
1512 .dev_release = spi_master_release,
1518 * spi_alloc_master - allocate SPI master controller
1519 * @dev: the controller, possibly using the platform_bus
1520 * @size: how much zeroed driver-private data to allocate; the pointer to this
1521 * memory is in the driver_data field of the returned device,
1522 * accessible with spi_master_get_devdata().
1523 * Context: can sleep
1525 * This call is used only by SPI master controller drivers, which are the
1526 * only ones directly touching chip registers. It's how they allocate
1527 * an spi_master structure, prior to calling spi_register_master().
1529 * This must be called from context that can sleep. It returns the SPI
1530 * master structure on success, else NULL.
1532 * The caller is responsible for assigning the bus number and initializing
1533 * the master's methods before calling spi_register_master(); and (after errors
1534 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1537 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1539 struct spi_master *master;
1544 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1548 device_initialize(&master->dev);
1549 master->bus_num = -1;
1550 master->num_chipselect = 1;
1551 master->dev.class = &spi_master_class;
1552 master->dev.parent = get_device(dev);
1553 spi_master_set_devdata(master, &master[1]);
1557 EXPORT_SYMBOL_GPL(spi_alloc_master);
1560 static int of_spi_register_master(struct spi_master *master)
1563 struct device_node *np = master->dev.of_node;
1568 nb = of_gpio_named_count(np, "cs-gpios");
1569 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1571 /* Return error only for an incorrectly formed cs-gpios property */
1572 if (nb == 0 || nb == -ENOENT)
1577 cs = devm_kzalloc(&master->dev,
1578 sizeof(int) * master->num_chipselect,
1580 master->cs_gpios = cs;
1582 if (!master->cs_gpios)
1585 for (i = 0; i < master->num_chipselect; i++)
1588 for (i = 0; i < nb; i++)
1589 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1594 static int of_spi_register_master(struct spi_master *master)
1601 * spi_register_master - register SPI master controller
1602 * @master: initialized master, originally from spi_alloc_master()
1603 * Context: can sleep
1605 * SPI master controllers connect to their drivers using some non-SPI bus,
1606 * such as the platform bus. The final stage of probe() in that code
1607 * includes calling spi_register_master() to hook up to this SPI bus glue.
1609 * SPI controllers use board specific (often SOC specific) bus numbers,
1610 * and board-specific addressing for SPI devices combines those numbers
1611 * with chip select numbers. Since SPI does not directly support dynamic
1612 * device identification, boards need configuration tables telling which
1613 * chip is at which address.
1615 * This must be called from context that can sleep. It returns zero on
1616 * success, else a negative error code (dropping the master's refcount).
1617 * After a successful return, the caller is responsible for calling
1618 * spi_unregister_master().
1620 int spi_register_master(struct spi_master *master)
1622 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1623 struct device *dev = master->dev.parent;
1624 struct boardinfo *bi;
1625 int status = -ENODEV;
1631 status = of_spi_register_master(master);
1635 /* even if it's just one always-selected device, there must
1636 * be at least one chipselect
1638 if (master->num_chipselect == 0)
1641 if ((master->bus_num < 0) && master->dev.of_node)
1642 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1644 /* convention: dynamically assigned bus IDs count down from the max */
1645 if (master->bus_num < 0) {
1646 /* FIXME switch to an IDR based scheme, something like
1647 * I2C now uses, so we can't run out of "dynamic" IDs
1649 master->bus_num = atomic_dec_return(&dyn_bus_id);
1653 INIT_LIST_HEAD(&master->queue);
1654 spin_lock_init(&master->queue_lock);
1655 spin_lock_init(&master->bus_lock_spinlock);
1656 mutex_init(&master->bus_lock_mutex);
1657 master->bus_lock_flag = 0;
1658 init_completion(&master->xfer_completion);
1659 if (!master->max_dma_len)
1660 master->max_dma_len = INT_MAX;
1662 /* register the device, then userspace will see it.
1663 * registration fails if the bus ID is in use.
1665 dev_set_name(&master->dev, "spi%u", master->bus_num);
1666 status = device_add(&master->dev);
1669 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1670 dynamic ? " (dynamic)" : "");
1672 /* If we're using a queued driver, start the queue */
1673 if (master->transfer)
1674 dev_info(dev, "master is unqueued, this is deprecated\n");
1676 status = spi_master_initialize_queue(master);
1678 device_del(&master->dev);
1683 mutex_lock(&board_lock);
1684 list_add_tail(&master->list, &spi_master_list);
1685 list_for_each_entry(bi, &board_list, list)
1686 spi_match_master_to_boardinfo(master, &bi->board_info);
1687 mutex_unlock(&board_lock);
1689 /* Register devices from the device tree and ACPI */
1690 of_register_spi_devices(master);
1691 acpi_register_spi_devices(master);
1695 EXPORT_SYMBOL_GPL(spi_register_master);
1697 static void devm_spi_unregister(struct device *dev, void *res)
1699 spi_unregister_master(*(struct spi_master **)res);
1703 * dev_spi_register_master - register managed SPI master controller
1704 * @dev: device managing SPI master
1705 * @master: initialized master, originally from spi_alloc_master()
1706 * Context: can sleep
1708 * Register a SPI device as with spi_register_master() which will
1709 * automatically be unregister
1711 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1713 struct spi_master **ptr;
1716 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1720 ret = spi_register_master(master);
1723 devres_add(dev, ptr);
1730 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1732 static int __unregister(struct device *dev, void *null)
1734 spi_unregister_device(to_spi_device(dev));
1739 * spi_unregister_master - unregister SPI master controller
1740 * @master: the master being unregistered
1741 * Context: can sleep
1743 * This call is used only by SPI master controller drivers, which are the
1744 * only ones directly touching chip registers.
1746 * This must be called from context that can sleep.
1748 void spi_unregister_master(struct spi_master *master)
1752 if (master->queued) {
1753 if (spi_destroy_queue(master))
1754 dev_err(&master->dev, "queue remove failed\n");
1757 mutex_lock(&board_lock);
1758 list_del(&master->list);
1759 mutex_unlock(&board_lock);
1761 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1762 device_unregister(&master->dev);
1764 EXPORT_SYMBOL_GPL(spi_unregister_master);
1766 int spi_master_suspend(struct spi_master *master)
1770 /* Basically no-ops for non-queued masters */
1771 if (!master->queued)
1774 ret = spi_stop_queue(master);
1776 dev_err(&master->dev, "queue stop failed\n");
1780 EXPORT_SYMBOL_GPL(spi_master_suspend);
1782 int spi_master_resume(struct spi_master *master)
1786 if (!master->queued)
1789 ret = spi_start_queue(master);
1791 dev_err(&master->dev, "queue restart failed\n");
1795 EXPORT_SYMBOL_GPL(spi_master_resume);
1797 static int __spi_master_match(struct device *dev, const void *data)
1799 struct spi_master *m;
1800 const u16 *bus_num = data;
1802 m = container_of(dev, struct spi_master, dev);
1803 return m->bus_num == *bus_num;
1807 * spi_busnum_to_master - look up master associated with bus_num
1808 * @bus_num: the master's bus number
1809 * Context: can sleep
1811 * This call may be used with devices that are registered after
1812 * arch init time. It returns a refcounted pointer to the relevant
1813 * spi_master (which the caller must release), or NULL if there is
1814 * no such master registered.
1816 struct spi_master *spi_busnum_to_master(u16 bus_num)
1819 struct spi_master *master = NULL;
1821 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1822 __spi_master_match);
1824 master = container_of(dev, struct spi_master, dev);
1825 /* reference got in class_find_device */
1828 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1831 /*-------------------------------------------------------------------------*/
1833 /* Core methods for SPI master protocol drivers. Some of the
1834 * other core methods are currently defined as inline functions.
1838 * spi_setup - setup SPI mode and clock rate
1839 * @spi: the device whose settings are being modified
1840 * Context: can sleep, and no requests are queued to the device
1842 * SPI protocol drivers may need to update the transfer mode if the
1843 * device doesn't work with its default. They may likewise need
1844 * to update clock rates or word sizes from initial values. This function
1845 * changes those settings, and must be called from a context that can sleep.
1846 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1847 * effect the next time the device is selected and data is transferred to
1848 * or from it. When this function returns, the spi device is deselected.
1850 * Note that this call will fail if the protocol driver specifies an option
1851 * that the underlying controller or its driver does not support. For
1852 * example, not all hardware supports wire transfers using nine bit words,
1853 * LSB-first wire encoding, or active-high chipselects.
1855 int spi_setup(struct spi_device *spi)
1857 unsigned bad_bits, ugly_bits;
1860 /* check mode to prevent that DUAL and QUAD set at the same time
1862 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1863 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1865 "setup: can not select dual and quad at the same time\n");
1868 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1870 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1871 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1873 /* help drivers fail *cleanly* when they need options
1874 * that aren't supported with their current master
1876 bad_bits = spi->mode & ~spi->master->mode_bits;
1877 ugly_bits = bad_bits &
1878 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1881 "setup: ignoring unsupported mode bits %x\n",
1883 spi->mode &= ~ugly_bits;
1884 bad_bits &= ~ugly_bits;
1887 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1892 if (!spi->bits_per_word)
1893 spi->bits_per_word = 8;
1895 if (!spi->max_speed_hz)
1896 spi->max_speed_hz = spi->master->max_speed_hz;
1898 spi_set_cs(spi, false);
1900 if (spi->master->setup)
1901 status = spi->master->setup(spi);
1903 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1904 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1905 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1906 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1907 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1908 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1909 spi->bits_per_word, spi->max_speed_hz,
1914 EXPORT_SYMBOL_GPL(spi_setup);
1916 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1918 struct spi_master *master = spi->master;
1919 struct spi_transfer *xfer;
1922 if (list_empty(&message->transfers))
1925 /* Half-duplex links include original MicroWire, and ones with
1926 * only one data pin like SPI_3WIRE (switches direction) or where
1927 * either MOSI or MISO is missing. They can also be caused by
1928 * software limitations.
1930 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1931 || (spi->mode & SPI_3WIRE)) {
1932 unsigned flags = master->flags;
1934 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1935 if (xfer->rx_buf && xfer->tx_buf)
1937 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1939 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1945 * Set transfer bits_per_word and max speed as spi device default if
1946 * it is not set for this transfer.
1947 * Set transfer tx_nbits and rx_nbits as single transfer default
1948 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1950 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1951 message->frame_length += xfer->len;
1952 if (!xfer->bits_per_word)
1953 xfer->bits_per_word = spi->bits_per_word;
1955 if (!xfer->speed_hz)
1956 xfer->speed_hz = spi->max_speed_hz;
1958 if (master->max_speed_hz &&
1959 xfer->speed_hz > master->max_speed_hz)
1960 xfer->speed_hz = master->max_speed_hz;
1962 if (master->bits_per_word_mask) {
1963 /* Only 32 bits fit in the mask */
1964 if (xfer->bits_per_word > 32)
1966 if (!(master->bits_per_word_mask &
1967 BIT(xfer->bits_per_word - 1)))
1972 * SPI transfer length should be multiple of SPI word size
1973 * where SPI word size should be power-of-two multiple
1975 if (xfer->bits_per_word <= 8)
1977 else if (xfer->bits_per_word <= 16)
1982 /* No partial transfers accepted */
1983 if (xfer->len % w_size)
1986 if (xfer->speed_hz && master->min_speed_hz &&
1987 xfer->speed_hz < master->min_speed_hz)
1990 if (xfer->tx_buf && !xfer->tx_nbits)
1991 xfer->tx_nbits = SPI_NBITS_SINGLE;
1992 if (xfer->rx_buf && !xfer->rx_nbits)
1993 xfer->rx_nbits = SPI_NBITS_SINGLE;
1994 /* check transfer tx/rx_nbits:
1995 * 1. check the value matches one of single, dual and quad
1996 * 2. check tx/rx_nbits match the mode in spi_device
1999 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2000 xfer->tx_nbits != SPI_NBITS_DUAL &&
2001 xfer->tx_nbits != SPI_NBITS_QUAD)
2003 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2004 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2006 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2007 !(spi->mode & SPI_TX_QUAD))
2010 /* check transfer rx_nbits */
2012 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2013 xfer->rx_nbits != SPI_NBITS_DUAL &&
2014 xfer->rx_nbits != SPI_NBITS_QUAD)
2016 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2017 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2019 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2020 !(spi->mode & SPI_RX_QUAD))
2025 message->status = -EINPROGRESS;
2030 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2032 struct spi_master *master = spi->master;
2036 trace_spi_message_submit(message);
2038 return master->transfer(spi, message);
2042 * spi_async - asynchronous SPI transfer
2043 * @spi: device with which data will be exchanged
2044 * @message: describes the data transfers, including completion callback
2045 * Context: any (irqs may be blocked, etc)
2047 * This call may be used in_irq and other contexts which can't sleep,
2048 * as well as from task contexts which can sleep.
2050 * The completion callback is invoked in a context which can't sleep.
2051 * Before that invocation, the value of message->status is undefined.
2052 * When the callback is issued, message->status holds either zero (to
2053 * indicate complete success) or a negative error code. After that
2054 * callback returns, the driver which issued the transfer request may
2055 * deallocate the associated memory; it's no longer in use by any SPI
2056 * core or controller driver code.
2058 * Note that although all messages to a spi_device are handled in
2059 * FIFO order, messages may go to different devices in other orders.
2060 * Some device might be higher priority, or have various "hard" access
2061 * time requirements, for example.
2063 * On detection of any fault during the transfer, processing of
2064 * the entire message is aborted, and the device is deselected.
2065 * Until returning from the associated message completion callback,
2066 * no other spi_message queued to that device will be processed.
2067 * (This rule applies equally to all the synchronous transfer calls,
2068 * which are wrappers around this core asynchronous primitive.)
2070 int spi_async(struct spi_device *spi, struct spi_message *message)
2072 struct spi_master *master = spi->master;
2074 unsigned long flags;
2076 ret = __spi_validate(spi, message);
2080 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2082 if (master->bus_lock_flag)
2085 ret = __spi_async(spi, message);
2087 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2091 EXPORT_SYMBOL_GPL(spi_async);
2094 * spi_async_locked - version of spi_async with exclusive bus usage
2095 * @spi: device with which data will be exchanged
2096 * @message: describes the data transfers, including completion callback
2097 * Context: any (irqs may be blocked, etc)
2099 * This call may be used in_irq and other contexts which can't sleep,
2100 * as well as from task contexts which can sleep.
2102 * The completion callback is invoked in a context which can't sleep.
2103 * Before that invocation, the value of message->status is undefined.
2104 * When the callback is issued, message->status holds either zero (to
2105 * indicate complete success) or a negative error code. After that
2106 * callback returns, the driver which issued the transfer request may
2107 * deallocate the associated memory; it's no longer in use by any SPI
2108 * core or controller driver code.
2110 * Note that although all messages to a spi_device are handled in
2111 * FIFO order, messages may go to different devices in other orders.
2112 * Some device might be higher priority, or have various "hard" access
2113 * time requirements, for example.
2115 * On detection of any fault during the transfer, processing of
2116 * the entire message is aborted, and the device is deselected.
2117 * Until returning from the associated message completion callback,
2118 * no other spi_message queued to that device will be processed.
2119 * (This rule applies equally to all the synchronous transfer calls,
2120 * which are wrappers around this core asynchronous primitive.)
2122 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2124 struct spi_master *master = spi->master;
2126 unsigned long flags;
2128 ret = __spi_validate(spi, message);
2132 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2134 ret = __spi_async(spi, message);
2136 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2141 EXPORT_SYMBOL_GPL(spi_async_locked);
2144 /*-------------------------------------------------------------------------*/
2146 /* Utility methods for SPI master protocol drivers, layered on
2147 * top of the core. Some other utility methods are defined as
2151 static void spi_complete(void *arg)
2156 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2159 DECLARE_COMPLETION_ONSTACK(done);
2161 struct spi_master *master = spi->master;
2162 unsigned long flags;
2164 status = __spi_validate(spi, message);
2168 message->complete = spi_complete;
2169 message->context = &done;
2173 mutex_lock(&master->bus_lock_mutex);
2175 /* If we're not using the legacy transfer method then we will
2176 * try to transfer in the calling context so special case.
2177 * This code would be less tricky if we could remove the
2178 * support for driver implemented message queues.
2180 if (master->transfer == spi_queued_transfer) {
2181 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2183 trace_spi_message_submit(message);
2185 status = __spi_queued_transfer(spi, message, false);
2187 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2189 status = spi_async_locked(spi, message);
2193 mutex_unlock(&master->bus_lock_mutex);
2196 /* Push out the messages in the calling context if we
2199 if (master->transfer == spi_queued_transfer)
2200 __spi_pump_messages(master, false);
2202 wait_for_completion(&done);
2203 status = message->status;
2205 message->context = NULL;
2210 * spi_sync - blocking/synchronous SPI data transfers
2211 * @spi: device with which data will be exchanged
2212 * @message: describes the data transfers
2213 * Context: can sleep
2215 * This call may only be used from a context that may sleep. The sleep
2216 * is non-interruptible, and has no timeout. Low-overhead controller
2217 * drivers may DMA directly into and out of the message buffers.
2219 * Note that the SPI device's chip select is active during the message,
2220 * and then is normally disabled between messages. Drivers for some
2221 * frequently-used devices may want to minimize costs of selecting a chip,
2222 * by leaving it selected in anticipation that the next message will go
2223 * to the same chip. (That may increase power usage.)
2225 * Also, the caller is guaranteeing that the memory associated with the
2226 * message will not be freed before this call returns.
2228 * It returns zero on success, else a negative error code.
2230 int spi_sync(struct spi_device *spi, struct spi_message *message)
2232 return __spi_sync(spi, message, 0);
2234 EXPORT_SYMBOL_GPL(spi_sync);
2237 * spi_sync_locked - version of spi_sync with exclusive bus usage
2238 * @spi: device with which data will be exchanged
2239 * @message: describes the data transfers
2240 * Context: can sleep
2242 * This call may only be used from a context that may sleep. The sleep
2243 * is non-interruptible, and has no timeout. Low-overhead controller
2244 * drivers may DMA directly into and out of the message buffers.
2246 * This call should be used by drivers that require exclusive access to the
2247 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2248 * be released by a spi_bus_unlock call when the exclusive access is over.
2250 * It returns zero on success, else a negative error code.
2252 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2254 return __spi_sync(spi, message, 1);
2256 EXPORT_SYMBOL_GPL(spi_sync_locked);
2259 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2260 * @master: SPI bus master that should be locked for exclusive bus access
2261 * Context: can sleep
2263 * This call may only be used from a context that may sleep. The sleep
2264 * is non-interruptible, and has no timeout.
2266 * This call should be used by drivers that require exclusive access to the
2267 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2268 * exclusive access is over. Data transfer must be done by spi_sync_locked
2269 * and spi_async_locked calls when the SPI bus lock is held.
2271 * It returns zero on success, else a negative error code.
2273 int spi_bus_lock(struct spi_master *master)
2275 unsigned long flags;
2277 mutex_lock(&master->bus_lock_mutex);
2279 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2280 master->bus_lock_flag = 1;
2281 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2283 /* mutex remains locked until spi_bus_unlock is called */
2287 EXPORT_SYMBOL_GPL(spi_bus_lock);
2290 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2291 * @master: SPI bus master that was locked for exclusive bus access
2292 * Context: can sleep
2294 * This call may only be used from a context that may sleep. The sleep
2295 * is non-interruptible, and has no timeout.
2297 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2300 * It returns zero on success, else a negative error code.
2302 int spi_bus_unlock(struct spi_master *master)
2304 master->bus_lock_flag = 0;
2306 mutex_unlock(&master->bus_lock_mutex);
2310 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2312 /* portable code must never pass more than 32 bytes */
2313 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2318 * spi_write_then_read - SPI synchronous write followed by read
2319 * @spi: device with which data will be exchanged
2320 * @txbuf: data to be written (need not be dma-safe)
2321 * @n_tx: size of txbuf, in bytes
2322 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2323 * @n_rx: size of rxbuf, in bytes
2324 * Context: can sleep
2326 * This performs a half duplex MicroWire style transaction with the
2327 * device, sending txbuf and then reading rxbuf. The return value
2328 * is zero for success, else a negative errno status code.
2329 * This call may only be used from a context that may sleep.
2331 * Parameters to this routine are always copied using a small buffer;
2332 * portable code should never use this for more than 32 bytes.
2333 * Performance-sensitive or bulk transfer code should instead use
2334 * spi_{async,sync}() calls with dma-safe buffers.
2336 int spi_write_then_read(struct spi_device *spi,
2337 const void *txbuf, unsigned n_tx,
2338 void *rxbuf, unsigned n_rx)
2340 static DEFINE_MUTEX(lock);
2343 struct spi_message message;
2344 struct spi_transfer x[2];
2347 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2348 * copying here, (as a pure convenience thing), but we can
2349 * keep heap costs out of the hot path unless someone else is
2350 * using the pre-allocated buffer or the transfer is too large.
2352 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2353 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2354 GFP_KERNEL | GFP_DMA);
2361 spi_message_init(&message);
2362 memset(x, 0, sizeof(x));
2365 spi_message_add_tail(&x[0], &message);
2369 spi_message_add_tail(&x[1], &message);
2372 memcpy(local_buf, txbuf, n_tx);
2373 x[0].tx_buf = local_buf;
2374 x[1].rx_buf = local_buf + n_tx;
2377 status = spi_sync(spi, &message);
2379 memcpy(rxbuf, x[1].rx_buf, n_rx);
2381 if (x[0].tx_buf == buf)
2382 mutex_unlock(&lock);
2388 EXPORT_SYMBOL_GPL(spi_write_then_read);
2390 /*-------------------------------------------------------------------------*/
2392 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2393 static int __spi_of_device_match(struct device *dev, void *data)
2395 return dev->of_node == data;
2398 /* must call put_device() when done with returned spi_device device */
2399 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2401 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2402 __spi_of_device_match);
2403 return dev ? to_spi_device(dev) : NULL;
2406 static int __spi_of_master_match(struct device *dev, const void *data)
2408 return dev->of_node == data;
2411 /* the spi masters are not using spi_bus, so we find it with another way */
2412 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2416 dev = class_find_device(&spi_master_class, NULL, node,
2417 __spi_of_master_match);
2421 /* reference got in class_find_device */
2422 return container_of(dev, struct spi_master, dev);
2425 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2428 struct of_reconfig_data *rd = arg;
2429 struct spi_master *master;
2430 struct spi_device *spi;
2432 switch (of_reconfig_get_state_change(action, arg)) {
2433 case OF_RECONFIG_CHANGE_ADD:
2434 master = of_find_spi_master_by_node(rd->dn->parent);
2436 return NOTIFY_OK; /* not for us */
2438 spi = of_register_spi_device(master, rd->dn);
2439 put_device(&master->dev);
2442 pr_err("%s: failed to create for '%s'\n",
2443 __func__, rd->dn->full_name);
2444 return notifier_from_errno(PTR_ERR(spi));
2448 case OF_RECONFIG_CHANGE_REMOVE:
2449 /* find our device by node */
2450 spi = of_find_spi_device_by_node(rd->dn);
2452 return NOTIFY_OK; /* no? not meant for us */
2454 /* unregister takes one ref away */
2455 spi_unregister_device(spi);
2457 /* and put the reference of the find */
2458 put_device(&spi->dev);
2465 static struct notifier_block spi_of_notifier = {
2466 .notifier_call = of_spi_notify,
2468 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2469 extern struct notifier_block spi_of_notifier;
2470 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2472 static int __init spi_init(void)
2476 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2482 status = bus_register(&spi_bus_type);
2486 status = class_register(&spi_master_class);
2490 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2491 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2496 bus_unregister(&spi_bus_type);
2504 /* board_info is normally registered in arch_initcall(),
2505 * but even essential drivers wait till later
2507 * REVISIT only boardinfo really needs static linking. the rest (device and
2508 * driver registration) _could_ be dynamically linked (modular) ... costs
2509 * include needing to have boardinfo data structures be much more public.
2511 postcore_initcall(spi_init);