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/kmod.h>
20 #include <linux/device.h>
21 #include <linux/init.h>
22 #include <linux/cache.h>
23 #include <linux/dma-mapping.h>
24 #include <linux/dmaengine.h>
25 #include <linux/mutex.h>
26 #include <linux/of_device.h>
27 #include <linux/of_irq.h>
28 #include <linux/clk/clk-conf.h>
29 #include <linux/slab.h>
30 #include <linux/mod_devicetable.h>
31 #include <linux/spi/spi.h>
32 #include <linux/of_gpio.h>
33 #include <linux/pm_runtime.h>
34 #include <linux/pm_domain.h>
35 #include <linux/export.h>
36 #include <linux/sched/rt.h>
37 #include <linux/delay.h>
38 #include <linux/kthread.h>
39 #include <linux/ioport.h>
40 #include <linux/acpi.h>
42 #define CREATE_TRACE_POINTS
43 #include <trace/events/spi.h>
45 static void spidev_release(struct device *dev)
47 struct spi_device *spi = to_spi_device(dev);
49 /* spi masters may cleanup for released devices */
50 if (spi->master->cleanup)
51 spi->master->cleanup(spi);
53 spi_master_put(spi->master);
58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
60 const struct spi_device *spi = to_spi_device(dev);
63 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
67 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
69 static DEVICE_ATTR_RO(modalias);
71 static struct attribute *spi_dev_attrs[] = {
72 &dev_attr_modalias.attr,
75 ATTRIBUTE_GROUPS(spi_dev);
77 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
78 * and the sysfs version makes coldplug work too.
81 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
82 const struct spi_device *sdev)
85 if (!strcmp(sdev->modalias, id->name))
92 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
94 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
96 return spi_match_id(sdrv->id_table, sdev);
98 EXPORT_SYMBOL_GPL(spi_get_device_id);
100 static int spi_match_device(struct device *dev, struct device_driver *drv)
102 const struct spi_device *spi = to_spi_device(dev);
103 const struct spi_driver *sdrv = to_spi_driver(drv);
105 /* Attempt an OF style match */
106 if (of_driver_match_device(dev, drv))
110 if (acpi_driver_match_device(dev, drv))
114 return !!spi_match_id(sdrv->id_table, spi);
116 return strcmp(spi->modalias, drv->name) == 0;
119 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
121 const struct spi_device *spi = to_spi_device(dev);
124 rc = acpi_device_uevent_modalias(dev, env);
128 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
132 #ifdef CONFIG_PM_SLEEP
133 static int spi_legacy_suspend(struct device *dev, pm_message_t message)
136 struct spi_driver *drv = to_spi_driver(dev->driver);
138 /* suspend will stop irqs and dma; no more i/o */
141 value = drv->suspend(to_spi_device(dev), message);
143 dev_dbg(dev, "... can't suspend\n");
148 static int spi_legacy_resume(struct device *dev)
151 struct spi_driver *drv = to_spi_driver(dev->driver);
153 /* resume may restart the i/o queue */
156 value = drv->resume(to_spi_device(dev));
158 dev_dbg(dev, "... can't resume\n");
163 static int spi_pm_suspend(struct device *dev)
165 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
168 return pm_generic_suspend(dev);
170 return spi_legacy_suspend(dev, PMSG_SUSPEND);
173 static int spi_pm_resume(struct device *dev)
175 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
178 return pm_generic_resume(dev);
180 return spi_legacy_resume(dev);
183 static int spi_pm_freeze(struct device *dev)
185 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
188 return pm_generic_freeze(dev);
190 return spi_legacy_suspend(dev, PMSG_FREEZE);
193 static int spi_pm_thaw(struct device *dev)
195 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
198 return pm_generic_thaw(dev);
200 return spi_legacy_resume(dev);
203 static int spi_pm_poweroff(struct device *dev)
205 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
208 return pm_generic_poweroff(dev);
210 return spi_legacy_suspend(dev, PMSG_HIBERNATE);
213 static int spi_pm_restore(struct device *dev)
215 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
218 return pm_generic_restore(dev);
220 return spi_legacy_resume(dev);
223 #define spi_pm_suspend NULL
224 #define spi_pm_resume NULL
225 #define spi_pm_freeze NULL
226 #define spi_pm_thaw NULL
227 #define spi_pm_poweroff NULL
228 #define spi_pm_restore NULL
231 static const struct dev_pm_ops spi_pm = {
232 .suspend = spi_pm_suspend,
233 .resume = spi_pm_resume,
234 .freeze = spi_pm_freeze,
236 .poweroff = spi_pm_poweroff,
237 .restore = spi_pm_restore,
239 pm_generic_runtime_suspend,
240 pm_generic_runtime_resume,
245 struct bus_type spi_bus_type = {
247 .dev_groups = spi_dev_groups,
248 .match = spi_match_device,
249 .uevent = spi_uevent,
252 EXPORT_SYMBOL_GPL(spi_bus_type);
255 static int spi_drv_probe(struct device *dev)
257 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
260 ret = of_clk_set_defaults(dev->of_node, false);
264 ret = dev_pm_domain_attach(dev, true);
265 if (ret != -EPROBE_DEFER) {
266 ret = sdrv->probe(to_spi_device(dev));
268 dev_pm_domain_detach(dev, true);
274 static int spi_drv_remove(struct device *dev)
276 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
279 ret = sdrv->remove(to_spi_device(dev));
280 dev_pm_domain_detach(dev, true);
285 static void spi_drv_shutdown(struct device *dev)
287 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
289 sdrv->shutdown(to_spi_device(dev));
293 * spi_register_driver - register a SPI driver
294 * @sdrv: the driver to register
297 int spi_register_driver(struct spi_driver *sdrv)
299 sdrv->driver.bus = &spi_bus_type;
301 sdrv->driver.probe = spi_drv_probe;
303 sdrv->driver.remove = spi_drv_remove;
305 sdrv->driver.shutdown = spi_drv_shutdown;
306 return driver_register(&sdrv->driver);
308 EXPORT_SYMBOL_GPL(spi_register_driver);
310 /*-------------------------------------------------------------------------*/
312 /* SPI devices should normally not be created by SPI device drivers; that
313 * would make them board-specific. Similarly with SPI master drivers.
314 * Device registration normally goes into like arch/.../mach.../board-YYY.c
315 * with other readonly (flashable) information about mainboard devices.
319 struct list_head list;
320 struct spi_board_info board_info;
323 static LIST_HEAD(board_list);
324 static LIST_HEAD(spi_master_list);
327 * Used to protect add/del opertion for board_info list and
328 * spi_master list, and their matching process
330 static DEFINE_MUTEX(board_lock);
333 * spi_alloc_device - Allocate a new SPI device
334 * @master: Controller to which device is connected
337 * Allows a driver to allocate and initialize a spi_device without
338 * registering it immediately. This allows a driver to directly
339 * fill the spi_device with device parameters before calling
340 * spi_add_device() on it.
342 * Caller is responsible to call spi_add_device() on the returned
343 * spi_device structure to add it to the SPI master. If the caller
344 * needs to discard the spi_device without adding it, then it should
345 * call spi_dev_put() on it.
347 * Returns a pointer to the new device, or NULL.
349 struct spi_device *spi_alloc_device(struct spi_master *master)
351 struct spi_device *spi;
353 if (!spi_master_get(master))
356 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
358 spi_master_put(master);
362 spi->master = master;
363 spi->dev.parent = &master->dev;
364 spi->dev.bus = &spi_bus_type;
365 spi->dev.release = spidev_release;
366 spi->cs_gpio = -ENOENT;
367 device_initialize(&spi->dev);
370 EXPORT_SYMBOL_GPL(spi_alloc_device);
372 static void spi_dev_set_name(struct spi_device *spi)
374 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
377 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
381 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
385 static int spi_dev_check(struct device *dev, void *data)
387 struct spi_device *spi = to_spi_device(dev);
388 struct spi_device *new_spi = data;
390 if (spi->master == new_spi->master &&
391 spi->chip_select == new_spi->chip_select)
397 * spi_add_device - Add spi_device allocated with spi_alloc_device
398 * @spi: spi_device to register
400 * Companion function to spi_alloc_device. Devices allocated with
401 * spi_alloc_device can be added onto the spi bus with this function.
403 * Returns 0 on success; negative errno on failure
405 int spi_add_device(struct spi_device *spi)
407 static DEFINE_MUTEX(spi_add_lock);
408 struct spi_master *master = spi->master;
409 struct device *dev = master->dev.parent;
412 /* Chipselects are numbered 0..max; validate. */
413 if (spi->chip_select >= master->num_chipselect) {
414 dev_err(dev, "cs%d >= max %d\n",
416 master->num_chipselect);
420 /* Set the bus ID string */
421 spi_dev_set_name(spi);
423 /* We need to make sure there's no other device with this
424 * chipselect **BEFORE** we call setup(), else we'll trash
425 * its configuration. Lock against concurrent add() calls.
427 mutex_lock(&spi_add_lock);
429 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
431 dev_err(dev, "chipselect %d already in use\n",
436 if (master->cs_gpios)
437 spi->cs_gpio = master->cs_gpios[spi->chip_select];
439 /* Drivers may modify this initial i/o setup, but will
440 * normally rely on the device being setup. Devices
441 * using SPI_CS_HIGH can't coexist well otherwise...
443 status = spi_setup(spi);
445 dev_err(dev, "can't setup %s, status %d\n",
446 dev_name(&spi->dev), status);
450 /* Device may be bound to an active driver when this returns */
451 status = device_add(&spi->dev);
453 dev_err(dev, "can't add %s, status %d\n",
454 dev_name(&spi->dev), status);
456 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
459 mutex_unlock(&spi_add_lock);
462 EXPORT_SYMBOL_GPL(spi_add_device);
465 * spi_new_device - instantiate one new SPI device
466 * @master: Controller to which device is connected
467 * @chip: Describes the SPI device
470 * On typical mainboards, this is purely internal; and it's not needed
471 * after board init creates the hard-wired devices. Some development
472 * platforms may not be able to use spi_register_board_info though, and
473 * this is exported so that for example a USB or parport based adapter
474 * driver could add devices (which it would learn about out-of-band).
476 * Returns the new device, or NULL.
478 struct spi_device *spi_new_device(struct spi_master *master,
479 struct spi_board_info *chip)
481 struct spi_device *proxy;
484 /* NOTE: caller did any chip->bus_num checks necessary.
486 * Also, unless we change the return value convention to use
487 * error-or-pointer (not NULL-or-pointer), troubleshootability
488 * suggests syslogged diagnostics are best here (ugh).
491 proxy = spi_alloc_device(master);
495 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
497 proxy->chip_select = chip->chip_select;
498 proxy->max_speed_hz = chip->max_speed_hz;
499 proxy->mode = chip->mode;
500 proxy->irq = chip->irq;
501 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
502 proxy->dev.platform_data = (void *) chip->platform_data;
503 proxy->controller_data = chip->controller_data;
504 proxy->controller_state = NULL;
506 status = spi_add_device(proxy);
514 EXPORT_SYMBOL_GPL(spi_new_device);
516 static void spi_match_master_to_boardinfo(struct spi_master *master,
517 struct spi_board_info *bi)
519 struct spi_device *dev;
521 if (master->bus_num != bi->bus_num)
524 dev = spi_new_device(master, bi);
526 dev_err(master->dev.parent, "can't create new device for %s\n",
531 * spi_register_board_info - register SPI devices for a given board
532 * @info: array of chip descriptors
533 * @n: how many descriptors are provided
536 * Board-specific early init code calls this (probably during arch_initcall)
537 * with segments of the SPI device table. Any device nodes are created later,
538 * after the relevant parent SPI controller (bus_num) is defined. We keep
539 * this table of devices forever, so that reloading a controller driver will
540 * not make Linux forget about these hard-wired devices.
542 * Other code can also call this, e.g. a particular add-on board might provide
543 * SPI devices through its expansion connector, so code initializing that board
544 * would naturally declare its SPI devices.
546 * The board info passed can safely be __initdata ... but be careful of
547 * any embedded pointers (platform_data, etc), they're copied as-is.
549 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
551 struct boardinfo *bi;
557 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
561 for (i = 0; i < n; i++, bi++, info++) {
562 struct spi_master *master;
564 memcpy(&bi->board_info, info, sizeof(*info));
565 mutex_lock(&board_lock);
566 list_add_tail(&bi->list, &board_list);
567 list_for_each_entry(master, &spi_master_list, list)
568 spi_match_master_to_boardinfo(master, &bi->board_info);
569 mutex_unlock(&board_lock);
575 /*-------------------------------------------------------------------------*/
577 static void spi_set_cs(struct spi_device *spi, bool enable)
579 if (spi->mode & SPI_CS_HIGH)
582 if (spi->cs_gpio >= 0)
583 gpio_set_value(spi->cs_gpio, !enable);
584 else if (spi->master->set_cs)
585 spi->master->set_cs(spi, !enable);
588 #ifdef CONFIG_HAS_DMA
589 static int spi_map_buf(struct spi_master *master, struct device *dev,
590 struct sg_table *sgt, void *buf, size_t len,
591 enum dma_data_direction dir)
593 const bool vmalloced_buf = is_vmalloc_addr(buf);
594 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
595 const int sgs = DIV_ROUND_UP(len, desc_len);
596 struct page *vm_page;
601 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
605 for (i = 0; i < sgs; i++) {
606 min = min_t(size_t, len, desc_len);
609 vm_page = vmalloc_to_page(buf);
614 sg_set_page(&sgt->sgl[i], vm_page,
615 min, offset_in_page(buf));
618 sg_set_buf(&sgt->sgl[i], sg_buf, min);
626 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
639 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
640 struct sg_table *sgt, enum dma_data_direction dir)
642 if (sgt->orig_nents) {
643 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
648 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
650 struct device *tx_dev, *rx_dev;
651 struct spi_transfer *xfer;
654 if (!master->can_dma)
657 tx_dev = master->dma_tx->device->dev;
658 rx_dev = master->dma_rx->device->dev;
660 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
661 if (!master->can_dma(master, msg->spi, xfer))
664 if (xfer->tx_buf != NULL) {
665 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
666 (void *)xfer->tx_buf, xfer->len,
672 if (xfer->rx_buf != NULL) {
673 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
674 xfer->rx_buf, xfer->len,
677 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
684 master->cur_msg_mapped = true;
689 static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
691 struct spi_transfer *xfer;
692 struct device *tx_dev, *rx_dev;
694 if (!master->cur_msg_mapped || !master->can_dma)
697 tx_dev = master->dma_tx->device->dev;
698 rx_dev = master->dma_rx->device->dev;
700 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
701 if (!master->can_dma(master, msg->spi, xfer))
704 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
705 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
710 #else /* !CONFIG_HAS_DMA */
711 static inline int __spi_map_msg(struct spi_master *master,
712 struct spi_message *msg)
717 static inline int spi_unmap_msg(struct spi_master *master,
718 struct spi_message *msg)
722 #endif /* !CONFIG_HAS_DMA */
724 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
726 struct spi_transfer *xfer;
728 unsigned int max_tx, max_rx;
730 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
734 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
735 if ((master->flags & SPI_MASTER_MUST_TX) &&
737 max_tx = max(xfer->len, max_tx);
738 if ((master->flags & SPI_MASTER_MUST_RX) &&
740 max_rx = max(xfer->len, max_rx);
744 tmp = krealloc(master->dummy_tx, max_tx,
745 GFP_KERNEL | GFP_DMA);
748 master->dummy_tx = tmp;
749 memset(tmp, 0, max_tx);
753 tmp = krealloc(master->dummy_rx, max_rx,
754 GFP_KERNEL | GFP_DMA);
757 master->dummy_rx = tmp;
760 if (max_tx || max_rx) {
761 list_for_each_entry(xfer, &msg->transfers,
764 xfer->tx_buf = master->dummy_tx;
766 xfer->rx_buf = master->dummy_rx;
771 return __spi_map_msg(master, msg);
775 * spi_transfer_one_message - Default implementation of transfer_one_message()
777 * This is a standard implementation of transfer_one_message() for
778 * drivers which impelment a transfer_one() operation. It provides
779 * standard handling of delays and chip select management.
781 static int spi_transfer_one_message(struct spi_master *master,
782 struct spi_message *msg)
784 struct spi_transfer *xfer;
785 bool keep_cs = false;
787 unsigned long ms = 1;
789 spi_set_cs(msg->spi, true);
791 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
792 trace_spi_transfer_start(msg, xfer);
794 if (xfer->tx_buf || xfer->rx_buf) {
795 reinit_completion(&master->xfer_completion);
797 ret = master->transfer_one(master, msg->spi, xfer);
799 dev_err(&msg->spi->dev,
800 "SPI transfer failed: %d\n", ret);
806 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
807 ms += ms + 100; /* some tolerance */
809 ms = wait_for_completion_timeout(&master->xfer_completion,
810 msecs_to_jiffies(ms));
814 dev_err(&msg->spi->dev,
815 "SPI transfer timed out\n");
816 msg->status = -ETIMEDOUT;
820 dev_err(&msg->spi->dev,
821 "Bufferless transfer has length %u\n",
825 trace_spi_transfer_stop(msg, xfer);
827 if (msg->status != -EINPROGRESS)
830 if (xfer->delay_usecs)
831 udelay(xfer->delay_usecs);
833 if (xfer->cs_change) {
834 if (list_is_last(&xfer->transfer_list,
838 spi_set_cs(msg->spi, false);
840 spi_set_cs(msg->spi, true);
844 msg->actual_length += xfer->len;
848 if (ret != 0 || !keep_cs)
849 spi_set_cs(msg->spi, false);
851 if (msg->status == -EINPROGRESS)
854 spi_finalize_current_message(master);
860 * spi_finalize_current_transfer - report completion of a transfer
861 * @master: the master reporting completion
863 * Called by SPI drivers using the core transfer_one_message()
864 * implementation to notify it that the current interrupt driven
865 * transfer has finished and the next one may be scheduled.
867 void spi_finalize_current_transfer(struct spi_master *master)
869 complete(&master->xfer_completion);
871 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
874 * spi_pump_messages - kthread work function which processes spi message queue
875 * @work: pointer to kthread work struct contained in the master struct
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.
882 static void spi_pump_messages(struct kthread_work *work)
884 struct spi_master *master =
885 container_of(work, struct spi_master, pump_messages);
887 bool was_busy = false;
890 /* Lock queue and check for queue work */
891 spin_lock_irqsave(&master->queue_lock, flags);
892 if (list_empty(&master->queue) || !master->running) {
894 spin_unlock_irqrestore(&master->queue_lock, flags);
897 master->busy = false;
898 spin_unlock_irqrestore(&master->queue_lock, flags);
899 kfree(master->dummy_rx);
900 master->dummy_rx = NULL;
901 kfree(master->dummy_tx);
902 master->dummy_tx = NULL;
903 if (master->unprepare_transfer_hardware &&
904 master->unprepare_transfer_hardware(master))
905 dev_err(&master->dev,
906 "failed to unprepare transfer hardware\n");
907 if (master->auto_runtime_pm) {
908 pm_runtime_mark_last_busy(master->dev.parent);
909 pm_runtime_put_autosuspend(master->dev.parent);
911 trace_spi_master_idle(master);
915 /* Make sure we are not already running a message */
916 if (master->cur_msg) {
917 spin_unlock_irqrestore(&master->queue_lock, flags);
920 /* Extract head of queue */
922 list_first_entry(&master->queue, struct spi_message, queue);
924 list_del_init(&master->cur_msg->queue);
929 spin_unlock_irqrestore(&master->queue_lock, flags);
931 if (!was_busy && master->auto_runtime_pm) {
932 ret = pm_runtime_get_sync(master->dev.parent);
934 dev_err(&master->dev, "Failed to power device: %d\n",
941 trace_spi_master_busy(master);
943 if (!was_busy && master->prepare_transfer_hardware) {
944 ret = master->prepare_transfer_hardware(master);
946 dev_err(&master->dev,
947 "failed to prepare transfer hardware\n");
949 if (master->auto_runtime_pm)
950 pm_runtime_put(master->dev.parent);
955 trace_spi_message_start(master->cur_msg);
957 if (master->prepare_message) {
958 ret = master->prepare_message(master, master->cur_msg);
960 dev_err(&master->dev,
961 "failed to prepare message: %d\n", ret);
962 master->cur_msg->status = ret;
963 spi_finalize_current_message(master);
966 master->cur_msg_prepared = true;
969 ret = spi_map_msg(master, master->cur_msg);
971 master->cur_msg->status = ret;
972 spi_finalize_current_message(master);
976 ret = master->transfer_one_message(master, master->cur_msg);
978 dev_err(&master->dev,
979 "failed to transfer one message from queue\n");
984 static int spi_init_queue(struct spi_master *master)
986 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
988 INIT_LIST_HEAD(&master->queue);
989 spin_lock_init(&master->queue_lock);
991 master->running = false;
992 master->busy = false;
994 init_kthread_worker(&master->kworker);
995 master->kworker_task = kthread_run(kthread_worker_fn,
996 &master->kworker, "%s",
997 dev_name(&master->dev));
998 if (IS_ERR(master->kworker_task)) {
999 dev_err(&master->dev, "failed to create message pump task\n");
1000 return PTR_ERR(master->kworker_task);
1002 init_kthread_work(&master->pump_messages, spi_pump_messages);
1005 * Master config will indicate if this controller should run the
1006 * message pump with high (realtime) priority to reduce the transfer
1007 * latency on the bus by minimising the delay between a transfer
1008 * request and the scheduling of the message pump thread. Without this
1009 * setting the message pump thread will remain at default priority.
1012 dev_info(&master->dev,
1013 "will run message pump with realtime priority\n");
1014 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1021 * spi_get_next_queued_message() - called by driver to check for queued
1023 * @master: the master to check for queued messages
1025 * If there are more messages in the queue, the next message is returned from
1028 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1030 struct spi_message *next;
1031 unsigned long flags;
1033 /* get a pointer to the next message, if any */
1034 spin_lock_irqsave(&master->queue_lock, flags);
1035 next = list_first_entry_or_null(&master->queue, struct spi_message,
1037 spin_unlock_irqrestore(&master->queue_lock, flags);
1041 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1044 * spi_finalize_current_message() - the current message is complete
1045 * @master: the master to return the message to
1047 * Called by the driver to notify the core that the message in the front of the
1048 * queue is complete and can be removed from the queue.
1050 void spi_finalize_current_message(struct spi_master *master)
1052 struct spi_message *mesg;
1053 unsigned long flags;
1056 spin_lock_irqsave(&master->queue_lock, flags);
1057 mesg = master->cur_msg;
1058 master->cur_msg = NULL;
1060 queue_kthread_work(&master->kworker, &master->pump_messages);
1061 spin_unlock_irqrestore(&master->queue_lock, flags);
1063 spi_unmap_msg(master, mesg);
1065 if (master->cur_msg_prepared && master->unprepare_message) {
1066 ret = master->unprepare_message(master, mesg);
1068 dev_err(&master->dev,
1069 "failed to unprepare message: %d\n", ret);
1072 master->cur_msg_prepared = false;
1076 mesg->complete(mesg->context);
1078 trace_spi_message_done(mesg);
1080 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1082 static int spi_start_queue(struct spi_master *master)
1084 unsigned long flags;
1086 spin_lock_irqsave(&master->queue_lock, flags);
1088 if (master->running || master->busy) {
1089 spin_unlock_irqrestore(&master->queue_lock, flags);
1093 master->running = true;
1094 master->cur_msg = NULL;
1095 spin_unlock_irqrestore(&master->queue_lock, flags);
1097 queue_kthread_work(&master->kworker, &master->pump_messages);
1102 static int spi_stop_queue(struct spi_master *master)
1104 unsigned long flags;
1105 unsigned limit = 500;
1108 spin_lock_irqsave(&master->queue_lock, flags);
1111 * This is a bit lame, but is optimized for the common execution path.
1112 * A wait_queue on the master->busy could be used, but then the common
1113 * execution path (pump_messages) would be required to call wake_up or
1114 * friends on every SPI message. Do this instead.
1116 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1117 spin_unlock_irqrestore(&master->queue_lock, flags);
1118 usleep_range(10000, 11000);
1119 spin_lock_irqsave(&master->queue_lock, flags);
1122 if (!list_empty(&master->queue) || master->busy)
1125 master->running = false;
1127 spin_unlock_irqrestore(&master->queue_lock, flags);
1130 dev_warn(&master->dev,
1131 "could not stop message queue\n");
1137 static int spi_destroy_queue(struct spi_master *master)
1141 ret = spi_stop_queue(master);
1144 * flush_kthread_worker will block until all work is done.
1145 * If the reason that stop_queue timed out is that the work will never
1146 * finish, then it does no good to call flush/stop thread, so
1150 dev_err(&master->dev, "problem destroying queue\n");
1154 flush_kthread_worker(&master->kworker);
1155 kthread_stop(master->kworker_task);
1161 * spi_queued_transfer - transfer function for queued transfers
1162 * @spi: spi device which is requesting transfer
1163 * @msg: spi message which is to handled is queued to driver queue
1165 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1167 struct spi_master *master = spi->master;
1168 unsigned long flags;
1170 spin_lock_irqsave(&master->queue_lock, flags);
1172 if (!master->running) {
1173 spin_unlock_irqrestore(&master->queue_lock, flags);
1176 msg->actual_length = 0;
1177 msg->status = -EINPROGRESS;
1179 list_add_tail(&msg->queue, &master->queue);
1181 queue_kthread_work(&master->kworker, &master->pump_messages);
1183 spin_unlock_irqrestore(&master->queue_lock, flags);
1187 static int spi_master_initialize_queue(struct spi_master *master)
1191 master->transfer = spi_queued_transfer;
1192 if (!master->transfer_one_message)
1193 master->transfer_one_message = spi_transfer_one_message;
1195 /* Initialize and start queue */
1196 ret = spi_init_queue(master);
1198 dev_err(&master->dev, "problem initializing queue\n");
1199 goto err_init_queue;
1201 master->queued = true;
1202 ret = spi_start_queue(master);
1204 dev_err(&master->dev, "problem starting queue\n");
1205 goto err_start_queue;
1211 spi_destroy_queue(master);
1216 /*-------------------------------------------------------------------------*/
1218 #if defined(CONFIG_OF)
1219 static struct spi_device *
1220 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1222 struct spi_device *spi;
1226 /* Alloc an spi_device */
1227 spi = spi_alloc_device(master);
1229 dev_err(&master->dev, "spi_device alloc error for %s\n",
1235 /* Select device driver */
1236 rc = of_modalias_node(nc, spi->modalias,
1237 sizeof(spi->modalias));
1239 dev_err(&master->dev, "cannot find modalias for %s\n",
1244 /* Device address */
1245 rc = of_property_read_u32(nc, "reg", &value);
1247 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1251 spi->chip_select = value;
1253 /* Mode (clock phase/polarity/etc.) */
1254 if (of_find_property(nc, "spi-cpha", NULL))
1255 spi->mode |= SPI_CPHA;
1256 if (of_find_property(nc, "spi-cpol", NULL))
1257 spi->mode |= SPI_CPOL;
1258 if (of_find_property(nc, "spi-cs-high", NULL))
1259 spi->mode |= SPI_CS_HIGH;
1260 if (of_find_property(nc, "spi-3wire", NULL))
1261 spi->mode |= SPI_3WIRE;
1262 if (of_find_property(nc, "spi-lsb-first", NULL))
1263 spi->mode |= SPI_LSB_FIRST;
1265 /* Device DUAL/QUAD mode */
1266 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1271 spi->mode |= SPI_TX_DUAL;
1274 spi->mode |= SPI_TX_QUAD;
1277 dev_warn(&master->dev,
1278 "spi-tx-bus-width %d not supported\n",
1284 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1289 spi->mode |= SPI_RX_DUAL;
1292 spi->mode |= SPI_RX_QUAD;
1295 dev_warn(&master->dev,
1296 "spi-rx-bus-width %d not supported\n",
1303 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1305 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1309 spi->max_speed_hz = value;
1312 spi->irq = irq_of_parse_and_map(nc, 0);
1314 /* Store a pointer to the node in the device structure */
1316 spi->dev.of_node = nc;
1318 /* Register the new device */
1319 request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
1320 rc = spi_add_device(spi);
1322 dev_err(&master->dev, "spi_device register error %s\n",
1335 * of_register_spi_devices() - Register child devices onto the SPI bus
1336 * @master: Pointer to spi_master device
1338 * Registers an spi_device for each child node of master node which has a 'reg'
1341 static void of_register_spi_devices(struct spi_master *master)
1343 struct spi_device *spi;
1344 struct device_node *nc;
1346 if (!master->dev.of_node)
1349 for_each_available_child_of_node(master->dev.of_node, nc) {
1350 spi = of_register_spi_device(master, nc);
1352 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1357 static void of_register_spi_devices(struct spi_master *master) { }
1361 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1363 struct spi_device *spi = data;
1365 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1366 struct acpi_resource_spi_serialbus *sb;
1368 sb = &ares->data.spi_serial_bus;
1369 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1370 spi->chip_select = sb->device_selection;
1371 spi->max_speed_hz = sb->connection_speed;
1373 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1374 spi->mode |= SPI_CPHA;
1375 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1376 spi->mode |= SPI_CPOL;
1377 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1378 spi->mode |= SPI_CS_HIGH;
1380 } else if (spi->irq < 0) {
1383 if (acpi_dev_resource_interrupt(ares, 0, &r))
1387 /* Always tell the ACPI core to skip this resource */
1391 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1392 void *data, void **return_value)
1394 struct spi_master *master = data;
1395 struct list_head resource_list;
1396 struct acpi_device *adev;
1397 struct spi_device *spi;
1400 if (acpi_bus_get_device(handle, &adev))
1402 if (acpi_bus_get_status(adev) || !adev->status.present)
1405 spi = spi_alloc_device(master);
1407 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1408 dev_name(&adev->dev));
1409 return AE_NO_MEMORY;
1412 ACPI_COMPANION_SET(&spi->dev, adev);
1415 INIT_LIST_HEAD(&resource_list);
1416 ret = acpi_dev_get_resources(adev, &resource_list,
1417 acpi_spi_add_resource, spi);
1418 acpi_dev_free_resource_list(&resource_list);
1420 if (ret < 0 || !spi->max_speed_hz) {
1425 adev->power.flags.ignore_parent = true;
1426 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1427 if (spi_add_device(spi)) {
1428 adev->power.flags.ignore_parent = false;
1429 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1430 dev_name(&adev->dev));
1437 static void acpi_register_spi_devices(struct spi_master *master)
1442 handle = ACPI_HANDLE(master->dev.parent);
1446 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1447 acpi_spi_add_device, NULL,
1449 if (ACPI_FAILURE(status))
1450 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1453 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1454 #endif /* CONFIG_ACPI */
1456 static void spi_master_release(struct device *dev)
1458 struct spi_master *master;
1460 master = container_of(dev, struct spi_master, dev);
1464 static struct class spi_master_class = {
1465 .name = "spi_master",
1466 .owner = THIS_MODULE,
1467 .dev_release = spi_master_release,
1473 * spi_alloc_master - allocate SPI master controller
1474 * @dev: the controller, possibly using the platform_bus
1475 * @size: how much zeroed driver-private data to allocate; the pointer to this
1476 * memory is in the driver_data field of the returned device,
1477 * accessible with spi_master_get_devdata().
1478 * Context: can sleep
1480 * This call is used only by SPI master controller drivers, which are the
1481 * only ones directly touching chip registers. It's how they allocate
1482 * an spi_master structure, prior to calling spi_register_master().
1484 * This must be called from context that can sleep. It returns the SPI
1485 * master structure on success, else NULL.
1487 * The caller is responsible for assigning the bus number and initializing
1488 * the master's methods before calling spi_register_master(); and (after errors
1489 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1492 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1494 struct spi_master *master;
1499 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1503 device_initialize(&master->dev);
1504 master->bus_num = -1;
1505 master->num_chipselect = 1;
1506 master->dev.class = &spi_master_class;
1507 master->dev.parent = get_device(dev);
1508 spi_master_set_devdata(master, &master[1]);
1512 EXPORT_SYMBOL_GPL(spi_alloc_master);
1515 static int of_spi_register_master(struct spi_master *master)
1518 struct device_node *np = master->dev.of_node;
1523 nb = of_gpio_named_count(np, "cs-gpios");
1524 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1526 /* Return error only for an incorrectly formed cs-gpios property */
1527 if (nb == 0 || nb == -ENOENT)
1532 cs = devm_kzalloc(&master->dev,
1533 sizeof(int) * master->num_chipselect,
1535 master->cs_gpios = cs;
1537 if (!master->cs_gpios)
1540 for (i = 0; i < master->num_chipselect; i++)
1543 for (i = 0; i < nb; i++)
1544 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1549 static int of_spi_register_master(struct spi_master *master)
1556 * spi_register_master - register SPI master controller
1557 * @master: initialized master, originally from spi_alloc_master()
1558 * Context: can sleep
1560 * SPI master controllers connect to their drivers using some non-SPI bus,
1561 * such as the platform bus. The final stage of probe() in that code
1562 * includes calling spi_register_master() to hook up to this SPI bus glue.
1564 * SPI controllers use board specific (often SOC specific) bus numbers,
1565 * and board-specific addressing for SPI devices combines those numbers
1566 * with chip select numbers. Since SPI does not directly support dynamic
1567 * device identification, boards need configuration tables telling which
1568 * chip is at which address.
1570 * This must be called from context that can sleep. It returns zero on
1571 * success, else a negative error code (dropping the master's refcount).
1572 * After a successful return, the caller is responsible for calling
1573 * spi_unregister_master().
1575 int spi_register_master(struct spi_master *master)
1577 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1578 struct device *dev = master->dev.parent;
1579 struct boardinfo *bi;
1580 int status = -ENODEV;
1586 status = of_spi_register_master(master);
1590 /* even if it's just one always-selected device, there must
1591 * be at least one chipselect
1593 if (master->num_chipselect == 0)
1596 if ((master->bus_num < 0) && master->dev.of_node)
1597 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1599 /* convention: dynamically assigned bus IDs count down from the max */
1600 if (master->bus_num < 0) {
1601 /* FIXME switch to an IDR based scheme, something like
1602 * I2C now uses, so we can't run out of "dynamic" IDs
1604 master->bus_num = atomic_dec_return(&dyn_bus_id);
1608 spin_lock_init(&master->bus_lock_spinlock);
1609 mutex_init(&master->bus_lock_mutex);
1610 master->bus_lock_flag = 0;
1611 init_completion(&master->xfer_completion);
1612 if (!master->max_dma_len)
1613 master->max_dma_len = INT_MAX;
1615 /* register the device, then userspace will see it.
1616 * registration fails if the bus ID is in use.
1618 dev_set_name(&master->dev, "spi%u", master->bus_num);
1619 status = device_add(&master->dev);
1622 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1623 dynamic ? " (dynamic)" : "");
1625 /* If we're using a queued driver, start the queue */
1626 if (master->transfer)
1627 dev_info(dev, "master is unqueued, this is deprecated\n");
1629 status = spi_master_initialize_queue(master);
1631 device_del(&master->dev);
1636 mutex_lock(&board_lock);
1637 list_add_tail(&master->list, &spi_master_list);
1638 list_for_each_entry(bi, &board_list, list)
1639 spi_match_master_to_boardinfo(master, &bi->board_info);
1640 mutex_unlock(&board_lock);
1642 /* Register devices from the device tree and ACPI */
1643 of_register_spi_devices(master);
1644 acpi_register_spi_devices(master);
1648 EXPORT_SYMBOL_GPL(spi_register_master);
1650 static void devm_spi_unregister(struct device *dev, void *res)
1652 spi_unregister_master(*(struct spi_master **)res);
1656 * dev_spi_register_master - register managed SPI master controller
1657 * @dev: device managing SPI master
1658 * @master: initialized master, originally from spi_alloc_master()
1659 * Context: can sleep
1661 * Register a SPI device as with spi_register_master() which will
1662 * automatically be unregister
1664 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1666 struct spi_master **ptr;
1669 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1673 ret = spi_register_master(master);
1676 devres_add(dev, ptr);
1683 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1685 static int __unregister(struct device *dev, void *null)
1687 spi_unregister_device(to_spi_device(dev));
1692 * spi_unregister_master - unregister SPI master controller
1693 * @master: the master being unregistered
1694 * Context: can sleep
1696 * This call is used only by SPI master controller drivers, which are the
1697 * only ones directly touching chip registers.
1699 * This must be called from context that can sleep.
1701 void spi_unregister_master(struct spi_master *master)
1705 if (master->queued) {
1706 if (spi_destroy_queue(master))
1707 dev_err(&master->dev, "queue remove failed\n");
1710 mutex_lock(&board_lock);
1711 list_del(&master->list);
1712 mutex_unlock(&board_lock);
1714 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1715 device_unregister(&master->dev);
1717 EXPORT_SYMBOL_GPL(spi_unregister_master);
1719 int spi_master_suspend(struct spi_master *master)
1723 /* Basically no-ops for non-queued masters */
1724 if (!master->queued)
1727 ret = spi_stop_queue(master);
1729 dev_err(&master->dev, "queue stop failed\n");
1733 EXPORT_SYMBOL_GPL(spi_master_suspend);
1735 int spi_master_resume(struct spi_master *master)
1739 if (!master->queued)
1742 ret = spi_start_queue(master);
1744 dev_err(&master->dev, "queue restart failed\n");
1748 EXPORT_SYMBOL_GPL(spi_master_resume);
1750 static int __spi_master_match(struct device *dev, const void *data)
1752 struct spi_master *m;
1753 const u16 *bus_num = data;
1755 m = container_of(dev, struct spi_master, dev);
1756 return m->bus_num == *bus_num;
1760 * spi_busnum_to_master - look up master associated with bus_num
1761 * @bus_num: the master's bus number
1762 * Context: can sleep
1764 * This call may be used with devices that are registered after
1765 * arch init time. It returns a refcounted pointer to the relevant
1766 * spi_master (which the caller must release), or NULL if there is
1767 * no such master registered.
1769 struct spi_master *spi_busnum_to_master(u16 bus_num)
1772 struct spi_master *master = NULL;
1774 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1775 __spi_master_match);
1777 master = container_of(dev, struct spi_master, dev);
1778 /* reference got in class_find_device */
1781 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1784 /*-------------------------------------------------------------------------*/
1786 /* Core methods for SPI master protocol drivers. Some of the
1787 * other core methods are currently defined as inline functions.
1791 * spi_setup - setup SPI mode and clock rate
1792 * @spi: the device whose settings are being modified
1793 * Context: can sleep, and no requests are queued to the device
1795 * SPI protocol drivers may need to update the transfer mode if the
1796 * device doesn't work with its default. They may likewise need
1797 * to update clock rates or word sizes from initial values. This function
1798 * changes those settings, and must be called from a context that can sleep.
1799 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1800 * effect the next time the device is selected and data is transferred to
1801 * or from it. When this function returns, the spi device is deselected.
1803 * Note that this call will fail if the protocol driver specifies an option
1804 * that the underlying controller or its driver does not support. For
1805 * example, not all hardware supports wire transfers using nine bit words,
1806 * LSB-first wire encoding, or active-high chipselects.
1808 int spi_setup(struct spi_device *spi)
1810 unsigned bad_bits, ugly_bits;
1813 /* check mode to prevent that DUAL and QUAD set at the same time
1815 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1816 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1818 "setup: can not select dual and quad at the same time\n");
1821 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1823 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1824 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1826 /* help drivers fail *cleanly* when they need options
1827 * that aren't supported with their current master
1829 bad_bits = spi->mode & ~spi->master->mode_bits;
1830 ugly_bits = bad_bits &
1831 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1834 "setup: ignoring unsupported mode bits %x\n",
1836 spi->mode &= ~ugly_bits;
1837 bad_bits &= ~ugly_bits;
1840 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1845 if (!spi->bits_per_word)
1846 spi->bits_per_word = 8;
1848 if (!spi->max_speed_hz)
1849 spi->max_speed_hz = spi->master->max_speed_hz;
1851 if (spi->master->setup)
1852 status = spi->master->setup(spi);
1854 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1855 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1856 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1857 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1858 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1859 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1860 spi->bits_per_word, spi->max_speed_hz,
1865 EXPORT_SYMBOL_GPL(spi_setup);
1867 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1869 struct spi_master *master = spi->master;
1870 struct spi_transfer *xfer;
1873 if (list_empty(&message->transfers))
1876 /* Half-duplex links include original MicroWire, and ones with
1877 * only one data pin like SPI_3WIRE (switches direction) or where
1878 * either MOSI or MISO is missing. They can also be caused by
1879 * software limitations.
1881 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1882 || (spi->mode & SPI_3WIRE)) {
1883 unsigned flags = master->flags;
1885 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1886 if (xfer->rx_buf && xfer->tx_buf)
1888 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1890 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
1896 * Set transfer bits_per_word and max speed as spi device default if
1897 * it is not set for this transfer.
1898 * Set transfer tx_nbits and rx_nbits as single transfer default
1899 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1901 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1902 message->frame_length += xfer->len;
1903 if (!xfer->bits_per_word)
1904 xfer->bits_per_word = spi->bits_per_word;
1906 if (!xfer->speed_hz)
1907 xfer->speed_hz = spi->max_speed_hz;
1909 if (master->max_speed_hz &&
1910 xfer->speed_hz > master->max_speed_hz)
1911 xfer->speed_hz = master->max_speed_hz;
1913 if (master->bits_per_word_mask) {
1914 /* Only 32 bits fit in the mask */
1915 if (xfer->bits_per_word > 32)
1917 if (!(master->bits_per_word_mask &
1918 BIT(xfer->bits_per_word - 1)))
1923 * SPI transfer length should be multiple of SPI word size
1924 * where SPI word size should be power-of-two multiple
1926 if (xfer->bits_per_word <= 8)
1928 else if (xfer->bits_per_word <= 16)
1933 /* No partial transfers accepted */
1934 if (xfer->len % w_size)
1937 if (xfer->speed_hz && master->min_speed_hz &&
1938 xfer->speed_hz < master->min_speed_hz)
1941 if (xfer->tx_buf && !xfer->tx_nbits)
1942 xfer->tx_nbits = SPI_NBITS_SINGLE;
1943 if (xfer->rx_buf && !xfer->rx_nbits)
1944 xfer->rx_nbits = SPI_NBITS_SINGLE;
1945 /* check transfer tx/rx_nbits:
1946 * 1. check the value matches one of single, dual and quad
1947 * 2. check tx/rx_nbits match the mode in spi_device
1950 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
1951 xfer->tx_nbits != SPI_NBITS_DUAL &&
1952 xfer->tx_nbits != SPI_NBITS_QUAD)
1954 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
1955 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
1957 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
1958 !(spi->mode & SPI_TX_QUAD))
1961 /* check transfer rx_nbits */
1963 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
1964 xfer->rx_nbits != SPI_NBITS_DUAL &&
1965 xfer->rx_nbits != SPI_NBITS_QUAD)
1967 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
1968 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
1970 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
1971 !(spi->mode & SPI_RX_QUAD))
1976 message->status = -EINPROGRESS;
1981 static int __spi_async(struct spi_device *spi, struct spi_message *message)
1983 struct spi_master *master = spi->master;
1987 trace_spi_message_submit(message);
1989 return master->transfer(spi, message);
1993 * spi_async - asynchronous SPI transfer
1994 * @spi: device with which data will be exchanged
1995 * @message: describes the data transfers, including completion callback
1996 * Context: any (irqs may be blocked, etc)
1998 * This call may be used in_irq and other contexts which can't sleep,
1999 * as well as from task contexts which can sleep.
2001 * The completion callback is invoked in a context which can't sleep.
2002 * Before that invocation, the value of message->status is undefined.
2003 * When the callback is issued, message->status holds either zero (to
2004 * indicate complete success) or a negative error code. After that
2005 * callback returns, the driver which issued the transfer request may
2006 * deallocate the associated memory; it's no longer in use by any SPI
2007 * core or controller driver code.
2009 * Note that although all messages to a spi_device are handled in
2010 * FIFO order, messages may go to different devices in other orders.
2011 * Some device might be higher priority, or have various "hard" access
2012 * time requirements, for example.
2014 * On detection of any fault during the transfer, processing of
2015 * the entire message is aborted, and the device is deselected.
2016 * Until returning from the associated message completion callback,
2017 * no other spi_message queued to that device will be processed.
2018 * (This rule applies equally to all the synchronous transfer calls,
2019 * which are wrappers around this core asynchronous primitive.)
2021 int spi_async(struct spi_device *spi, struct spi_message *message)
2023 struct spi_master *master = spi->master;
2025 unsigned long flags;
2027 ret = __spi_validate(spi, message);
2031 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2033 if (master->bus_lock_flag)
2036 ret = __spi_async(spi, message);
2038 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2042 EXPORT_SYMBOL_GPL(spi_async);
2045 * spi_async_locked - version of spi_async with exclusive bus usage
2046 * @spi: device with which data will be exchanged
2047 * @message: describes the data transfers, including completion callback
2048 * Context: any (irqs may be blocked, etc)
2050 * This call may be used in_irq and other contexts which can't sleep,
2051 * as well as from task contexts which can sleep.
2053 * The completion callback is invoked in a context which can't sleep.
2054 * Before that invocation, the value of message->status is undefined.
2055 * When the callback is issued, message->status holds either zero (to
2056 * indicate complete success) or a negative error code. After that
2057 * callback returns, the driver which issued the transfer request may
2058 * deallocate the associated memory; it's no longer in use by any SPI
2059 * core or controller driver code.
2061 * Note that although all messages to a spi_device are handled in
2062 * FIFO order, messages may go to different devices in other orders.
2063 * Some device might be higher priority, or have various "hard" access
2064 * time requirements, for example.
2066 * On detection of any fault during the transfer, processing of
2067 * the entire message is aborted, and the device is deselected.
2068 * Until returning from the associated message completion callback,
2069 * no other spi_message queued to that device will be processed.
2070 * (This rule applies equally to all the synchronous transfer calls,
2071 * which are wrappers around this core asynchronous primitive.)
2073 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2075 struct spi_master *master = spi->master;
2077 unsigned long flags;
2079 ret = __spi_validate(spi, message);
2083 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2085 ret = __spi_async(spi, message);
2087 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2092 EXPORT_SYMBOL_GPL(spi_async_locked);
2095 /*-------------------------------------------------------------------------*/
2097 /* Utility methods for SPI master protocol drivers, layered on
2098 * top of the core. Some other utility methods are defined as
2102 static void spi_complete(void *arg)
2107 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2110 DECLARE_COMPLETION_ONSTACK(done);
2112 struct spi_master *master = spi->master;
2114 message->complete = spi_complete;
2115 message->context = &done;
2118 mutex_lock(&master->bus_lock_mutex);
2120 status = spi_async_locked(spi, message);
2123 mutex_unlock(&master->bus_lock_mutex);
2126 wait_for_completion(&done);
2127 status = message->status;
2129 message->context = NULL;
2134 * spi_sync - blocking/synchronous SPI data transfers
2135 * @spi: device with which data will be exchanged
2136 * @message: describes the data transfers
2137 * Context: can sleep
2139 * This call may only be used from a context that may sleep. The sleep
2140 * is non-interruptible, and has no timeout. Low-overhead controller
2141 * drivers may DMA directly into and out of the message buffers.
2143 * Note that the SPI device's chip select is active during the message,
2144 * and then is normally disabled between messages. Drivers for some
2145 * frequently-used devices may want to minimize costs of selecting a chip,
2146 * by leaving it selected in anticipation that the next message will go
2147 * to the same chip. (That may increase power usage.)
2149 * Also, the caller is guaranteeing that the memory associated with the
2150 * message will not be freed before this call returns.
2152 * It returns zero on success, else a negative error code.
2154 int spi_sync(struct spi_device *spi, struct spi_message *message)
2156 return __spi_sync(spi, message, 0);
2158 EXPORT_SYMBOL_GPL(spi_sync);
2161 * spi_sync_locked - version of spi_sync with exclusive bus usage
2162 * @spi: device with which data will be exchanged
2163 * @message: describes the data transfers
2164 * Context: can sleep
2166 * This call may only be used from a context that may sleep. The sleep
2167 * is non-interruptible, and has no timeout. Low-overhead controller
2168 * drivers may DMA directly into and out of the message buffers.
2170 * This call should be used by drivers that require exclusive access to the
2171 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2172 * be released by a spi_bus_unlock call when the exclusive access is over.
2174 * It returns zero on success, else a negative error code.
2176 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2178 return __spi_sync(spi, message, 1);
2180 EXPORT_SYMBOL_GPL(spi_sync_locked);
2183 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2184 * @master: SPI bus master that should be locked for exclusive bus access
2185 * Context: can sleep
2187 * This call may only be used from a context that may sleep. The sleep
2188 * is non-interruptible, and has no timeout.
2190 * This call should be used by drivers that require exclusive access to the
2191 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2192 * exclusive access is over. Data transfer must be done by spi_sync_locked
2193 * and spi_async_locked calls when the SPI bus lock is held.
2195 * It returns zero on success, else a negative error code.
2197 int spi_bus_lock(struct spi_master *master)
2199 unsigned long flags;
2201 mutex_lock(&master->bus_lock_mutex);
2203 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2204 master->bus_lock_flag = 1;
2205 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2207 /* mutex remains locked until spi_bus_unlock is called */
2211 EXPORT_SYMBOL_GPL(spi_bus_lock);
2214 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2215 * @master: SPI bus master that was locked for exclusive bus access
2216 * Context: can sleep
2218 * This call may only be used from a context that may sleep. The sleep
2219 * is non-interruptible, and has no timeout.
2221 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2224 * It returns zero on success, else a negative error code.
2226 int spi_bus_unlock(struct spi_master *master)
2228 master->bus_lock_flag = 0;
2230 mutex_unlock(&master->bus_lock_mutex);
2234 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2236 /* portable code must never pass more than 32 bytes */
2237 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2242 * spi_write_then_read - SPI synchronous write followed by read
2243 * @spi: device with which data will be exchanged
2244 * @txbuf: data to be written (need not be dma-safe)
2245 * @n_tx: size of txbuf, in bytes
2246 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2247 * @n_rx: size of rxbuf, in bytes
2248 * Context: can sleep
2250 * This performs a half duplex MicroWire style transaction with the
2251 * device, sending txbuf and then reading rxbuf. The return value
2252 * is zero for success, else a negative errno status code.
2253 * This call may only be used from a context that may sleep.
2255 * Parameters to this routine are always copied using a small buffer;
2256 * portable code should never use this for more than 32 bytes.
2257 * Performance-sensitive or bulk transfer code should instead use
2258 * spi_{async,sync}() calls with dma-safe buffers.
2260 int spi_write_then_read(struct spi_device *spi,
2261 const void *txbuf, unsigned n_tx,
2262 void *rxbuf, unsigned n_rx)
2264 static DEFINE_MUTEX(lock);
2267 struct spi_message message;
2268 struct spi_transfer x[2];
2271 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2272 * copying here, (as a pure convenience thing), but we can
2273 * keep heap costs out of the hot path unless someone else is
2274 * using the pre-allocated buffer or the transfer is too large.
2276 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2277 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2278 GFP_KERNEL | GFP_DMA);
2285 spi_message_init(&message);
2286 memset(x, 0, sizeof(x));
2289 spi_message_add_tail(&x[0], &message);
2293 spi_message_add_tail(&x[1], &message);
2296 memcpy(local_buf, txbuf, n_tx);
2297 x[0].tx_buf = local_buf;
2298 x[1].rx_buf = local_buf + n_tx;
2301 status = spi_sync(spi, &message);
2303 memcpy(rxbuf, x[1].rx_buf, n_rx);
2305 if (x[0].tx_buf == buf)
2306 mutex_unlock(&lock);
2312 EXPORT_SYMBOL_GPL(spi_write_then_read);
2314 /*-------------------------------------------------------------------------*/
2316 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2317 static int __spi_of_device_match(struct device *dev, void *data)
2319 return dev->of_node == data;
2322 /* must call put_device() when done with returned spi_device device */
2323 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2325 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2326 __spi_of_device_match);
2327 return dev ? to_spi_device(dev) : NULL;
2330 static int __spi_of_master_match(struct device *dev, const void *data)
2332 return dev->of_node == data;
2335 /* the spi masters are not using spi_bus, so we find it with another way */
2336 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2340 dev = class_find_device(&spi_master_class, NULL, node,
2341 __spi_of_master_match);
2345 /* reference got in class_find_device */
2346 return container_of(dev, struct spi_master, dev);
2349 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2352 struct of_reconfig_data *rd = arg;
2353 struct spi_master *master;
2354 struct spi_device *spi;
2356 switch (of_reconfig_get_state_change(action, arg)) {
2357 case OF_RECONFIG_CHANGE_ADD:
2358 master = of_find_spi_master_by_node(rd->dn->parent);
2360 return NOTIFY_OK; /* not for us */
2362 spi = of_register_spi_device(master, rd->dn);
2363 put_device(&master->dev);
2366 pr_err("%s: failed to create for '%s'\n",
2367 __func__, rd->dn->full_name);
2368 return notifier_from_errno(PTR_ERR(spi));
2372 case OF_RECONFIG_CHANGE_REMOVE:
2373 /* find our device by node */
2374 spi = of_find_spi_device_by_node(rd->dn);
2376 return NOTIFY_OK; /* no? not meant for us */
2378 /* unregister takes one ref away */
2379 spi_unregister_device(spi);
2381 /* and put the reference of the find */
2382 put_device(&spi->dev);
2389 static struct notifier_block spi_of_notifier = {
2390 .notifier_call = of_spi_notify,
2392 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2393 extern struct notifier_block spi_of_notifier;
2394 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2396 static int __init spi_init(void)
2400 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2406 status = bus_register(&spi_bus_type);
2410 status = class_register(&spi_master_class);
2414 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2415 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2420 bus_unregister(&spi_bus_type);
2428 /* board_info is normally registered in arch_initcall(),
2429 * but even essential drivers wait till later
2431 * REVISIT only boardinfo really needs static linking. the rest (device and
2432 * driver registration) _could_ be dynamically linked (modular) ... costs
2433 * include needing to have boardinfo data structures be much more public.
2435 postcore_initcall(spi_init);