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 #define SPI_STATISTICS_ATTRS(field, file) \
71 static ssize_t spi_master_##field##_show(struct device *dev, \
72 struct device_attribute *attr, \
75 struct spi_master *master = container_of(dev, \
76 struct spi_master, dev); \
77 return spi_statistics_##field##_show(&master->statistics, buf); \
79 static struct device_attribute dev_attr_spi_master_##field = { \
80 .attr = { .name = file, .mode = S_IRUGO }, \
81 .show = spi_master_##field##_show, \
83 static ssize_t spi_device_##field##_show(struct device *dev, \
84 struct device_attribute *attr, \
87 struct spi_device *spi = container_of(dev, \
88 struct spi_device, dev); \
89 return spi_statistics_##field##_show(&spi->statistics, buf); \
91 static struct device_attribute dev_attr_spi_device_##field = { \
92 .attr = { .name = file, .mode = S_IRUGO }, \
93 .show = spi_device_##field##_show, \
96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
100 unsigned long flags; \
102 spin_lock_irqsave(&stat->lock, flags); \
103 len = sprintf(buf, format_string, stat->field); \
104 spin_unlock_irqrestore(&stat->lock, flags); \
107 SPI_STATISTICS_ATTRS(name, file)
109 #define SPI_STATISTICS_SHOW(field, format_string) \
110 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
111 field, format_string)
113 SPI_STATISTICS_SHOW(messages, "%lu");
114 SPI_STATISTICS_SHOW(transfers, "%lu");
115 SPI_STATISTICS_SHOW(errors, "%lu");
116 SPI_STATISTICS_SHOW(timedout, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
120 SPI_STATISTICS_SHOW(spi_async, "%lu");
122 SPI_STATISTICS_SHOW(bytes, "%llu");
123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
126 static struct attribute *spi_dev_attrs[] = {
127 &dev_attr_modalias.attr,
131 static const struct attribute_group spi_dev_group = {
132 .attrs = spi_dev_attrs,
135 static struct attribute *spi_device_statistics_attrs[] = {
136 &dev_attr_spi_device_messages.attr,
137 &dev_attr_spi_device_transfers.attr,
138 &dev_attr_spi_device_errors.attr,
139 &dev_attr_spi_device_timedout.attr,
140 &dev_attr_spi_device_spi_sync.attr,
141 &dev_attr_spi_device_spi_sync_immediate.attr,
142 &dev_attr_spi_device_spi_async.attr,
143 &dev_attr_spi_device_bytes.attr,
144 &dev_attr_spi_device_bytes_rx.attr,
145 &dev_attr_spi_device_bytes_tx.attr,
149 static const struct attribute_group spi_device_statistics_group = {
150 .name = "statistics",
151 .attrs = spi_device_statistics_attrs,
154 static const struct attribute_group *spi_dev_groups[] = {
156 &spi_device_statistics_group,
160 static struct attribute *spi_master_statistics_attrs[] = {
161 &dev_attr_spi_master_messages.attr,
162 &dev_attr_spi_master_transfers.attr,
163 &dev_attr_spi_master_errors.attr,
164 &dev_attr_spi_master_timedout.attr,
165 &dev_attr_spi_master_spi_sync.attr,
166 &dev_attr_spi_master_spi_sync_immediate.attr,
167 &dev_attr_spi_master_spi_async.attr,
168 &dev_attr_spi_master_bytes.attr,
169 &dev_attr_spi_master_bytes_rx.attr,
170 &dev_attr_spi_master_bytes_tx.attr,
174 static const struct attribute_group spi_master_statistics_group = {
175 .name = "statistics",
176 .attrs = spi_master_statistics_attrs,
179 static const struct attribute_group *spi_master_groups[] = {
180 &spi_master_statistics_group,
184 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
185 struct spi_transfer *xfer,
186 struct spi_master *master)
190 spin_lock_irqsave(&stats->lock, flags);
194 stats->bytes += xfer->len;
195 if ((xfer->tx_buf) &&
196 (xfer->tx_buf != master->dummy_tx))
197 stats->bytes_tx += xfer->len;
198 if ((xfer->rx_buf) &&
199 (xfer->rx_buf != master->dummy_rx))
200 stats->bytes_rx += xfer->len;
202 spin_unlock_irqrestore(&stats->lock, flags);
204 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
206 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
207 * and the sysfs version makes coldplug work too.
210 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
211 const struct spi_device *sdev)
213 while (id->name[0]) {
214 if (!strcmp(sdev->modalias, id->name))
221 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
223 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
225 return spi_match_id(sdrv->id_table, sdev);
227 EXPORT_SYMBOL_GPL(spi_get_device_id);
229 static int spi_match_device(struct device *dev, struct device_driver *drv)
231 const struct spi_device *spi = to_spi_device(dev);
232 const struct spi_driver *sdrv = to_spi_driver(drv);
234 /* Attempt an OF style match */
235 if (of_driver_match_device(dev, drv))
239 if (acpi_driver_match_device(dev, drv))
243 return !!spi_match_id(sdrv->id_table, spi);
245 return strcmp(spi->modalias, drv->name) == 0;
248 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
250 const struct spi_device *spi = to_spi_device(dev);
253 rc = acpi_device_uevent_modalias(dev, env);
257 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
261 struct bus_type spi_bus_type = {
263 .dev_groups = spi_dev_groups,
264 .match = spi_match_device,
265 .uevent = spi_uevent,
267 EXPORT_SYMBOL_GPL(spi_bus_type);
270 static int spi_drv_probe(struct device *dev)
272 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
275 ret = of_clk_set_defaults(dev->of_node, false);
279 ret = dev_pm_domain_attach(dev, true);
280 if (ret != -EPROBE_DEFER) {
281 ret = sdrv->probe(to_spi_device(dev));
283 dev_pm_domain_detach(dev, true);
289 static int spi_drv_remove(struct device *dev)
291 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
294 ret = sdrv->remove(to_spi_device(dev));
295 dev_pm_domain_detach(dev, true);
300 static void spi_drv_shutdown(struct device *dev)
302 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
304 sdrv->shutdown(to_spi_device(dev));
308 * spi_register_driver - register a SPI driver
309 * @sdrv: the driver to register
312 int spi_register_driver(struct spi_driver *sdrv)
314 sdrv->driver.bus = &spi_bus_type;
316 sdrv->driver.probe = spi_drv_probe;
318 sdrv->driver.remove = spi_drv_remove;
320 sdrv->driver.shutdown = spi_drv_shutdown;
321 return driver_register(&sdrv->driver);
323 EXPORT_SYMBOL_GPL(spi_register_driver);
325 /*-------------------------------------------------------------------------*/
327 /* SPI devices should normally not be created by SPI device drivers; that
328 * would make them board-specific. Similarly with SPI master drivers.
329 * Device registration normally goes into like arch/.../mach.../board-YYY.c
330 * with other readonly (flashable) information about mainboard devices.
334 struct list_head list;
335 struct spi_board_info board_info;
338 static LIST_HEAD(board_list);
339 static LIST_HEAD(spi_master_list);
342 * Used to protect add/del opertion for board_info list and
343 * spi_master list, and their matching process
345 static DEFINE_MUTEX(board_lock);
348 * spi_alloc_device - Allocate a new SPI device
349 * @master: Controller to which device is connected
352 * Allows a driver to allocate and initialize a spi_device without
353 * registering it immediately. This allows a driver to directly
354 * fill the spi_device with device parameters before calling
355 * spi_add_device() on it.
357 * Caller is responsible to call spi_add_device() on the returned
358 * spi_device structure to add it to the SPI master. If the caller
359 * needs to discard the spi_device without adding it, then it should
360 * call spi_dev_put() on it.
362 * Returns a pointer to the new device, or NULL.
364 struct spi_device *spi_alloc_device(struct spi_master *master)
366 struct spi_device *spi;
368 if (!spi_master_get(master))
371 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
373 spi_master_put(master);
377 spi->master = master;
378 spi->dev.parent = &master->dev;
379 spi->dev.bus = &spi_bus_type;
380 spi->dev.release = spidev_release;
381 spi->cs_gpio = -ENOENT;
383 spin_lock_init(&spi->statistics.lock);
385 device_initialize(&spi->dev);
388 EXPORT_SYMBOL_GPL(spi_alloc_device);
390 static void spi_dev_set_name(struct spi_device *spi)
392 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
395 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
399 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
403 static int spi_dev_check(struct device *dev, void *data)
405 struct spi_device *spi = to_spi_device(dev);
406 struct spi_device *new_spi = data;
408 if (spi->master == new_spi->master &&
409 spi->chip_select == new_spi->chip_select)
415 * spi_add_device - Add spi_device allocated with spi_alloc_device
416 * @spi: spi_device to register
418 * Companion function to spi_alloc_device. Devices allocated with
419 * spi_alloc_device can be added onto the spi bus with this function.
421 * Returns 0 on success; negative errno on failure
423 int spi_add_device(struct spi_device *spi)
425 static DEFINE_MUTEX(spi_add_lock);
426 struct spi_master *master = spi->master;
427 struct device *dev = master->dev.parent;
430 /* Chipselects are numbered 0..max; validate. */
431 if (spi->chip_select >= master->num_chipselect) {
432 dev_err(dev, "cs%d >= max %d\n",
434 master->num_chipselect);
438 /* Set the bus ID string */
439 spi_dev_set_name(spi);
441 /* We need to make sure there's no other device with this
442 * chipselect **BEFORE** we call setup(), else we'll trash
443 * its configuration. Lock against concurrent add() calls.
445 mutex_lock(&spi_add_lock);
447 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
449 dev_err(dev, "chipselect %d already in use\n",
454 if (master->cs_gpios)
455 spi->cs_gpio = master->cs_gpios[spi->chip_select];
457 /* Drivers may modify this initial i/o setup, but will
458 * normally rely on the device being setup. Devices
459 * using SPI_CS_HIGH can't coexist well otherwise...
461 status = spi_setup(spi);
463 dev_err(dev, "can't setup %s, status %d\n",
464 dev_name(&spi->dev), status);
468 /* Device may be bound to an active driver when this returns */
469 status = device_add(&spi->dev);
471 dev_err(dev, "can't add %s, status %d\n",
472 dev_name(&spi->dev), status);
474 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
477 mutex_unlock(&spi_add_lock);
480 EXPORT_SYMBOL_GPL(spi_add_device);
483 * spi_new_device - instantiate one new SPI device
484 * @master: Controller to which device is connected
485 * @chip: Describes the SPI device
488 * On typical mainboards, this is purely internal; and it's not needed
489 * after board init creates the hard-wired devices. Some development
490 * platforms may not be able to use spi_register_board_info though, and
491 * this is exported so that for example a USB or parport based adapter
492 * driver could add devices (which it would learn about out-of-band).
494 * Returns the new device, or NULL.
496 struct spi_device *spi_new_device(struct spi_master *master,
497 struct spi_board_info *chip)
499 struct spi_device *proxy;
502 /* NOTE: caller did any chip->bus_num checks necessary.
504 * Also, unless we change the return value convention to use
505 * error-or-pointer (not NULL-or-pointer), troubleshootability
506 * suggests syslogged diagnostics are best here (ugh).
509 proxy = spi_alloc_device(master);
513 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
515 proxy->chip_select = chip->chip_select;
516 proxy->max_speed_hz = chip->max_speed_hz;
517 proxy->mode = chip->mode;
518 proxy->irq = chip->irq;
519 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
520 proxy->dev.platform_data = (void *) chip->platform_data;
521 proxy->controller_data = chip->controller_data;
522 proxy->controller_state = NULL;
524 status = spi_add_device(proxy);
532 EXPORT_SYMBOL_GPL(spi_new_device);
534 static void spi_match_master_to_boardinfo(struct spi_master *master,
535 struct spi_board_info *bi)
537 struct spi_device *dev;
539 if (master->bus_num != bi->bus_num)
542 dev = spi_new_device(master, bi);
544 dev_err(master->dev.parent, "can't create new device for %s\n",
549 * spi_register_board_info - register SPI devices for a given board
550 * @info: array of chip descriptors
551 * @n: how many descriptors are provided
554 * Board-specific early init code calls this (probably during arch_initcall)
555 * with segments of the SPI device table. Any device nodes are created later,
556 * after the relevant parent SPI controller (bus_num) is defined. We keep
557 * this table of devices forever, so that reloading a controller driver will
558 * not make Linux forget about these hard-wired devices.
560 * Other code can also call this, e.g. a particular add-on board might provide
561 * SPI devices through its expansion connector, so code initializing that board
562 * would naturally declare its SPI devices.
564 * The board info passed can safely be __initdata ... but be careful of
565 * any embedded pointers (platform_data, etc), they're copied as-is.
567 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
569 struct boardinfo *bi;
575 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
579 for (i = 0; i < n; i++, bi++, info++) {
580 struct spi_master *master;
582 memcpy(&bi->board_info, info, sizeof(*info));
583 mutex_lock(&board_lock);
584 list_add_tail(&bi->list, &board_list);
585 list_for_each_entry(master, &spi_master_list, list)
586 spi_match_master_to_boardinfo(master, &bi->board_info);
587 mutex_unlock(&board_lock);
593 /*-------------------------------------------------------------------------*/
595 static void spi_set_cs(struct spi_device *spi, bool enable)
597 if (spi->mode & SPI_CS_HIGH)
600 if (spi->cs_gpio >= 0)
601 gpio_set_value(spi->cs_gpio, !enable);
602 else if (spi->master->set_cs)
603 spi->master->set_cs(spi, !enable);
606 #ifdef CONFIG_HAS_DMA
607 static int spi_map_buf(struct spi_master *master, struct device *dev,
608 struct sg_table *sgt, void *buf, size_t len,
609 enum dma_data_direction dir)
611 const bool vmalloced_buf = is_vmalloc_addr(buf);
612 const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
613 const int sgs = DIV_ROUND_UP(len, desc_len);
614 struct page *vm_page;
619 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
623 for (i = 0; i < sgs; i++) {
624 min = min_t(size_t, len, desc_len);
627 vm_page = vmalloc_to_page(buf);
632 sg_set_page(&sgt->sgl[i], vm_page,
633 min, offset_in_page(buf));
636 sg_set_buf(&sgt->sgl[i], sg_buf, min);
644 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
657 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
658 struct sg_table *sgt, enum dma_data_direction dir)
660 if (sgt->orig_nents) {
661 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
666 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
668 struct device *tx_dev, *rx_dev;
669 struct spi_transfer *xfer;
672 if (!master->can_dma)
675 tx_dev = master->dma_tx->device->dev;
676 rx_dev = master->dma_rx->device->dev;
678 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
679 if (!master->can_dma(master, msg->spi, xfer))
682 if (xfer->tx_buf != NULL) {
683 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
684 (void *)xfer->tx_buf, xfer->len,
690 if (xfer->rx_buf != NULL) {
691 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
692 xfer->rx_buf, xfer->len,
695 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
702 master->cur_msg_mapped = true;
707 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
709 struct spi_transfer *xfer;
710 struct device *tx_dev, *rx_dev;
712 if (!master->cur_msg_mapped || !master->can_dma)
715 tx_dev = master->dma_tx->device->dev;
716 rx_dev = master->dma_rx->device->dev;
718 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
719 if (!master->can_dma(master, msg->spi, xfer))
722 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
723 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
728 #else /* !CONFIG_HAS_DMA */
729 static inline int __spi_map_msg(struct spi_master *master,
730 struct spi_message *msg)
735 static inline int __spi_unmap_msg(struct spi_master *master,
736 struct spi_message *msg)
740 #endif /* !CONFIG_HAS_DMA */
742 static inline int spi_unmap_msg(struct spi_master *master,
743 struct spi_message *msg)
745 struct spi_transfer *xfer;
747 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
749 * Restore the original value of tx_buf or rx_buf if they are
752 if (xfer->tx_buf == master->dummy_tx)
754 if (xfer->rx_buf == master->dummy_rx)
758 return __spi_unmap_msg(master, msg);
761 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
763 struct spi_transfer *xfer;
765 unsigned int max_tx, max_rx;
767 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
771 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
772 if ((master->flags & SPI_MASTER_MUST_TX) &&
774 max_tx = max(xfer->len, max_tx);
775 if ((master->flags & SPI_MASTER_MUST_RX) &&
777 max_rx = max(xfer->len, max_rx);
781 tmp = krealloc(master->dummy_tx, max_tx,
782 GFP_KERNEL | GFP_DMA);
785 master->dummy_tx = tmp;
786 memset(tmp, 0, max_tx);
790 tmp = krealloc(master->dummy_rx, max_rx,
791 GFP_KERNEL | GFP_DMA);
794 master->dummy_rx = tmp;
797 if (max_tx || max_rx) {
798 list_for_each_entry(xfer, &msg->transfers,
801 xfer->tx_buf = master->dummy_tx;
803 xfer->rx_buf = master->dummy_rx;
808 return __spi_map_msg(master, msg);
812 * spi_transfer_one_message - Default implementation of transfer_one_message()
814 * This is a standard implementation of transfer_one_message() for
815 * drivers which impelment a transfer_one() operation. It provides
816 * standard handling of delays and chip select management.
818 static int spi_transfer_one_message(struct spi_master *master,
819 struct spi_message *msg)
821 struct spi_transfer *xfer;
822 bool keep_cs = false;
824 unsigned long ms = 1;
825 struct spi_statistics *statm = &master->statistics;
826 struct spi_statistics *stats = &msg->spi->statistics;
828 spi_set_cs(msg->spi, true);
830 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
831 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
833 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
834 trace_spi_transfer_start(msg, xfer);
836 spi_statistics_add_transfer_stats(statm, xfer, master);
837 spi_statistics_add_transfer_stats(stats, xfer, master);
839 if (xfer->tx_buf || xfer->rx_buf) {
840 reinit_completion(&master->xfer_completion);
842 ret = master->transfer_one(master, msg->spi, xfer);
844 SPI_STATISTICS_INCREMENT_FIELD(statm,
846 SPI_STATISTICS_INCREMENT_FIELD(stats,
848 dev_err(&msg->spi->dev,
849 "SPI transfer failed: %d\n", ret);
855 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
856 ms += ms + 100; /* some tolerance */
858 ms = wait_for_completion_timeout(&master->xfer_completion,
859 msecs_to_jiffies(ms));
863 SPI_STATISTICS_INCREMENT_FIELD(statm,
865 SPI_STATISTICS_INCREMENT_FIELD(stats,
867 dev_err(&msg->spi->dev,
868 "SPI transfer timed out\n");
869 msg->status = -ETIMEDOUT;
873 dev_err(&msg->spi->dev,
874 "Bufferless transfer has length %u\n",
878 trace_spi_transfer_stop(msg, xfer);
880 if (msg->status != -EINPROGRESS)
883 if (xfer->delay_usecs)
884 udelay(xfer->delay_usecs);
886 if (xfer->cs_change) {
887 if (list_is_last(&xfer->transfer_list,
891 spi_set_cs(msg->spi, false);
893 spi_set_cs(msg->spi, true);
897 msg->actual_length += xfer->len;
901 if (ret != 0 || !keep_cs)
902 spi_set_cs(msg->spi, false);
904 if (msg->status == -EINPROGRESS)
907 if (msg->status && master->handle_err)
908 master->handle_err(master, msg);
910 spi_finalize_current_message(master);
916 * spi_finalize_current_transfer - report completion of a transfer
917 * @master: the master reporting completion
919 * Called by SPI drivers using the core transfer_one_message()
920 * implementation to notify it that the current interrupt driven
921 * transfer has finished and the next one may be scheduled.
923 void spi_finalize_current_transfer(struct spi_master *master)
925 complete(&master->xfer_completion);
927 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
930 * __spi_pump_messages - function which processes spi message queue
931 * @master: master to process queue for
932 * @in_kthread: true if we are in the context of the message pump thread
934 * This function checks if there is any spi message in the queue that
935 * needs processing and if so call out to the driver to initialize hardware
936 * and transfer each message.
938 * Note that it is called both from the kthread itself and also from
939 * inside spi_sync(); the queue extraction handling at the top of the
940 * function should deal with this safely.
942 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
945 bool was_busy = false;
949 spin_lock_irqsave(&master->queue_lock, flags);
951 /* Make sure we are not already running a message */
952 if (master->cur_msg) {
953 spin_unlock_irqrestore(&master->queue_lock, flags);
957 /* If another context is idling the device then defer */
958 if (master->idling) {
959 queue_kthread_work(&master->kworker, &master->pump_messages);
960 spin_unlock_irqrestore(&master->queue_lock, flags);
964 /* Check if the queue is idle */
965 if (list_empty(&master->queue) || !master->running) {
967 spin_unlock_irqrestore(&master->queue_lock, flags);
971 /* Only do teardown in the thread */
973 queue_kthread_work(&master->kworker,
974 &master->pump_messages);
975 spin_unlock_irqrestore(&master->queue_lock, flags);
979 master->busy = false;
980 master->idling = true;
981 spin_unlock_irqrestore(&master->queue_lock, flags);
983 kfree(master->dummy_rx);
984 master->dummy_rx = NULL;
985 kfree(master->dummy_tx);
986 master->dummy_tx = NULL;
987 if (master->unprepare_transfer_hardware &&
988 master->unprepare_transfer_hardware(master))
989 dev_err(&master->dev,
990 "failed to unprepare transfer hardware\n");
991 if (master->auto_runtime_pm) {
992 pm_runtime_mark_last_busy(master->dev.parent);
993 pm_runtime_put_autosuspend(master->dev.parent);
995 trace_spi_master_idle(master);
997 spin_lock_irqsave(&master->queue_lock, flags);
998 master->idling = false;
999 spin_unlock_irqrestore(&master->queue_lock, flags);
1003 /* Extract head of queue */
1005 list_first_entry(&master->queue, struct spi_message, queue);
1007 list_del_init(&master->cur_msg->queue);
1011 master->busy = true;
1012 spin_unlock_irqrestore(&master->queue_lock, flags);
1014 if (!was_busy && master->auto_runtime_pm) {
1015 ret = pm_runtime_get_sync(master->dev.parent);
1017 dev_err(&master->dev, "Failed to power device: %d\n",
1024 trace_spi_master_busy(master);
1026 if (!was_busy && master->prepare_transfer_hardware) {
1027 ret = master->prepare_transfer_hardware(master);
1029 dev_err(&master->dev,
1030 "failed to prepare transfer hardware\n");
1032 if (master->auto_runtime_pm)
1033 pm_runtime_put(master->dev.parent);
1038 trace_spi_message_start(master->cur_msg);
1040 if (master->prepare_message) {
1041 ret = master->prepare_message(master, master->cur_msg);
1043 dev_err(&master->dev,
1044 "failed to prepare message: %d\n", ret);
1045 master->cur_msg->status = ret;
1046 spi_finalize_current_message(master);
1049 master->cur_msg_prepared = true;
1052 ret = spi_map_msg(master, master->cur_msg);
1054 master->cur_msg->status = ret;
1055 spi_finalize_current_message(master);
1059 ret = master->transfer_one_message(master, master->cur_msg);
1061 dev_err(&master->dev,
1062 "failed to transfer one message from queue\n");
1068 * spi_pump_messages - kthread work function which processes spi message queue
1069 * @work: pointer to kthread work struct contained in the master struct
1071 static void spi_pump_messages(struct kthread_work *work)
1073 struct spi_master *master =
1074 container_of(work, struct spi_master, pump_messages);
1076 __spi_pump_messages(master, true);
1079 static int spi_init_queue(struct spi_master *master)
1081 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1083 master->running = false;
1084 master->busy = false;
1086 init_kthread_worker(&master->kworker);
1087 master->kworker_task = kthread_run(kthread_worker_fn,
1088 &master->kworker, "%s",
1089 dev_name(&master->dev));
1090 if (IS_ERR(master->kworker_task)) {
1091 dev_err(&master->dev, "failed to create message pump task\n");
1092 return PTR_ERR(master->kworker_task);
1094 init_kthread_work(&master->pump_messages, spi_pump_messages);
1097 * Master config will indicate if this controller should run the
1098 * message pump with high (realtime) priority to reduce the transfer
1099 * latency on the bus by minimising the delay between a transfer
1100 * request and the scheduling of the message pump thread. Without this
1101 * setting the message pump thread will remain at default priority.
1104 dev_info(&master->dev,
1105 "will run message pump with realtime priority\n");
1106 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1113 * spi_get_next_queued_message() - called by driver to check for queued
1115 * @master: the master to check for queued messages
1117 * If there are more messages in the queue, the next message is returned from
1120 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1122 struct spi_message *next;
1123 unsigned long flags;
1125 /* get a pointer to the next message, if any */
1126 spin_lock_irqsave(&master->queue_lock, flags);
1127 next = list_first_entry_or_null(&master->queue, struct spi_message,
1129 spin_unlock_irqrestore(&master->queue_lock, flags);
1133 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1136 * spi_finalize_current_message() - the current message is complete
1137 * @master: the master to return the message to
1139 * Called by the driver to notify the core that the message in the front of the
1140 * queue is complete and can be removed from the queue.
1142 void spi_finalize_current_message(struct spi_master *master)
1144 struct spi_message *mesg;
1145 unsigned long flags;
1148 spin_lock_irqsave(&master->queue_lock, flags);
1149 mesg = master->cur_msg;
1150 spin_unlock_irqrestore(&master->queue_lock, flags);
1152 spi_unmap_msg(master, mesg);
1154 if (master->cur_msg_prepared && master->unprepare_message) {
1155 ret = master->unprepare_message(master, mesg);
1157 dev_err(&master->dev,
1158 "failed to unprepare message: %d\n", ret);
1162 spin_lock_irqsave(&master->queue_lock, flags);
1163 master->cur_msg = NULL;
1164 master->cur_msg_prepared = false;
1165 queue_kthread_work(&master->kworker, &master->pump_messages);
1166 spin_unlock_irqrestore(&master->queue_lock, flags);
1168 trace_spi_message_done(mesg);
1172 mesg->complete(mesg->context);
1174 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1176 static int spi_start_queue(struct spi_master *master)
1178 unsigned long flags;
1180 spin_lock_irqsave(&master->queue_lock, flags);
1182 if (master->running || master->busy) {
1183 spin_unlock_irqrestore(&master->queue_lock, flags);
1187 master->running = true;
1188 master->cur_msg = NULL;
1189 spin_unlock_irqrestore(&master->queue_lock, flags);
1191 queue_kthread_work(&master->kworker, &master->pump_messages);
1196 static int spi_stop_queue(struct spi_master *master)
1198 unsigned long flags;
1199 unsigned limit = 500;
1202 spin_lock_irqsave(&master->queue_lock, flags);
1205 * This is a bit lame, but is optimized for the common execution path.
1206 * A wait_queue on the master->busy could be used, but then the common
1207 * execution path (pump_messages) would be required to call wake_up or
1208 * friends on every SPI message. Do this instead.
1210 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1211 spin_unlock_irqrestore(&master->queue_lock, flags);
1212 usleep_range(10000, 11000);
1213 spin_lock_irqsave(&master->queue_lock, flags);
1216 if (!list_empty(&master->queue) || master->busy)
1219 master->running = false;
1221 spin_unlock_irqrestore(&master->queue_lock, flags);
1224 dev_warn(&master->dev,
1225 "could not stop message queue\n");
1231 static int spi_destroy_queue(struct spi_master *master)
1235 ret = spi_stop_queue(master);
1238 * flush_kthread_worker will block until all work is done.
1239 * If the reason that stop_queue timed out is that the work will never
1240 * finish, then it does no good to call flush/stop thread, so
1244 dev_err(&master->dev, "problem destroying queue\n");
1248 flush_kthread_worker(&master->kworker);
1249 kthread_stop(master->kworker_task);
1254 static int __spi_queued_transfer(struct spi_device *spi,
1255 struct spi_message *msg,
1258 struct spi_master *master = spi->master;
1259 unsigned long flags;
1261 spin_lock_irqsave(&master->queue_lock, flags);
1263 if (!master->running) {
1264 spin_unlock_irqrestore(&master->queue_lock, flags);
1267 msg->actual_length = 0;
1268 msg->status = -EINPROGRESS;
1270 list_add_tail(&msg->queue, &master->queue);
1271 if (!master->busy && need_pump)
1272 queue_kthread_work(&master->kworker, &master->pump_messages);
1274 spin_unlock_irqrestore(&master->queue_lock, flags);
1279 * spi_queued_transfer - transfer function for queued transfers
1280 * @spi: spi device which is requesting transfer
1281 * @msg: spi message which is to handled is queued to driver queue
1283 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1285 return __spi_queued_transfer(spi, msg, true);
1288 static int spi_master_initialize_queue(struct spi_master *master)
1292 master->transfer = spi_queued_transfer;
1293 if (!master->transfer_one_message)
1294 master->transfer_one_message = spi_transfer_one_message;
1296 /* Initialize and start queue */
1297 ret = spi_init_queue(master);
1299 dev_err(&master->dev, "problem initializing queue\n");
1300 goto err_init_queue;
1302 master->queued = true;
1303 ret = spi_start_queue(master);
1305 dev_err(&master->dev, "problem starting queue\n");
1306 goto err_start_queue;
1312 spi_destroy_queue(master);
1317 /*-------------------------------------------------------------------------*/
1319 #if defined(CONFIG_OF)
1320 static struct spi_device *
1321 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1323 struct spi_device *spi;
1327 /* Alloc an spi_device */
1328 spi = spi_alloc_device(master);
1330 dev_err(&master->dev, "spi_device alloc error for %s\n",
1336 /* Select device driver */
1337 rc = of_modalias_node(nc, spi->modalias,
1338 sizeof(spi->modalias));
1340 dev_err(&master->dev, "cannot find modalias for %s\n",
1345 /* Device address */
1346 rc = of_property_read_u32(nc, "reg", &value);
1348 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1352 spi->chip_select = value;
1354 /* Mode (clock phase/polarity/etc.) */
1355 if (of_find_property(nc, "spi-cpha", NULL))
1356 spi->mode |= SPI_CPHA;
1357 if (of_find_property(nc, "spi-cpol", NULL))
1358 spi->mode |= SPI_CPOL;
1359 if (of_find_property(nc, "spi-cs-high", NULL))
1360 spi->mode |= SPI_CS_HIGH;
1361 if (of_find_property(nc, "spi-3wire", NULL))
1362 spi->mode |= SPI_3WIRE;
1363 if (of_find_property(nc, "spi-lsb-first", NULL))
1364 spi->mode |= SPI_LSB_FIRST;
1366 /* Device DUAL/QUAD mode */
1367 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1372 spi->mode |= SPI_TX_DUAL;
1375 spi->mode |= SPI_TX_QUAD;
1378 dev_warn(&master->dev,
1379 "spi-tx-bus-width %d not supported\n",
1385 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1390 spi->mode |= SPI_RX_DUAL;
1393 spi->mode |= SPI_RX_QUAD;
1396 dev_warn(&master->dev,
1397 "spi-rx-bus-width %d not supported\n",
1404 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1406 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1410 spi->max_speed_hz = value;
1413 spi->irq = irq_of_parse_and_map(nc, 0);
1415 /* Store a pointer to the node in the device structure */
1417 spi->dev.of_node = nc;
1419 /* Register the new device */
1420 rc = spi_add_device(spi);
1422 dev_err(&master->dev, "spi_device register error %s\n",
1435 * of_register_spi_devices() - Register child devices onto the SPI bus
1436 * @master: Pointer to spi_master device
1438 * Registers an spi_device for each child node of master node which has a 'reg'
1441 static void of_register_spi_devices(struct spi_master *master)
1443 struct spi_device *spi;
1444 struct device_node *nc;
1446 if (!master->dev.of_node)
1449 for_each_available_child_of_node(master->dev.of_node, nc) {
1450 spi = of_register_spi_device(master, nc);
1452 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1457 static void of_register_spi_devices(struct spi_master *master) { }
1461 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1463 struct spi_device *spi = data;
1465 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1466 struct acpi_resource_spi_serialbus *sb;
1468 sb = &ares->data.spi_serial_bus;
1469 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1470 spi->chip_select = sb->device_selection;
1471 spi->max_speed_hz = sb->connection_speed;
1473 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1474 spi->mode |= SPI_CPHA;
1475 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1476 spi->mode |= SPI_CPOL;
1477 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1478 spi->mode |= SPI_CS_HIGH;
1480 } else if (spi->irq < 0) {
1483 if (acpi_dev_resource_interrupt(ares, 0, &r))
1487 /* Always tell the ACPI core to skip this resource */
1491 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1492 void *data, void **return_value)
1494 struct spi_master *master = data;
1495 struct list_head resource_list;
1496 struct acpi_device *adev;
1497 struct spi_device *spi;
1500 if (acpi_bus_get_device(handle, &adev))
1502 if (acpi_bus_get_status(adev) || !adev->status.present)
1505 spi = spi_alloc_device(master);
1507 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1508 dev_name(&adev->dev));
1509 return AE_NO_MEMORY;
1512 ACPI_COMPANION_SET(&spi->dev, adev);
1515 INIT_LIST_HEAD(&resource_list);
1516 ret = acpi_dev_get_resources(adev, &resource_list,
1517 acpi_spi_add_resource, spi);
1518 acpi_dev_free_resource_list(&resource_list);
1520 if (ret < 0 || !spi->max_speed_hz) {
1525 adev->power.flags.ignore_parent = true;
1526 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1527 if (spi_add_device(spi)) {
1528 adev->power.flags.ignore_parent = false;
1529 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1530 dev_name(&adev->dev));
1537 static void acpi_register_spi_devices(struct spi_master *master)
1542 handle = ACPI_HANDLE(master->dev.parent);
1546 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1547 acpi_spi_add_device, NULL,
1549 if (ACPI_FAILURE(status))
1550 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1553 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1554 #endif /* CONFIG_ACPI */
1556 static void spi_master_release(struct device *dev)
1558 struct spi_master *master;
1560 master = container_of(dev, struct spi_master, dev);
1564 static struct class spi_master_class = {
1565 .name = "spi_master",
1566 .owner = THIS_MODULE,
1567 .dev_release = spi_master_release,
1568 .dev_groups = spi_master_groups,
1573 * spi_alloc_master - allocate SPI master controller
1574 * @dev: the controller, possibly using the platform_bus
1575 * @size: how much zeroed driver-private data to allocate; the pointer to this
1576 * memory is in the driver_data field of the returned device,
1577 * accessible with spi_master_get_devdata().
1578 * Context: can sleep
1580 * This call is used only by SPI master controller drivers, which are the
1581 * only ones directly touching chip registers. It's how they allocate
1582 * an spi_master structure, prior to calling spi_register_master().
1584 * This must be called from context that can sleep. It returns the SPI
1585 * master structure on success, else NULL.
1587 * The caller is responsible for assigning the bus number and initializing
1588 * the master's methods before calling spi_register_master(); and (after errors
1589 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1592 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1594 struct spi_master *master;
1599 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1603 device_initialize(&master->dev);
1604 master->bus_num = -1;
1605 master->num_chipselect = 1;
1606 master->dev.class = &spi_master_class;
1607 master->dev.parent = get_device(dev);
1608 spi_master_set_devdata(master, &master[1]);
1612 EXPORT_SYMBOL_GPL(spi_alloc_master);
1615 static int of_spi_register_master(struct spi_master *master)
1618 struct device_node *np = master->dev.of_node;
1623 nb = of_gpio_named_count(np, "cs-gpios");
1624 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1626 /* Return error only for an incorrectly formed cs-gpios property */
1627 if (nb == 0 || nb == -ENOENT)
1632 cs = devm_kzalloc(&master->dev,
1633 sizeof(int) * master->num_chipselect,
1635 master->cs_gpios = cs;
1637 if (!master->cs_gpios)
1640 for (i = 0; i < master->num_chipselect; i++)
1643 for (i = 0; i < nb; i++)
1644 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1649 static int of_spi_register_master(struct spi_master *master)
1656 * spi_register_master - register SPI master controller
1657 * @master: initialized master, originally from spi_alloc_master()
1658 * Context: can sleep
1660 * SPI master controllers connect to their drivers using some non-SPI bus,
1661 * such as the platform bus. The final stage of probe() in that code
1662 * includes calling spi_register_master() to hook up to this SPI bus glue.
1664 * SPI controllers use board specific (often SOC specific) bus numbers,
1665 * and board-specific addressing for SPI devices combines those numbers
1666 * with chip select numbers. Since SPI does not directly support dynamic
1667 * device identification, boards need configuration tables telling which
1668 * chip is at which address.
1670 * This must be called from context that can sleep. It returns zero on
1671 * success, else a negative error code (dropping the master's refcount).
1672 * After a successful return, the caller is responsible for calling
1673 * spi_unregister_master().
1675 int spi_register_master(struct spi_master *master)
1677 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1678 struct device *dev = master->dev.parent;
1679 struct boardinfo *bi;
1680 int status = -ENODEV;
1686 status = of_spi_register_master(master);
1690 /* even if it's just one always-selected device, there must
1691 * be at least one chipselect
1693 if (master->num_chipselect == 0)
1696 if ((master->bus_num < 0) && master->dev.of_node)
1697 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1699 /* convention: dynamically assigned bus IDs count down from the max */
1700 if (master->bus_num < 0) {
1701 /* FIXME switch to an IDR based scheme, something like
1702 * I2C now uses, so we can't run out of "dynamic" IDs
1704 master->bus_num = atomic_dec_return(&dyn_bus_id);
1708 INIT_LIST_HEAD(&master->queue);
1709 spin_lock_init(&master->queue_lock);
1710 spin_lock_init(&master->bus_lock_spinlock);
1711 mutex_init(&master->bus_lock_mutex);
1712 master->bus_lock_flag = 0;
1713 init_completion(&master->xfer_completion);
1714 if (!master->max_dma_len)
1715 master->max_dma_len = INT_MAX;
1717 /* register the device, then userspace will see it.
1718 * registration fails if the bus ID is in use.
1720 dev_set_name(&master->dev, "spi%u", master->bus_num);
1721 status = device_add(&master->dev);
1724 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1725 dynamic ? " (dynamic)" : "");
1727 /* If we're using a queued driver, start the queue */
1728 if (master->transfer)
1729 dev_info(dev, "master is unqueued, this is deprecated\n");
1731 status = spi_master_initialize_queue(master);
1733 device_del(&master->dev);
1737 /* add statistics */
1738 spin_lock_init(&master->statistics.lock);
1740 mutex_lock(&board_lock);
1741 list_add_tail(&master->list, &spi_master_list);
1742 list_for_each_entry(bi, &board_list, list)
1743 spi_match_master_to_boardinfo(master, &bi->board_info);
1744 mutex_unlock(&board_lock);
1746 /* Register devices from the device tree and ACPI */
1747 of_register_spi_devices(master);
1748 acpi_register_spi_devices(master);
1752 EXPORT_SYMBOL_GPL(spi_register_master);
1754 static void devm_spi_unregister(struct device *dev, void *res)
1756 spi_unregister_master(*(struct spi_master **)res);
1760 * dev_spi_register_master - register managed SPI master controller
1761 * @dev: device managing SPI master
1762 * @master: initialized master, originally from spi_alloc_master()
1763 * Context: can sleep
1765 * Register a SPI device as with spi_register_master() which will
1766 * automatically be unregister
1768 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1770 struct spi_master **ptr;
1773 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1777 ret = spi_register_master(master);
1780 devres_add(dev, ptr);
1787 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1789 static int __unregister(struct device *dev, void *null)
1791 spi_unregister_device(to_spi_device(dev));
1796 * spi_unregister_master - unregister SPI master controller
1797 * @master: the master being unregistered
1798 * Context: can sleep
1800 * This call is used only by SPI master controller drivers, which are the
1801 * only ones directly touching chip registers.
1803 * This must be called from context that can sleep.
1805 void spi_unregister_master(struct spi_master *master)
1809 if (master->queued) {
1810 if (spi_destroy_queue(master))
1811 dev_err(&master->dev, "queue remove failed\n");
1814 mutex_lock(&board_lock);
1815 list_del(&master->list);
1816 mutex_unlock(&board_lock);
1818 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1819 device_unregister(&master->dev);
1821 EXPORT_SYMBOL_GPL(spi_unregister_master);
1823 int spi_master_suspend(struct spi_master *master)
1827 /* Basically no-ops for non-queued masters */
1828 if (!master->queued)
1831 ret = spi_stop_queue(master);
1833 dev_err(&master->dev, "queue stop failed\n");
1837 EXPORT_SYMBOL_GPL(spi_master_suspend);
1839 int spi_master_resume(struct spi_master *master)
1843 if (!master->queued)
1846 ret = spi_start_queue(master);
1848 dev_err(&master->dev, "queue restart failed\n");
1852 EXPORT_SYMBOL_GPL(spi_master_resume);
1854 static int __spi_master_match(struct device *dev, const void *data)
1856 struct spi_master *m;
1857 const u16 *bus_num = data;
1859 m = container_of(dev, struct spi_master, dev);
1860 return m->bus_num == *bus_num;
1864 * spi_busnum_to_master - look up master associated with bus_num
1865 * @bus_num: the master's bus number
1866 * Context: can sleep
1868 * This call may be used with devices that are registered after
1869 * arch init time. It returns a refcounted pointer to the relevant
1870 * spi_master (which the caller must release), or NULL if there is
1871 * no such master registered.
1873 struct spi_master *spi_busnum_to_master(u16 bus_num)
1876 struct spi_master *master = NULL;
1878 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1879 __spi_master_match);
1881 master = container_of(dev, struct spi_master, dev);
1882 /* reference got in class_find_device */
1885 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1888 /*-------------------------------------------------------------------------*/
1890 /* Core methods for SPI master protocol drivers. Some of the
1891 * other core methods are currently defined as inline functions.
1895 * spi_setup - setup SPI mode and clock rate
1896 * @spi: the device whose settings are being modified
1897 * Context: can sleep, and no requests are queued to the device
1899 * SPI protocol drivers may need to update the transfer mode if the
1900 * device doesn't work with its default. They may likewise need
1901 * to update clock rates or word sizes from initial values. This function
1902 * changes those settings, and must be called from a context that can sleep.
1903 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1904 * effect the next time the device is selected and data is transferred to
1905 * or from it. When this function returns, the spi device is deselected.
1907 * Note that this call will fail if the protocol driver specifies an option
1908 * that the underlying controller or its driver does not support. For
1909 * example, not all hardware supports wire transfers using nine bit words,
1910 * LSB-first wire encoding, or active-high chipselects.
1912 int spi_setup(struct spi_device *spi)
1914 unsigned bad_bits, ugly_bits;
1917 /* check mode to prevent that DUAL and QUAD set at the same time
1919 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
1920 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
1922 "setup: can not select dual and quad at the same time\n");
1925 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1927 if ((spi->mode & SPI_3WIRE) && (spi->mode &
1928 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
1930 /* help drivers fail *cleanly* when they need options
1931 * that aren't supported with their current master
1933 bad_bits = spi->mode & ~spi->master->mode_bits;
1934 ugly_bits = bad_bits &
1935 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
1938 "setup: ignoring unsupported mode bits %x\n",
1940 spi->mode &= ~ugly_bits;
1941 bad_bits &= ~ugly_bits;
1944 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
1949 if (!spi->bits_per_word)
1950 spi->bits_per_word = 8;
1952 if (!spi->max_speed_hz)
1953 spi->max_speed_hz = spi->master->max_speed_hz;
1955 spi_set_cs(spi, false);
1957 if (spi->master->setup)
1958 status = spi->master->setup(spi);
1960 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1961 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
1962 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
1963 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
1964 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
1965 (spi->mode & SPI_LOOP) ? "loopback, " : "",
1966 spi->bits_per_word, spi->max_speed_hz,
1971 EXPORT_SYMBOL_GPL(spi_setup);
1973 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
1975 struct spi_master *master = spi->master;
1976 struct spi_transfer *xfer;
1979 if (list_empty(&message->transfers))
1982 /* Half-duplex links include original MicroWire, and ones with
1983 * only one data pin like SPI_3WIRE (switches direction) or where
1984 * either MOSI or MISO is missing. They can also be caused by
1985 * software limitations.
1987 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
1988 || (spi->mode & SPI_3WIRE)) {
1989 unsigned flags = master->flags;
1991 list_for_each_entry(xfer, &message->transfers, transfer_list) {
1992 if (xfer->rx_buf && xfer->tx_buf)
1994 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
1996 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2002 * Set transfer bits_per_word and max speed as spi device default if
2003 * it is not set for this transfer.
2004 * Set transfer tx_nbits and rx_nbits as single transfer default
2005 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2007 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2008 message->frame_length += xfer->len;
2009 if (!xfer->bits_per_word)
2010 xfer->bits_per_word = spi->bits_per_word;
2012 if (!xfer->speed_hz)
2013 xfer->speed_hz = spi->max_speed_hz;
2015 if (master->max_speed_hz &&
2016 xfer->speed_hz > master->max_speed_hz)
2017 xfer->speed_hz = master->max_speed_hz;
2019 if (master->bits_per_word_mask) {
2020 /* Only 32 bits fit in the mask */
2021 if (xfer->bits_per_word > 32)
2023 if (!(master->bits_per_word_mask &
2024 BIT(xfer->bits_per_word - 1)))
2029 * SPI transfer length should be multiple of SPI word size
2030 * where SPI word size should be power-of-two multiple
2032 if (xfer->bits_per_word <= 8)
2034 else if (xfer->bits_per_word <= 16)
2039 /* No partial transfers accepted */
2040 if (xfer->len % w_size)
2043 if (xfer->speed_hz && master->min_speed_hz &&
2044 xfer->speed_hz < master->min_speed_hz)
2047 if (xfer->tx_buf && !xfer->tx_nbits)
2048 xfer->tx_nbits = SPI_NBITS_SINGLE;
2049 if (xfer->rx_buf && !xfer->rx_nbits)
2050 xfer->rx_nbits = SPI_NBITS_SINGLE;
2051 /* check transfer tx/rx_nbits:
2052 * 1. check the value matches one of single, dual and quad
2053 * 2. check tx/rx_nbits match the mode in spi_device
2056 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2057 xfer->tx_nbits != SPI_NBITS_DUAL &&
2058 xfer->tx_nbits != SPI_NBITS_QUAD)
2060 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2061 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2063 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2064 !(spi->mode & SPI_TX_QUAD))
2067 /* check transfer rx_nbits */
2069 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2070 xfer->rx_nbits != SPI_NBITS_DUAL &&
2071 xfer->rx_nbits != SPI_NBITS_QUAD)
2073 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2074 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2076 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2077 !(spi->mode & SPI_RX_QUAD))
2082 message->status = -EINPROGRESS;
2087 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2089 struct spi_master *master = spi->master;
2093 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2094 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2096 trace_spi_message_submit(message);
2098 return master->transfer(spi, message);
2102 * spi_async - asynchronous SPI transfer
2103 * @spi: device with which data will be exchanged
2104 * @message: describes the data transfers, including completion callback
2105 * Context: any (irqs may be blocked, etc)
2107 * This call may be used in_irq and other contexts which can't sleep,
2108 * as well as from task contexts which can sleep.
2110 * The completion callback is invoked in a context which can't sleep.
2111 * Before that invocation, the value of message->status is undefined.
2112 * When the callback is issued, message->status holds either zero (to
2113 * indicate complete success) or a negative error code. After that
2114 * callback returns, the driver which issued the transfer request may
2115 * deallocate the associated memory; it's no longer in use by any SPI
2116 * core or controller driver code.
2118 * Note that although all messages to a spi_device are handled in
2119 * FIFO order, messages may go to different devices in other orders.
2120 * Some device might be higher priority, or have various "hard" access
2121 * time requirements, for example.
2123 * On detection of any fault during the transfer, processing of
2124 * the entire message is aborted, and the device is deselected.
2125 * Until returning from the associated message completion callback,
2126 * no other spi_message queued to that device will be processed.
2127 * (This rule applies equally to all the synchronous transfer calls,
2128 * which are wrappers around this core asynchronous primitive.)
2130 int spi_async(struct spi_device *spi, struct spi_message *message)
2132 struct spi_master *master = spi->master;
2134 unsigned long flags;
2136 ret = __spi_validate(spi, message);
2140 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2142 if (master->bus_lock_flag)
2145 ret = __spi_async(spi, message);
2147 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2151 EXPORT_SYMBOL_GPL(spi_async);
2154 * spi_async_locked - version of spi_async with exclusive bus usage
2155 * @spi: device with which data will be exchanged
2156 * @message: describes the data transfers, including completion callback
2157 * Context: any (irqs may be blocked, etc)
2159 * This call may be used in_irq and other contexts which can't sleep,
2160 * as well as from task contexts which can sleep.
2162 * The completion callback is invoked in a context which can't sleep.
2163 * Before that invocation, the value of message->status is undefined.
2164 * When the callback is issued, message->status holds either zero (to
2165 * indicate complete success) or a negative error code. After that
2166 * callback returns, the driver which issued the transfer request may
2167 * deallocate the associated memory; it's no longer in use by any SPI
2168 * core or controller driver code.
2170 * Note that although all messages to a spi_device are handled in
2171 * FIFO order, messages may go to different devices in other orders.
2172 * Some device might be higher priority, or have various "hard" access
2173 * time requirements, for example.
2175 * On detection of any fault during the transfer, processing of
2176 * the entire message is aborted, and the device is deselected.
2177 * Until returning from the associated message completion callback,
2178 * no other spi_message queued to that device will be processed.
2179 * (This rule applies equally to all the synchronous transfer calls,
2180 * which are wrappers around this core asynchronous primitive.)
2182 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2184 struct spi_master *master = spi->master;
2186 unsigned long flags;
2188 ret = __spi_validate(spi, message);
2192 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2194 ret = __spi_async(spi, message);
2196 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2201 EXPORT_SYMBOL_GPL(spi_async_locked);
2204 /*-------------------------------------------------------------------------*/
2206 /* Utility methods for SPI master protocol drivers, layered on
2207 * top of the core. Some other utility methods are defined as
2211 static void spi_complete(void *arg)
2216 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2219 DECLARE_COMPLETION_ONSTACK(done);
2221 struct spi_master *master = spi->master;
2222 unsigned long flags;
2224 status = __spi_validate(spi, message);
2228 message->complete = spi_complete;
2229 message->context = &done;
2232 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2233 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2236 mutex_lock(&master->bus_lock_mutex);
2238 /* If we're not using the legacy transfer method then we will
2239 * try to transfer in the calling context so special case.
2240 * This code would be less tricky if we could remove the
2241 * support for driver implemented message queues.
2243 if (master->transfer == spi_queued_transfer) {
2244 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2246 trace_spi_message_submit(message);
2248 status = __spi_queued_transfer(spi, message, false);
2250 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2252 status = spi_async_locked(spi, message);
2256 mutex_unlock(&master->bus_lock_mutex);
2259 /* Push out the messages in the calling context if we
2262 if (master->transfer == spi_queued_transfer) {
2263 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2264 spi_sync_immediate);
2265 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2266 spi_sync_immediate);
2267 __spi_pump_messages(master, false);
2270 wait_for_completion(&done);
2271 status = message->status;
2273 message->context = NULL;
2278 * spi_sync - blocking/synchronous SPI data transfers
2279 * @spi: device with which data will be exchanged
2280 * @message: describes the data transfers
2281 * Context: can sleep
2283 * This call may only be used from a context that may sleep. The sleep
2284 * is non-interruptible, and has no timeout. Low-overhead controller
2285 * drivers may DMA directly into and out of the message buffers.
2287 * Note that the SPI device's chip select is active during the message,
2288 * and then is normally disabled between messages. Drivers for some
2289 * frequently-used devices may want to minimize costs of selecting a chip,
2290 * by leaving it selected in anticipation that the next message will go
2291 * to the same chip. (That may increase power usage.)
2293 * Also, the caller is guaranteeing that the memory associated with the
2294 * message will not be freed before this call returns.
2296 * It returns zero on success, else a negative error code.
2298 int spi_sync(struct spi_device *spi, struct spi_message *message)
2300 return __spi_sync(spi, message, 0);
2302 EXPORT_SYMBOL_GPL(spi_sync);
2305 * spi_sync_locked - version of spi_sync with exclusive bus usage
2306 * @spi: device with which data will be exchanged
2307 * @message: describes the data transfers
2308 * Context: can sleep
2310 * This call may only be used from a context that may sleep. The sleep
2311 * is non-interruptible, and has no timeout. Low-overhead controller
2312 * drivers may DMA directly into and out of the message buffers.
2314 * This call should be used by drivers that require exclusive access to the
2315 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2316 * be released by a spi_bus_unlock call when the exclusive access is over.
2318 * It returns zero on success, else a negative error code.
2320 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2322 return __spi_sync(spi, message, 1);
2324 EXPORT_SYMBOL_GPL(spi_sync_locked);
2327 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2328 * @master: SPI bus master that should be locked for exclusive bus access
2329 * Context: can sleep
2331 * This call may only be used from a context that may sleep. The sleep
2332 * is non-interruptible, and has no timeout.
2334 * This call should be used by drivers that require exclusive access to the
2335 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2336 * exclusive access is over. Data transfer must be done by spi_sync_locked
2337 * and spi_async_locked calls when the SPI bus lock is held.
2339 * It returns zero on success, else a negative error code.
2341 int spi_bus_lock(struct spi_master *master)
2343 unsigned long flags;
2345 mutex_lock(&master->bus_lock_mutex);
2347 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2348 master->bus_lock_flag = 1;
2349 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2351 /* mutex remains locked until spi_bus_unlock is called */
2355 EXPORT_SYMBOL_GPL(spi_bus_lock);
2358 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2359 * @master: SPI bus master that was locked for exclusive bus access
2360 * Context: can sleep
2362 * This call may only be used from a context that may sleep. The sleep
2363 * is non-interruptible, and has no timeout.
2365 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2368 * It returns zero on success, else a negative error code.
2370 int spi_bus_unlock(struct spi_master *master)
2372 master->bus_lock_flag = 0;
2374 mutex_unlock(&master->bus_lock_mutex);
2378 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2380 /* portable code must never pass more than 32 bytes */
2381 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2386 * spi_write_then_read - SPI synchronous write followed by read
2387 * @spi: device with which data will be exchanged
2388 * @txbuf: data to be written (need not be dma-safe)
2389 * @n_tx: size of txbuf, in bytes
2390 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2391 * @n_rx: size of rxbuf, in bytes
2392 * Context: can sleep
2394 * This performs a half duplex MicroWire style transaction with the
2395 * device, sending txbuf and then reading rxbuf. The return value
2396 * is zero for success, else a negative errno status code.
2397 * This call may only be used from a context that may sleep.
2399 * Parameters to this routine are always copied using a small buffer;
2400 * portable code should never use this for more than 32 bytes.
2401 * Performance-sensitive or bulk transfer code should instead use
2402 * spi_{async,sync}() calls with dma-safe buffers.
2404 int spi_write_then_read(struct spi_device *spi,
2405 const void *txbuf, unsigned n_tx,
2406 void *rxbuf, unsigned n_rx)
2408 static DEFINE_MUTEX(lock);
2411 struct spi_message message;
2412 struct spi_transfer x[2];
2415 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2416 * copying here, (as a pure convenience thing), but we can
2417 * keep heap costs out of the hot path unless someone else is
2418 * using the pre-allocated buffer or the transfer is too large.
2420 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2421 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2422 GFP_KERNEL | GFP_DMA);
2429 spi_message_init(&message);
2430 memset(x, 0, sizeof(x));
2433 spi_message_add_tail(&x[0], &message);
2437 spi_message_add_tail(&x[1], &message);
2440 memcpy(local_buf, txbuf, n_tx);
2441 x[0].tx_buf = local_buf;
2442 x[1].rx_buf = local_buf + n_tx;
2445 status = spi_sync(spi, &message);
2447 memcpy(rxbuf, x[1].rx_buf, n_rx);
2449 if (x[0].tx_buf == buf)
2450 mutex_unlock(&lock);
2456 EXPORT_SYMBOL_GPL(spi_write_then_read);
2458 /*-------------------------------------------------------------------------*/
2460 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2461 static int __spi_of_device_match(struct device *dev, void *data)
2463 return dev->of_node == data;
2466 /* must call put_device() when done with returned spi_device device */
2467 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2469 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2470 __spi_of_device_match);
2471 return dev ? to_spi_device(dev) : NULL;
2474 static int __spi_of_master_match(struct device *dev, const void *data)
2476 return dev->of_node == data;
2479 /* the spi masters are not using spi_bus, so we find it with another way */
2480 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2484 dev = class_find_device(&spi_master_class, NULL, node,
2485 __spi_of_master_match);
2489 /* reference got in class_find_device */
2490 return container_of(dev, struct spi_master, dev);
2493 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2496 struct of_reconfig_data *rd = arg;
2497 struct spi_master *master;
2498 struct spi_device *spi;
2500 switch (of_reconfig_get_state_change(action, arg)) {
2501 case OF_RECONFIG_CHANGE_ADD:
2502 master = of_find_spi_master_by_node(rd->dn->parent);
2504 return NOTIFY_OK; /* not for us */
2506 spi = of_register_spi_device(master, rd->dn);
2507 put_device(&master->dev);
2510 pr_err("%s: failed to create for '%s'\n",
2511 __func__, rd->dn->full_name);
2512 return notifier_from_errno(PTR_ERR(spi));
2516 case OF_RECONFIG_CHANGE_REMOVE:
2517 /* find our device by node */
2518 spi = of_find_spi_device_by_node(rd->dn);
2520 return NOTIFY_OK; /* no? not meant for us */
2522 /* unregister takes one ref away */
2523 spi_unregister_device(spi);
2525 /* and put the reference of the find */
2526 put_device(&spi->dev);
2533 static struct notifier_block spi_of_notifier = {
2534 .notifier_call = of_spi_notify,
2536 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2537 extern struct notifier_block spi_of_notifier;
2538 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2540 static int __init spi_init(void)
2544 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2550 status = bus_register(&spi_bus_type);
2554 status = class_register(&spi_master_class);
2558 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2559 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2564 bus_unregister(&spi_bus_type);
2572 /* board_info is normally registered in arch_initcall(),
2573 * but even essential drivers wait till later
2575 * REVISIT only boardinfo really needs static linking. the rest (device and
2576 * driver registration) _could_ be dynamically linked (modular) ... costs
2577 * include needing to have boardinfo data structures be much more public.
2579 postcore_initcall(spi_init);